The vitamin C:vitamin K3 system - enhancers and inhibitors of the anticancer effect.

ABSTRACT

The oxidizing anticancer system of vitamin C and vitamin K3 (VCVK3, producing hydrogen peroxide via superoxide) was combined individually with melatonin, curcumin, quercetin, or cholecalciferol (VD3) to determine interactions. Substrates were LNCaP and PC-3 prostate cancer cell lines. Three of the tested antioxidants displayed differences in cell line cytotoxicity. Melatonin combined with VCVK3 quenched the oxidizing effect, while VCVK3 applied 24 hours after melatonin showed no quenching. With increasing curcumin concentrations, an apparent combined effect of VCVK3 and curcumin occurred in LNCaP cells, but not PC-3 cells. Quercetin alone was cytotoxic on both cell lines, but demonstrated an additional 50-percent cytotoxicity on PC-3 cells when combined with VCVK3. VD3 was effective against both cell lines, with more effect on PC-3. This effect was negated on LNCaP cells with the addition of VCVK3. In conclusion, a natural antioxidant can enhance or decrease the cytotoxicity of an oxidizing anticancer system in vitro, but generalizations about antioxidants cannot be made.