Effect of ginsenoside-Rg1 on experimental Parkinson's disease: A systematic review and meta-analysis of animal studies

Previous studies have reported that ginsenoside-Rg1 (G-Rg1) was able to mitigate the loss of dopaminergic neurons in animal models of Parkinson's disease (PD). The present study provided a systematic review and meta-analysis of preclinical studies to pool current evidence on the effect of G-Rg1 on neurogenesis in the treatment of PD. Eligible studies were identified through a search from six databases: PubMed, EMBASE, Web of Science, VIP, Chinese National Knowledge Infrastructure and the Wanfang database. Primary outcomes were tyrosine hydroxylase (TH)-positive cells in the nigra, Nissl staining-positive cells in the nigra, pole test time and dopamine (DA) levels in the striatum. A total of 18 eligible studies were identified, involving 343 animals. Of these, 13 reported a significant relationship between G-Rg1 and improved TH-positive cells in the nigra compared with the control group (P<0.00001). Furthermore, 3 studies reported a significant relationship between G-Rg1 and improved Nissl-positive cells in the nigra compared with the control group (P<0.00001). In addition, 4 studies reported a significant effect of G-Rg1 to reduce the total pole test time compared with that in the control group (P=0.001). A total of 3 studies indicated a significant association between G-Rg1 and improved DA levels in the striatum compared with the control group (P<0.00001). These results suggested that G-Rg1 has positive effects in attenuating damage in models of PD, and thus, it is a potential candidate neuroprotective drug for human PD.