The compounds found in plants are of many kinds, but most can be grouped into four major biosynthetic classes: alkaloids, phenylpropanoids, polyketides, and terpenoids.
The major classes of pharmacologically active phytochemicals are described below, with examples of medicinal plants that contain them.
[2][3] Many phytochemicals, including curcumin, epigallocatechin gallate, genistein, and resveratrol are pan-assay interference compounds and are not useful in drug discovery.
Medicines of different classes include atropine, scopolamine, and hyoscyamine (all from nightshade),[6] the traditional medicine berberine (from plants such as Berberis and Mahonia), caffeine (Coffea), cocaine (Coca), ephedrine (Ephedra), morphine (opium poppy), nicotine (tobacco), reserpine (Rauvolfia serpentina), quinidine and quinine (Cinchona), vincamine (Vinca minor), and vincristine (Catharanthus roseus).
[13] Polyphenols are secondary metabolites produced by almost every part of plants, including fruits, flowers, leaves and bark.