Several of the compounds have outlived their usefulness in light of better alternatives, however, and are exhibiting declines in sales. On the other hand, as a consequence of new drug developments, single entities overall are projected to increase their market share of the combined total future dollar sales. BCC estimates that terpenes will contribute the most to the dollar sales of plant-derived drugs. As the taxoids gain as treatment for cancer, the terpene category should increase its share still further in the next several years. Steroids are another key group in the terpene category.
Glycosides are the next most significant category.
Flavonoids, saponins, anthraglycosides and digitalis compounds are among the most important groups within this category. BCC points out that alkaloids are the third most significant category of plant-derived drugs, in terms of sales. Included are the belladonnas, camptothecins, opiates, Rauwolfias, and Vincas, among others. All other plant-derived drugs include miscellaneous substances and plant drugs for which the active principles have not been well characterized. Among the important groups within this category are plant-derived vitamins, psoralens, ephedrines, salicylates and various others.