The polyphenol hesperidin inhibited mitochondrial apoptotic pathway (increased Bcl2 levels and decreased Bax, caspase-3, and caspase-9 activities and inhibited cytochrome c release), maintained mitochondrial membrane potential, inhibited ROS production, and increased glutathione levels in in vitro human neuroblastoma SK-N-SH cells model of rotenone-induced Parkinson's disease [98]. Here, CASP9 is linked to Parkinson disease.