Hydroxylation of a hederagenin derived saponin by a xylareaceous fungus found in fruits of Sapindus saponaria

Abstract

During our screening of tropical plants for endophyte microorganisms, a Xylareaceous fungus was found living on the internal part of Sapindus saponaria fruits. The fruits of S. saponaria accumulate great amounts of triterpenoidal and sesquiterpenoidal saponins. The saponin 3-O-(β-D-xylopyranosyl)- (1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl- hederagenin was isolated using chromatographic methods, after alkaline hydrolysis of the crude extract obtained from S. saponaria fruits and added to the culture medium used to grows the fungus. A new saponin was isolated from this experiment by preparative scale HPLC and characterized as a 22α-hydroxy derivative. The structure of this hydroxylated saponin was elucidated based on interpretation of MS/MS data and NMR spectra. ©2008 Sociedade Brasileira de Química.