Anti-inflammatory and Antioxidant Activity of a Methanolic Extract of Phyllanthus orbicularis and its Derived Flavonols

Abstract

In order to validate the use of Phyllanthus orbicularis (Phyllantaceae) in the traditional medicine of Cuba as an anti-inflammatory remedy, the methanolic (MeOH) extract has been evaluated in vivo for anti-inflammatory activity on 12-O-tetradecanoyl-13-acetate phrobol (TPA) assay in mouse and in vitro for the antioxidant activity on Ferric Reduction Antioxidant Power assay. This extract exerted in vivo a significant anti-inflammatory activity. Subsequent fractionation and analysis of the extract has led to the isolation and characterization as major constituents of apigenin (1), rutin (quercetin 3-O—L-rhamnopyranosyl-(1->6)—D-glucopyranoside) (2) and quercetin (3) and of rutin decaacetate (4) and quercetin pentaacetate (5) from acetylated methanolic extract. Their structures were elucidated by spectral methods. The bioassay-directed analysis of flavonols 1–3 indicated that rutin (2) and quercetin (3) were the most active compounds, whereas apigenin showed no significant activity. The acetylation process increased the anti-inflammatory activity but decreased the antioxidant activity. The MeOH extract and all of flavonoids tested did not show in vitro significant cytotoxic effect in J774.A1 macrophage cell line. [Editor's note: The five compounds under discussion are denoted throughout this paper by bolded number (1, 2, etc.). This should not be confused with the referenced ancillary texts, denoted in non-bolded font and within parentheses.]