Anti-Inflammatory and α-Glucosidase Inhibitory Triterpenoid with Diverse Carbon Skeletons from the Fruits of .

The fruits of Tratt. are edible nutritional food with high medicinal value and have been traditionally used as Chinese folk medicine for a long time. In this study, 26 triterpenoids including four new pentacyclic triterpenoids, roxbuterpenes A-D (, , , and ), along with 22 known analogues (, , -, , and ), were isolated from the fruits of . Their chemical structures were determined on the basis of extensive spectroscopic analyses (including IR, HRESIMS and NMR spectroscopy). The absolute configuration of roxbuterpene A () was determined by an X-ray crystallographic analysis. This is the first report of the crystal structure of 5/6/6/6/6-fused system pentacyclic triterpenoid. Notably, roxbuterpenes A and B ( and ) possessed the A-ring contracted triterpenoid and nortriterpenoid skeletons with a rare 5/6/6/6/6-fused system, respectively. Compounds -, , -, -, , and exhibited moderate or potent inhibitory activities against α-glucosidase. Compounds , , , , and showed strong activities against α-glucosidase with IC values of 8.4 ± 1.6, 7.3 ± 2.2, 13.6 ± 1.4, 0.9 ± 0.4, and 12.5 ± 2.4 μM, respectively (positive control acarbose, 10.1 ± 0.8 μM). Compounds , , and moderately inhibited the release of NO (nitric oxide) with IC values ranging from 25.1 ± 2.0 to 51.4 ± 3.1 μM. Furthermore, the expressions of TNF-α (tumor necrosis factor-α) and IL-6 (interleukin-6) were detected by ELISA (enzyme-linked immunosorbent assay), and compounds , , and exhibited moderate inhibitory effects on TNF-α and IL-6 release in a dose-dependent manner ranging from 12.5 to 50 μM.