Antioxidant and neuroprotective activities of Hyptis suaveolens (L.) Poit. against oxidative stress-induced neurotoxicity.

The present study was carried out to investigate the antioxidant and neuroprotective effects of Hyptis suaveolens methanol extract (HSME) using various in vitro systems. The total phenol and flavonoids contents of the HSME were quantified by colorimetric methods. The HSME extract exhibited potent antioxidant activity as determined by 2,20-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, 2,2-diphenyl-1-picrylhydrazyl, and ferric reducing antioxidant power assays. The neuroprotective activity of HSME was determined on mouse N2A neuroblastoma cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, lactate dehydrogenase, intracellular ROS assays, and upregulation of brain neuronal markers at genetic level. The N2A cells were pretreated with different concentrations (0.5, 1, 1.5, and 2 mg/ml) of the extract and then exposed to H2O2 to induce oxidative stress and neurotoxicity. The survival of the cells treated with different concentrations of HSME and H2O2 increased as compared to cells exposed only to H2O2 (47.3 %) (p < 0.05). The HSME also dose-dependently reduced LDH leakage and intracellular ROS production (p < 0.05). Pretreatment with HSME promotes the upregulation of tyrosine hydroxylase (2.41-fold, p < 0.05), and brain-derived neurotrophic factor genes (2.15-fold, p < 0.05) against H2O2-induced cytotoxicity in N2A cells. Moreover, the HSME showed antioxidant activity and decreased neurotoxicity. These observations suggest that HSME have marked antioxidant and neuroprotective activities.