ESR2 and Parkinson disease: In agreement with our original studies, this study confirmed that purified γ- and δ-tocotrienol bind to ERβ in vitro and that γ- and δ-tocotrienol were cytoprotective against Parkinson’s disease-related toxicities such as 1-methyl-4-phenylpyridinium ion (MPP+) thanks to a marked activation of the phosphoinositide-3-kinase/serine/threonine kinase-1 (PI3K/Akt) signaling pathway downstream to ERβ binding.