Neuroprotective potential of Ocimum sanctum (Linn) leaf extract in monosodium glutamate induced excitotoxicity

The aim of this study was to investigate the potent neuroprotective property of ethanol extract of Ocimum sanctum (EEOS) leaf (Holy basil, Family: Labiataea) against excitotoxicity induced neurodegeneration by using monosodium-L-glutamate (MSG) in Sprague-Dawley rats. The animals received EEOS (50, 100 and 200 mg/kg) and memantine (MMT, 20 mg/kg) daily for 7 days. On all the 7 days, MSG (2g/kg, i.p.) was administered one hour before drug treatment. The animals were observed for neurobehavioral performance on 1st, 3rd, 5th and 7th day. Oxidative damage and histopathological analysis were also assessed. EEOS (100 and 200 mg/kg, p.o.) and MMT (20 mg/kg, i.p.) administration significantly improved body weight and attenuated locomotor activity, rotarod performance and foot-fault test  as compared with MSG treated group. In addition, EEOS was found to restore reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), super oxide dismutase (SOD) and Na+-K+ ATPase. Conversely, the elevated level of lipid peroxidation and nitrite concentration in MSG treated group was attenuated significantly in EEOS group in comparison to MSG treated group. Histopathological evaluation showed that treatment with EEOS and MMT signicantly attenuated neuronal death and increased the density of neurons after MSG treatment. Thus, these findings suggest that EEOS contains rosmarinic acid and ursolic acid in addition to other bioactive principles may have utility in the preventing and/or treating the neurodegenerative diseases and its protective effects may be due to the amelioration of excitotoxicity, oxidative stress, neurological and behavioral alterations.However, further studies are necessary to clearly define mechanism responsible.   Key words: Ocimum sanctum, F Holy basil, sodium glutamate, neurological, neurodegeneration. rosmarinic acid