Immunomodulatory activity of Semecarpus anacardium extract in mononuclear cells of normal individuals and rheumatoid arthritis patients

Semecarpus anacardium (SA) Linn. (family Anacardiaceae), is a plant well-known for its medicinal value in Ayurveda. The nut extracts of this plant have been traditionally used as antihelminthic, anti-fungal, anti-carcinogenic and in the treatment of nervous debilities and arthritis. In this study we have evaluated crude ethanolic extract of SA nuts for its anti-inflammatory activities in vitro using peripheral blood and synovial fluid mononuclear cells of healthy individuals and rheumatoid arthritis (RA) patients. SA extract inhibited the spontaneous and LPS induced production of proinflammatory cytokines IL-1β and IL-12p40 but had no effect on TNF-α and IL-6 production, both at protein and mRNA level.The crude extract also suppressed LPS induced nuclear translocation of transcription factors, NF-κB and AP-1; the inhibition of NF-κB was through the inhibition of IκBα phosphorylation. The extract also suppressed LPS activated nitric oxide production in mouse macrophage cell line, RAW 264.7. Our results for the first time show that SA extract can inhibit proinflammatory cytokine production and demonstrate its mechanism of action.