Identification of (+)-7R-Actinidine and its Biosynthetic Pathway in Rove beetles, Cafius spp. (Coleoptera: Staphylinidae)

Actinidine, a terpene alkaloid, is commonly found in various plants and insects. However, in recent years, it has been suggested that the presence of actinidine in these organisms may be due to artifacts resulting from heating during sample preparation and analysis. In this study, actinidine was successfully isolated and identified from rove beetles, specifically Cafius vestitus and Cafius pectoralis, using a nonheating extraction and purification method. Gas chromatography/mass spectrometry (GC/MS) and nuclear magnetic resonance analyses confirmed actinidine production by these rove beetle species. Additionally, employing a chiral column for GC/MS analysis revealed that the compound is (+)-7R-actinidine, marking its first discovery in natural products. To elucidate the actinidine biosynthesis pathway, D-glucose-1-13C and mevalolactone-2-13C were fed to C. vestitus. Results indicated that both compounds were incorporated into actinidine in the beetles, leading to the conclusion that C. vestitus accumulates (+)-7R-actinidine, which is derived from the mevalonic acid pathway.