New Iridoid Glucosides from Caryopteris incana (Thunb.) Miq. and Their α-Glucosidase Inhibitory Activities

摘要

In our continued investigations of the plant Caryopteris incana, five new iridoid glucosides >1–>5, including two cis-trans-isomers, >3 and >4, along with six known compounds >6–>11, were isolated from the n-butyl alcohol (n-BuOH) soluble fraction of whole dried material of Caryopteris incana. Their structures were established by a combination of spectroscopic techniques, including 1D and 2D NMR and high resolution electrospray ionization mass spectroscopy (HR-ESI-MS). Furthermore, all isolates were evaluated for their yeast α-glucosidase inhibitory effects. Among these compounds, >4–>8 and >10 exhibited potent inhibition of α-glucosidase.