Clausanisumine, a Prenylated Bicarbazole Alkaloid from the Fruits of and Its Potential Anti-HIV Activity.

A unique prenylated bicarbazole alkaloid, clausanisumine (), and two biogenetically related known monomer carbazole alkaloids, mukonal () and 3-methylcarbazole (), were isolated from the fruits of . Clausanisumine () was an uncommon prenylated bicarbazole alkaloid, possessing an unprecedented carbon skeleton, which was composed of a simple carbazole alkaloid and a prenylated carbazole alkaloid. The chemical structure of was established by a combination of comprehensive spectral methods. A plausible biosynthetic pathway of was also proposed. Additionally, the potential anti-HIV activities of all isolates - were evaluated. Compound exhibited remarkable anti-HIV-1 reverse transcriptase effects showing an EC value of 18.58 nM. The discovery of the prenylated bicarbazole alkaloid from with notable anti-HIV activity would be meaningful to discovering and developing new anti-HIV drugs.