Anti-inflammatory activity and chemical analysis of extracts from Trifolium riograndense

Abstract

Aiming to investigate new therapeutic agents with fewer side effects, the number of studies about naturalproducts has increased. Phenolic compounds comprise a well-studied class of abundant plant-derivedcompounds, whose anti-inflammatory activity has been described. Isoflavones are phenolic compoundsthat occur mainly in the Leguminosae family, and can be found in many species, such as Trifoliumriograndense Burkart, Leguminosae (clover). In this study an HPLC method was used to determine andquantify four isoflavones (genistein, daidzein, formononetin, and biochanin A) in hydrolyzed leaf, flower,stolon, and root extracts of T. riograndense. In vivo anti-inflammatory activity was investigated using therat paw edema method and in vitro chemotaxis model with a dry extract from the leaves, which had thehighest amount of isoflavones. The major isoflavone found in all parts of the plant was formononetin.The chemotaxis assay revealed that the different concentrations (0.2–50 g/ml) of the dry extract sig-nificantly inhibited neutrophil migration in a concentration-dependent manner (more than 90%). In therat paw edema test, oral administration of clover extract 100 mg/kg was able to significantly inhibitthe edema formation induced by carrageenan. In conclusion, chemical analyses showed that Trifoliumriograndense is a plant rich in isoflavones and a new interesting option as isoflavone source. The results ofthe biological tests taken together show that the extract of T. riograndense has anti-inflammatory effectin rodents.