Oxidative stress in brain and antioxidant activity of Ocimum sanctum in noise exposure

Noise is a pervasive aspect of many modern communities, work environments and its damaging effects, particularly the production of free radicals are not limited to the auditory organ. The oxidative stress in three discrete brain regions, in wistar strain male albino rats subjected to three different durations of noise exposures (acute, sub-acute and chronic noise stress) and the in vivo as well as the in vitro antioxidant activity of Ocimum sanctum has been analyzed. Broadband white noise (100 dB) exposure significantly increased the levels of superoxide dismutase (EC 1.15. 1.1), catalase (EC 1.11.1.6), glutathione peroxidase (EC 1.11.1.9), lipid peroxidation, oxidized glutathione (GSSG) and decreased the levels of reduced glutathione (GSH), GSH/GSSG ratio. However, administration of ethanolic extract of O. sanctum attenuates the alterations induced by noise exposure. The antioxidant activity of O. sanctum is also evident from its effectiveness in scavenging the free radicals in a dose dependent manner in the herbal antioxidant assays. The results indicate that adaptation to noise does not occur in the brain regions even after 30 days of noise exposure. The abundance of phytochernicals such as phenolics and flavanoids in O. sanctum may be held responsible for its attenuating activity. Therefore, this study indicates that O. sanctum has the potential for further evaluation as an ideal antioxidant for the noise induced oxidative stress. (C) 2007 Elsevier Inc. All rights reserved.