Curcumin (diferuloyl), from the Indian spice turmeric, reduces oxidative damage and induces apoptosis. Utilizing DNA microarrays, we have demonstrated that a low (5 microM) dose of curcumin added to a mixture of astrocytes and oligodendrocytes (C6 rat glioma cells) in culture for 24 and 48 h significantly modulates gene expression in four primary pathways: oxidative stress, cell cycle control, and DNA transcription and metabolism. Contribution of the pentose phosphate pathway to the pool of NADH upregulates glutathione and activates aldehyde oxidase. We have identified also several new genes, up- or downregulated by curcumin, namely, aldo-keto reductase, glucose-6-phosphate dehydrogenase, and aldehyde oxidase that protect against oxidative stress. The identification of several new cell cycle control genes, including the apoptosis-related protein (pirin) and insulin-like growth factor (IGF), and of the neurofilament M protein involved in neurogenesis suggests that curcumin may have applicability in the treatment of a spectrum of neurodegenerative diseases.