Protective effects of some medicinal plants from Lamiaceae family against beta-amyloid induced toxicity in PC12 cell

Excessive accumulation of beta-amyliod peptide (Aβ), the major component of senile plaques in Alzheimer's disease (AD), causes neuronal cell death through induction of oxidative stress. Therefore, antioxidants may be of use in the treatment of AD. The medicinal plants from the Lamiaceae family have been widely used in Iranian traditional medicine. These plants contain compounds with antioxidant activity and some species in this family have been reported to have neuroprotective properties. In the present study, methanolic extract of seven plants from salvia and satureja species were evaluated for their protective effects against beta-amyloid induced neurotoxicity. Aerial parts of the plants were extracted with ethyl acetate and methanol, respectively, by percolation at room temperature and subsequently, methanolic extracts of the plants were prepared. PC12 cells were incubated with different concentrations of the extracts in culture medium 1h prior to incubation with Aβ. Cell toxicity was assessed 24h after addition of Aβ by MTT assay. Satureja bachtiarica, Salvia officinalis and Salvia macrosiphon methanolic extracts exhibited high protective effects against Aβ induced toxicity (P<0.001). Protective effects of Satureja bachtiarica and Salvia officinalis were dose-dependent. The main constituents of these extracts are polyphenolic and flavonoid compounds such as rosmarinic acid, naringenin, apigenin and luteolin which have antioxidant properties and may have a role in neuroprotection. Based on neuroprotective effect of these plants against Aβ induced toxicity, we recommend greater attention to their use in the treatment of Alzheimer disease.