Prenylated apigenin derivatives from Cannabis sativa L.: isolation, biosynthesis, and anti-inflammatory properties

BACKGROUND: Cannabis sativa L. accumulates a wide array of specialized compounds, many of which are non-psychotropic and show significant promise in medical and therapeutic applications. One such group of C. sativa compounds is prenylated flavonoids, which have emerged as potential treatments for chronic pain and inflammation. Accordingly, the aim of this study was to isolate, identify, and synthesize prenylated flavonoids from C. sativa and test their efficacy as anti-inflammatory agents. METHODS: An enriched polyphenol extract from C. sativa was fractionated using flash chromatography and high-performance liquid chromatography to isolate prenylated flavonoids. Liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectroscopy were employed to determine their structures. Phylogenomic and classical biochemical approaches were combined to identify the enzyme involved in the biosynthesis of the isolated compounds. Finally, these prenylated flavonoids were tested to determine their inhibitory properties against microsomal prostaglandin E synthase-1 (mPGES-1) activity. RESULTS: Two prenylated flavonoids were isolated from the aerial parts of the C. sativa plant using classical chromatographic procedures and identified as 6-prenylapigenin (6-PA) and 6-geranylapigenin (6-GA). A C. sativa prenyltransferase (CsPT3) from the UbiA superfamily was identified to complete the final prenylation step in 6-PA and 6-GA biosynthesis from the widespread plant flavonoid known as apigenin. The inhibitory potentials of 6-PA and 6-GA against mPGES-1 activity were approximately as effective as, or better than, that of a leading commercially available inhibitor, MK-886. Molecular docking simulations confirmed strong binding affinities of 6-PA and 6-GA to mPGES-1 compared to its natural substrate. CONCLUSIONS: 6-PA and 6-GA are prenylated derivatives of the widespread plant flavonoid known as apigenin. These non-psychotropic flavonoids accumulate in C. sativa and exhibit potent inhibition of mPGES-1, a chief mediator in the pro-inflammatory pathway. Identification of the final step in 6-PA and 6-GA biosynthesis, together with their now-established anti-inflammatory activity, presents propitious biotechnological avenues for these therapeutically relevant C. sativa compounds.