Determination of il-10 expression in peripheral blood mononuclear cells (PBMCs) treated with ethanolic extract of Gynura procumbens / Muhammad Azim Aizuddin Shokhimi

Gynura procumbens (G. procumbens) is a traditional medicinal herb that commonly used in South-East Asia as food consumption to treat inflammation, skin rashes and viral infection. Interleukin-10 (IL-10) is an anti-inflammatory cytokine act to activate macrophages and B cells, inhibit mast cells and T-helper 1 (Th1) cells, and stimulate T-helper 2 (Th2) cells. This cytokine activated from monocytes, macrophages, and different T-cell subsets which can be mainly found in peripheral blood mononuclear cells (PBMCs). Our aim was to determine the expression of IL-10 in PBMCs treated with G. Procumbens aqueous extraction. Peripheral Blood Mononuclear Cells (PBMCs) isolated from whole blood by using Ficoll gradient density were used to determine the activities of G. Procumbens on lymphocytes, monocytes and macrophages function to induce the expression of inflammatory cytokines, IL-10 with different concentrations of G. Procumbens aqueous extraction (50, 200 and 800 µg/ml). Viability of PBMCs was observed and calculated after staining with Trypan blue and Wright stain. A specific Toll-like receptor (TLR) 4 inhibitor, CLI095 was used to determine whether or not G. Procumbens exerts its effects through TLR4. An antagonist of lipopolysaccharides (LPS), polymyxin B, was used to evaluate whether endotoxin properties in G. Procumbens contributed to its immunomodulatory activity. Cell culture supernatants were analysed by using Luminex® Human Screening Magnetic Assay. G. procumbens exhibited not significantly potent immunomodulatory activity of IL-10 by PBMCs. The expression of IL-10 were increased upon exposure to different concentrations of G. procumbens by co-treatment with CLI-095 (TLR4 inhibitor) but partially decreased by polymyxin B (LPS-neutralizer). One-way ANOVA of those treatment groups compared to control group give p>0.05 followed by post-hoc multiple comparison Dunnett’s test. We demonstrate impotent immunomodulatory activity of G. procumbens towards the expression of IL-10 by PBMCs. We believe that this immunomodulatory activity is due to endotoxin-like properties of G. procumbens via TLR4 receptor and MyD88 or Toll/IL-1R domain-containing adaptor inducing IFN-β (TRIF) - signalling pathways.