Biochemical Production - Plants are the source of a large variety of biochemicals, which are metabolites of both primary and secondary metabolisms. But secondary metabolites are of much greater interest since they have impressive biological activities like antimicrobial, antibiotic, insecticidal, molluscidal, hormonal properties, and valuable pharmacological and pharmaceutical activities, and many are used as flavours, fragrances, colours, etc.

The term secondary metabolite is ill defined but convenient; it is applied to all those compounds, which are not directly involved in the primary metabolic processes, e.g., photosynthesis, respiration, protein and lipid biosyntheses, etc. Secondary metabolites include a wide variety of compounds, e.g., alkaloids, terpenoids, phenyl propanoids, Etc.