Quinolizidine alkaloids with anti-HBV activity from Sophora tonkinensis

A new matrine-type alkaloid, (-)-14 beta-hydroxyoxymatrine (1), was isolated from the roots and rhizomes of Sophora tonkinensis Gapnep. (Leguminosae), together with five known matrine-type alkaloids, (-)-14 beta-hydroxymatrine (2), (+)-oxymatrine (3), (+)-matrine (4), (+)-sophoranol (5), and (-)-5 alpha-hydroxysophocarpine (6), as well as with two known cytisine-type alkaloids, (-)cytisine (7) and (-)-N-methylcytisine (8). Their structures were elucidated by spectroscopic methods. Compounds 1, 5 and 7 showed potent anti-HBV activity with an inhibitory potency against HBsAg secretion of 22.6%, 31.1% and 33.2%, and against HBeAg secretion of 30.4%, 26.3% and 27.8%, respectively.