Evaluation of Soluble Epoxide Hydrolase Inhibition Activity of 50 Traditional Medicinal Plants: Exploring Old Drugs for the New Pharmacological Target

Abstract

Soluble epoxide hydrolase inhibitors have been reported as antihypertensive, anti-inflammatory, antiulcer and anticancer actions and protect the brain, heart and kidney from damage. Exploring soluble epoxide hydrolase inhibition activity of traditional medicinal plants helps to uncover the new target to treat various complications associated with inflammatory mediators. The present study was planned to explore soluble epoxide hydrolase inhibition activity of fifty medicinal plants commonly used in the traditional medicinal system. The dried plant material of each species was grounded into a coarse powder and separately macerated with absolute methanol and ethyl acetate for 7 d. Then the solvents were evaporated and obtained extracts were solubilized in dimethyl sulfoxide (10 mg/ml) and soluble epoxide hydrolase enzyme inhibitory potencies were evaluated using a fluorescent reporting system. Moreover, preliminary phytochemical screening and high-performance thin layer chromatography analysis were carried out for two extracts that showed potent soluble epoxide hydrolase inhibition activities. The results revealed that 10 methanolic extracts and 20 ethyl acetate extracts were potentially effective in suppressing soluble epoxide hydrolase activity with inhibitory concentration value of less than 10 μg/ml. Among the 30 potentially effective plants, four seed extracts (Celastrus paniculatus, Nigella sativa, Wrightia tinctorial, Vernonia anthhelmintica and Embelia ribes), one leaves extracts (Bergera koengii), one rhizome extracts (Curcuma longa) and one root extracts (Vetiveria zizanioides) were common in both methanolic and ethyl acetate extract. In conclusion, the study report suggests that various natural products used in the traditional medicinal system have many promising soluble epoxide hydrolase inhibitors. Methanolic extracts of seeds of Celastrus paniculatus and Nigella sativa have potent soluble epoxide hydrolase inhibition activities. Further research is warranted to identify a greater number of medicinal plants and active principles responsible for soluble epoxide hydrolase inhibition activities