Inhibition of Nitric oxide Production and Nitric oxide Synthase Gene Expression in LPS Activated RAW 264 .7 Macrophages by Thyme oleoresin from Thymus vulgaris

Abstract

<p style="text-align: justify;"><strong>Objective:</strong> To evaluate the effect of Thyme oleoresin on nitric oxide production and nitric oxide synthase gene expression in RAW264.7 macrophage cell lines. <strong>Materials and Methods:</strong> The efficacy of Thyme oleoresin at different concentrations (3.175&ndash;150&mu;g/ml) was determined on nitric oxide production in RAW264.7 cells macrophages. The optical density was measured at 540 nm with a microplate reader. RT - PCR was used to examine the expression of the iNOS gene in activated macrophages. The Statistical analysis of the data was carried out by Dunnett&rsquo;s following one way ANOVA and Posthoc comparisons in Graph pad Prism 5.0 software version. <strong>Results:</strong> Thyme oleoresin at its tested concentrations exhibited dose &ndash; dependent decrease in the production of NO. The IC₅₀ value was 24.24 &mu;g/ml. LPS stimulated RAW macrophages strongly up regulated the iNOS gene expression levels. Thyme oleoresin at three different concentration, 12.5&mu;g/ml, 25&mu;g/ml and 50&mu;g/ml, significantly suppressed the iNOS levels compared to that of LPS treatment only. <strong>Conclusion:</strong> Thyme oleoresin extract may be used for its anti-inflammatory effect as it could significantly suppress the iNOS gene expression as well as the production of NO. <p style="text-align: justify;"><strong>Key words:</strong> Anti inflammatory, Macrophage cell line, Nitric oxide, Thyme oleoresin.