Concentration-dependent biphasic effects of resveratrol on human natural killer cells in vitro.

Resveratrol (RES) is a polyphenol phytoalexin from plants, which has been reported to possess a variety of biological effects. The properties of RES on human natural killer (NK) cells were assessed in this study. Results showed that RES has concentration-dependent biphasic effects on NK cells. In high concentration (50 muM), RES can inhibit viability and promoted apoptosis of NK cells and human lymphoblastoid T (Jurkat) cells, which may affect the caspase signaling pathway. The Jurkat cells were more sensitive than NK cells on the RES caused cell death. However, when the concentration range reduced from 3.13 to 1.56 muM, RES showed the positive effects on NK cells by increasing the NK cells cytotoxicity via up-regulating the expression of NKG2D and IFN-gamma (in mRNA and protein levels). These results indicated that one needs to pay more attention to the dosage and biphasic effects when RES was applied as antitumor drugs or health products.