Role of ethanolic extract of Bacopa monnieri against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced mice model via inhibition of apoptotic pathways of dopaminergic neurons.

Abstract

Parkinson's disease (PD) is a neurodegenerative disease which causes rigidity, resting tremor and postural instability. The neuroprotective effects of an ethanolic extract of Bacopa monnieri (BM) were evaluated in a Parkinsonian mice model induced by the MPTP. The present study investigates the mechanisms of neuroprotection elicited by BM, an herb traditionally recognized by the Indian system of medicine, Ayurveda. An ethanolic extract of BM was co-treated with the MPTP induced mouse model of PD and was shown to significantly rescue the motor behaviour (Rotarod, Grip Strength and Foot Printing test). Furthermore, on biochemical parameters too BM significantly showed protective effect as Catalase, LPO, Nitrite, SOD, GR, GPx parameters showed marked improvement and levels of Dopamine, DOPAC and HVA were enhanced significantly. There was a significant reduction in tyrosine hydroxylase (TH) immunoreactivity in the substantia nigra (SN) in MPTP treated group, which was considerably restored by the use of BM extract. BM also facilitated neuroprotection by creating an anti-apoptotic environment indicated by reduced apoptotic (Bax and caspase-3) and increased levels of anti-apoptotic (Bcl2) protein expression, respectively. Altogether, the present study suggests that BM treatment provides nigrostriatal dopaminergic neuroprotection against MPTP induced Parkinsonism by the modulation of oxidative stress and apoptotic machinery possibly accounting for the behavioural effects.