Protective effect of aqueous and ethanolic extracts of Lippia citriodora Kunth. on acrylamide-induced neurotoxicity

Acrylamide (ACR) neurotoxicity is induced by different mechanisms such as oxidative stress and apoptosis. Scientific researchs have indicated the antioxidative properties of Lippia citriodora. The protective effect of L. citriodora aqueous and ethanolic extracts on ACR-induced neurotoxicity was investigated. Male Wistar rats were randomly divided into 13 groups: (1) control, (2) ACR (50 mg/kg, i.p.), (3-6) ACR+aqueous extract (12.5, 25, 50, and 100 mg/kg, i.p.), (7-10) ACR+ethanolic extract (12.5, 25, 50, and 100 mg/kg, i.p.), (11) aqueous extract (100 mg/kg), (12) ethanolic extract (100 mg/kg), and (13) ACR+Vitamin E (200 mg/kg, every other day, i.p.). After 11 days, gait score, MDA, and GSH levels in brain cortical tissue were measured. In the in vitro test, the viability of PC12 cells (using MTT test), the amount of reactive oxygen species (ROS; using DCFH-DA method), and the protein levels of Bax, Bcl2 and caspase 3 (by western blotting) were measured. In the in vitro study, the IC50 for the treatment of PC 12 cells with ACR after 24 hr was 6 mM.  ACR decreased cell viability, but increased ROS level, Bax/Bcl-2 ratio, and caspase-3 protein level. Pre-treatment by L. citriodora extracts (15-120 µg/ml) ameliorated the toxic effects of ACR on PC12 cells. In the in vivo experiment, ACR-induced movement disorders increased MDA but decreased GSH content. The extracts of L. citriodora improved ACR toxic effects. Aqueous and ethanolic extracts of L. citriodora were found to reduce ACR-induced neurotoxicity via inhibiting oxidative stress and apoptosis.