Pharmacological anti-inflammatory activity of Lablab purpureus Linn

Abstract

The present study systematically explores the phytochemical and pharmacological potential of Lablab purpureus Linn., with a focus on its anti-inflammatory activity. The anti-inflammatory effect was evaluated using the carrageenan-induced paw oedema model in rats—a well-established biphasic model to assess acute inflammation. Various extracts, including aqueous, methanolic, ethanolic, and chloroform, were administered at different dose levels. Among them, the methanolic extract (MEL) showed the most significant inhibition of oedema, with 200 and 300 mg/kg body weight producing 80% and 82% inhibition, respectively. These effects were superior to those of the standard drug diclofenac, which showed 74% inhibition. Ethyl acetate, aqueous, and chloroform extracts exhibited comparatively lower activity, ranging from 60% to 73% inhibition. Acute toxicity studies confirmed the safety of the methanolic extract up to 2000 mg/kg body weight according to OECD guideline 423. The methanolic extract at 200 mg/kg was selected for further analysis due to its optimal efficacy. Mechanistic studies suggest that MEL inhibits the release of key inflammatory mediators such as histamine, serotonin, and prostaglandins. In vitro assays using LPS-stimulated RAW 264.7 macrophages revealed that MEL significantly suppressed cyclooxygenase (COX) activity and reduced nitric oxide (NO) production, likely via downregulation of inducible nitric oxide synthase (iNOS). Additionally, the extract may inhibit lipoxygenase (LOX) pathways, contributing to decreased leukotriene formation and oxidative stress. These findings indicate that the methanolic extract of Lablab purpureus Linn. possesses potent anti-inflammatory properties and holds promise as a therapeutic agent for the management of acute inflammatory conditions.