Phenolic constituents with potent α-glucosidase inhibitory and cytotoxic activities from Rumex nepalensis var. remotiflorus.

Quantitative analysis of Rumex nepalensis var. remotiflorus revealed that its roots contain rich anthraquinones, which has emodin, chrysophanol, and physcion contents of up to 0.30, 0.67, and 0.98 mg/g, respectively. Further phytochemical study led to the isolation and purification of seven undescribed phenolic constituents, including one flavan derivative with a 13-membered ring, polygorumin A (1), two dianthrone glucosides, polygonumnolides F and G (2, 3), two diphenylmethanones, rumepalens A and B (4, 5), and a pair of epimeric oxanthrone C-glucosides, rumejaposides K and L (6a, 6b) from the roots of R. nepalensis var. remotiflorus. Furthermore, 1 undescribed natural product, 1-ß-D-glucoside-6'-[(2E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate]-3-hydroxy-5-methylphenyl (19), and 21 known phenolic compounds were obtained from the aforementioned plant for the first time. Their structures were elucidated through extensive spectroscopic data analysis. Notably, compounds 1, 4-5, and 7-9 exhibited inhibitory activity on α-glucosidase with IC50 values ranging from 1.61 ± 0.17 to 32.41 ± 0.87 µM. In addition, the isolated dianthrone, chrysophanol bianthrone (14), showed obvious cytotoxicity against four human cancer cell lines (HL-60, SMMC-7721, A-549, and MDA-MB-231) with IC50 values ranging from 3.81 ± 0.17 to 35.15 ± 2.24 µM. In silico target prediction and molecular docking studies demonstrated that the mechanism of the anticancer activity of 14 may be related to the interaction with protein kinase CK2.

Four new phenolic constituents from the roots of Rumex dentatus L.

Four new phenolic compounds, including two naphthalenes, musizin-8-O-ß-D-(6'-O-malonyl-3''-methoxy)glucopyranoside (1) and 2-acetyl-3-methyl-1,4-naphtho-quinone-8-O-ß-D-glucopyranoside (2), one chromone, (2'R)-7-hydroxy-2-(2'-hydroxypropyl)-5-methyl acetate chromone (3), and one xanthone, 2,8-dimethyl-3,6-dihydroxyxanthone (4) were isolated from the roots of Rumex dentatus L. (Polygonaceae). In addition, five known including four naphthalenes (5-8) and one chromone (9) were also obtained. Their structures were determined by means of extensive spectroscopic analysis and acidic hydrolysis. Compound 1 showed moderate antifungal activity against Epidermophyton floccosum, with inhibitory rate of 39.539 ± 0.412% at a concentration of 100 µM.