IMMUNOMODULATORY EFFECTS OF THAI MEDICINAL PLANTS ON THE MITOGEN STIMULATED PROLIFERATION OF HUMAN PERIPHERAL BLOOD MONONUCLEAR CELLS IN VITRO

ABSTRACT

The immunomodulatory effects of Thai medicinal plants, including Murdannialoriformis, Cymbopogon citratus, Momornica charantia, Centella asiatica, Alliumsativum, Carthamus tinctorius, Eclipta alba, Cyperus rotundus, lotus pollen (Dee-Buo),and plant embryos in seeds of the lotus (Ke-Sorn-Buo), on the mitogen stimulatedproliferation of human peripheral blood mononuclear cells (PBMCs) were investigated.The results obtained from this study indicated that only water extracts from C. asiaticahad an immunostimulating effect on mitogen-stimulated proliferation of human PBMCs.In contrast, the ethanol extract from this plant showed immunosuppressive activity.Moreover, the water and ethanol extracts of Ke-Sorn-Buo, Dee-Buo, C. rotundus andE. alba had immunosuppressive effects. These extracts strongly decreased PBMCproliferation in a dose-dependent manner. Ethanol extract of C. tinctorius also showedimmunosuppressive activity at a high concentration. Other medicinal plants did not showany mitogenic responses. This in vitro study revealed various effects of Thai medicinalplant extracts on non-specific cellular immune responses. Further investigation should beconsidered on the effect of extracts on other immune parameters such as macrophageactivity, NK cell activity including cell signaling and cytokine production. Chiang MaiMed Bull 2005;44(1)1-12.