Constituents from the root and stem of Aristolochia elegans.

Four new tetralones, aristelegone-A (1), aristelegone-B (2), aristelegone-C (3), and aristelegone-D (4); one new isoquinoline, pericampylinone-A (5); four new biphenyl ethers, aristogin-A (6), aristogin-B (7), aristogin-D (8), and aristogin-E (9); three new lignans, aristelegin-A (10), aristelegin-B (11), and aristelegin-C (12); and a new dimer, aristolin (13), have been isolated from the root and stem of Aristolochia elegans. The structures were established on the basis of 1D and 2D NMR and mass spectral data. This is the first report of isoquinolones and biphenyl ethers from this plant which may be representative units for the formation of bisbenzylisoquinoline alkaloids that are common metabolites of Aristolochia species. Aristolin (13) is also the first report of a diterpene linked with an aristolochic acid.