ABSTRACT
The accumulation of beta-amyloid peptide [Abeta] in the brain, is the main characteristic of Alzheimer's disease [AD] that cause oxidative stress and neurotoxicity. Melissa officinalis can protect cells against oxidative damages. This plant is also used in traditional medicine as a memory enhancer and diseases that are associated with neurological disorders. This study investigated the effects of ethanolic extract of Melissa officinalis on Abeta induced neurotoxicity and its antioxidant mechanism. Aerial parts of Melissa officinalis were extracted with ethanol 80% using maceration method. PC12 cells were incubated with the extract prior to incubation with Abeta and cell toxicity, production of reactive oxygen species [ROS], lipid peroxidation and glutathione peroxidase activity were measured 24 h later. Incubation of PC12 cells with Abeta significantly caused cell death in PC 12 cells, this was accompanied by increasing in ROS and lipid peroxidation but decreasing in glutathione peroxidase activity. Pretreatment with Melissa officinalis extract significantly protected PC 12 cells against Abeta induced toxicity and attenuated Abeta induced changes in oxidative stress biomarkers in PC 12 cells. Melissa officinalis extract, prevents Abeta induced neurotoxicity through attenuating oxidative stress. It may act as an ROS scavenger and can be a candidate for AD therapy