Tricalysionoside A, a Megastigmane Gentiobioside, Sulfatricalysines A—F, and Tricalysiosides X—Z, ent-Kaurane Glucosides, from the Leaves of Tricalysia dubia

Abstract

Further isolation work on the water-soluble fraction of a MeOH extract of Tricalysia dubia afforded one new megastigmane gentiobioside, named tricalysionoside A (1), and three sulfates, named sulfatricalysines A—C (2—4). Extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of T. dubia yielded sulfatricalysines D—F (5—7) and three new ent-kaurane glucosides, named tricalysiosides X—Z (8—10). The structures of the new compounds were elucidated by analyses of one- and two-dimensional NMR spectroscopic data. The absolute stereochemistry of tricalysionoside A (1) was established by modified Mosher's method.