Cannabinoids and Terpenes

Marijuana plants contain glandular hairs, also called trichomes, which are particularly concentrated around the female inflorescence (flowers). These trichomes excrete a sticky resin that accumulates in little droplets at the tip of each hair (Potter, 2014). The resin contains the compounds that are considered pharmacologically most valuable, particularly cannabinoids and terpenes.

Cannabinoids are considered to be the main biologically active constituents of the Marijuana plant, and they are found, with few exceptions nowhere else in nature. The naturally occurring cannabinoids form a complex group of closely related terpeno-phenolic compounds of which currently about 100 are known. The most well-known cannabinoids are delta-9-tetrahydrocannabinol (THC or Δ9-THC) and cannabidiol (CBD). THC is the pharmacologically and toxicologically most relevant constituent of the Marijuana plant, producing a myriad of effects in animals and humans. Through activation of the CB1 receptor, higher doses of THC may cause a feeling of intoxication known as being ‘high’. Additional cannabinoids are also making their appearance in new products, despite the fact almost nothing is known about the pharmacology and toxicology of these compounds.
Terpenes are volatile compounds that commonly occur in many plant species and these molecules have been of great interest to various industries (food, perfume, cosmetics, aromatherapy) mainly due to their pleasant odors. To date more than 120 different terpenes have been identified in Marijuana, mainly of the mono- and sesquiterpene type. Most notably, terpenes are responsible for the distinct smell of specific Marijuana varieties. However, these compounds also display a wide range of biological activities and hence may play a role in some of the pharmacological effects of various Marijuana preparations. Some of the terpenes may work in tandem with the cannabinoids to enhance or modify the biological activities of these compounds in a synergistic manner, such as including enhancement of cannabinoid uptake in the intestines, lungs or skin and influencing receptor binding or metabolism. Individual terpenes have also been shown to produce their own pharmacological effects.

An obvious question is whether the wide range of Marijuana varieties reflect an actual difference in medicinal properties. And if so, what cannabinoids and/or terpenes are responsible for the major differences in claimed therapeutic effects between varieties. With a better understanding of Marijuana constituents, it may be possible to move away from the current system of Marijuana classification, dominated by sativa/indica and hemp/marijuana labeling, toward a more comprehensive classification based on a well-defined and reproducible chemical profile or phenotype.