Dihydrostilbene glycosides from Camellia sasanqua and their α-glucosidase and α-amylase inhibitory activities.

Using chromatographic methods, three new dihydrostilbene glycosides, sasastilbosides A-C (1-3) and four known compounds, catechin (4), rutin (5), nicotiflorin (6), and rehmaionoside A (7) have been isolated from Camellia sasanqua Thunb. Their chemical structures were elucidated by spectroscopic methods (1 D-, 2 D-NMR) and mass spectra. Compounds 1-7 were evaluated for α-glucosidase and α-amylase inhibitory effects. Compounds 3 and 4 showed α-glucosidase inhibitory activity with IC₅₀ values of 77.6 ± 1.6 and 72.4 ± 1.3 μM, respectively. Compound 1 showed α-amylase inhibitory activity with IC₅₀ value of 53.7 ± 1.6 μM.