Structural elucidation of two new megastigmane glycosides from the leaves of Aquilaria sinensis

The present study was designed to determine the chemical constituents and identify new components of the leaves of Aquilaria sinensis (Lour.) Gilg. The compounds were isolated and purified by repeated silica gel, Sephadex LH-20, and ODS column chromatography and their structures were elucidated by NMR and HR-ESI-MS spectrometry. Eight megastigmane glycosides and two cucurbitacins were isolated and identified as (9S) megastigma-4,7-diene-2,3,9-triol 9-O--D-glucopyranoside (1), (9S) megastigma-4(13),7-diene-3,6,9-triol 9-O--D-glucopyranoside (2), macarangloside D (3), corchoionoside C (4), staphylionoside H (5), (+) 3-oxo--ionol--D-glucopyranoside (6), (-) 3-oxo--ionol--D-glucopyranoside (7), citroside B (8), 2-O--D-glucopyranosyl cucurbitacin I (9), bryoamaride (10). Compounds 1 and 2 were newly identified megstigmane glucosides and reported from this genus for the first time.