Xanthone-rich dichloromethane fraction of Securidaca inappendiculata, the possible antirheumatic material base with anti-inflammatory, analgesic, and immunodepressive effects

Abstract

Context: Securidaca inappendiculata Hassk. is an traditional Chinese medicine curing rheumatoid arthritis, but there is a lack of reports on material base research. Objective: To find the active fraction of S. inappendiculata contributing the most to antirheumatic activity. Materials and methods: Prior to assays in vivo, mice were treated with different fractions from S. inappendiculata for 5d at doses relative to 10, 5, and 2.5g/kg of crude drug. Hot plate test and carrageenan-induced paw edema test were used to investigate analgesic and anti-inflammatory activities. PGE2 levels in inflammatory paws were determined by a colorimetric method. Carbon clearance test in vivo and lymphocyte transformation test in vitro were employed to assess the immune regulation activity. HPLC was used to explore the main compounds in the active fraction. Results: All the fractions, especially the dichloromethane fraction (SID), alleviated inflammation. High dose of SID (112mg/kg) inhibited paw swelling by 63.1%, and decreased PGE2 level to 38ng/mL. The ethyl acetate fraction (SIE) and SID suppressed the carbon clearance rate (K=0.044, 0.038 for high dose) efficiently. All fractions hindered the transformation and proliferation of lymphocyte, and prolonged the reaction time of rats in the hot plate test. The concentrations of two typical xanthones: 2-hydroxyl-1,7-dimethoxyl-xanthone and 1,7-dihydroxyl-xanthone in SID were 0.93% and 1.19%, respectively, by HPLC analysis. Conclusion: SID exhibited significant anti-inflammatory, analgesic, and immunodepressive effects in vivo and vitro, and deemed as the main material base for the antirheumatic activity.