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Welcome to the Higher Learning LV Study Summary Series. This series provides summaries of the latest peer-reviewed scientific research studies that are written in plain English for cannabis and hemp industry professionals, including budtenders, managers, and C-suite executives.
An April 2023 study entitled "Leaves of Cannabis Sativa and Their Trichomes Studied by DESI and MALDI Mass Spectrometry Imaging for their Contents of Cannabinoids and Flavonoids" that was published in the journal Phytochemical Analysis explored "the distribution of the different cannabinoids and flavonoids" in the leaves of cannabis plants, particularly the glandular trichomes.
The study explained that cannabis features a long history of use in traditional medicine. According to the United Nations, cannabis "is the most widely used illegal drug worldwide." The scientists reported that awareness is increasing of the "potential pharmacological benefits" of cannabis and hemp. It noted that the global market for legal cannabis and cannabis-derived products is estimated to reach $57 billion USD by 2027.
2023 Cannabis Leaf Study
The 2023 cannabis leaf study analyzed the fan leaves and sugar leaves of cannabis plants. It found the following cannabinoids: CBD, CBDA, CBGA, CBN , CBNA, THC , and THCA.
The following flavonoids were also detected (cannflavins are exclusive to cannabis and not produced by other botanical species): apigenin, Cannaflavin A, Cannaflavin B, Cannaflavin C, isovitexsin, kaempferol, luteolin, orientin, quercetin, vitexin.
Interestingly, the study reported that the major cannabinoid acidic precursors, CBDA and THCA, as well as CBD and THC, are "isomeric pairs, which due to their identical molecular masses, cannot be distinguished by MS [mass spectrometry] without the use of chromatography or other separation techniques."
The study explained that CBDA and THCA are also isometric pairs with cannabichromenic acid (CBCA) and cannabicyclolic acid (CBLA) and that their neutral analogs CBD and THC are isomers of cannabichromene (CBC).
Cannabis trichome glands under magnification
Cannabinoids, Not Flavonoids, Made in Trichomes
The scientists reported that the distribution of cannabinoids and flavonoids on the sugar leaves and fan leaves of cannabis plants "are different" and reported that "there is no indication...that the trichomes are involved in the biosynthesis of flavonoids." The scientists explained that this was anticipated because flavonoids are found primarily in the leaves of cannabis plants, not the flowers.
"The study found zero evidence that flavonoids are produced in the glandular trichomes."
The researchers found that, on marijuana fan leaves, "flavonoids do not accumulate in the same areas as THCA and the other cannabinoids." It noted that it found zero evidence of flavonoids accumulating in the same areas as cannabinoids or that flavonoids are produced in the glandular trichomes.
CBGA & Capitate-stalked Trichomes
The study found a connection between the acidic precursor cannabinoid CBGA (often called the "mother of all cannabinoids") and a particular type of cannabis glandular trichome called capitate-stalked.
"Cannabinoids were not an integral part of the leaf tissue itself, but originated from the trichomes on the surface of the leaf."
The research also found that capitate-stalked trichomes feature plentiful CBDA and THCA, but that these pivotal cannabinoids were also produced by small glandular trichomes. Overall, the study revealed that "cannabinoids were not an integral part of the leaf tissue itself, but originated from the trichomes on the surface of the leaf."
2023 Cannabis Leaf Study Conclusions
The scientists concluded that their data support that cannabis cannabinoids are produced and accumulate in the glandular trichomes on the sugar leaves and fan leaves.
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