Glycoside constituents of Camellia amplexicaulis and their α-glucosidase inhibitory activity

Four new glycosides, named amplexicosides A-D (1-4), and five known compounds: benzyl 2-((beta-D-glucopyranosyl-(1 -> 6)-(beta-D-glucopyranosyloxy]-benzoate (5), benzyl 2-neohesperidosyloxy-6-hydroxybenzoate (6), chrysandroside A (7), chrysandroside B (8) and camelliquercetiside C (9) were isolated from the branches and leaves of Camellia amplexicaulis (Pit.) Cohen-Stuart. Their structures were elucidated using HR-ESI-MS and 1D- and 2D-NMR spectra and compared to reported NMR data. All of the isolated compounds were screened in an alpha-glucosidase assay. Compounds 4, 8, and 9 significantly inhibited alpha-glucosidase with respective IC50 values of 254.9 +/- 4.2, 304.8 +/- 11.9 and 228.1 +/- 16.4 mu M. [GRAPHICS] .

Automated summary

Four new glycosides, named amplexicosides A-D, and five known compounds were isolated from the branches and leaves of Camellia amplexicaulis. Their structures were determined using spectroscopic and NMR techniques. Three compounds showed significant inhibition against alpha-glucosidase.