Characterisation of the anti-inflammatory potential of Vitex trifolia L. (Labiatae), a multipurpose plant of the Pacific traditional medicine

Aim of the study: Vitex trifolia L (Labiatae) is a plant commonly employed against Ciguatera Fish Poisoning (CFP) in the Pacific region. Here, the anti-inflammatory potential of an aqueous extract of Vitex trifolia leaves was evaluated by monitoring its effects on the modulation of cytokines, the mediators of inflammation, as well as on the expression profiles of inducible nitric oxide synthase (iNOS) which produces the free radical nitric oxide (NO). Materials and methods: We prepared an aqueous extract from Vitex trifolia leaves and evaluated its anti-inflammatory potency by monitoring its effect on the lipopolysaccharide (LPS)-induced cytokines and iNOS mRNA over-production in RAW 264.7 macrophages using quantitative Polymerase Chain Reaction (qPCR) and Enzyme-Linked Immunosorbent Assay (ELISA) methods. Results: Aqueous extract of Vitex trifolia leaves showed significant dose- and time-dependent inhibitory activity on interleukin (IL)-1 beta, IL-6 and iNOS mRNA synthesis, but slight effect on tumor necrosis factor (TNF)-alpha, all of which are involved in the inflammatory response. Moreover, the plant extract seemed to induce the LPS-dependant IL-10 anti-inflammatory cytokine. These results were further confirmed by ELISA using specific antibodies to mouse IL-6, IL-10 and TNF-alpha. Conclusion: The anti-inflammatory effects of Vitex trifolia could validate its utilization as a traditional remedy against CFP and emphasises its potential therapeutic value against other inflammatory diseases. Therefore, this plant is a promising candidate for further screening of its active compounds through activity-guided fractionation. (C) 2009 Elsevier Ireland Ltd. All rights reserved.