Triterpenoid saponins from the roots of Rosa rugosa Thunb. as rat intestinal sucrase inhibitors.

Medicinal plants constitute an important source of potential therapeutic agents for diabetes. The purpose of present study is to investigate the effect of root extract of Rosa rugosa Thunb. on inhibition of sucrase related to diabetes mellitus (DM). Bioassay-guided fractionation of the methanol extract led to the identification of 13 triterpenoid saponins (1-13). Their structures were elucidated on the basis of extensive spectroscopic analysis, including 1D, 2D NMR, and MS. The n-butanol fraction showed potent rat intestinal sucrase inhibitory activity with value of 87.62 ± 5.84 % inhibition compared to the positive control acarbose (50.96 ± 2.97 % inhibition at 0.02 mM). Subsequently, compounds 11-13 (1.0 mM) exhibited significant sucrase inhibitory activity, with inhibition percentage values of 41.17 ± 3.52, 46.80 ± 4.00, and 39.39 ± 4.19 %, respectively. Whereas, compounds 2-6, 8, and 10 showed moderate sucrase inhibitory activity (ranging from 13.26 ± 7.00 to 32.08 ± 6.04 % inhibition) at a same concentration. The data provide a starting point for creating new sucrase inhibitors, which may be useful for the development of effective therapies for the treatment of DM.