Below is my overview from 2015 of "Taming THC: potential cannabis synergy and phytocannabinoid-terpinoid entourage effects" which was published in the British Journal of Pharmacology by Dr. Ethan Russo. This has proven to be a groundbreaking and highly cited study, spawning new avenues of research and product development. To date, it is still one of the most authoritative papers on the subject and Dr. Ethan Russo has since published more papers on the subject.
Dr. Ethan Russo, is a board-certified neurologist, psychopharmacology researcher, and former Senior Medical Advisor to GW Pharmaceuticals. He served as study physician to GW Pharmaceuticals for three Phase III clinical trials of Sativex (an oral THC spray). He was a clinical neurologist in Missoula, Montana for 20 years in a practice with a strong chronic pain component as well as working in Child and Adult Neurology at the University of Washington in Seattle. He currently serves as Director of Research and Development for the International Cannabis and Cannabinoids Institute (ICCI) He is widely recognized for his pioneering and ongoing work in understanding the Endocannabinoid System (ECS) and terpenes within Cannabis.
THC has been the primary focus of Marijuana research since 1964, when THC was discovered and synthesized by Dr. Raphael Mechoulam. This review explores the terpenoids present in Cannabis. Terpenoids are found all over in nature and are designated as GRAS (Generally Recognized as Safe) by the US Food and Drug Administration. Terpenoids by themselves are quite potent and have been shown to affect behavior in animal and human studies. Terpenes have unique therapeutic effects (demonstrated by aroma-therapy) and may contribute to entourage (enhanced) effects in Cannabis.
Terpenes are produced in the secretory cells inside the glandular trichome. Trichomes are the "frost" or "crystals" on the outside of your cannabis. Terpenoids, not cannabinoids are responsible for the aroma of your marijuana.
Mice exposed to terpenoid odors (terpenes) from ambient air for one hour, "demonstrated profound effects on activity levels, suggesting a direct pharmacological effect on the brain, even at extremely low serum concentrations." Compelling confirmatory evidence in humans was provided in 1995, in a clinical study by Komori et al. Hospitalized, depressed patients were exposed to a citrus fragrance in ambient air. Using the Hamilton Depression Scores system, there was a "successful discontinuation of antidepressant medication in 9 of 12 patients.
Dr. Russo’s study reports that cannabinoid-terpenoid interactions “could produce synergy with respect to treatment of pain, inflammation, depression, anxiety, addiction, epilepsy, cancer, fungal, and bacterial infections.
Synergism may play a role in the widely held (but not experimentally based) view that in some cases whole plant medicines are better drugs than the singular components isolated from them. An example provided in the study was the ability of CBD to reduce side effects of THC. It was shown that "CBD modulates the psychoactivity of THC and reduces its adverse event profile." This is one example of why whole plant medicine is so important and States that pass CBD only laws are misunderstanding the science.
Another connection of note published in this paper was "the ability of monoterpenoids to enhance skin permeability and entry of other drugs which may further enhance antibiotic benefits." This could be of large benefit when using topical applications.
The conclusion of the study can be summarized as : Selective breeding of Marijuana strains in regards to cannabinoid and terpene profiles can offer complimentary pharmacological activities that may strengthen and broaden clinical applications and improve the therapeutic index. Psychopharmalogical and dermatological indications show great promise.
Our conclusion is : There is a whole lot of science out there that supports the wide variety of benefits offered by the whole plant medicine of Cannabis. We also agree that terpene profiles provide distinctly different experiences and benefits as pointe out in this paper.
Link to the paper - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3165946/