Lanostane-Type Triterpenes From Poria cocos Peels and Their α-Glucosidase Inhibitory Activity.

From the methanol extract of the Poria cocos peels, two novel tetracyclic triterpenoid (1-2) and six known triterpenenes (3-8) were isolated. The structures of the new compounds were determined to be (20R)-16α,24,31-trihydroxy-3,4-seco-lanosta-4(28),7,9(11)-triene-3,21-dioic acid 3-oate (1), (20R)-3β,23-dihydroxy-lanosta-7,9(11),24(25)-triene-21-oic acid (2). Their structures were elucidated by analyses of the HRESI/MS, 1D and 2D NMR spectra. All isolated triterpeoids were evaluated for their α-glucosidase inhibitory activities in vitro. Compounds 2 and 6 exhibited moderate α-glucosidase inhibitory activity with the IC50 values of 132.1 ± 3.4 and 271.0 ± 5.2 µM, respectively.