Anti-inflammatory and antinociceptive activities of the aqueous leaf extract of Phyllanthus amarus Schum (Euphorbiaceae) in some laboratory animals.

Abstract

Phyllanthus amarus has a history of use in Ayurvedic medicine for over 2000 years as well as a wide variety of traditional applications and has gained popularity in many continents as a herbal remedy; hence, it is being assessed for its safety potential and anti-inflammatory and analgesic properties in some laboratory animals. Standard phytochemical methods were used to test for the presence of phytoactive compounds in the plant. Acute toxicity testing was carried out in mice to determine safe doses for the extract. The anti-inflammatory activity of the leaf extract of this plant was assessed using carrageenan-induced and histamine-induced paw edema. The analgesic effect was determined using the acetic acid writhing method as well as formalin test. The extract at 100 and 200 mg/kg body weight reduced significantly, the formation of edema induced by carrageenan and histamine. In the acetic acid-induced writhing model, the extract showed a good analgesic effect characterized by reduction in the number of writhes when compared to the control. The extract caused dose-dependent decrease of licking time in rats injected with 2.5% formalin, signifying its analgesic effect. These results were also comparable to those of ibuprofen, the reference drug used in this study. The plant extract reduced significantly the formation of edema induced by carrageenan and histamine as well as reducing the number of writhes in acetic acid-induced writhing models and dose-dependent decrease of licking time in rats injected with 2.5% formalin. The results have validated the basis for the traditional use of P. amarus as a medicinal plant.