Abstract

It is a curious fact that we owe a great deal of our insight into pharmacological treatment of pain to the plant world. Willow bark from Salix spp. led to development of aspirin and eventual elucidation of the analgesic effects of prostaglandins and their role in inflammation. The opium poppy (Papaver somniferum) provided the prototypic narcotic analgesic morphine, the first alkaloid discovered, and stimulated the much later discovery of the endorphin and enkephalin systems. Similarly, the pharmacological properties of cannabis (Cannabis sativa) prompted the isolation of Δ9-tetrahydrocannabinol (THC), the major psychoactive ingredient in cannabis, in 1964. It is this breakthrough that subsequently prompted the more recent discovery of the body’s own cannabis-like system, the endocannabinoid system (ECS), which modulates pain under physiological conditions.