Immunomodulatory effects of Ziziphora tenuior L. extract on the dendritic cells.

Ziziphora tenuior L. (Kakuti in Persian) is used in traditional medicine for treatment of gastrointestinal disorders as carminative and analgesic plant. The other usages of this plant are included treatment of diarrhea and nausea. Therefore in the present study we evaluated the immunomodulatory effects of the ethanolic extract of this plant on the dendritic cells (DCs). Ziziphora tenuior L. extract significantly (p = 0.002) increased the level of surface expression of CD40 as an important co-stimulatory marker on DCs compared to the control. However this extract did not change CD86 and MHC-II molecules, so it could promote DCs phenotypic maturation. Treatment of DCs with the extract resulted in slightly increased of the production of (IL-12); however, this change was not significant. In addition, the ability of treated DCs to stimulate allogenic T cells proliferation and cytokines secretion was examined in the co-cuture of these cells with T cells in mixed lymphocyte reaction (MLR). Z. tenuior L. at the 100 μg/ml concentration inhibited the proliferation of allogenic T cells and also significantly (P < 0.001) increased the level of IL-10. Moreover, the extract at 10-100 μg/ml concentration caused slightly increase in IFN-γ production and decreased IL-4 cytokines but these changes were not significant. These findings indicated that Z. tenuior L. extract can modulate immune response by induction of CD40 expression on DCs and cytokine production; whereas it can inhibit T cell stimulating activity of DCs in high concentration. These findings possibly in part explain the traditional use of this plant in treatment of immune-mediated disorders. However future studies are needed.