NEW OXINDOLE ALKALOID GLYCOSIDES FROM UNCARIA SINENSIS

Two 16-carboxy derivatives of pentacyclic oxindole alkaloids and its glucopyra nosyl esters have been isolated from the ethanolic extract of the leaves of Uncaria siuensis (Olive.) Havil. These structures were deduced on the basis of spectroscopic evidences and chemical correlations, and named mitraphyllic acid (Ⅰ), isomitraphyllic acid (Ⅱ), isomitraphyllic acid (16-1)-β-D-glucopyranosyl ester (Ⅲ) and mitraphyllic acid (16-1)-β-D-glucopyranosyl ester (Ⅳ).