polyketides and classes of other bioactive compounds.16 Some of the microbial metabolites are used as antineoplastic agents,antimicrobial agents and bioinsecticides.17 (Animal sources Microbial sources Natural Product Sources Plant sources (Marine sources Fg.1.2 The marine environment is a rich source of natural bioactive compounds as more than 70%of earth's surface is covered by oceans.18-20 Thus we broadly have four categories of natural product sources. 1.5.1.Natural products from plant sources. Since ages,plants have been an excellent source for the bioactive natural products.Several plant extracts were used as medicines in the treatment of various diseases.Higher plants are extremely popular for the production of variety of biologically active compounds that include,paclitaxel 1,morphine 2 and others.21.22 9 OH HO Paclitaxel(1) morphine (2) Source:Taxus brevifolia Source:Papaver somniferum polyketides and classes of other bioactive compounds.16 Some of the microbial metabolites are used as antineoplastic agents, antimicrobial agents and bioinsecticides.17 Microbial sources Natural Product Sources Marine sources Plant sources Animal sources Fig. 1.2 The marine environment is a rich source of natural bioactive compounds as more than 70% of earth’s surface is covered by oceans.18-20 Thus we broadly have four categories of natural product sources. 1.5.1. Natural products from plant sources: Since ages, plants have been an excellent source for the bioactive natural products. Several plant extracts were used as medicines in the treatment of various diseases. Higher plants are extremely popular for the production of variety of biologically active compounds that include, paclitaxel 1, morphine 2 and others.21,22 O NH OH O O O O O H O O HO O HO OH H Paclitaxel (1) Source: T axus brevif olia HO O H HO H N morphine (2) Source: Papaver somnif erum