Examination of the Neuroprotective Effects of Various Formulations of Curcumin Against Methylmercury induced Toxicity in Human Neuroblastoma (SH‐SY5Y) Cells

Abstract

Methylmercury (MeHg) has been shown to cause numerous effects including oxidative stress and tau phosphorylation. Curcumin, the active ingredient of tumeric, has been reported to have antioxidant activity. A major limitation to therapeutic use of curcumin is its relatively low bioavailability. Strategies to increase curcumin's bioavailability include encapsulation within a liposome and/or binding to cyclodextrin. This study was conducted to assess the efficacy and potency of 4 forms of curcumin including: liposomal curcumin (LC), cyclodextrinated curcumin (CDC), liposomal cyclodextrinated curcumin (LC‐CDC) and DMSO‐dissolved curcumin (DC) against the toxic effects of MeHg in human neuroblastoma cells (SH‐SY5Y). The minimal concentrations found to produce complete protection against the effects of MeHg for DC, LC and LC‐CDC were 0.92μg/ml, 0.23μg/ml, 0.11μg/ml, respectively (n=9 p<0.001). The above doses of DC, LC and LC‐CDC completely attenuated MeHg induced tau phosphorylation (n=9, p<0.01). CDC did not protect the cells from the effects of MeHg at any tested dose (n=9). Results of this study indicate that curcumin was protective against the effects of MeHg and that LC‐CDC was significantly more potent than other formulations of curcumin. These results support the hypothesis that curcumin may be a useful tool to treat methylmercury induced neurological diseases.