Spices and herbs often contain active phenolic substances endowed with potent antioxidative properties. We had previously shown that curcumin, the yellow pigment in curry, strongly induced HO-1 expression and activity in rat astrocytes. In the CNS, HO-1 has been reported to operate as a fundamental defensive mechanism for neurons exposed to an oxidant challenge. Treatment of astrocytes with curcumin upregulated expression of HO-1 protein at both cytoplasmic and nuclear levels, as shown by immunofluorescence analysis under laser-scanning confocal microscopy. A significant expression of quinone reductase and glutathione S-transferase, two members of phase II detoxification enzymes, was found in astrocytes exposed to 5-15 mu m curcumin. Moreover, the effects of curcumin on HO-I activity were explored in cultured hippocampal neurons. Elevated expression of HO-1 mRNA and protein were detected after 6 h incubation with 5-25 mu M curcumin. Higher concentrations of curcumin (50-100 mu M) caused a substantial cytotoxic effect with no change in HO-1 protein expression. Interestingly, pre-incubation (18 h) with curcumin resulted in an enhanced cellular resistance to glucose oxidase-mediated oxidative damage; this cytoprotective effect was considerably attenuated by zinc protoporphyrin IX, an inhibitor of heme oxygenase activity. This study gives additional support to the possible use of curcumin as a dietary preventive agent against oxidative stress-related diseases.
File in questo prodotto:
Non ci sono file associati a questo prodotto.