Neuroprotective Effects of Longan (Dimocarpus longan Lour.) Flower Water Extract on MPP+‑Induced Neurotoxicity in Rat Brain

In this study, the neuroprotective effect of Dimocarpus longan Lour. flower water extract (LFWE) was investigated. First, an in vitro study showed that LFWE concentration-dependently inhibited lipid peroxidation of brain homogenates incubated at 37 °C. The antioxidative activity of LFWE was more potent than that of glutathione or Trolox. Furthermore, an ex vivo study found that the basal lipid peroxidation (0 °C) and lipid peroxidation incubated at 37 °C were lower in the brain homogenates of LFWE-treated (500 mg/day) rats, indicating that the brain of LFWE-treated rats was more resistant to oxidative stress. Moreover, a Parkinsonian animal model was employed to demonstrate that oral administration of LFWE (125–500 mg/kg/day) dose-dependently attenuated 1-methyl-4-phenylpyridinium (MPP+)-induced neurotoxicity in the nigrostriatal dopaminergic system of rat brain. In conclusion, this study suggests that LFWE is antioxidative, anti-inflammatory, and anti-apoptotic. Furthermore, oral administration of LFWE appears to be useful in preventing and/or treating central nervous system neurodegenerative diseases, including Parkinsonism.