medically important plants presented by: ms liziwe mugivhisa
TRANSCRIPT
Medically Important Plants
PRESENTED BY:Ms Liziwe Mugivhisa
Main objective
Plant derived substances of
medical & veterinary
significanceRelationship between botany & medicine
Strategies for
collecting medicinal
plants
Remedial drugs of plant
origin
Drugs with origin in
indigenous ethno-
pharmacology
Secondary plant
metabolites
Psychoactive drugs of plant origin
Poisonous plants
Objectives
• Methods for collecting plants with medicinal
value
• Plant parts used for medicinal purposes
• Methods of preparation & administration
• Secondary plant metabolites
IntroductionImportance of Medicinal plants
•Medicinal plants & plant-derived medicines widely used in
traditional cultures
•120 drugs extracted from plants
•Examples of plant-derived medicines
– Quinine (tree called Cinchona), morphine & codeine
(poppy), colchicines (Colchicum autumnale), atropine
(Belladonna or Deadly Nightshade), reserpine (Rauwolfia
Vomitoria), & digoxin (Digitalis spp)
– new anticancer drugs
•taxol [Pacific yew tree (Taxus brevifolia)]
•vincristine (periwinkle)
AFRICAN TRADITIONAL MEDICINE
• oldest & most diverse of all medicine systems
• wide range of plants therapeutically used by indigenous
peoples to maintain health
• The Khoi-Sans have a:
– material medica (with about 86 plant species)
typically for medicinal use including:
• general tonics, fever remedies, Sedatives,
Stomachics, Diuretics, laxatives, numerous wound
healing plants
AFRICAN TRADITIONAL MEDICINE
Well known S.A medicinal plants
–Agathosma betulina (buchu)
–Aloe ferox (Cape aloe)
–Artemisia afra (African wormwood)
–Aspalathus linearis (rooibos tea)
–Harpagophytum procumbens (devil’s
claw)
–Hypoxis hemerocallidea (African potato)
Agathosma betulina (buchu)
–Evergreen flowering plant–In Western parts of S.A–Uses:• Flavouring agent
in teas, candy, liquor
• Herbal remedy
AFRICAN TRADITIONAL MEDICINEmedicinal plants
Aloe ferox (Cape aloe)
–Indigenous to S.A
–Uses:• Bitter aloes– Purgative
medication• Non-bitter aloes– Gel in cosmetics
AFRICAN TRADITIONAL MEDICINEmedicinal plants
Artemisia afra (African wormwood)
–Found as far as in Ethopia
–Uses:
• Roots, stems & leaves
– Used as enemas, lotions,
inhalations (smoked /
snuffed) or as essential
oils
– Used as moth repellent &
organic insecticidal spray
AFRICAN TRADITIONAL MEDICINEmedicinal plants
Aspalathus linearis (rooibos tea)
–Endemic to western coast of Western Cape–Uses:
• Herbal tea• levels of antioxidants• caffein & tannin• Assists with nervous
tension, allergies, digestive problems
• Alleviates colic, asthmas, dermatological problems
• Cancer fighting qualities
AFRICAN TRADITIONAL MEDICINEmedicinal plants
Harpagophytum procumbens (devil’s claw)
–Found in Namibia–Uses:• To reduce pain &
fever• Anti-inflammatory• Stimulates
digestion• Treatment of
arthritis
AFRICAN TRADITIONAL MEDICINEmedicinal plants
Hypoxis
hemerocallidea
(African potato)
•Miracle muti / wonder
potato
•Most traded
•Believed to cure HIV
AFRICAN TRADITIONAL MEDICINEmedicinal plants
BOTANY & MEDICINE• Relationship between botany & medicine
– Carl Linnaeus
• Father of modern botany
• Had a medical degree
• Used knowledge in study of plants in
practice of medicine
– Asa Gray
• Founder of the Harvard’s Gray Herbarium
• Studied medicine
ETHNOBOTANY IN DRUG DEVELOPMENT
Ethnobotany•Inter-relationship between plants & medicine
– Study of how plants are utilized by human cultures
– Relates & interacts with Botany, Medicine, Nutrition,
Agriculture & anthropology
•Employs local peoples knowledge about medical uses of plants
& their environment
•Ethnobotanists:
– work as mediators & facillitators
• Preserve indigenous discoveries & make them accessible
& useful
Methods for collecting plants with medicinal value
• Collection & analysis of information on
plants’ uses essential
– For drug development
– Plants used as starting materials
• Ethnobotany
– Use of plants by indigenous cultures
– Provides information to pre-screen for
selection of specific plants for
pharmacological studies
Methods for collecting plants with medicinal value
Random Method
Targeted Plant Families
Selective Harvesting
Ethnobotanical approach
• Complete
collection of
plants in an
area
• Plants
collected &
screened
without
regard of
other intrinsic
qualities
• Targets plant
families
known to be
rich in
biologically
active
compounds
• Close
relatives of
plants known
to produce
useful
compounds
collected &
analysed
• Careful
selection of a
particular
plant for a
particular
patient
• Involves
having a prior
knowledge,
training &
experience
• Employs local
people’s
knowledge
•Drugs with
origins in
indigenous
ethnopharmacol
ogy
• reserpine,
quinine, aspirin,
vincristine
Methods for collecting plants with medicinal value
Random Method
•Complete collection of plants in an area
•Large number of plants collected for screening
depending on:
– season
– no. of fertile plants present
•Plants collected & screened without regard of:
– taxonomic affinities / ethnobotanical context / other
essential qualities
Methods for collecting plants with medicinal value
Targeted Plant Families
•Targets plant families known to be rich in biologically active
compounds
•Phylogenetic survey
– Close relatives of plants known to produce useful
compounds collected & analysed
– Families which are of focus of collection because they are
known to produce biologically active compounds
• Apocynaceae
• Euphorbiaceae
• Minispermaceae
• Solanaceae
Methods for collecting plants with medicinal value
Selective Harvesting
•Careful selection of a particular plant needed for a
particular patient
•Involves having a prior:
– knowledge, training & experience
•Factors considered before collection:
– Particular favoured locality
– Correct season of collection
– Best area on a mountain slope
– Soil type & soil moisture
– Time of the day
Methods for collecting plants with medicinal value
Ethnobotanical approach
•Uses knowledge of local people about plants & their
environment
•Requires:
– collaboration between
• Ethnobotanist, chemists, pharmacologists
– Protection & recognition of local & indigenous
knowledge, practises
– Agreement among parties on
• Responsibilities
• Benefit sharing
• compensation
Plant parts usedPart used Characteristics Example of plant
Roots Fleshy / woodyDestructive (whole plant uprooted)
Thesium hystrix - kleinswartsorm
Bulbs Fleshy underground structure made ofnumerous layers of fleshy scales which are leaf basesDestructive (whole plant removed)
Crinum macowanii – umduze
Rhizomes Woody / fleshy elongated stem grows horizontally below ground & roots into the ground
Siphonochilus aethiopicus - isiphephetho
Tubers Swollen, fleshy structure below groundOf stem origin partly stem & partly root
Hypoxis hemerocallidea – African potato
Bark Outer protective layer of tree trunkFormed by layers of living cells above wood
Warburgia salutaris - shibaha
Leaves, stems & flowers
Leaves & twigs rarely separated when used in medicine
Cannabis sativa - dagga
Gum & nectar
defense mechanism to seal off wound Acacia senegal
Fruit & seeds
Rarely used for medicinal purposes Papaver somniferum & Atropa Belladonna –Deadly night shade
Roots
•Fleshy / woody
•Harvesting destructive
– whole plant often
destroyed
– Eg. Thesium hystrix -
kleinswartsorm
Plant parts used
Roots
Bulbs•Fleshy underground structure
– numerous layers of fleshy
scales which are leaf bases
•Harvesting destructive
– whole plant removed
– Eg. Crinum macowanii – umduze
– Onions & garlic bulbs
•Bulbs contain alkaloids
•Uses:
– Treat Kidney & bladder
infections
– Protective charm
Plant parts used
bulb
Crinum macowanii - umduze
Rhizomes•Woody / fleshy elongated stem
•usually grows horizontally
below ground
•Roots into the ground
– Eg. Siphonochilus
aethiopicus – isiphephetho
– Wild ginger
•Uses:
– Protection against
lightening & snakes
– Chewed to treat asthma
Plant parts used
Rhizomes
Siphonochilus aethiopicus -
isiphephetho
Plant parts used
Tubers •Swollen, fleshy structure below
ground
•Of stem origin
– partly stem & partly root
– Eg. Hypoxis hemerocallidea –
African potato
•Uses:
– May boost immune system
– For diabetes, haemorrhaging
– (nutrient status – 50 thousand
times more than in veggies) Tubers
Hypoxis hemerocallidea – African
potato
Plant parts used
Rhizomes
Bark
•Outer protective layer of tree trunk
•Formed by layers of living cells above
wood
•high conc. of active ingredients
– Eg. Warburgia salutaris –
shibaha –(pepper bark)
– Oak bark, willow bark
•Uses:
– Dried & ground
• Smoked or as expectorant
– Powder – snuff (clear sinuses)
– Powder in water (cure sores on
mouth)Bark
Warburgia salutaris – shibaha
Plant parts used
Leaves, stems & flowers
Leaves,stems & flowers•Leaves & twigs rarely separated
– Eg. Cannabis sativa – dagga
•Uses:
– Through smoking, vapourising,
oral ingestion, in teas
– With psychoactive chemical
compounds
– Recreation, religious & spiritual
moods
– food
Cannabis sativa
Plant parts used
Gum & nectar•Gum from a damaged stem
– defense mechanism
against wood-boring
insects &
– to seal off wound to keep
wood-rotting fungi &
bacteria out
– Eg. Acacia senegal
•Uses:
– Treatment of bleeding,
diarrhea, gonorrhea
– Dried seeds - food Gum & nectar
Acacia senegal
Plant parts used
Fruit & seeds
•Seeds within fruit or on their
own
– Eg. Moringa seeds
– Roasted & pounded
– Antibiotic & anti-inflammatory
•Fruit used dried
– Eg. Prunes – laxatives
– Apricots – treat anemia
– Lemon – epilepsy & colds
– Almonds - headaches
Fruit & seeds
Methods of administration & Preparation
Method of preparation
•Critical
– includes knowing amount of dry plant material to be used
– addition of appropriate volumes of solvents (water/alcohol)
& boiling time
Methods used
Extracts
•prepared by extracting active ingredients with suitable solvents
such as water / alcohol
Methods of administration & Preparation cont.
Infusion
•Macerating (soaking) crude drug in cold or boiling water
•Problem
– there may be fungus / bacterial growth
•Advisable to use within 12 hrs (bottled / refrigerated)
•Eg. tea
Methods of administration & Preparation cont.
Inhalations
•Liquid preparations
– containing part / all volatile ingredients
• to be brought in contact with lining of respiratory tract
by inhaling
• (Eg. Steaming)
Linctuses
•Viscous liquid containing sugar & medicinal substances / syrups
•Possess demulcent (soothing agent)
•expectorant/ sedative properties
•Local action on mucous membrane
•Sipped / swallowed without addition of water
Methods of administration & Preparation cont.
Liniments
•Liquid / semi-liquid preparations intended for external
application
•May contain substances possessing analgesic, soothing /
stimulating properties
•Eg. Balms (rubbed to create friction for sore muscles)
Lotions •Intended for application to skin
•May be aqueous / alcoholic solutions
•For eczema
•Eg. Calamine
Methods of administration & Preparation cont.
Mixtures
•Can be used orally
•Can consist of combinations of medicaments
dissolved, suspended / diffused in water /
aqueous solution
Nasal Drops
•for instillation into nostrils by means of pipette
•consist of liquid preparations
Methods of administration & Preparation cont.
Ointments
•Semi-solid preparations
•dissolved / dispersed in suitable basis of
animal, vegetable, mineral / synthetic origin
•Used as emollients (balms), as protective preparations on skin or as
vehicles for topical applications of medicaments
Tinctures
•Alcoholic liquids containing active ingredients of
vegetable drugs
•prepared by maceration (soaking) / percolation
•obtained by dilution of corresponding liquid extracts
Snuffs
•Preparations of finely powdered, dried medicinal plants
•drawn up into nostrils through inhalation
Common methods of administrationMethod Characteristics
Orally • For infusions, decoctions, syrups & tinctures, powdered herbs
• Followed by mouthful of water
Sublingually(Under the tongue)
• For rapid absorption• No acidic action of stomach, no metabolism by liver
Rectally • By use of syringes / tubes• For drugs made in form of enema• Rapid absorption
Topically • Directly to skin into underlying tissues / to sprains, bruises, burns
• Eg. Specific infusions, decoctions, tinctures, lotions, ointments
Nasally • For dried & powdered snuffs• To induce sneezing• soluble phytochemicals directly into the cerebral circulation
Steaming • Inhalations by steaming in hot water• Herbal steaming to introduce volatile phytochemicals into
lungs or nose
Bathing • Herbal mixtures added to bath to relieve rash / measels
Secondary Plant Metabolites
• Phytochemicals (Chemical & biochemical) adaptations for protection of
plants
• Perform non-vital functions not related to growth & development in plants
• Play a role in defense & survival of plants
• Perform non-vital functions (not related to growth & development)
• Render plants useful:
– in traditional medicine
– As flavouring agents
– For recreational purposes
– Extracted & purified for use in modern medicine
– Eg. Family Brassicaceae
• Plants have mustard oil glycosides
• Only insects tolerant to these can feed on leaves
• Beneficial to the plant & restrict palatability of the plant
Secondary Plant MetabolitesPlant Metabolites
properties structure Examples
Alkaloids • Basic substances
• Nitrogen bound in a ring system
• Most have an effect on the body
• Caffein from tea & bean plants
• Camellia sinensis
• Coffea arabica• Nicotine from
Nicotiana tabacum
Glycosides
• Yield 1 / more sugar & other compounds when hydrolysed
Secondary Plant MetabolitesPlant
Metabolite
s
properties structure
Flavonoids • Polyphenolic
• Contain 15 carbon atoms in 2 benzene
rings joined by linear carbon atoms
• Contribute to yellow colours in plants
• Eg. In rooibos tea
Essential
oils
• Highly concentrated
• Highly volatile & Evaporate in open air
• Complex chemistry
• Consist of hundreds of components
• For treatment of a wide variety of
disorders
• Due to tiny molecular structure
absorbed into the bloodstream