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

The fruits of Rosa roxburghii 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 ( 1 , 4 , 5 , and 24 ), along with 22 known analogues ( 2 , 3 , 6 - 23 , 25 , and 26 ), were isolated from the fruits of R. roxburghii . Their chemical structures were determined on the basis of extensive spectroscopic analyses (including IR, HRESIMS and NMR spectroscopy). The absolute configuration of roxbuterpene A ( 1 ) 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 ( 1 and 4 ) possessed the A-ring contracted triterpenoid and nortriterpenoid skeletons with a rare 5/6/6/6/6-fused system, respectively. Compounds 1 - 7 , 11 , 13 - 15 , 18 - 20 , 24 , and 25 exhibited moderate or potent inhibitory activities against α-glucosidase. Compounds 2 , 4 , 6 , 11 , and 14 showed strong activities against α-glucosidase with IC50 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 13 , 14 , and 16 moderately inhibited the release of NO (nitric oxide) with IC50 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 13 , 14 , and 16 exhibited moderate inhibitory effects on TNF-α and IL-6 release in a dose-dependent manner ranging from 12.5 to 50 μM.