n-Propanol extract of boiled and fermented koro benguk (Mucuna pruriens seed) shows a neuroprotective effect in paraquat dichloride-induced Parkinson’s disease rat model

AIM: n-Propanol extracts from fresh, boiled, and fermented seeds were studied to evaluate their neuroprotective effects in a Parkinson’s disease (PD) rat model, based on the total number of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). MATERIALS AND METHODS: Rats were induced with paraquat dichloride at a dosage of 7 mg/kg BW intraperitoneally twice a week and at the same time supplemented with extract at a dosage of 70 mg/kg BW orally every day for 3 weeks. On the 24(th) day, all rats were perfused and fixed with 4% paraformaldehyde. The left part of the SNpc was processed for immunohistochemical staining with tyrosine hydroxylase (TH)-antibody. The total number of DA neurons in SNpc was evaluated with a stereological method. RESULTS: TH-immunoreactive cells found in the SNpc were identified as DA neurons. The average total number of DA neurons in the SNpc increased significantly in the PD rat model that was given an n-propanol extract of boiled and fermented seeds compared with a control PD rat model. Surprisingly, there was no significant difference in the average total number of DA neurons in SNpc between the PD rat model that was given n-propanol extract of fresh seeds and the control PD rat model. CONCLUSION: n-Propanol extract of boiled and fermented seeds could produce a higher neuroprotective effect against DA neuron than fresh seeds in a PD rat model.