Understanding Phytocannabinoid Discoveries

Readers benefit from being cognizant of the inherent ambiguity of the term "discovery" and the differences between the identification, isolation, and synthesis of particular molecules.

British cannabinoid chemist Lord Todd

Two families of cannabinoids, both of which bind with the receptors of the ECS (explained in detail below), are produced throughout nature. Endocannabinoids are those that are synthesized by the human/mammalian/vertebrate body, while phytocannabinoids originate in the cannabis/hemp/marijuana plant. It should be noted that all phytocannabinoids are exclusive to the hemp plant. In other words, no other plant species in existence produces them

Interestingly, phytocannabinoids were discovered nearly a century prior to endocannabinoids. In 1896, a group of British chemists first identified cannabinol, or CBN, by isolating the molecule. This cannabinoid results from both a dedicated acidic precursor (CBNA) and also the lifecycle degradation of the most infamous phytocannabinoid in modern day, tetrahydrocannabinol, or THC.

While THC is categorized as "strongly psychoactive," CBN is only mildly so. However, because CBN is normally found in only trace amounts in samples of hemp, consumers rarely experience overt psychoactivity from this molecule. When they do, it is often mixed with the psychoactivity resulting from its cousin delta-9 THC, further confusing the issue for patients, consumers, and wellness professionals.

In 1932, several decades following its discovery, the molecular structure of CBN was partially determined by a group of British researchers. In 1940, two separate teams of chemists—one in the United States (Roger Adams) and another in the United Kingdom (Lord Todd)—synthesized CBN. In the same year, Adams first isolated CBD. The acclaimed scientist was even granted a U.S. patent in 1942 for his proprietary method of extracting CBD from hemp oil.

U.S. cannabinoid chemist Roger Adams

It was also Adams who first identified tetrahydrocannabinol, or THC in 1940, while theorizing that it was the chemical responsible for the psychoactivity of cannabis (referred to almost exclusively as "marijuana" during the period). Decades ahead of his time, the celebrated chemist published 27 studies regarding cannabis in the American Journal of Chemistry. However, Adams was never able to isolate the controversial euphoria-causing phytocannabinoid.

Another group of American scientists composed of H. J. Wollner, John Matchett, Joseph Levine, and S. Loewe conducted research based on work published by Adams in 1940. The team produced a study paper in 1942 entitled "Isolation of a Physiologically Active Tetrahydrocannabinol from Cannabis Sativa Resin" that was published in the Journal of the American Chemical Society. The study documented the first successful isolation of THC by the researchers and served as a pivotal milestone for the coming dearth of cannabinoid research that would endure for more than two decades.

Israeli cannabinoid researcher Dr. Raphael Mechoulam

In 1963 through 1965, a group of Israeli scientists led by Raphael Mechoulam isolated and synthesized CBD and THC, renewing international academic interest in the compounds produced by the hemp plant. The pioneering work of Mechoulam and his team led to the discoveries of more than 100 phytocannabinoids, a scientific exploration that continues to this day.

In December 2019, a team of Italian researchers discovered two new phytocannabinoids: Cannabidiphorol (CBDP) and tetrahydrocannabiphorol (THCP). More significantly, the researchers also uncovered an entirely novel category of phytocannabinoid called phorols.