New antifungal xanthones from the seeds of Rhus coriaria L.

Phytochemical investigations of the ethanolic extract of the seeds of Rhus coriaria L. (Anacardiaceae) led to the identification of four new xanthones, characterized as 2,3-dihydroxy-7-methyl xanthone (1), 2,3,6-trihydroxy-7-hydroxymethylene xanthone-1-carboxylic acid (2), 2-methoxy-4-hydroxy-7-methyl-3-O-beta-D-glucopyranosyl xanthone-1,8-dicarboxylic acid (4), and 2-hydroxy-7-hydroxymethylene xanthone-1,8-dicarboxylic acid 3-O-beta-D-glucopyranosyl-(2'-->3")-3"-O-stigmast-5-ene (5), along with the known steroidal glucoside beta-sitosterol-beta-D-glucoside (3). The structures of the isolated compounds have been identified on the basis of spectral data analysis and chemical reactions. All xanthones were active against Aspergillus flavus.