Effects of polyphenol on motor function in mice with Parkinson's disease: a systematic review and meta-analysis

Polyphenols have been reported to have a multi-targeted neuroprotective effect on Parkinson's disease (PD). However, there has been no comprehensive analysis of the effect of polyphenol therapy on improving motor symptoms in PD. We used keywords to search the electronic databases PubMed, Scopus, EBSCO, SpringerLink, China National Knowledge Infrastructure (CNKI), Wan Fang and Web of Science from the establishment of the database to April 2023. A randomized effects model systematic review and meta-analysis of 83 included studies were conducted to investigate the ameliorative effects of polyphenols on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced motor dysfunction in a rodent model of PD. The results showed that compared with PD control group, polyphenols significantly improved balance, exploration, vertical crawling, horizontal crawling, muscle strength and sensorimotor function motor dysfunction of rodents. Subgroup analysis showed that the types of polyphenols had different recovery effects on motor symptoms of PD. Oral polyphenol intervention was superior to intraperitoneal and intravenous administration. This meta-analysis provides comprehensive evidence for the prevention or treatment of Parkinson's motor symptoms with polyphenols and expands the idea of future clinical application of polyphenols.