Immunomodulatory effects of combined Hyssopus officinalis and Teucrium polium extracts on cytokine production and Th17/Treg balance in human peripheral blood mononuclear cells

Purpose The balance between T regulatory (Treg) and T helper 17 (Th17) cells plays a major role in inflammatory and autoimmune diseases. Due to their immunomodulatory potential, medicinal plants are attractive therapeutic options. This study examined the effects of Hyssopus officinalis and Teucrium polium extracts, individually and in combination, on Treg/Th17 balance in activated human T lymphocytes in vitro. Methods Peripheral blood mononuclear cells (PBMCs) were isolated from healthy donors and used exclusively for the isolation of untouched human Pan T cells by negative magnetic selection. Purified Pan T cells were activated and cultured under standard conditions. Experimental groups included untreated control, H. officinalis, T. polium, and combined extracts. Cell viability and non-toxic extract concentrations were assessed by MTT assay. Treg cells (CD4⁺CD25⁺CD127^low/-) and Th17 cells (CD4⁺IL-17A⁺) were analyzed by flow cytometry. IL-10, TGF-β, and IL-17A levels were measured by ELISA, and gene expression of FOXP3, RORγt, IL-10, TGF-β, and IL-17A was analyzed by quantitative real-time PCR. Results The MTT assay showed no significant reduction in cellular metabolic activity at the selected extract concentrations. Combined treatment significantly increased the frequency of Treg cells and reduced Th17 cells compared with controls (p < 0.05). ELISA revealed increased IL-10 and TGF-β secretion with decreased IL-17A production. Real-time PCR showed upregulation of FOXP3, IL-10, and TGF-β and downregulation of RORγt and IL-17A. Conclusion Combined extracts of Hyssopus officinalis and Teucrium polium modulated Treg/Th17-associated markers in activated human Pan T cells under in vitro conditions, suggesting potential immunomodulatory effects in inflammatory and immune-mediated conditions.