The flavonoid baicalein inhibited in vitro apoptotic mitochondrial cell death and maintained mitochondrial integrity and function in both SH-SYTY and PC12 cells in 6-OHDA and rotenone Parkinson's disease models as evidenced in the decrease in caspase-3, caspase-7, caspase-9, and JNK activities and in the maintenance of mitochondrial membrane potential, increment of ATP content and reduction of ROS production [82–84]. This evidence concerns the gene CASP9 and Parkinson disease.