The protections of DA neurons in PD models against DA-related toxicity including anti-oxidative capacity, inhibition of DA oxidation, detoxification of deleterious by-products of DA oxidation, inhibition of MAOB, potential modulations of protective Nrf2-Keap1 and PGC-1α signaling pathways by tea polyphenols and other agents are investigated. The gene discussed is NFE2L2; the disease is Parkinson disease.