Terpenoids are a large and diverse class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene and the isoprene polymers, terpenes. Terpenoids are the most abundant plant secondary metabolites accounting for about 60% of known natural products. Many terpenoids have significant pharmacological activity and are therefore of interest to medicinal chemists.
Terpenoids are used for their fragrant qualities and are an important component of traditional herbal remedies. Terpenoids are responsible for the scent and flavor of eucalyptus, cinnamon, cloves, and ginger, the color of sunflowers, and the color of tomatoes.
Known terpenoids include citral, menthol, camphor, salvinorin A in the plant Salvia divinorum, the cannabinoids found in cannabis, and ginkgolides and bilobalides.