Neuroprotective effects of hydroalcoholic extract of Ocimum sanctum against H2O2 induced neuronal cell damage in SH-SY5Y cells via its antioxidative defence mechanism.

Oxidative stress mediates the cell damage in several ailments including neurodegenerative conditions. Ocimum sanctum is widely used in Indian ayurvedic medications to cure various ailments. The present study was carried out to investigate the antioxidant activity and neuroprotective effects of hydroalcoholic extract of O. sanctum (OSE) on hydrogen peroxide (H2O2)-induced oxidative challenge in SH-SY5Y human neuronal cells. The extract exhibited strong antioxidant activity against DPPH, 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical and hydroxyl radicals with IC50 values of 395 ± 16.2, 241 ± 11.5 and 188.6 ± 12.2 µg/ml respectively, which could be due to high amount of polyphenols and flavonoids. The observed data demonstrates 41.5% cell survival with 100 µM H2O2 challenge for 24 h, which was restored to 73% by pre-treatment with OSE for 2 h. It also decreased the lactate dehydrogenase leakage and preserved the cellular morphology. Similarly OSE inhibited lipid peroxidation, DNA damage, reactive oxygen species generation and depolarization of mitochondrial membrane. The extract restored superoxide dismutase and catalase enzyme/protein levels and further downregulated HSP-70 over-expression. These findings suggest that OSE ameliorates H2O2 induced neuronal damage via its antioxidant defence mechanism and might be used to treat oxidative stress mediated neuronal disorders.

Neuroprotective effects of Cyperus rotundus on SIN-1 induced nitric oxide generation and protein nitration: ameliorative effect against apoptosis mediated neuronal cell damage.

Nitrosylation of tyrosine (3-nitro tyrosine, 3-NT) has been implicated in the pathophysiology of various disorders particularly neurodegenerative conditions and aging. Cyperus rotundus rhizome is being used as a traditional folk medicine to alleviate a variety of disorders including neuronal stress. The herb has recently found applications in food and confectionary industries also. In current study, we have explored the protective effects of C. rotundus rhizome extract (CRE) through its oxido-nitrosative and anti apoptotic mechanism to attenuate peroxynitrite (ONOO(-)) induced neurotoxicity using human neuroblastoma SH-SY5Y cells. Our results elucidate that pre-treatment of neurons with CRE ameliorates the mitochondrial and plasma membrane damage induced by 500 µM SIN-1 to 80% and 24% as evidenced by MTT and LDH assays. CRE inhibited NO generation by downregulating i-NOS expression. SIN-1 induced depletion of antioxidant enzyme status was also replenished by CRE which was confirmed by immunoblot analysis of SOD and CAT. The CRE pre-treatment efficiently potentiated the SIN-1 induced apoptotic biomarkers such as bcl-2 and caspase-3 which orchestrate the proteolytic damage of the cell. The ONOO(-) induced damage to cellular, nuclear and mitochondrial integrity was also restored by CRE. Furthermore, CRE pre-treatment also regulated the 3-NT formation which shows the potential of plant extract against tyrosine nitration. Taken together, our findings suggest that CRE might be developed as a preventive agent against ONOO(-) induced apoptosis.