Novel epoxyfuranoid lignans and antitubercular constituents from the leaves of Beilschmiedia tsangii

Three new epoxyfuranoid lignans, 4a,5a-epoxybeilschmin A (1), 4a,5a-epoxybeitschmin B (2), and beilschmin D (3), together with nine known compounds have been isolated from the leaves of Beilschmiedia tsangii. The structures of these new compounds were determined through spectral analyses. Among the isolates, beilschmin A (4) and beilschmin B (5) exhibited potent antitubercular activities (MICs = 2.5 and 7.5 mu g/mL, respectively) against Mycobacteriurn tuberculosis 90- 221387 in vitro.