UNRAVELING FACTORS FOR THE BIOSYNTHESIS OF NON-TERPENOID VOLATILES IN CANNABIS SATIVA AND OTHER TRICHOME BEARING GENERA

Austin Alt

Though usually only present at trace amounts in plants, non-terpenoid volatiles are knownto play powerful roles in scent and flavor which often far surpass terpenoids. As a result, these compounds are frequently used as flavorants by food, beverage, and perfumery industries alike to enhance or modulate sensory bouquets. Given the recent discovery of these compounds in cannabis (Cannabis sativa L.), the overarching focus of this dissertation is to investigate the presence of non-terpenoid volatile flavorants, both in this species and other trichome bearing species, to further understand regulatory factors underlying production. The contribution of several distinct non-terpenoid classes to overall metabolic flux is examined in cannabis, where these compounds have been shown to play a significant role in sensory perception but are largely understudied in terms of production. Targeted efforts are also undertaken to identify and characterize precursors for sulfur containing volatiles, responsible for the signature “skunky” odor of cannabis. Lastly, the chemotaxonomic presence of non-terpenoids across Lamiaceae is examined in detail, given genera of this family are similarly diverse in aroma, rich in trichomes, and act as comparable experimental model systems for the production of volatiles in glandular trichomes. In cannabis, our investigations indicated that the contribution of non-terpenoid volatiles to the overall distribution of carbon flux is likely to be fairly low, despite a high importance to sensory bouquets. This work also established simplified protocols for the detection of trace non-terpenoids and confirmed the presence of several previously understudied volatile classes, including pyrazines, pyridines, and pyrroles – which are well known contributors to roasted and nutty flavors in other species. Additional efforts in cannabis focused on the discovery of precursors for sulfur containing non-terpenoids revealed chemically reducible, and mechanistically labile pools of amino acid conjugates which develop throughout plant maturation and contribute to volatile release under a wide range of conditions. Quantitative differences in precursor composition were demonstrated across both hemp and high cannabinoid chemovars, illuminating a hierarchical storage–activation framework which underlies differential volatile release between chemovars and product types. Chemotaxonomic assessment of similar non-terpenoid volatiles across Lamiaceae exposed a vast depth of previously unreported compounds which possess established roles as flavorants and exhibited defining patterns among genera. Because Lamiaceae genera such as Mentha serve as comparable models to cannabis for the investigation of glandular trichomes and terpenoid metabolism, these findings provide translative insights into the biochemical pathways underlying non-terpenoid production across herbal species.

UNRAVELING FACTORS FOR THE BIOSYNTHESIS OF NON-TERPENOID VOLATILES IN CANNABIS SATIVA AND OTHER TRICHOME BEARING GENERA

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