Isolation and structure determination of anti-influenza component from Mahonia bealei.

The fraction possessing anti-influenza activity, which is obtained from the roots of Mahonia bealei (Fort), has been studied regarding its chemical compositions and molecular structure. The previous experiment on this fraction in vitro suggested that the anti-influenza effect was due to the existence of alkaloids in M. bealei (Fort), and mainly from one bisbenzylisoquinoline alkaloid. In this paper the structure of this bisbenzylisoquinoline alkaloid has been determined as 1R, 1'S-(+)-isotetrandrine by means of MS, 1H NMR, 13C NMR, FT-IR and HPLC analyses.