These gentlemen pictured below may not have invented cannabis, but their work let to the discovery of THC & CBD: the active components in the cannabis plant. The discovery of these chemicals allows for modern day scientists to complete extensive potency testing, which is both required by law and helpful for the end consumer.
A brief history: The discovery of THC and CBD
Raphael Mechoulam, known as the 'father of marijuana', was the first to isolate THC, the main psychoactive ingredient of the plant in the 1960s. He also managed to synthesize both THC and cannabidiol (CBD) and prove their effectiveness for the treatment of different diseases.
In the 1960's, together with his colleague Yechiel Gaoni, Mechoulam began to investigate the composition and active ingredients of the 'Cannabis Sativa' plant. "Although painkillers had been isolated from controlled substances within the early nineteenth century and cocaine from coca leaves within the middle of it, the chemistry of cannabis wasn't familiar," said Mechoulaim.
Marijuana had been in use for many years for therapeutic and recreational functions, but no one had dedicated time and resources to review its chemical properties. Mechoulam and Gaoni's investigations shortly bore fruit: they recognized a dozen compounds, but noted that only 2 of them modified the behavior of the primates used in their testing. These two were CBD and THC.
So, for the first time, Mechoulam and his team discovered, isolated and synthesized mind-altering drug (THC) and cannabidiol (CBD).
Present day: Cannabis potency testing methods
Because of Mechoulam & Gaoni and their discoveries, both scientists and growers are able to analyze, test, and classify different strains of cannabis based on their THC & CBD characteristics.
The testing of THC and CBD today is done via two different methods: High-performance liquid chromatography (HPLC) & Gas Chromatography (GC).
GC is more cost-effective and relatively simpler than HPLC. But, GC requires the additional step of sample derivatization to provide both the free and acid forms of THC and CBD. Derivatization is a technique used in chemistry which converts a chemical compound into a product of a similar chemical structure.
In order for GC testing to work, the cannabis extract must be heated so it can be converted into its gas form. The heat causes the acid forms (THCa and CBDa) to convert to the free forms (THC and CBD). Without taking the additional step of derivatization, GC would only allow for the testing of the free forms of THC and CBD, but not their acid forms. And this would result in a narrower scope of testing possibilities.
In contrast, HPLC can separately quantify THC, THCa, CBD, and CBDa without derivatization, which is particularly useful for edible cannabis products because they will typically be consumed without additional heating. For edibles, GC might provide erroneously high potency values because the technique itself converts THCa into THC, and CBDa into CBD.
HPLC, formerly referred to as high-pressure liquid chromatography, is a technique in analytical chemistry used to separate, identify, and quantify each component in a mixture. It relies on pumps to pass a pressurized liquid solvent containing the sample mixture through a column filled with a solid adsorbent material. Each component in the sample interacts slightly differently with the adsorbent material, causing different flow rates for the different components and leading to the separation of the components as they flow out of the column.
Derivatization methods are highly subject to error and difficult to validate, so many labs are choosing to invest in Liquid Chromatography (LC) equipment. In a recent lab proficiency testing program, a survey of preferred potency testing methods found that 90% of the labs use LC. However, GC without derivatization can provide a "quick and dirty" estimate of cannabinoid potency (THC + THCa, CBD + CBDa), which may be helpful for process monitoring.
To learn more about cannabis potency testing, check out the following articles:
The end result: Safe and informed cannabis consumption
All this to say, that modern day testing of THC and CBD is possible thanks to two scientists in the 1960’s who began the research on the “Cannabis Sativa” plant. Their discoveries and contributions opened the door for testing of cannabis products. This allows for end consumers to make informed decisions to safely consume a variety of cannabis products. We tip our hats to Raphael Mechoulam & Yechiel Gaoni.
If you want to read more of Gaoni's and Mechoulam's work, check out the 1964 publication of their findings- Isolation, Structure, and Partial Synthesis of an Active Constituent of Hashish.