Cannadicas A and B: two new oligosaccharide esters from the roots of Canna indica L.

Abstract

Two new sucrose derivatives, named as cannadica A (1) and cannadica B (2), and eight known compounds, 6 -O-acetyl-3-O-(E)-p-coumaroylsucrose (3), heterophylloside C (4), 6 -O-vanilloylarbutin (5), isotachioside (6), 2,6-dimethoxy-p-hydroquinone 1-O-β-D-glucopyranoside (7), 3,5-dimethoxy-p-hydroquinone 1-O-β-D-glucopyranoside (8), benzyl glucoside (9), and 3,4-dihydroxybenzaldehyde (10) were isolated from the roots of Canna indica L. by various chromatographic methods. Their structures were established by extensive spectroscopic analysis (UV, IR, HR-ESI-MS and NMR) and by comparison of the spectral data with those reported in the literature. Compounds 1-10 were evaluated their antioxidant activity by peroxyl radical absorbance capacity assay. Compounds 4 and 5 exhibited the most peroxyl radical absorbance capacity. At concentration of 1\u2009µM, their ORACROO* values were 4.86\u2009±\u20090.39 and 3.11\u2009±\u20090.26, respectively, fold-up to that of trolox as an internal standard.