Anti-inflammatory effects of the Portulaca oleracea hydroalcholic extract on human peripheral blood mononuclear cells

Abstract

<b>Background:</b> <i>Portulaca oleracea</i>, known as Purslane, is an annual growing herb with wide distribution around the world and traditionally used to manage several diseases. Different therapeutic properties as an anti-fever agent as well as anti-inflammatory and analgesic effects have been attributed to <i>P. oleracea</i>. The aim of this study was to investigate the effects of <i>P. oleracea</i> aerial extract on production of pro- and anti-inflammatory cytokines by human peripheral blood mononuclear cells (PBMCs). <b>Methods:</b> Aerial parts of <i>P. oleracea</i> (stems and leaves) were collected and extracted by percolation using methanol. The optimal and non-cytotoxic dose of hydro-alcoholic extract for cell culture analysis was determined by MTT assay. To assess the antiinflammatory effects of <i>P. oleracea</i>, PBMCs obtained from 12 normal volunteers were cultured in RPMI complete medium and cotreated with E. coli lipopolysaccharide (LPS) and <i>P. oleracea</i> hydro-alcoholic extract. Following 18-hour incubation, culture supernatants were harvested for measurement of secreted TNF-α, IL-6 and IL-10 by ELISA. Statistical analyses were performed using the SPSS v.20, and data analyzed by Kolmogorov-Smirnov, Mann-Whitney U, Kruskal-Wallis and post Hoc tests. P-values<0.05 were considered significant. <b>Results:</b> The optimal non-cytotoxic concentration of <i>P. oleracea</i> aerial extract was defined as 100 μg/ml based on MTT viability assay. <i>P. oleracea</i> hydro-alcoholic extract significantly decreased the concentration of both pro-inflammatory cytokines TNF-α and IL-6 in LPS-stimulated PBMCs (p<0.001 and p<0.001, respectively). However, the concentration of IL-10 as an anti-inflammatory cytokine, did not show any statistically significant change (p=0.390). <b>Conclusion:</b> Our findings highlighted the potential anti-inflammatory properties of <i>P. oleracea</i> in herbal medicine. Future analysis on different constituents of total extract may confirm its therapeutic effects as a promising anti-inflammatory compound.