Rauvolfia yunnanensis Tsiang, belonging to the Apocynaceae,is indigenous to southwestern China, and its roots are utilized locally for the remedy of scab. Recently, several structurally interesting indole alkaloids were isolated from this plant.6–8 As one part of our research program exploring bioactive monoterpene indole alkaloids from Chinese species of Rauvolfia, phytochemical analysis from the methanol extract of aerial parts of R. yunnanensis led to the isolation of three new alkaloids, rauvoyunines A–C. This paper reports the isolation and structure elucidation of new compounds and cytotoxic evaluation of selected compounds.
Three new indole alkaloids, 10-methoxy-16-de(methoxycarbonyl)pagicerine (1), (5β)-17-O-deacetyl-5,11-dimethoxyakuammiline (2), and ((16S,19E)-N1-(hydroxymethyl)isositsirikine (3) were isolated from the roots of Rauvolfia yunnanensis, together with seven known alkaloids. The structures of the new compounds were elucidated by in-depth spectroscopic and mass-spectrometric analyses.