Determination of IL-10 expression in peripheral blood mononuclear cells (PBMCs) treated with aqueous extract of gynura procumbens / Zuraini Danial

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 (Thl) 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 IL10 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 ug/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/?>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-IR domain-containing adaptor inducing IFN-P (TRIF) - signalling pathways.