Vicenin-2 and vitexin participate in the in vitro modulation of the anti- inflammatory and antioxidant activities exerted by two Urtica circularis extracts

Urtica circularis is an Argentinean species traditionally used to treat inflammation symptoms and oxidative stress-related diseases. Considering the uses in folk medicine, the purpose of this work was to evaluate and compare the anti-inflammatory and antioxidant activities of two different U. circularis extracts. The contribution of vicenin-2 and vitexin, two compounds identified in the phytochemical analysis, in the biological activity of the extracts was evaluated. The anti-inflammatory activity of the extracts and the isolated compounds was tested on lipopolysaccharide (LPS)-stimulated macrophages, while the antioxidant activity was evaluated through the 2,2 ' diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2 '-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) scavenging activities. The popular uses of both extracts were validated, i.e., the use of U. circularis ethanol extract for the treatment of inflammation, and the use of the aqueous extract to treat oxidative stress related-diseases. The differences in the biological activities observed between the extracts are probably due to qualitative and/or quantitative differences in the chemical composition and/or the occurrence of synergism between compounds.