Plants as chemical and pharmaceutical factories

V.P.S. Shekhawat

Plants as a source of Chemicals !

• Role– Color or fragrance – Taste and Color of food– Resistance against pests and diseases

• Production of chemicals– Drugs– Antioxidants– Flavors– Fragrance– Dyes– Insecticides and Pheromones

Some Facts !

• 13000 plants species

• 25% of materia medica is derived from plants

• 100,000 compounds are known today

• 4000 are added every year

• Largest proportion of these compound consists of terpenoids (~30%), followed by alkaloid (~20%)

Secondary metabolites !

• These compounds are not involved in the basic metabolic processes of the living cells, but are involved in the interaction of the living cells, but are involved in the interaction of the producing organism with its environment.

Production of Phytochemicals

• Total chemical synthesis

• Extraction and purification from plant material

• Partial chemical synthesis

Sources

• Wild plant resources

• Cultivation of medicinal plants by conventional farming

Biotechnological Production of Phytochemicals

• Plant Cell Cultures

• Transgenic microorganisms

• Transgenic plants or plant cell cultures

• Isolated enzymes

Plant Cell Cultures and Production of Phytochemicals

Advantages

• Production can be more reliable, simpler and Predictable

• Easy Isolation

• Interfering compounds can be avoided

• To test various enhancement treatments

Strategies to improve productivity

• Screening and selection

• Medium optimization

• Differentiated Cells

• Immobilized cells

• Elicitation

Metabolic Engineering

• Metabolic engineering involves the targeted and purposeful alteration of metabolic pathways found in an organism to achieve better understanding and use of cellular pathways for chemical transformation, energy transduction, and supra-molecular assembly (Lessard,1996).

Metabolic engineering to Improve yields

• The carbon flux towards the desired product – Overcoming rate-limiting steps– Blocking competitive pathways.

• Blocking of catabolism

• Increasing activity of an enzyme

Metabolic engineering require:

• Thorough knowledge of the biosynthetic pathways

• Identify the enzymes involved

• Rate limiting (regulatory) step

• Feedback mechanisms and Compartmentation.