Nepetifoliol - a new glutinane-triterpenoid from .

A new glutinane-triterpenoid, nepetifoliol (), together with two known compounds, dymacrin D (), and (+)-ar-tumerone () were isolated from the -hexane extract of the aerial parts of . Their chemical structures were elucidated by spectroscopic data analysis as well as the comparison of their NMR data with the ones published in the literatures. A putative biosynthetic pathway for the formation of the new compound (diaxial-5,6-diol) () from the precursor triterpene glutinol was proposed. Compounds (), () and some previously reported ones, isolated from this extract, including 5α-stigmasta-22-ene-3-one (), friedelin (), chrysophanol (), physcion (), and 4'--methylalpinumisoflavone () were evaluated for their α-glucosidase inhibition. Among tested compounds, and showed good activities with their IC values of 5.3 ± 0.2 and 4.9 ± 0.3 µg/mL, respectively, comparing to the positive control, acarbose (IC 127.7 ± 0.2 µg/mL).