Phytocannabinoid

Phytocannabinoids are plant-derived cannabinoids, the vast majority described from Cannabis sativa but with structurally similar compounds reported in Rhododendron, Helichrysum, and some liverworts (Radula spp., which produce perrottetinene). They are synthesized in glandular trichomes as prenylated polyketides and exist in the living plant predominantly as carboxylic acid precursors (THCA, CBDA, CBGA, CBCA) that decarboxylate to their neutral forms on heating, ageing, or UV exposure. More than 150 phytocannabinoids have been cataloged (ElSohly & Slade, 2005, Life Sciences 78:539; Hanuš et al., 2016). Pharmacology varies widely: Δ⁹-THC is a CB1 partial agonist, CBD is a multitarget non-intoxicant, and β-caryophyllene — classified by some authors as a phytocannabinoid because of its CB2 selectivity — is a terpene. → See also: Cannabinoid, Decarboxylation, Terpenoid.