An Unusual Piceatannol Dimer from Rheum austral D. Don with Antioxidant Activity

• Main Authors: Lin Hu, Na-Na Chen, Qun Hu, Cui Yang, Qing-Song Yang, Fang-Fang Wang
• Format: Article
• Language: English
• Published: MDPI AG 2014-08-01
• Series: Molecules
• Subjects: Rheum austral D. Don; piceatannol dimer; rheumaustralin; DPPH radical
• Online Access: http://www.mdpi.com/1420-3049/19/8/11453

A novel dimer of piceatannol glycoside, named rheumaustralin (1) was isolated from the underground parts of the ethnomedicinal plant Rheum austral (Polygonaceae) collected from Tibet together with 17 known compounds, including rheumin (2), 2,5-dimethyl-7-hydroxychromone (3), 2,5-dimethylchromone-7-O-β-d-glucopyranoside (4), 7-hydroxy-2-(2'-hydroxypropyl)-5-methylchromone (5), torachrysone (6) torachrysone-8-O-β-d-glucopyranoside (7), 4-(4'-hydroxyphenyl)-2-butanone-4'-O-β-d-glucopyranoside (8), amabiloside (9), N-trans-feruloyl tyramine (10), chrysophanol (11), aloe-emodin (12), emodin (13), physcion (14), physcion-1-O-β-d-glucopyranoside (15), emodin-8-O-β-d-glucopyranoside (16), d-catechin (17) and gallic acid (18). Their structures were determined by combined spectroscopic methods and by comparison of their spectral data with those reported in literature. Compounds 1–10 were tested for their ability to scavenge 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical.