Anti-inflammatory Activity Of Rhaponticum Uniflorum(l.)dc. Flower Ethanol Extract And The Isolation Of Main Bioactive Fractions And Compounds

Rhaponticum uniflorum(L.)DC. flowers(LLH) have been generally used as traditional Mongolian medicine in the treatment of inflammatory diseases since ancient times. In this study, we performed a preliminary animal study to ascertain its ethno pharmacological claims and aimed to identify active fractions and compounds which are responsible for anti-inflammatory activity from LLH.Methods: Anti-inflammatory activities of LLH flowers raw herb powder and ethanol crude extract were investigated in vivo by using acute(dimethyl benzene-induced mice ear edema, carrageenan-induced rat paw edema) and chronic inflammation models(cotton pellet-induced rat granuloma). Then, to identify the anti-inflammatory fractions and components from the bioactive LLH ethanol crude extract, we investigated the inhibitory effects of the crude extract, fractions and pure compounds isolated from LLH on LPS induced production of nitric oxide(NO) in mouse macrophage RAW264.7 cells.Results: LLH ethanol crude extract exhibited excellent inhibitory effects on the three inflammation models. Using in vitro bioassay-guided fractionation and isolation, two main bioactive fractions(A2-2 and A2-3) were found to effectively inhibit NO(inhibition: 89.94%, 75.43%, respectively) production at 400 μg/ml(p<0.01), and consequently, 10 compounds(1-10), consequently identified as 20-hydroxyecdysone(1), β-sitosterol(2), Hemislin B glucoside(3), Luteolin(4), Apigenin(5), Quercetin(6), Quercitrin(7), Afzelin(8), Stearic acid(9), Gallic acid(10) were isolated from A2-2. 8 of these 10 compounds(1, 3-5, 7-10) were isolated from LLH for the first time. NO production assay showed that compound 1, 3-8, 10 had inhibitory activities on NO production(p<0.01) at concentrations ranging from 0.39 to 400 μg/ml.Conclusion: Results obtained in vivo and in vitro bioassay indicate that LLH ethanol extract possess potential anti-inflammatory activities, which justify the traditional application of LLH as a remedy for inflammatory diseases; two main anti-inflammatory bioactive fractions were identified, and compound 1, 3-8, 10 were parts of the active constituents in the bioactive fractions.