Pharmacognosy, Medicinal Plants and Natural Products

Phytochemistry

Phytochemistry is the study of phytochemicals, which are chemicals derived from plants. Plants synthesize phytochemicals for many reasons, including protecting themselves against insect attacks and plant diseases. Phytochemicals in food plants are often active in human biology, and in many cases have health benefits. The compounds found in plants are of many kinds, but most are in four major biochemical classes, the alkaloids, glycosides, polyphenols, and terpenes.

Many plants produce chemical compounds for defense against herbivores. These are often useful as drugs, and the content and known pharmacological activity of these substances in medicinal plants is the scientific basis for their use. Secondary metabolites and pigments can have therapeutic actions in humans and can be refined to produce drugs—examples are inulin from the roots of dahlias, quinine from the cinchona, THC and CBD from the flowers of cannabis, morphine and codeine from the poppy, and digoxin from the foxglove. Human settlements are often surrounded by weeds useful as medicines, such as nettle, dandelion and chickweed.

Many phytochemicals, including curcumin, epigallocatechin gallate, genistein and resveratrol are pan-assay interference compounds and are not useful in drug discovery.

To meet the increasing demand for raw material, to conserve wild resources, and to reduce the potential variability in the active ingredient content in medicinal plants from different collection areas, it is important to implement more controlled cultivation programs to ensure quality and to protect resources. The global market for botanical and plant-derived drugs was valued at $23.2 billion in 2013 and $24.4 billion in 2014. This total market is expected to reach $25.6 billion in 2015 and nearly $35.4 billion in 2020, with a compound annual growth rate (CAGR) of 6.6% from 2015 to 2020.