Constituents from the testas of Castanea mollissima Blume with alpha-glucosidase inhibitory activity.

In the screening of biologically active constituents from medicinal plants, the 75% EtOH extract of the testas of Castanea mollissima Blume showed potent alpha-glucosidase inhibitory activity. By means of various chromatographic methods, the extract gave a new dammarane-type triterpene 1 along with 17 known compounds. The structure of 1 was determined to be 3beta-acetoxy-20-oxo-21-nordammaran-23-oic acid by HRMS and NMR studies including 2D NMR experiments. The new compound and some known compounds showed potent alpha-glucosidase inhibitory activity with acarbose as a positive control.