Phytochemicals: Some Basics

The medicinal substances in plants are not miracles–they are molecules. These molecules, like those of synthesized pharmaceuticals, have medicinal properties related to their chemical structures. The molecules in plants, collectively known as phytochemicals, are classified into the general categories of carbohydrates; lipids, including fatty acids, terpenes, and steroids; phenolics; and alkaloids. Carbohydrates are found in all plants and share the basic chemical formula of Cn(H₂O)n. They can be found as simple sugars or as the complex interconnected sugar molecules of polysaccharides, starches, and cellulose. Lipids include the fatty acids, terpenes, and steroids. The fatty acids and related triglycerides are generally more important as nutrients than as substances pharmacologically active in modest concentration. Animals also produce terpenes, and many, such as cholesterol and other steroids, are essential to life. The medically important heart drug digoxin and the ginsenosides from the revered ginseng plant are modified terpenes, i.e., terpene glycosides.