<i>Ziziphora clinopodioides</i> Flavonoids Exert a Protective Effect Against MPP ⁺ /MPTP-induced Cell Damage in Parkinson’s Disease Model Through Activating the AMPK/miR-181b Axis

Background and Purpose Parkinson’s disease (PD) is a common age-related neurodegenerative disorder. Mitochondrial dysfunction is considered an important initiating factor for the lack of dopaminergic (DA) neurons. Therefore, identifying drugs that effectively protect DA neurons from mitochondrial damage represents a promising therapeutic strategy. Methods In this study, an anti-atherosclerosis (AS) drug, Ziziphora clinopodioides flavonoids (ZCF), was shown to inhibit 1-methyl-4-phenylpyridinium (MPP + )-induced DA neuron damage in vitro and in vivo and this was verified by a variety of experimental methods. Cell viability assays, cell fluorescence staining, Western blot experiments, flow cytometry analysis, and quantitative real-time polymerase chain reaction (qPCR) experiments were conducted to assess the protective effect and mechanism of ZCF on SH-SY5Y cells. Additionally, behavioral tests and immunohistochemistry (IHC) were performed to validate the protective effect of ZCF in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD animal model. Results ZCF significantly ameliorated MPP + -induced cell viability loss and elevated lactate dehydrogenase (LDH) in SH-SY5Y cells. Moreover, ZCF treatment improved mitochondrial morphological abnormalities, reduced adenosine triphosphate (ATP) content, attenuated mitochondrial membrane potential loss, cell apoptosis, mitoROS levels, and increased the level of tyrosine hydroxylase (TH). Further results indicate that ZCF treatment significantly stimulated the phosphorylation of AMP-activated protein kinase (AMPK) and its downstream target miR-181b. Additionally, the blockage of the level of AMPK with Compound C or knocking down the expression of miR-181b significantly attenuated the protective effect of ZCF. These results indicate that the AMPK/miR-181b axis plays a vital role in the protective effect of ZCF. Moreover, ZCF treatment alleviated MPTP-induced motor dysfunction and loss of TH-positive neurons in the PD mice model. Conclusion In brief, our findings suggest that ZCF may have potential applications for the treatment and prevention of PD.