Chemical Profiles of Cannabis Samples Show Lack of Diversity
Cannabis users feel that individuals cultivars (often referred to as "strains") possess different characteristics. This informs their decisions as consumers. Some rely on well-known names like Granddaddy Purple or Jack Herer to make a decision. Some focus solely on whether a product is Indica or Sativa dominant. Others try to look to specific terpenes and cannabinoids that appear in far lower concentrations than either tetrahydrocannabinol (THC) or cannabidiol (CBD). Even within Medical Marijuana: A Clinical Handbook, there is a clear assumption that different cultivars of cannabis have different terpene and cannabinoid profiles, and that these disparities can and do affect patients’ subjective experience.
That cannabis can have wildly disparate chemical profiles and subjective effects on users is well known. Hemp and marijuana (cannabis plants defined as containing less than 0.3% THC and 0.3% or more THC on a dry weight basis, respectively) are clear examples of this phenomenon. In the case of different cultivars of THC-rich cannabis, the disparities in subjective effect were thought to be more subtle and largely due to the wide variety of their cannabinoid and terpene content.
However, this variety may be less wide than previously thought.
A recent analysis of 396 different cultivars and 2,662 individual samples of cannabis flower collected in Nevada between January 2016 and June 2017 by the state’s medical marijuana program showed extremely limited variability. When analyzing cannabinoid content, they found that 93% of the samples fell into one of three clusters, and that most contained very high amounts of THC (>22% on average) except for a handful of high-CBD samples. When analyzing terpene content, there were once against three clusters where a single terpene predominated: ß-myrcene (59% of samples), α-terpinene (33% of samples), or limonene (8% of samples).
The authors, Reimann-Philipp and colleagues, proposed two potential reasons for the clustering. One reason may be due to a focus on THC content among growers. “When creating new chemovars, plants were predominantly selected for high-THC content and to a much lesser degree for CBD content, across different terpene backgrounds. All the other cannabinoids seem to have been mostly ignored in the breeding efforts, even though they have known or suspected specific medical values,” the authors wrote.
Another conclusion could be that environmental factors have more of an influence on the chemical profiles of cannabis than previously believed. If this is the case, it would mean that climates and weather patterns impart a specific fingerprint to cannabis grown in specific regions. Such a finding would be revolutionary.
While the question remains open, what is clear is that consumers cannot rely on the name of a cultivar to determine the chemical profile of an individual product if the analysis is true across other states. This is unfortunate, since more variety would allow medical cannabis patients more access to cannabis products with unique profiles that may also possess unique therapeutic profiles.
Cannabis and Cannabinoid Research has more.