Antioxidant effects of bioavailability-enhanced curcuminoids in patients with solid tumors: A randomized double-blind placebo-controlled trial

The present study investigated the impact of a bioavailability-enhanced preparation of curcuminoids on the biomarkers of systemic oxidative stress in patients with solid tumors receiving standard chemotherapy regimens. In a randomized double blind placebo-controlled trial, eighty subjects were allocated to bioavailability-enhanced curcuminoids (900 mg/day equivalent to 180 mg/day of curcuminoids; n = 40) or matched placebo (n = 40) for a period of 8 weeks. Serum activities of superoxide dismutase (SOD) and catalase (CAT) as well as concentrations of reduced glutathione (GSH) and thiobarbituric acid reactive species (TBARS) (as malondialdehyde equivalents) were evaluated at baseline and at the end of treatment period. Health-related quality of life (QoL) score was also calculated for each patient using the University of Washington index. Supplementation with curcuminoids was associated with a significantly greater elevation in the activities of SOD and CAT, and concentrations of GSH compared to the control group (p < 0.001). In contrast, serum TBARS were significantly reduced by curcuminoids (p < 0.001). Comparison of QoL scores also revealed a beneficial effect of curcuminoids versus placebo (p < 0.001). Likewise, the ratio of subjects with improved QoL at the end of study was significantly higher in the curcuminoids versus the placebo group (p = 0.003). Supplementation with bioavailability-enhanced curcuminoids in patients with solid tumors under concurrent chemotherapy is associated with a significant improvement of systemic oxidative stress and QoL.