Mahimbrine A, a Novel Isoquinoline Alkaloid Bearing a Benzotropolone Moiety from Mahonia imbricata.

A novel isoquinoline alkaloid, mahimbrine A, possessing a rare benzotropolone framing scaffold, was isolated from the endemic plant of Mahonia imbricata. Its structure was established on the basis of extensive spectroscopic analysis. A plausible biosynthetic route of mahimbrine A was proposed. Mahimbrine A showed no antimicrobial activity at the concentration of 1 mg/mL.