Two flavanones, 5,5′-dihydroxy-4′-methoxy-7-O-(α-L-rhamnosyl-(1′′′>6′′)-β-D-glucopyranosyl) flavanone 1 and (5,5′-dihydroxy-4′-methoxy-5-O-β-D-glucopyranosyl) flavanone 2, were isolated by liquid chromatography from ethanolic extracts of Glycosmis arborea (Roxb.) leaves and tested for hydrolysis by various β-glucosidases. The β-glucosidases from Dalbergia cochinchinensis, Dalbergia nigrescens, barley, rice and almond were compared for their ability to hydrolyze the conjugated flavanone glycosides from G. arborea by thin layer chromatography of the reaction products. The disaccharide glycoside, compound 1 was only hydrolyzed by the D. nigrescens β- glucosidase, which appeared to release the sugar mainly as a disaccharide, while compound 2 was hydrolyzed by all β-glucosidases tested, except Os9BGlu31. These compounds also showed significant antifeedant activity toward the polyphagous crop pest Spodoptera litura. This is the first report about the structural elucidation using enzymatic studies of bioactive flavanone glycosides from G. arborea.
D.S. Negi, A. Kumar, R.K. Sharma, N. Shukla, N. Negi, M.L. Tamta, Y. Bansal, Por-gnam Prasert and J.R. Kedutat Cairns, 2011. Structure Confirmation of Rare Conjugate Glycosides from Glycosmis arborea (Roxb.) with the Action of β-Glucosidases. Research Journal of Phytochemistry, 5: 32-40.