Ent-kaurane diterpenoids from the cherries of Coffea arabica.

Four new rearranged ent-kaurane diterpenoids named as caffruenol A (1), caffruenol B (2), caffruolide A (3), caffruolide B (4), along with eleven known analogues (5-15) were isolated from the cherries of Coffea arabica. The structures of new compounds were elucidated by extensive spectroscopic analysis and X-ray crystallography. Coffruenols A and B (1 and 2) possessed an ent-4(18)-kaurene framework and might play an important role on the biosynthesis of the rearranged diterpenes that occurred in C. arabica. Moreover, inhibitory effects of compounds 1-4 on nitric oxide (NO) production in lipopolysaccharide-activited RAW 264.7 macrophages were evaluated.