chrysophanol-8-o-glucoside and aloe-emodin

The methanolic extract from the roots of Polygonum (P.) cuspidatum was found to enhance cell proliferation at 30 or 100 microg/mL in MCF-7, an estrogen-sensitive cell line. By bioassay-guided separation from P. cuspidatum with the most potent activity, emodin and emodin 8-O-beta-D-glucopyranoside were isolated as active principles. The methanolic extracts from Polygonum, Cassia, Aloe, and Rheum species, which were known to contain anthraquinones, also showed the MCF-7 proliferation. As a result of the evaluation of various anthraquinones from plant sources and synthetic anthraquinones, aloe-emodin, chrysophanol, chrysophanol 8-O-beta-D-glucopyranoside, and 1,8-dihydroxyanthraquinone showed weak activity. On the other hand, alizalin and 2,6-dihydroxyanthraquinone as well as emodin having the 2- and/or 6-hydroxyl groups showed potent activity. These results show that the unchelated hydroxyl group is essential for strong activity. Emodin and 2,6-dihydroxyanthraquinone also inhibited 17beta-estradiol binding to human estrogen receptors (ERs) with K(i) values of 0.77 and 0.31microM for ERalpha and 1.5 and 0.69 microM for ERbeta. These findings indicate that hydroxyanthraquinones such as emodin are phytoestrogens with an affinity to human estrogen receptors.

Topics: Anthraquinones; Cell Division; Cells, Cultured; Emodin; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Estrogens, Non-Steroidal; Genistein; Humans; Isoflavones; Phytoestrogens; Plant Preparations; Polygonaceae; Protein Binding; Receptors, Estrogen; Structure-Activity Relationship

Two new anthraquinone glucosides [chrysophanol 8-O-beta-D-(6'-galloyl)-glucopyranoside, aloe-emodin 1-O-beta-D-glucopyranoside] together with various known stilbenes and their glucosides, anthraquinone glucosides, and a naphthalene glucoside were isolated from the rhizome of Rheum undulatum L. Three stilbenes (rhapontigenin, piceatannol, resveratrol), a naphthalene glucoside (torachrysone 8-O-beta-D-glucopyranoside), and two stilbene glucoside gallates (rhaponticin 2''-O-gallate, rhaponticin 6''-O-gallate) showed inhibitory activity of NO production in lipopolysaccharide-activated macrophages, (IC50 = 11-69 microM). The oxygen functions (-OH,-OCH3) at the benzene ring were found to be essential to show the activity. Whereas, the glucoside moiety reduced the activity, while the alpha,beta-double bond did not affect the activity. Furthermore, the active stilbenes (rhapontigenin, piceatannol, resveratrol) inhibited iNOS induction.

Topics: Anthraquinones; Emodin; Gallic Acid; Glucosides; Lipopolysaccharides; Macrophage Activation; Macrophages; Naphthalenes; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Nitrites; Plant Extracts; Plants, Medicinal; Rheum; Stilbenes; Structure-Activity Relationship