basic concepts of ayurvedic pharmacology

Basic concepts of Ayurvedic pharmacology

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BASIC CONCEPTS OF

AYURVEDIC PHARMACOLOGY

Dr. K. NISHTESWAR M.D. (Ayu.), Ph.D.,

D.A.F.E., Professor & HOD,

Dept. of Dravyaguna, Dr. N.R.S. Govt. Ayurvedic College,

Vijayawada 520 002.

Chowkamba Sanskrit Series Office, Varanasi.

2007


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DEDICATION

My beloved father Dr. K. S. Sharma (Peruru Sharma)


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PREFACE

Herbs occupy the important place in the Ayurvedic Materia Medica

and therapeutics. Though the drugs that are employed in the management of

various diseases include vegetable, animal and mineral in origin, the

polyherbal formulations out number the mineral and other metallic

preparations. The modern scientists of phytochemistry have identified the

following important pharmacologically active principles in medicinal plants

viz.

a. Alkaloids (Basic substances containing cyclic nitrogen, which are

insoluble in water but combine with acids to form water soluble salts)

b. Glycosides (Ether like combinations of sugars with other organic

structures)

c. Glucosides (Yields glucose on acid hydrolysis)

d. Oils (Fixed oils, volatile oils and mineral oil)

e. Resins (insoluble in water and soluble in alcohol)

f. Oleoresins (mixtures of volatile oils and resins)

g. Gums (secretory products of plants and are dispersible in water)

h. Tannins (Non-nitrogenous plants constituents and precipitate proteins

of cells)

i. Antibacterial substances fungi and moulds.

In the current modern therapeutics the majority of the drugs that are

used belong to synthetic in nature.

In the modern pharmacology the drug action is quite often correlated

with its chemical structure or active principle. But in Ayurvedic

pharmacology the drug action is attributed to certain principles/attributes


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namely Rasa, Guna, Virya, Vipaka and Prabhava of the active principles of

the drug. Rasa or taste of the drug indicates the general behaviour or effect of

the drug on bodily or cellular components like Dosha (Vata, Pitta, Kapha),

Dhatus (seven types of tissue components), Mala (metabolic debris), Srotas

(channels/vessels) and Agni (energy useful to carryout digestion and

metabolism of foods & drugs). In the modern pharmacology the modus

operandi of the drug is explained through its drug molecule whereas

Ayurveda attributes the mode of action of the drug to the five principles

(Rasapanchaka). Majority of the times these Gunas (attributes) may not be

measurable but inferred through their pharmacological actions. The study of

the biological and therapeutic effects of the drugs (what drug does to the

body) are explained by these principles which can be identified as

pharmacodynamic principles of Ayurvedic pharmacology. These

pharmacodynamic principles also influence the pharmaco-kinetics (study of

the absorption, metabolism and excretion of drugs and their relationship to

the pharmacological response) of the drugs.

Routes of drug administration play an important role in the

elucidation of drug action. A drug may exert different effects when given by

different routes. Thus, oral magnesium sulphate acts as saline purgative.

When injected, it is a depressant of central nervous system and acts as an

anti-convulsant. On the other hand, hypertonic magnesium sulfate, given as a

retention enema, can be used to reduce intracranial tension. Madanaphala

when given orally acts as emetic and if administered with Vasti Dravays

(ingredients of enema) facilitates for its quicker transportation in the colon

by its Urdwabhagahara property and acts as a synergistic for toning up the

nervous system or relieving intracranial tension.


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Absorption &Bio-availability of a drug:

The route of administration largely determines the latent period

between administration and onset of action. Poor absorption of the drug,

inactivation in the gut or degradation of the drug during the first passage

through the liver can be prevented by administration of Anupanas like honey,

pepper, betel leaf juice etc. The particle size of the drug also affects the

absorption. Fine powders of the herb quickly get absorbed than coarse

particled Churna. Metals in Bhasma (incinerated fine powder) form absorb

quickly than coarse powder of metals or minerals. Acid drugs (Amalaki,

Nimbu, Amlavetasa etc.) are rapidly absorbed from the stomach. Basic drugs

(containing Ksharas) are not absorbed until they reach alkaline environment

of the small intestine (Eg. Apamarga, Aswagandha, Sourjakshara, Shank

Bhasma etc.) The alakaline environment, in which the major component of

the drug exists in an unionised form, facilitates its absorption.

Biopharmaceutics:

The study of the influence of formulation on the therapeutic activity

of drugs is known as Biopharmaceutics and Ayurveda dealt the subject

under Panchavidha Kashaya Kalpana i.e., Swasa (fresh juice), Kalka

(pounded fresh drug), Kashaya (decoction), Phanta (hot infusion processed

in boiling water) and Hima (cold infusion). The juice of the drug

administered having Guruguna (Heaviness) may absorb slowly when

compared to the decoction or hot infusion. A faulty formulation process can

render a useful drug totally useless therapeutically. A drug having volatile oil

/ substances processed by Kwatha Kalpana (process of decoction) may loose

its major portion of volatile active principles resulting in poor therapeutic

response. The drugs that are absorbed in lipid media are suggested to be

processed in oil or ghee medium (Eg. Aswagandha). The active principles


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soluble in alcohol are available by Asava Sandhana Kalpana but not by

Arista Sandhana Kalpana. It is evident that the various Kalpanas

(pharmaceutical procedures) were evolved in the light of principles of

biopharmaceutics.

Biological lag:

The time between the administration of a drug and the development

of response is known as the biological lag. Rasoushadhis (mercurial

preparation) show a quicker response with less biological lag when

compared to herbal formulations.

Bioavailability of drugs:

Bio-availability of a drug (availability of biologically active drug) is

defined as the amount or percentage of drug that is absorbed from a given

dosage form and reaches the systemic circulation following non-vascular

administration. When the drug is given I.V., the bio-availability is 100%.

This may not be so after oral administration. Acharyas of Ayurveda preached

and practiced the oral route of administration for majority of drugs.

Anupana (substance administered either with the drug or after its

administration) facilitates for better absorption of the drug and helps in

achieving higher percentage of bio-availability of the drug.

1. Drugs are metabolised by the enzymes.

2. Drugs could change spontaneously into other substance without

intervention of enzymes.

3. Drug could be excreted unchanged.


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The alteration of drugs form and modification of action are well

elucidated in Ayurveda in terms of Pratyayarbadhata i.e. Samana and

Vichitra Pratyayarabdhata. It may be interpreted that Samana Pratyayarbdhi

Dravya may be excreted unchanged while Vichitra Pratyyarabdha Dravya

may change into other substances.

A careful review of principles of Ayurvedic physiology and

pharmacology indicates that Ahara (food substances) and Oushadha (drugs)

Dravyas undergo digestion and metabolism synthesises nutritive and active

principles along with Kitta formation. The substances like Mutra, Purisha,

Sweda are the bi-products of drug metabolism and drug metabolites are

excreted through them. The metabolism of drug usually tends to make the

less polar, lipid soluble substances (Guru Guna Dravyas) as more polar and

water soluble (Laghu) thus facilitating their excretion by kidneys. If a drug is

already highly polar and water soluble, then it may not get metabolised and

may get excreted as such. Excretion of each and every herb was not studied

and reported so far.

The important channels of drug excretion are

1. Kidneys

2. Lungs

3. Skin

4. Bile

5. Intestines

6. Milk and

7. Saliva.


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Some fraction of the administered drug disappears (eliminated) from

the body and is reflected in the rate of lowering of its plasma concentration

(plasma half-life or biological half life). It is very difficult to calculate

biological half-life for herbs as the plant contains many active principles and

research to assess the concentration of the particular active principle by

analysing blood/plasma has not been so far developed. To study the total

pharmaco-kinetics of the herb one has to administer it with radioisotopes and

plot the journey of the drug which may facilitate also to identify the route of

excretion of the drug.

Site of Drug Action:

The site of drug action (Adhikarana) and mechanism of drug action

(Dravya Prabhava & Guna Prabhava), are the two most fundamental and yet

most complex problems in pharmacodynamics.

Generalising about the site of drug action (Dosha-Dhatu-Mala-Agni-

Sutas) is easy, but the precise determination of specific site and the

mechanism of action of the drug is difficult and often impossible.

A drug may act

at the point of application (Nipata) during transportation in the body (Adhivasa) by reflex effects through nerves by reaching a definite concentration in a particular tissue.

Drugs that act only at the site of application are said to have local or

topical action (through Nipata by Rasa & virya) while those that act after


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absorption are said to have a systemic or general actions (through

Nishtakarma & Adhivasa by Vipaka & Virya)

Modern pharmacology attributes the activity of a drug to its chemical

structure and Ayurveda explains it by the drugs Panchabhautic configuration

and the profile of Panchabhautic ratio is inferred with the general principles

like Rasa, Guna, Virya and Vipaka.

The ability of a drug to get bound to a receptor is termed as the

affinity of the drug for the receptor. The ability of the drug to elicit a

pharmacological response after its interaction with the receptor is termed as

the intrinsic activity of the drug or efficacy of the drug. A drug which

initiates a pharmacological action after combining with the receptors is

termed as an agonist. Drugs which bind to the receptors but are not capable

of eliciting a pharmacological response are termed as antagonists. An

antagonist, therefore, has the affinity as the agonist for the receptor but its

intrinsic activity is poor.

Facilitation of a pharmacological response by the concomitant use of

two or more drugs is called synergism. This combination usually results in a

total effect greater than the sum of their independent actions. By combining

Tulya Virya (similar potency) drugs the formulation acts by synergism. The

phenomenon of opposing actions of two drugs on the same physiological

system is termed as drug antagonism. The best example is administration of

Viruddha (opposite) Virya drugs. Eg. The combination of Rasna (Vathara

drug) with Jambu (Vatakara drug)


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Though the term potentiation is not acceptable to modern

pharmacology Charaka has explicitly promulgated the concept of

potentiation of drug efficacy by triturating the drug with its own juice

(Swarasa Bhavana). Drug incompatability is similar to the concept of

Virudhatwa described in Ayurveda. Ayurveda has also recorded adverse

drug reaction with certain herbs like Bhallataka (marking nut) etc.

It was my preveilage to work under late Prof. Shivcharan Dhyani,

H.O.D. Dept. of Dravyaguna, I.P.G.T & R, Gujarat Ayurved University,

Jamnagar, who was a fountain source of inspiration and rendered his ablest

guidance during my Post-Graduate studies. The research work carried out

under his guidance on the concept of Virya was published already in some of

the standard Ayurvedic Journals. For the benefit of students of Ayurveda and

academicians, I have reproduced some of the salient concepts of Ayurvedic

Pharmacology along with the summary of Research Studies carried out by

me on Virya one of the fundamental principles of Drug action. I believe the

readers will find the study of this book rewarding and satisfying. I specially

acknowledge M/S Chowkhamba Sanskrit Series, Varanasi for publishing this

work.

Date: 22-5-2007

K. NISHTESWAR


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CONTENTS

PREFACE

INTRODUCTION

1. PRINCIPLES OF DRUG ACTION

2. ESSENTIAL COMPONENTS OF DRUG EVALUATION

3. VIRYA AN IMPORTANT ATTRIBUTE OF DRUG

ACTION

4. EXPERIMENTAL STUDIES

BIBLIOGRAPHY


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INTRODUCTION

The subject of usage of herbs and herbo-mineral drugs is as old as

disease. Illness has been human beings heritage from the beginning of the

existence of life and the search for remedies to combat it is perhaps is

equally old.

The herbs and other things were in use as medicine to a limited extent

from the very Vedic period. Over and above these medicinal plants, metals

like gold, lead, tin, copper etc. were known to the Vedic Rishis, but there is

no evidence to show that they were put to any medicinal use in those days.

Their medicinal use receives more attention during the Samhita period. Due

to great influence of Atharvan more importance was attributed to divine


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therapy (Daivavyapasraya medicine) viz. incantations, gems or magical

stones, herbal amulets and sacred water etc. This was just an incipient gleam

of knowledge of therapeutics. The object of such reference to the drugs of

the Vedic times is to show that there was no definite theory to explain the

actions of drugs in those days and even if there was one, we have no means

of knowing it.

Gradually, the floating ideas of Vedic times received more thinking

and more criticism till they were put together to form a comprehensive

theory regarding the pharmacology of drugs. In this course of development,

the fundamentals must have faced great controversies and after long

scientific discussions only, they could have attained their stability as we find

such illustrations in Charaka and Sushruta Samhitas. On account of incessant

intellectual activities and numerous observations by several workers, the

number of drugs enormously increased during the Samhita period. Not only

this but the old empiricism had disappeared, giving place to a definite theory,

known as a theory of Rasa, Guna, Veerya, Vipaka and Prabhava. With this

effect the herbal therapy went on progressing as a rational (Yuktivyapasraya)

school of medicine.

Ayurveda is mainly concerned with prescribing drugs to balance the

vitiated doshas. Its pathology is concerned with doshas, dhatus and malas.

So, any action of the drug is to be explained only on this basis.

Modern Pharmacology being interested in studying the actions of the

drug on different systems or parts of the body describes all drugs on the basis

of Karma, they perform. In Ayurveda, in relation to pharmaco dynamics, the


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properties of drugs have been described in terms of Rasa, Vipaka, Guna,

Virya and Prabhava.

Drayva i.e., substance (food or drug) acts by its innate qualities

(Gunas) such as Rasa, Guna, Virya, Vipaka and Prabhava or through its own

Prabhava.

Panchamaha Bhutas act as contributing factors for the formation of a

dravya as well as its Gunas. The elementary substances (Panchamula Bhutas)

with which every substance is constituted are the Karana or the cause and

hence they are called as Karana Dravyas. Whereas Rasa, Guna, Virya,

Vipaka and Prabhava of the substances which arise out of the permutations

& combinations of the 5 elementary substances in various modes and

patterns are really the effects or Karyas. Substances arise out of the various

modes of permutations and combinations of the five elementary substances

are described as Karya Dravyas.

The properties which exist in the causative factors (Panchamaha

Bhutas) are present in the resultant factors (Karya Dravyas). These properties

become actualized in the effect or Karya; which are described in terms of

Rasa, Guna, Virya, Vipaka and Prabhava. Rasadi Panchaka are the modes of

Gunas of Panchamaha Bhutas and stated in terms of recent trends in the

modern physics The initial state of a system wholly determines its

subsequent states. The Dravyas arise on the substrate of Prithvi.

A review about the scientific implications of these principles

(Rasapanchaka) of drug action is mandatory to understand the rationality of

modus operandi of Ayurvedic drugs.


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RASA

It is an important quality manifested at the level of tongue and is the

only principle or quality which can be directly perceivable. The Rasa or taste

which is cognized first (by impact with the tongue) is considered as Rasa

(Primary taste) and the Rasas which are less apparent or cognizable are

called Anurasas (Secondary Taste).

Scholar of Dravya Guna of Modern Ayurveda namely Acharya Priya

Vrat Sharma has discussed concept of Rasa basing on the Physico-Chemical

constitution of substances as follows:

Madhura - Sugar, Fat and Amino Acids

Amla - Acids

Lavana - Salts

Katu - Essential Oils, Phenols etc.,

Tikta - Certain Alkaloids and Glycosides

Kashaya - Tannins

According to his hypothesis carbohydrates and proteins are present

in Madhua Rasa Dravyas. All the Amla Rasa Dravyas have shown Acidic

Reaction and all the Dravyas in Lavana Varga are containing Sodium

Chloride. All the Dravyas of Katu Varga are containing essential oil while

50% of Katu Dravyas contain alkaloids or glycoside or phenols. All the Tikta

Drayvas contain alkaloids and only 10% of Dravyas contain Glycosides.

Many of the Kashaya Rasa Dravyas contain tannin. Professor Dwarakanath

has attempted to evolve a method known as Taste Threshold for

quantitative determination of Rasa in a given substance. The test is meant for


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evaluating the intensity or degree of the taste which finally depends on the

tongue only and not with any other laboratory instruments. The taste

perception and taste sensibility are complex Bio-Physical and Psychological

events and translation of Rasa cannot be exactly evaluated without the help

of tongue.

Rasa & Guna

Panchabhoutic combination and primary physical qualities or Gunas

of different Rasas are mentioned in the Ayurvedic Classics. Though it

appears that Gunas are intimately related to Rasas it is a fact that both are

separate principles co-existent in the Dravya. This statement reflects that

Rasa acts by its own Prabhava independent of the Gunas attributed to it.

Of the six Rasas Katu, Amla and Lavana possess consecutively

Ushna Virya in progressively increasing degrees. Likewise, Tikta, Kashaya

and Madhura Rasas possess consecutively Sita Virya in progressively

increasing order.

According to this reference the six Rasas finally exercise their

general actions by two principles or gunas namely Sita & Ushna and specific

action on malas by another pair of Gunas namely Ruksha (Badda Mala

Binding of waste products) and Snigdha (Srishtamaltwa Proper elimination

of waste products). Another pair of Gunas namely Guru and Laghu are

attributed to six Rasas. Lavana, Kshaya and Madhura Rasas possess Guru

Gunas in progressively increasing degree (relatively superior) and similarly

Amla, Katu, Tikta relatively attributed with Laghu Guna. Brimhana and

Langhana are the actions of Guru and Laghu Gunas and the specific action of

Rasas on Dhatus can be interpreted with Guru and Laghu Gunas.

In a nut shell, the Shad Rasas (six tastes) are bestowed with the

ability to participate in Shad Upakarmas (six therapeutic measures) with the


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help of six Gunas namely Ushna-Sheeta, Sringdha-Ruksha and Guru-Laghu.

Gunas Upakrama Rasa

Ushna Swedana Katu, Amla, Lavana

Sheeta Stambhana Tikta Kashaya, Madhura

Snigdha Snehana Lavana, Amla, Madhura

Ruksha Rukshana Tikta, Katu, Kashaya

Guru Brimhana Lavana, Kashaya, Madhura

Laghu Langhana Amla, Katu, Tikta

The above table clearly indicates that Dravya exercises its action

through Gunas only and the individual Rasas of Dravyas help to infer the

inherent Gunas of respective Dravyas.

Virya-Vipaka:

Next to the concept of Rasa, Acharyas have the concepts of Virya and

Vipaka which are directly related to Bio-Physical and Bio-Chemical events

of food substances and drugs. Ahara or food and Oushadha or medicinal

substances are subjected to physiochemical reactions or Pakas at Gastro-

intestinal and tissue levels.

Charaka defined that Virya as the power that performs work. All

actions takes place only because of Virya and there is no action which is not

due to Virya. According to this definition the principles like Rasa, Gurvadi

Guna, Vipaka and Prabhava which could be causative factor for the action is

generally identified as Virya. But, Sushruta, Vagbhata and their followers did

not agree with the views of Charaka and applied the term Virya to the eight

primary qualities of elementary substances viz., Mridu-Teekshana, Guru

Laghu, Snigdha-Ruksha, Ushna-Sita. Commenting on the concept of


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Dwividha Viryas Hemadri quotes Although the eight Gunas of Dravyas

become actualized in the process of their Paka by kayagni, they (the Gunas

eight or twenty) are ultimately transformed to Ushna and Sita due to the

greater exaltation of these two Gunas (i.e., Ushna and Sheeta) which obscure

or supercede the other Gunas.

Classification of twenty Gunas

Anna or Shoma or Sita

Virya or Potential Energy

Prana or Agni or Ushna

Virya or Kinetic Energy

Guru

Shita

Snigdha

Manda

Sthira

Kathina

Pichchila

Shlakshana

Sthula

Sandra

Laghu

Ushna

Ruksha

Tikshna

Sara

Mrudu

Vishada

Khara

Sukshma

Drava

Eight gunas with Virya status

Anna or Shoma or Sita Virya

or Potential Energy

Prana or Agni or Ushna

Virya or Kinetic Energy

Guru

Snigdha

Shita

Mridu

Laghu

Ruksha

Ushna

Tikshna


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Shivadas classified Virya as Sahaja (natural) and Kritrima (artificial)

Dravya Rasa Guna Vipaka Virya

Milk Madhura Guru Madhura Sita

Curd Amla Laghu Amla Ushna

Sali Madhura Guru Madhura Sita

Laja Madhura Laghu Katu or Amla Ushna

Viryas of Rasas:

Rasa Virya

Katu, Amla, Lavana Ushna

Tikta, Kashaya, Madhura Sita

Properties of different Viryas

Name of the Virya Action/Effect produced

Ushna Bhrama (giddiness)

Trishna (Thirst)

Glani (Bodily fatigue or exhaustion)

Sweda (Sweating)

Daha (Burning sensation)

Asupakita (Accelerates digestion or biochemical

reaction)

Vata-Kaphahara

Sita Hladana (cheerfulness or pleasure of mind)

Jivana (Surtains life)

Stambhana (Binding or preventing secretions)

Raktapitta Prasadana (cleanses Rakta & Pitta)


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Kledana

Vishyandana

Guru Brimhana (increases the body weight)

Vatahara

Laghu Langhana (reduces the body weight)

Kaphahara

Snigdha Snehana

Kledana

Balya

Varnya

Brhimhana

Vajeekarana

Rasa

Ruksha Soshana

Sangrahana

Peedana

Ropana

Mrudu Pitta Prasamana

Raktamamsa Prasadana

Slathana

Tikshna Sleshmahara

Samgrahana

Sravana

Dharana

Avachushana

Sodhana

Assessment of Rasa, Vipaka and Virya:


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The Rasa (taste) of a Dravya (substance) is felt at the commencement

only i.e. when the Dravya comes in contact with the tongue (Nipata) and

Vipaka is inferred only after perceiving the final effects of digestion and

metabolism is produced (Karma Nishta) while Virya is identified throughout

the stay of the substance in the body (Adhivasa) and also at the beginning

through the contact with the tongue. (Nipata)

Sushruta suggests the following assessment criteria for eight Virya:

Name of the Virya Method of assessment

Mridhu, Sheeta, Ushna Sparshagrahya (Tacticle Perception)

Pichchila, Visada Chakshu Sparshagraha (Visual & Tactile

Perception)

Snigdha, Ruksha, Tikshna Chakshu grahya (Visual perception)

Tikshna Mukhadukhodpana (Irritating the buccal

mucosa)

Though Sushruta considers that Virya by Pratyaksha Pramana,

Charaka opines that Virya of the dravya is identified through inference

(Anumana) according to its stay in the body while Virya of certain drug can

be assessed by Pratyaksha Pramana (direct perception) after its contact with

the tongue. Hemadri while commenting on the evaluation of Guna attributed

specific actions to certain Gunas which are given Virya status viz.,

Guru

Laghu

Sita

Ushna

Snigdha

-

-

-

-

-

Brimhana

Langhana

Sthambhana

Swedana

Kledana


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Ruksha

Mridu

Tikshna

-

-

-

Soshana

Slathana

Sodhana

An attempt to evaluate the attributed Karmas at biological level either

in animal or by human experiments may provide scientificity to the concept

of Virya.

Professor Dwarakanath explains the concept of Virya in the light of

Modern definition of energy the energy of a body is its capacity for doing

work; the measure of energy is work; when chemical changes take place

energy is liberated or absorbed; usually as heat but occasionally as light,

electricity or work. A reaction which liberates heat energy is said to be

exothermic (Ushna Virya) and one which absorbes heat energy is said to be

endothermic (Seeta Virya). Energy may be kinetic or potential. The energy

locked up in substances especially food is known as chemical potential

energy (Seeta Virya). The energy that is released for work by oxidation is

known as kinetic energy (Ushna Virya). For transformation of energy from

one form to another Paka Karma (Vipaka) in Dhatus or tissues is highly

essential.

The breakdown reactions (Catabolic) and reactions leading to

synthesis (Anabolic), involving the release and locking up of energy

respectively are together known as Paka Bhedas.

From the above discussion it can be concluded that various energy

forms are the modalities of Virya and reactions for the release or

conservation of energy are the various forms of Vipaka. Gunas or physical


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qualities or physical properties of substances are modes (or different

manifestations) of Virya or energy. All the twenty Gunas comprising ten

each of the opposites can be classified broadly under two Virya modes viz.,

Ushna and Sheeta corresponding to kinetic and potential energies

respectively. Out of twenty Gunas, considerable significance has been

attached to eight Gunas otherwise known as Asta Viryas as they are deemed

to be effective in the performance of actions.

Vipaka:

The Rasas of substances ingested being acted upon by Jatharagni are

changed to different other tastes after attaining Pakva. It is this

transformation of Rasas that is spoken of as Vipaka. A substance which is

Madhura (sweet) in taste and Vipaka, is Sita Virya, that which is Amla Rasa

and Vipaka, is Ushna in Virya. Similarly, that which is Katu in Rasa and

Vipaka is Ushna in Virya. Various Vipakas represent highly specialized

reaction to synthesise ultimate metabolic products.

Regarding the number of Vipakas different scholars held different

views. Some hold that there are as many Vipakas as there are Rasas.

According to Charaka Vipakas are three viz., Madhura, Amla and Katu.

According to Sushruta, Vipakas are only two viz., Madhua and Katu. Parashara has advanced another view that Tikta and Kashaya Rasas

undergo Madhura Paka.

In the view of some of the authorities quoted by Sushruta, there are as many Vipakas as there are Rasas.

In the opinion of Ayurveda Sutra substances that possess Katu Rasa may undergo Lavana Paka, Tikta Rasa may undergo Madhura Vipaka


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and Kashaya Rasa may undergo Amla Vipaka.

Some interpret Vipakas as the specific mode of Pancha Bhoutic

structure of the elemental units of the ultimate metabolic products.

According to Hemadri that evokes taste perception is Rasa and all the rest

are Gunas. Particular or distinct Visishta Rasa or taste that occur as the result

of Kayagnipaka is Vipaka and generated Guna at this stage is known as

Virya.

The substances are identified by two varieties of tastes i.e., Rasa

(general) of a Dravya at tongue level (Shad Rasas) and Rasa (specific or

Visishta) of a Dravya which has undergone Paka and specially named as

Vipaka. Rasa and Vipaka are the two forms for the identifying the actions of

substances either by direct perception at tongue level (Nipata) and by

inference assessed through final action (Nishta Paka).

The final action achieved by Dravya continues as long as the bodily

contact with engendered Guna or Virya through Vipaka maintains

(Adhivasa). The action ceases when Virya (Virya Yukta Dravya i.e., Drug

Molecule) is excreted or expelled out of the body.

The action attributed to Rasa, Virya and Vipaka are explained in

terms of Guna only. Charaka has tried to explain regarding the identification

or recognition of these Gunas at various contact points in the body during the

journey of the drug such as Gunas identification at tongue level with the help

of Rasa (Nipatat) by direct perception and through inference at Dhatu (tissue)

level; with the terms such as Vipaka (Nishtapaka) and Virya (Adhivasa)


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Prabhava:

Prabhava has been defined as the special property of a substance

which produces actions different from and contrary to those ascribed to Rasa,

Guna, Virya and Vipaka.

The concept of Prabhava appears to be generally resembling the

concept of isomerism and isomerides of modern physical compositions and

yet exhibit different properties. The chemical composition which largely

determines the secondary qualities of a Dravya such as Rasa, Guna, Virya

and Vipaka does not determine a chemical compound. The Rasa, Guna,

Virya and Vipaka of Danti and Chitraka being apparently identical, the

former produces purgation, whereas the latter does not produce this action

and the specific purgative action of Danti is attributed to its Prabhava

(inexplicable nature).

It is easy to evaluate or assess different Karmas (pharmacological

actions) of drugs through various experimental models but it is a tough task

to evolve objective methodology for demonstration or identification of

principles of drug action. Acharyas of Ayurveda clearly mentioned that

Gunas are inferred by their Karmas or actions which are perceivable.

In order to test the medicinal value of any drug, three methods i.e. (i)

Clinical, (ii) Pharmacological and (iii Experimental are in practice

from a time immemorial. In those days the experimental trial was in

rudimentary stage and the clinical evaluation was very common. Now a days,

though more stress is being given on animal experimentation. But this does


26

not help to that extent, in order to declare the utility of a drug, as is

confirmed after clinical testings. Moreover, the results obtained in

experimental animal are often found to be different to that of human beings.

Thus, it becomes evident that the ancient drugs having clear cut indications,

ascribed in the texts should not be ignored or accepted only on experimental

basis, until they are tested clinically both with active principles (isolates) as

well as total drug.


27

1. PRINCIPLES OF DRUG ACTION

The Ayurvedic Science delineated important three principles

(Trisutra) viz., etiology (Hetujnana), symptomatology (Lingjnana) and

therapeutics (Oushadhajnana). Etiology includes the immediate and distant

cause of diseases. Similarly the symptomatology includes the entire signs

and symptoms of diseases and health and the therapeutics include

wholesome diet along with the treatment of diseases. Ayurvedic concepts of

pharmacology are included under Oushadhajnana.

Correct Application of the drug is essential:

The goatherds, shepherds, cowherds and other forest dwellers know

the drugs by name and form. No one can know the principles governing

correct application of drugs simply by knowing their names and forms. A

physician, even ignorant of their forms can be said to be a knower of the

essence [of science] if he is acquainted with the principles governing the

correct application of drugs, let alone the one who knows drugs in their

entirety. One who knows the principals governing their correct application

in consonance with the place, time and individual variation, should be

regarded as the best physician. Of course, the best physician is he who is

well acquainted with the drugs in their entirety.

One has to establish the correct identification of drug prior to its

collection. Sushruta suggests that the knowledge of identification of herbs

can be obtained by contact with cow-herds, herds, hermits, hunters and

others who roam in jungles and take root (of plants) as food.

A drug not known is likened to poison, weapon, fire and thunderbolt


28

while the one known, to the nectar. A drug known in respect of its name,

form and properties or even if known, improperly administered, leads to bad

consequences.

Proper application of drugs depends upon their proper knowledge.

Unless the physician knows the drugs properly he cannot cure a patient; his

prescription would rather kill his patient. The drug unknown, might act as

poison which kills after bringing about unconsciousness or as a weapon

which kills after piercing through the vital organs, or like fire which kills by

causing boils, etc. or as a thunderbolt which kills instantaneously. It is only

when a physician knows all the three aspects, viz., name, form and properties

of drugs. The physician can treat the patients successfully.

Even an acute poison can become an excellent drug if it is properly

administered. On the other hand even a drug, if not properly administered,

becomes an acute poison. So a wise patient desirous of longevity and health

should not accept any medicine prescribed by a physician ignorant of the

principles governing its application. Some times, one might escape (death)

even when thunderbolt of Indra has fallen on his head, but one can never

survive if he takes medicine prescribed by a physician ignorant of the

application.

To sum up, neither the patient should take medicine prescribed by

pseudo-physicians, nor a physician, without being proficient in the principles

governing the application of drugs.

Only that, which can bring about a cure, is a correct medicine. It is

only he who can relieve his patients of their ailments is the best physician.


29

For the purpose of the Science of medicine, it is necessary to explain the

qualities of correct medicine and a good physician. It is only that which

possesses the requisite curative values is to be treated as a correct medicine.

As regards physician, he should first of all know the principles underlying

the correct application of medicines. Unless he knows it, he will not be able

to relieve his patients of their ailments. Even if per chance, medicines

selected by him at random succeed in alleviating ailments, the credit is

considered as accidental one.

Classification of Dravya:

Akasa etc., (Prithvi, Ap, Tejas, Vayu and Akasa), soul, mind, time

and space constitute matter. Matter having sense organs is sentient while the

one devoid of them is insentient.

Chakrapani Dutta interprets that This definition applies also to the

vegetable kingdom; that is to say the vegetable kingdom is also sentient.

Many examples can be cited to prove this. The Suryabhakta (Helianthms

annus Linn.) moves according to the movement of the sun. The Lavali

(Gicea acida Merrill) gets fruits just on hearing the sound of the thunder.

The Bijapuraka (Citrus medica Linn.) tree produces fruits only by the smell

of the fat of jackals etc., similarly Amra (Mangifera indica Linn.) trees when

irrigated with the fat of fish, produces fruits in plenty. Ashoka tree (Saraca

indica Linn.) hit with the sole of the feet of a lady begets flowers. The above

example clearly indicates the presence of the various sense organs in the

vegetable kingdom as well. This is also attested from scriptures. If a

Brahmin does not give blessings in response to salutations, he is born in a

cemetery as a tree surrounded by vultures and Kankas. Trees, shrubs and

other varieties of grass are covered with darkness arising out of their sinful


30

acts but they all have consciousness full of happiness and miseries. The

extent of creation beginning with Brahma is up to vegetable kingdom.

Thus, the members of the vegetable kingdom have got life as well as

consciousness. So they belong to category of sentient matter. Vedic lorwe

clearly indicated that plants do have life and modern scientists like Jagadish

Chandra Bose have tried to revalidate these concepts through scientific

experiments.

Drugs are of three categories, some alleviate Doshas, some vitiate

Dhatus and some are good for the maintenance of positive health.

This three-fold classification of drugs also includes other type of

drugs which are responsible for elimination and suppression of Doshas.

Elixirs and aphrodisiac drugs come under the third category which are

responsible for the maintenance of positive health.

The use of the term Dosha and Dhatu in the first and second

category of classification is quite significant. Doshas include Dhatus

and Vice-Versa. So the drugs that are designated as alleviators of the Doshas

also alleviate Dhatus. Similarly, the drugs that have been designated as

vitiators of the Dhatus do as well vitiate Doshas. The drugs under the third

category are those which have potentialities to maintain the positive health.

Apparently it also means that the drugs have got potentialities to prevent the

diseases.

According to another classification, Dravyas are of three kinds viz.,

those of animal origin, those of vegetable origin and metals including

minerals. Different types of honey, products of cow milk, bile, fats of


31

muscle tissue, marrow, blood, flesh, faeces, urine, skin, semen, bone,

ligament, horn, nail, hoof, hair, Lomana, (hair of the body excluding those of

the head and face), Rochana (purified Ox bile) - are some of the drugs of

animal origin used in medicine.

Gold, five Lohas (copper, silver, tin, lead, and iron) along with their

byeproducts (different types of bitumen), calcites along with silica, red

arsenic, yellow arsenic, gems, salt, red chalk, collyrium are in brief the

metals and minerals used in medicine.

The drugs of vegetable origin are of four types viz. Vanaspati,

Vaanaspatya, Virudh, and Oshadhi. Vanaspati is the one having fruits only

(without flower). Vaanaspati has flowers as well as fruits. The drugs

belonging to the class of Virudh are those which spread with branches.

Oshadhis are those which die out when their fruits mature. The root, bark,

Sara (aqueous extract), secretions, fibre, juice, tender leaves, alkali

preparations, latex, fruits, flowers, ashes, oils, thorns, matured leaves,

adventitious roots, rhizomes, sprouts are belonging to the group of drugs of

vegetable origin.

In another classification the drugs are classified according to part

used viz., Moolini (Root) and Phalini (fruits). The Mula (Root), Twak

(bark), Sara (heartwood), Niryasa (Secretions/gums), Nala (fibre), Swarasa

(juice), Pallava (tender leaf), Kshara (Alkali), Ksheera (latex), Phala (fruit),

Bhasma (Ash), Taila (oil), Kantaka (Thorn), Patra (leaf), Sunga (adventitious

roots), Kanda (rhizome), Praroha (sprouts) are the useful parts of the drugs of

vegetable origin. Charaka also describes the plant with useful parts like roots


32

and fruits which are indicated in Panchakarma measures. He further explains

about the drugs that are useful for various elimination (sodhana) therapies in

Apamarga Tanduliyaka (Dehusked seeds of Apamarga) chapter. Drugs are

of two kinds one variety of drugs is used for internal cleaning (Abhyantara

Parimarjana) and the other for external cleaning (Bahi Parimarjana). The

drugs related to later category are described under Aragwadhiyam chapter.

In the chapter entitled Satvirechana Satashritiyam the drugs useful

both for internal as well as external cleansing are being explained. In this

chapter fifty groups consisting of ten drugs each on the basis of

pharmacological actions as well as therapeutic utility are introduced by

Charaka which are popularly known as Dasaemani. In total five hundred

drugs are listed among fifty groups and the same drug is repeatedly quoted in

a number of groups of decoctives. After elaborative descriptions about the

drugs of different groups Charaka humbly states that the description of 500

decoctives (Mahakashaya) is neither too exhaustive nor too brief. Physicians

of lower intelligence will, of course, find this list useful enough in the

treatment of various diseases but those possessing high intellectual caliber

need not confine themselves to this list. Physician may exercise his own

imaginative power in finding out other similar drugs as well, according to the

principles laid down in Ayurveda and keeping in view the requirements of

the patient.

Dravya Pradhanya (Importance of the substance):

Dravya (substance) is the chief (most important) among Rasa (tastes)

and others qualities; because all of them (qualities) are residing in it

(substance).


33

It (substance) is Panchabhutatmaka (composed of, born from the five

elements), it has Ksma (Prithvi Bhuta) as its substratum (mass, support), it

takes origin from Ambu (Apbhuta), Agni (Tejas Bhuta), Pavana (Vayu

Bhuta) and Nabhas (Akasa Bhuta), with their intimate (inseparable)

combination making for its formation and specify (of each substance). Its

identification/designation is by preponderance (predominance, of the Bhuta

present in it).

Nothing is Non Medicinal

There is nothing in this universe, which is non-medicinal, which

cannot be made use of for many purposes and by many modes.

Origin of substance takes place by combination of Prithvi, Ap, Tejas,

Vayu and Akasa. Only predominance of one of them creates distinctions

such as this is Parthiva, this is Apya, this is Taijasa, this is Vayavya and this

is Akasiya.

Parthiva Dravya Lakshana (Qualities of Parthiva substances)

The substance which possesses qualities such as Guru (heaviness),

Sthula (bulky), Sthira (stable) and predominant in Gandha (smell) is Parthiva

(earthy); it bestows heaviness, stability, compactness and growth.

Apya Dravya Lakshana (Qualities of Apya substances)

The substance which possesses qualities such as Drava (liquidity),

Sita (cold), Guru (heaviness), Snigdha (unctuousness, moisture, oiliness),

Manda (dull), Sandra (thickness, dense) and predominant in Rasa (taste) is

Apya (watery); it confers lubrication (moistness), secretion (moisture,

production), Kleda (keeping wet), satiation (contentment, satisfaction) and

cohesion (binding, holding together).


34

Agneya Dravya Lakshana (Qualities of Agneya substances)

The substance which possesses qualities such as Ruksha (dry),

Tikshna (penetrating, sharp), Ushna (hot), Vishada (non-slimy), Sukshma

(minute) and predominant in Rupa (appearance, showing, from); it causes

burning sensation, lustre, expression of colour and digestion (process of

transformation, putrefaction etc.)

Vayaviya Dravya Lakshana (Qualities of Vayaviya Substances)

Vayaviya substance possesses qualities such as Ruksha (dry),

Vishada (non-slimy), Laghu (lightness) and predominant in Sparsa (touch

tactile sensation), it produces dryness, lightness, transparency, movements

(different kinds of activities) and exhaustion.

Nabhasa Dravya Lakshana (Qualities of Nabhasa Substance)

Nabhasa (Akasiya) substance possess qualities such as Sukshma

(minuteness), Visada (transparence, clearness), Laghu (lightness) and

predominant in Sabda (sound, hearing); it produces cavitation (hollowness)

and lightness (weightlessness).

Purgative drugs are predominant in qualities of Prithvi and Ap which

are heavy and as such move downwards, hence, by inference, purgative is

predominant in qualities of down-moving elements eg. Prithvi and Ap;

emetic drugs are predominant in qualities of Agni and Vayu which are light

and as such move upwards, hence emetic is predominant in qualities of up-

moving elements e.g. Agni and Vayu. That acting in both ways in

predominant in qualities of both the above two; pacifying drug is

predominant in qualities of Akasa; astringent drug is predominant in qualities


35

of Vayu because of its drying nature; Dipana (stimulating digestive fire) is

predominant in qualities of Agni because of its similarity; Lekhana

(decreasing body-weight) is predominant in qualities of Vayu and Agni;

Brimhana (increasing body-weight) is predominant in qualities of Prithvi and

Ap. In this way, action of drugs may be interpreted by inference.

Here heaviness and lightness should be taken as governed by specific

potency situated in Trivrit, Madana etc. and not in the ordinary sense

otherwise fish, floury food, lentils etc. would be purgatives and grey

partridge, quail etc. might come into the emetic group; Lekhana decreasing

body-weight, by depleting Kapha and fat.

Vayu is pacified by substances composed of Prithvi, Tejas and Ap;

Pitta is pacified by those composed of Prithvi, Ap and Vayu while Kapha is

pacified by substances composed of Akasa, Tejas and Vayu. (On the

contrary), Vayu is increased by substances composed of Akasa and Vayu,

substance which is igneous in nature increases Pitta while Kapha is increased

by those composed of Prithvi and Ap.

In this way, in every substance, the predominance of qualities should

be observed and, considering its effect on two or more Doshas, that should

be applied in case of aggravated Doshas.

Drug classification according to Rasa (According to Sushruta):

Substances in reference to all are enumerated such as Kakolyadi

group, milk, ghee, muscle-fat, marrow, Sali and Sastika rice, barley, wheat,

blackgram, Sringataka, Kaseruka, Trapusa, Ervaruka, Karkaruka, Alabu,

Kalinda, Kataka, Gilodya, Priyala, Pushkarabija, Kashmarya, Madhuka,


36

Draksha, Kharjura, Rajadana, Tala, Narikela, products of Ikshu (sugarcane),

Bala, Atibala, Kapikacchu, Vidari, Payaysa, Gokshura, Kshiramorata,

Madhulika, Kushmanda etc. are included in the sweet group.

Dadima, Amalaka, Matulunga, Amrataka, Kapittha, Karamarda,

Badara, Kola, Prachinamalaka, Tintidika, Koamra, Bhavya, Paravata,

Vetraphala, Lakucha, Amlavetasa, Dantasatha, curd, buttermilk, Sura

(alcoholic beverage made of barley), vinegar, different types of sour gruel

etc. are included in the sour group.

Saindhava, Sauvarchala, Vida, Pakya, Romaka, Samudraka,

Paktrima, Yavakshara, that obtained from desert, Suvarchika etc. are briefly,

the members of the salty group.

Pippalyadi, Surasadi, Sigru, Madhusigru, Mulaka, Lasuna, Sumukha,

Sitasiva, Kustha, Devadaru, Harenuka, Bakuchiphala, Chanda, Guggulu,

Musta, Langali, Sukanasa, Pilu etc. and mostly Salasaradi group come in the

pungent group.

Aragvadhadi, Guduchyadi, Mandukaparni, sprouts of Vetra, two

types of Haridra, Indrayava, Varuna, Vikankata, Saptaparna, two types of

Brihati, Sankhini, Dravanti, Trivrit, Kritavedhana, Karkotaka, Karavellaka,

Vartaka, Karira, Karavira, Jati, Sankhapushpi, Apamarga, Trayamana,

Katuka, Vaijayanti (Tarkari), Suvarchala, Punarnava, Vrischikali, Jyotismati

etc. briefly, come in the bitter group.

Nyagrodhadi, Ambasthadi, Priyangvadi, Rodhradi, Triphala; fruits of

Sallaki, Jambu, Amra, Bakula, Tinduka, Saka and Nyagrodha etc;


37

Pasanabheda, mostly Salasaradi group, Kuruvaka, Kovidara, Jivanti, Chilli,

Palankya, Sunisannaka etc. and Varaka, Mudga etc. are included in the

astringent group.

DRUG ACTION

It is not that the various drugs and diets act only by virtue of their

qualities. In fact they act by virtue of their own nature or qualities or both on

a proper occasion, in a given location, in appropriate condition and

situations; the effect so produced is considered to be their action (Karma);

the factor responsible for the manifestation of the effect is known as Virya;

where they act is the Adhisthana (location); when they act is the time, how

they act is the Upaya or mode of action; what they accomplish is the

achievement or therapeutic effect. (Charaka Smhita)

Chkrapani Dutta further explains that some drugs act by virtue of

their own nature; e.g. Danti (Baliospermum montanum Muell-Arg.) is

purgative and precious stones are antitoxic. Some other drugs act by virtue

of their qualities; e.g. fever is cured by drugs having bitter taste and coldness

by the heat of the fire. Some other drugs act by virtue of their own nature as

well as their qualities; e.g. cow milk boiled with a gold ring is considered to

be aphrodisiac Rcf. Chikitsa2:3:11, by virtue of the very nature of gold as

well as its circularity.

When errhines are administered they eliminate Doshas from the head

that is their action. The factor like heat which is responsible for this action

is Virya (potency) relating either to the drug or its quality. The site where

the elimination takes place i.e.is the Adhikarana (location); errhines do not

act when administered elsewhere. The spring season or the time when the


38

head is heavy is the appropriate time or Kala for the administration of this

therapy. This therapy is not effective in other seasons or occasions. This

therapy is to be administered in accordance with the prescribed procedure.

Pradhamana and Avapidana are to be administered while the patient lies on a

bed covered with a bed sheet; his head is projected out of the bed and his

eyes are closed. This is Upaya or mode of administration. By the

administration of this therapy, heaviness and pain etc., of the head are cured.

This is Phala or the object of treatment.

The modern investigations on the action of drugs are carried out by

observing the effects when these are -

1. Administrated to living animals healthy or diseased.

2. Applied on the isolated organs or other tissues of certain animals &

also on various infecting organisms.

3. Investigated through radio-activate isotopes and by electron

microscope.

4. Also administered to a human being in healthy and in diseased states

for therapeutic purpose.

While explaining the drug action two points deserve attention (1) where a

drug acts and (2) How a drug acts?

Where a drug acts

A drug may act locally, exactly on the tissues it comes in intimate

contact with, either on the superficial epithelia of the skin, mouth, upper

respiratory tract or other parts of the body where the drug can have direct

access (also called direct or topical actions). A drug may act on certain

particular tissues or organs having selective affinity by the absorption into

the circulation. This is known as specific selective or systematic action of


39

the drug.

Recent conceptions of drug action

Whatever may be the mode of administration of a drug and its

distribution in the body, it acts only when it reaches certain specific tissue

cell either its surface or its interior. This is known as receptor theory.

Highly potent drugs probably act on the tissue through certain receptors

which are speculated to be localized on the surface of the cells or are parts of

an enzyme system. These fitting like keys in the locks. Cell theory was

described by Charak as Sharira Avayavasthu Paramanu Bhedana

Aprisanakyaya Bhavanti. The action is achieved depending upon

localization of receptors and the concentration of drug to which the receptor

is exposed. If a drug acts by interaction with relatively non-specialized

receptor, that is a receptor that serves functions common to most cells, its

effects will be wide spread (Doshapratyanika action). If a drug interacts with

specialized receptors its effects are more specific (Vyadhipratyanika action).

Sometimes same drug may exercise different actions in the body by

interaction with different Adhikaranas.

Enzymes

The enzymes play an important part in the body activity and many

drugs probably act through the enzymes. These are known as pitta

modalities which take part in the drug metabolism.

How a drug acts

Some of the drugs act purely by physical means. Oils applied

externally to skin (Abhyanga) and internally (Ghritapan )act in this manner.


40

Drug may act chemically by its chemical affinity it fixes up to certain tissues,

or produces a new active substances at the nerve ends where it acts or it

combines with some other substance in the blood or tissue and acts.

Special action

A drug may have well marked selective action on a particular part of

the body even in minute doses. Most of the alkaloids act in this way. A drug

may either increase (Vriddhi) or diminish the altered physiological functions

of a particular type of tissue in disease and the result is either stimulation or

depression of its function.

Rasas have mostly local and some general effects till the digestion is

completed. The Rasa, in the final form circulates through Rasa Dhatu all

over the body and influences the doshas and metabolic processes. When it

comes in contact with Doshas it increases or decreases them according to

similar or dissimilar properties. Rasa, Guna and sometimes Virya have local

action, while Vipaka and Virya have systematic action and Prabhava has got

specific action. External administration (Bahiparimarjanam) of drugs are

mostly directed towards local action while internal administration (Antah

Parimarjam) towards systematic action.

ROLE OF VIRYA IN THE PHARMACOKINETICS OF DRUGS

The term pharmacokinetics is used to describe the study of

absorption. distribution, metabolism and excretion of drugs. Absorption and

bio-availability of drugs play an important role in pharmacokinetics. Bio-

availability of a drug is decided by the rate of appearance and the total

amount of the active drug in the systemic circulation. The changes that a

drug undergoes in the body and its ultimate excretion are considered as the

fate of the drug. Alteration of a drug within a living organism is known as


41

Bio-transformation. Charaka has envisaged the concept about the pharmaco-

kinetics of drugs in the Kalpasthana as follows. The drugs that are Ushna

(hot), Tikshna (acute), Sukshma (subtle),Vyavayi (diffuse and

antispasmodic) reaching the heart by virtue of their potency and circulating

through the large and small blood vessels, pervade the entire body. They

liquefy the accumulated morbid matter therein by virtue of their quality and

break up their acuteness (ch. Kal.l). In this verse the drug absorption,

systematic circulation of the drug throughout the body with certain qualities

and specific actions on Malas was described. This gives generalized picture

about the pharmaco-kinetics of drugs described in Ayurved. Charaka has put

in his observation in Sutrasthana about the excretion of malas with the action

of drugs or certain pre-operative process for Sodhana karma as After a

person has taken the oleation he should be under observation for muhurta

(48minutes). One should recognize the liquefaction of morbid humor by the

appearance of perspiration of the body, the dislodgement of morbid humors

from their seats by horripilation; its reaching the stomach by the distension

of the belly, its separation and upward course by belching and salivation

(ch.sut.15).

Virya is a fundamental principle of drug action which dominates all

the other principles such as Rasa, Guna and Vipakas. The action of drug is

determined mostly by Virya. In view of Charaka, any principle which is

responsible for action is Virya has been grouped in to two as Sita and Ushna

which represent the primordial factors of Soma and Agni initiators of

creation of living world. Virya has been classified into two and eight types.

Eight Gunas out of twenty have deemed to be potent enough and they were

conferred by the Virya status. They are Laghu, Guru, Sita, Ushna, Snigdh,

Ruksha, Mrudu, and Tikshna. These eight viryas play an important role in


42

the pharmacokinetics of every drug. Snigdha and Ruksha Viryas invariably

influence the digestion of drugs in the gastrointestinal tract. The out come

after these chemical reaction by snigdha and Ruksha Virya is absorbed and

conveyed into the systematic circulation with the influence of Sita and Ushna

Viryas and pervaded to all the cells. Drug acts either on the cell wall or

intracellular substance and exercises its final action by Guru and Laghu

Viryas. End product of entire reactions in excreted through Malas which are

conveyed to certain excretory organs by Shita and Ushna Viryas. In fact all

the 8 Viryas can be incorporated into two groups only.

Shita Group Snigdha, Guru, Mrudu.

Ushna Group Ruksha, Laghu, Tikshna.

Any ingested drug is subjected to Jatharagnipaka, Bhutagnipaka and

Dhatwagnipaka. The so called Paka Kriya is Agneya Pradhana. So Ushna

Virya plays a main role in the drug metabolism, while Shita Virya also

having equal, opposite and most important role in pharmacokinetics.

One can admit without hesitation that Virya occupies an important

place in explaining the pharmacokinetics of Ayurvedic drugs. But most

scientific approach is imperative for the comprehension of the exact role of

Virya.


43

GUNA

The Gunas are of three types (i) those constituting the distinctive

features of the five elements, (ii) those common to five elements and (iii)

those relating to the soul.

The Gunas of the first category are sound (Sabda), touch (Sparsa),

vision (Rupa), taste (Rasa) and smell (Gandha) constituting the distinctive

features of Akasa, Vayu, Agni, Ap, and Prithvi respectively.

Those of the second category are heaviness (Guru), lightness

(Laghu), coldness (Sita), heat (Ushna), unctuousness (Snigdha), roughness

(Ruksa), dullness (Manda), sharpness (Tikshna), immobility (Sthira),

mobility (Sara), softness (Mridu), hardness (Kathina), non-slimness

(Visada), sliminess (Picchila), smoothness (Slaksana) and liquidity (Drava).

The Gunas of the third category are intellect (Budhi) including

memory (Smriti), consciousness (Chetana), patience (Dhriti) and ego

(Ahamkara) etc., desire (Iccha), hatred (Dvesa), happiness (Sukha), misery

(Duhkha), efforts (Prayatna) predominance (Para), subordination (Apara),

propriety (Yukti), number (Samkhya), combination (Samyoga), division

(Vibhaga), separation (Prithakiva), measurement (Parimana), transformation

(Samskara) and repetition (Abhyasa).

The one which is a substratum of the qualities and actions and which

is a concomitant cause is the matter.

By definition, matter happens to be the substratum of qualities and


44

actions and it is also the concomitant cause of another matter and qualities as

well as actions. The capacity to produce something out of its own rests only

in the matter. Neither the qualities nor action can produce something out of

their own. So the matter and not the qualities or action can constitute

concomitant cause.

Guna possesses inseparable concomitance; it is the cause and devoid

of efforts. Chakrapani interprets that Unlike Karma, Guna is devoid of any

(curative) efforts. Besides, Guna has also inseparable concomitance as

distinct from Akasa, etc. Which though devoid of efforts do not have

inseparable concomitance as their substrata. Similarly, Karman is quite

distinct from gross matter which forms the substratum for action. Unlike

generic concomitance (Samanya), variant factor (Visesa) and inseparable

concomitance (Samanya), which do not constitute causes, Guna represents a

causative factor as well. However, to say that the Guna is the cause is only

partially correct.

KARMA (ACTION) Karma (action) present in the matter is the cause of combination and

separation. Karma is the action relating to something to be achieved. It does

not require any other factor for its action.

Action is simultaneously the cause of combination and separation.

While combination does not cause separation and Vice Versa, the action

present in the matter causes both combination as well as separation.

Karman does not require any other subsequent help in the process of

causing separation from the previous position as well as combination with


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the subsequent position. Although matter is simultaneously a factor for

causing combination and separation, still it is so only when it possesses

Karma. Karman, on the other hand, does cause combination and separation

as soon as it is produced without requiring any other subsequent help except

the proximity to the substratum of the combination and separation.

By definition, Karma here implies only the action relating to

something to be achieved (like the action of drugs, etc.) and not something

like Vamanakarma (emetic therapy) or Adristakarma (invisible past action).

Charaka categories dravyas into three groups i.e. Doshaprasamaka

(alleviate doshas), Dhatu pradushana (vitiate dhatus) and Swasthahita

(maintenance of positive health). In this classification Doshas include

Dhatus and vice-versa. So the drugs that are designated as alleviators of the

doshas also alleviate dhatus. Similarly the drugs that are designated as

vitiators of the dhatus do as well vitiated doshas. The drugs under third

category are those which have potentialities to prevent the diseases. These

drugs are useful for maintenance of the equilibrium of the tissue elements so

that they are neither aggravated nor decreased and help in the normal

functioning of the body.

Charaka has furnished the following pharmacological actions with

certain examples.

1. Jeevaniya Varga (Invigorators) 2. Brimhaneeya Varga (Nourishing drugs) 3. Lekhaniya Varga (Reducing corpulency) 4. Bhedhaneeya Varga (Cathertics)


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5. Sandhaneeya Varga (Healers of wound) 6. Deepaniya Varga (Digestive stimulants) 7. Balya Varga (Strength Promoters) 8. Varnya (Complexion Promoters) 9. Kantya Varga (Useful for throat) 10. Hrudya Varga (Cardiac tonics) 11. Tripthighna Varga (Removes the sense of Pseudo contentment) 12. Arshoghna Varga (Anti-haemorroidals) 13. Kushtaghna Varga (Curatives of all skin diseases): 14. Kandooghna Varga (Anti pruritics) 15. Krimighna Varga (Anti- infectives) 16. Vishaghna Varga (Anti-toxics) 17. Sthanyajanana Varga (Galactogogues) 18. Sthanya shodhana Varga (Galacto-purificators) 19. Shukrajanana Varga (Spermatopoitics) 20. Shukra shodhana Varga (Spermato purificators) 21. Snehopaga Varga (Adjuvents of unction) 22. Swedhopaga Varga (Adjuvents of fomentation) 23. Vamanopaga Varga (Adjuvents of emesis) 24. Virechanopaga Varga (Adjuvents of purgation) 25. Asthapanopaga Varga (Adjuvents of decoction enema) 26. Anuvasanopaga Varga (Adjuvents of oil enema) 27. Sirovirechaneeya Varga (Adjuvents of for elimination of Doshas

from the head)

28. Chardinigrahana Varga (Anti emetics) 29. Thrusna Nigrahana (Thirst restraining drugs) 30. Hikkanigrahana Varga (Anti- Hiccup) 31. Pureeshasangrahaneeya Varga (Anti Diarrhoeal)


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32. Pureeshavirajaneeya Varga (Bowel Anti- discoloringagents) 33. Moothra Sangrahaneeya Varga (Anti diuretics) 34. Moothravivarjaneeya Varga (Urinary anti- discoloring agents): 35. Moothravirechaneeya Varga (Diuretics) 36. Kasahara Varga (Antitussives) 37. Swaasahara Varga (Broncho dilators) 38. Swayathuhara Varga (Anti inflammatory / curatives of oedema) 39. Jwarahara Varga (Anti pyretics) 40. Sramahara Varga (Fatigue relievers) 41. Dahaprashamana Varga (Curatives of Burning syndrome) 42. Sheethaprashamana Varga (Curatives of cold) 43. Udardaprashamana Varga (Curatives of urticaria) . 44. Shoolaprashamana Varga (Antispasmodics) 45. Angamardhaprasamana Varga (Bodyache relievers) 46. Sonithastapana Varga (Blood purifiers) 47. Vedanasthapa Varga (Analgesics) 48. Sangnasthapana Varga (Restoratives of conciousness) 49. Prajasthapana Varga (Anti-abortificiants or procreators) 50. Vayahasthapana Varga (Rejuvenators)

Chakrapani has rendered the following interpretation for certain

karmas (pharmacological actions) delineated by Charaka.

1. Jivaniya Drugs conducive to longevity (Ayushyam) are known as

Jivaniya.

2. Triptighna Kapha, when vitiated gives rise to a sense of pseudo-

contentment which tells upon normal health. Drugs, which remove

that sort of pseudo-contentment are known as Triptighnas.


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3. Snehopaga The drugs that help the process of unction achieved by

fats etc., are known as Snehopagas. Such drugs are known as

Vamanopagas as they help madanaphala etc. for emesis viz., honey,

yashtimadhu etc.

4. Purisha Virajakeeya such drugs as eliminate the vitiated doshas

from faeces are known as purisha virajaneeya.

5. Mutra Virechaniya Drugs which increase diuresis are known as

Mutra Virechaniyas.

6. Udardaprasamana Udarda in this context is to be taken as Sitapitta

(Urticaria) but not the disease described in Maharogadhyaya (Sut.20).

Otherwise the prescription of Tinduka etc. for the relief of udarda

cannot be justified because these drugs are not useful for vata.

7. Sonitasthapana Drug which restores blood in its pure form after

eliminating its eliminating its vitiating doshas.

8. Vadanasthapana In the event of physical pain, the class of drugs

which eliminates that pain and restores the body to its normal state is

known as Vedanasthapana.

9. Samjnasthapana It is the category of drugs that restores

consciousness.

10. Prajasthapana The drug which eliminate procreational defects and

thus restores embryo are known as prajasthapana.

11. Vayasthapana The drugs useful for restoration of youth are known

as vayasthapana.

Sarangadhara has enumerated the following pharmacological actions;

1. Deepana (Appetisers)

2. Pachana ( Digestives)

3. Sodhana (Expungents)


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4. Samana (Palliatives)

5. Anulomana (Aperients)

6. Sramsana (Laxatives)

7. Bhedana (Purgatives)

8. Rechana (Cathartics)

9. Vamana (Emetics)

10. Chedana (Sacrificants)

11. Lekhana (Anti-obese)

12. Grahi (Water absorbants and bowel binders)

13. Sthambhana (Constipative and bowel binder)

14. Rasayana (Rejuvenator)

15. Vajeekarana (Aphrodisiac)

16. Sukrala (Spermagogue)

17. Sukra pravartaka (Semen ejaculator)

18. Sukra Sthambhaka (Semen anti-ejaculator)

19. Sukra Soshaka (Semen dehydrant)

20. Sukshma (Subtle Penetrator)

21. Vyavayi (

22. Vikasi (

23. Madaqkari (Intoxicants)

24. Pramathi (

25. Abhishyandi (Obstructants)

Susruta has introduced certain pharmacological actions of the

drugs indicated in various surgical procedures Viz; Romasnjanana

(Hair growth promoters), Romasatana (Depilators), Savarnikarana

(Inducer of pigmentation), Vranaropana (Wound healers) etc.


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Ayurvedic pharmacological science identified certain novel pharmacological

actions viz.

Sukrasodhana (Semen purifiers)

Sthanyasodhana (Breast milk purifiers)

Sonitasthapana (Blood purifiers)

Medhyarasayana (Brain tonics / Memory boosters)

Vajeekarana (Aphrodisiacs)

Rasayana (Rejuvenators)

Chakshusya (Eye tonics)

Kesya (Hair tonics)

Dantya (Tooth and Gum tonics)

The scientists of modern pharmacology may take another century to

develop the drugs possessing the actions enumerated above. If the blood

culture report shows the growth of infective organism and the semen analysis

indicates the presence of pus cells one has to accept that blood and semen are

not pure and requires drugs which can restore normalcy of these tissues /

liquid substances. Modern medical scientists have initially not accepted the

claims of Ayurvedic aphrodiacs. After the invention of Viagra they are

constrained to accept the pharmacological actions described in the Ayurvedic

medical science.


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RASA (TASTE)

Rasa or taste is the object of gustatory sense organ, and

distinct from the objects of the other sense organs. Rasas in a substance and

formed by different combinations of Mahabhutas. There are only six types of

tastes viz., Madhura (sweet), Amla (sour), Lavana (saline), Katu (pungent),

Tikta (bitter) and Kashaya (astringent). The source material for the

manifestation of all these tastes is Jalamahabhuta. The qualities of preceding

basic elements (Akasa, Vayu, Agni, Ap and Prithvi) are included in the

succeeding ones; so the qualities of Ap is automatically included in Prithvi.

Ap and Prithvi are the substrata for the manifestation of taste (Rasa). That is

to say, taste (Rasa) can manifest itself only through Ap and Prithvi.

Rasa-Anurasa (Primary and secondary tastes)

Among tastes present in a substance that which is clearly manifests

(perceived, recognised) is designated as Rasa (chief/primary taste) and others

which are not clearly manifest or which are understood (recognised) at the

end are Anurasa (secondary tastes).

Vagbhata further quotes about the gustatory effect of the initial as

well as final contact of a dry as well as wet substance with the tongue are

known as Rasa or taste. When such an effect is not distinctly perceptible but

is inferred only by its actions, it is known as Anurasa (after taste).

Formation of six Rasas:

The moon is the presiding diety of water. The water in the

atmosphere (before it falls on the ground) is by nature cold and light, and its

Rasa is not manifested at this stage. The moment it starts falling from


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atmosphere and after it falls on the ground, it gets impregnated with the

qualities of the five Mahabhutas and it nourishes the individuals belonging to

the vegetable and animals kingdom. At this stage the six tastes manifest

themselves in these individuals.

Of the six tastes, sweet taste abounds in the qualities of Jala

Mahabhuta, sour taste of Prithvi and Agni, saline taste of Jala and Agni,

pungent taste of Agni and Vayu, bitter taste of Vayu and Akasa and

astringent taste of Vayu and Prithvi. So like the individuals belonging to the

vegetable and animal kingdom of diverse types, depending upon their colour

and shape (owing to the predominance or otherwise of the various

Mahabhutas), the Rasas are also six in number due to the predominance or

otherwise of the five Mahabhutas in turn depends on the six seasonal

variations.

As a mater of fact, all the five Mahabhutas are there in al the six

Rasas but the manifestation of the various Rasas depends on the

predominance or otherwise of the qualities of one or more of the Mahabhuta,

for example, Jala Mahabhuta is the root cause of all the six Rasas but it

predominates in sweet taste and as such it constitutes a distinctive causative

factor thereof. According to Susruta, saline taste is dominated by the

qualities of Prithvi and Agni. This apparently goes against the observation

made above. But as a matter of fact there is no contradiction so far as the

manifestation of saline taste is concerned. One might ask: if the saline taste is

caused by the predominance of Agni and Jala which are hot and cold

respectively the resultant substance having saline taste should also have both

hot and cold qualities; but how is it that salt is said to be of hot quality? The

reply is, it is not that the involved in the composition of substance always


53

manifest all of their qualities for example, Jala Mahabhutas brings about

sweetness and not unctuousness in Makusthaka (Phaseolus aconitifillus

Jacq.); similarly even though Agni Mahabhutas predominates in the

composition of rock salt, the latter does not possess heating property. The

combination of the Mahabhutas in a particular way and the diversity of their

manifestation are guided by some imperceptible factors which can only be

inferred from the manifested effect of the substance. For example, salt

posses heating and sticking properties and so it inferred that Agni and Jala

Mahabhutas dominate in its composition. If fact we mortals cannot easily

comprehend such combinations and their effects. They can only be

ascertained from scriptures. To cite another example, we cannot offer any

rational explanation as to how the Mahabhutas in isolation (other than Jala)

do not cause any other Rasa. This proves that there is something inherent in

the five Mahabhutas themselves which is responsible for their combinations

and manifestation of their effects in various ways. The five Mahabutas

constitute the efficient cause for the manifestations of the specific types of

Rasa like sweetness etc. it is therefore immaterial whether all the

Mahabhutas in themselves posses Rasas or not. Agni for example does not

posses any Rasa but it is still an efficient cause for the manifestation of a

Rasa like sourness.

Inter Relationship of Ritu & Panchamahabhuta:

The seasonal variations result in the predominance or otherwise of

the qualities of the five Mahabhutas and bring about the manifestation of the

various Rasas thereby. For example, in Hemanta (November-January) the

qualities of Jala Mahabuta manifest themselves in excess, resulting in the

production of drugs and deits having sweet taste; in Sisira (January-March)

Vayu and Akasa predominate, resulting in the manifestation of bitter tastes.


54

Even day and night and some other imperceptible factors are responsible for

the predominance of the one or the other of the Mahabhutas. Thus it is not

that in the Hemanta (November-January) every drug and diet will always

have sweet taste. There is a possibility of manifestation of other Rasas as

well, depending on the effect of other imperceptible factors. As a matter of

fact the predominance of Mahabhutas is responsible for the seasonal

variations and vice-versa. This inter-dependence may be compared to the

inter-dependence of the seed and the embryo.

Guru (heaviness) and other Gunas (qualities) present in the

Prithvivyadi Dravyas (substances of Prithvi and other Bhuta predominance)

are residing in the Rasas (tastes of those substances); they (Gunas) are

ascribed to (attributed to) the tastes, because of intimate co-existence.

Actions of different Rasas:

Madhura Rasa:

Drugs possessing Madhura Rasa Wholesome to the body Add to the growth of seven body tissues Imparts long life Soothing to the six sense organs Promote strength and complexion Alleviate Pitta, Vata and effects of poison Relieve thirst and burning sensation Promote healthy skin, hair, voice and strength Soothing, invigorating and nourishing Bring about stability and heal up emaciation and consumption Soothing to the nose, mouth, throat, lips, tongue and relieve fits. Much liked by bees and ants. They are cold, unctuous and heavy.

Amla Rasa:


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Drugs possessing Amla Rasa

Add to the deliciousness of food Stimulate appetite Nourish and energize the body Enlighten the mind Strengthen the sense organs Promote strength Alleviate Vata Nourish the heart Cause salivation Help in swallowing, moistening and digestion of food Refreshing They are light, hot and unctuous.

Lavana Rasa:

Drugs possessing Lavana Rasa

Help in carmination, production of stickiness, digestion, osnosia,

excision and incision Sharp, mobile, Vikasi and laxative. Avakasakara (deobstructent) Alleviate Vata Cure stiffness, obstruction and accumulation Nullify the effect of all other tastes Cause salivation Liquefy Kapha Clarify the channels of circulation Bring about the tenderness of all the bodily organs Cause deliciousness and essential ingredients of food They are neither heavy & unctuous nor hot.

Katu Rasa:

Drugs possessing Katu Rasa

Keep the mouth clean Promote digestion Help in absorption of food Cause secretion through nose, lacrimation Help proper action of sense organs


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Cure diseases like Alasaka, Swayadhu, Udarda, Abhishyandi, Kandu, Vrana, Krimi

Allay excessive growth of ulcers Corrode the muscle tissue Break blood clot and other obstructions Clear the passages They are light, hot and ununctuous.

Tikta Rasa:

Drugs possessing Tikta Rasa

Promote deliciousness Antitoxic and germicidal Cure fainting, burning sensation, itching, skin diseases including

leprosy, thirst and fever Promote firmness of skin and muscles Promote carmination and digestion Purify milk Cause dry and help in depletion of moisture, fat, muscle fat, bone

marrow, lymph, pus, sweat, urine, stool, Pitta and Kapha They are ununctuous, cold and light.

Kashaya Rasa:

Drugs possessing Kashaya Rasa

Palliative, constipative and promotive Produce pressure on the affected part Cause healing, absorption and stiffness Alleviate Kapha, Rakta and Pitta Absorb the body fluid They are ununctuous, cold and heavy.

Drugs having sweet, sour and saline taste alleviate Vata; those having

astringent, sweet and bitter (tastes) alleviate Pitta and those having

astringent, pungent and bitter (tastes) alleviate Kapha.


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The relative superiority or inferiority of the tastes of drugs of various categories is as below.

Property Superior Moderate Inferior Unctuousness Sweet Pungent Bitter

Dryness Astringent Sour Saline Heating Saline Sour Pungent Cooling Sweet Astringent Bitter

Heaviness Sweet Astringent Saline Lightness Bitter Pungent Sour

Determination of Virya Vipaka according to Rasa:

The drugs and diets which are sweet in Rasa (taste) and Vipaka (taste

after digestion) are of Sitavirya (that is potentially cold); those with sour or

pungent taste and Vipaka are of Ushnavirya (that is potentially hot).

Only such of the drugs and diets which are sweet in taste as well as

Vipaka are of Sitavirya. One cannot determine Sitavirya (or potential

coldness) of drugs and diets only on the basis of sweet taste. The same

principals is applicable to the drugs and diets of Ushna type as well.

The properties of such of the drugs and diets as possess Virya and

Vipaka in conformity with Rasa are explained here only in terms of Rasas

concerned. Thus the physician may explain the properties of milk, ghee,

Cavya (Piper Chaba Hunter) and Chitraka (Plumbazo Zeylanic Linn.) on the

basis of their tastes.

Drugs and diets having sweet taste and sweet Vipaka are generally of

Sitavirya (potentially cold). Similarly those of sour and pungent taste and

pungent Vipaka are Ushna Virya (potentially hot). In the case of such of the

drugs and diets where Virya and Vipaka are in conformity with Rasa, their

properties are explained in terms of Rasa only. As for example the


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properties of milk and ghee both of which are sweet in taste and Vipaka and

Sitavirya can be ascertained in terms of their taste only. The above principle

does not apply in the cases of such of the drugs and diets wh

basic concepts of ayurvedic pharmacology

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