HIF1A and Parkinson disease: We also showed that icaritin reversed the alterations observed in the levels of HIF-1α, taurine, ascorbic acid, glutamic acid, and glutamine, which are related to reduction in ROS levels and stabilization of the glutamate–glutamine cycle; these results further confirmed that icaritin inhibited oxidative stress and neuroinflammation, reduced DA neuronal damage, and that it may delay the development of PD.