PHENOLIC CONSTITUENTS FROM THE LEAVES OF CAMELLIA HAKODAE NINH WITH THEIR α-GLUCOSIDASE INHIBITORY ACTIVITY

Six phenolic compounds, including camelliquercetiside D (1), tsubakioside A (2), stachyanthuside A (3), rutin (4), kaempferol 3-rutinoside (5), and kaempferol 3-O-β-D glucopyranoside (6), were isolated from the methanol extract of Camellia hakodae Ninh. Their chemical structures were identified by HR-ESI-MS, 1D and 2D NMR spectra and compared with the published data in the literature. The compounds were screened for their α-glucosidase inhibitory activity. Compounds 1, 2, 4-6 showed significant inhibition with IC50 values of 35.41 ± 0.02, 15.43 ± 0.39, 10.64 ± 0.23, 17.21 ± 0.34, and 19.42 ± 0.25 µM, respectively, compared to that of positive control, acarbose, which showed IC50 value of 47.10 ± 1.40 µM.