Comprehensive analysis of chemical and enantiomeric stability of terpenes in Cannabis sativa L. flowers.

Objective: Cannabis sativa L. is renowned for its medicinal and recreational uses. With the increasing global legalization of C. sativa L.-based products for medicinal purposes, there is a growing need for well-characterized products. While the stability of cannabinoids such as tetrahydrocannabinol and cannabidiol is well understood, information on the chemical and enantiomeric stability of terpenes remains scarce. This is despite the fact that terpenes are also thought to have pharmacological activity and may contribute to the overall effect of C. sativa L.

Methods: To address these challenges, four analytical methods based on chiral, polar, and apolar gas chromatographic separation combined with either MS or FID detection were developed and validated. These methods successfully separated and quantified a total of 29 terpenes, including 13 enantiomers and 5 diastereomers specific to C. sativa L. Furthermore, terpenes and authentic C. sativa L. flowers and extracts were subjected to UV and heat treatments to observe potential degradation reactions over time.

Results: Each terpene generates a unique pattern of degradation products resulting in a diverse array of oxidation and cyclization products. P-cymene was identified as a major product of terpene aging. Notably, no enantiomeric conversion was detected, suggesting that the formation of (-)-α-pinene in cannabis extracts, for example, originates from other terpenes.

Conclusion: Terpenes have different degradation rates, even though they are structurally similar. In addition, cultivar- and growth-condition-specific enantiomeric ratios were observed in C. sativa L., confirming that enantiomer production is species-specific and has to be considered for therapeutical applications.