Pharmacognosy is the study of medicinal drugs that are taken from natural sources like plants, microbes, and animals. It includes analysis of their biological, chemical, organic chemistry, and physical properties.
The chemicals which are derived from plants are phytochemicals. Those studying phytochemistry strive to describe the structures of a large number of secondary metabolic compounds found in plants and natural products and the functions of these compounds in human and plant biology, and the biosynthesis of these compounds. Plants synthesize phytochemicals for several reasons, together with to guard themselves against insect attacks and plant diseases.
