rhapontin and aloe-emodin

To determine six effective components (aloe-emodin, rhein, emodin, rhaponticin, physcion and chrysophanol) in Rheum.. Using buffer solution containing 20 mmol.L-1 borax, 20 mmol.L-1 sodium deoxycholate (SDC), 20 mmol.L-1 sodium taurocholate (STC), 15 mmol.L-1 beta-cyclodextrin (beta-CD) and O-phthalic acid as the internal standard, the six components were determined by cyclodextrin modified micellar electrokinetic chromatography.. In less than 25 min, aloe-emodin, rhein, emodin, rhaponticin, physion and chrysophanol were separated. The separation conditions were optimized by adjusting buffer pH, concentrations of SDC, STC and beta-CD. The linearity ranges of aloe-emodin, rhein, emodin, rhaponticin, physcion and chrysophanol were 4-34, 5-40, 4-60, 5-80, 6-90 and 5-85 micrograms.mL-1 respectively. Relative standard deviation (RSD) of the method was less than 2.2%. The recoveries of aloe-emodin, rhein, emodin, rhaponticin, physcion and chrysophanol were 100.0%, 98.3%, 100.4%, 94.6%. 95.2% and 93.8% respectively. Raw Rheum, Mongolian Rheum and Rheum tanguticum samples were analyzed.. This method can be an effective one for identification of Rhubarb.

Topics: Anthraquinones; Chromatography, Micellar Electrokinetic Capillary; Cyclodextrins; Emodin; Plants, Medicinal; Quality Control; Rheum; Stilbenes

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