title: Curcumin activates defensive genes and protects neurons against oxidative stress.
abstract: 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 microM curcumin. Moreover, the effects of curcumin on HO-1 activity were explored in cultured hippocampal neurons. Elevated expression of HO-1 mRNA and protein were detected after 6 h incubation with 5-25 microM curcumin. Higher concentrations of curcumin (50-100 microM) 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.
authors: Institute of Neurological Sciences, National Research Council (CNR), Catania, Italy. g.scapagnini@isn.cnr.it
authors: Giovanni
authors: G
authors: Scapagnini
authors: Claudia
authors: C
authors: Colombrita
authors: Marialaura
authors: M
authors: Amadio
authors: Velia
authors: V
authors: D'Agata
authors: Enrico
authors: E
authors: Arcelli
authors: Maria
authors: M
authors: Sapienza
authors: Alessandro
authors: A
authors: Quattrone
authors: Vittorio
authors: V
authors: Calabrese