Withaperuvin O, a new withanolide from Physalis peruviana L.

Physalis peruviana L. (Solanaceae) has been used in tropical and subtropical countries of the world as medicinal and fruit trees. In this study, a new withanolide named withaperuvin O (1) and seven known ones, including physalolactone B-3-O-ß-D-glucopyranoside (2), withanolide J (3), physapruin A (4), physaperuvin G (5), withaperuvin (6), withaperuvin C (7) and 28-hydroxywithaperuvin C (8), were isolated from the whole plants of P. peruviana. Their structures were elucidated based on extensive spectroscopic analyses including NMR and HR-ESI-MS. The bioactivities of these compounds against lipopolysaccharide (LPS)-induced NO production in RAW264.7 cells and cytotoxicity against HepG2 were tested. Compound 3 showed strong anti-inflammatory activities with IC50 3.55 ± 0.12 µM (compared to positive control L-NMMA 7.72 ± 0.46 µM). Compounds 3 and 4 inhibited HepG2 cell line with the IC50 values of 2.01 ± 0.12 µM, 0.96 ± 0.05 µM, respectively (Ellipticine, 0.32 ± 0.02 µM). Our study indicated that compounds 3 and 4 could be new potential natural products for the development of anti-inflammatory and anti-cancer agents.

Stigmastane-type steroid saponins from the leaves of Vernonia amygdalina and their α-glucosidase and xanthine oxidase inhibitory activities.

Two new vernonioside K (1) and vernonioside L (2) and four known Δ7,9(11) stigmastane-type steroidal saponins-vernonioside B2 (3), vernoniacum B (4), vernonioside B1 (5), and vernoamyoside A (6)-were isolated from the leaves of Vernonia amygdalina. Their structures were determined by comprehensive spectroscopic analysis with one-dimensional nuclear magnetic resonance, two-dimensional nuclear magnetic resonance, and high-resolution mass spectrometry. All isolated compounds (1-6) were evaluated to determine their inhibitory effects on α-glucosidase and xanthine oxidase. Among them, two new compounds 1 and 2 showed significant inhibition of α-glucosidase with IC50 values of 78.56 ± 7.28 and 14.74 ± 1.57 (µM), respectively, comparable with acarbose as a positive control (127.53 ± 1.73 µM); none of these compounds inhibited xanthine oxidase activity. Compounds 1 and 2 are promising candidates for the development of antidiabetic agents from natural sources.