NOS2 and Parkinson disease: Furthermore, a substantial body of evidence indicates that herbal medicines can attenuate neuroinflammation in PD through diminishing iNOS-dependent nitric oxide release (thereby down-regulating the formation of damaging ONOO-), COX–2 activity in glial cells, unregulated ROS generation, and decreasing the expression of inflammatory cytokines such as TNF-α and IL–6 [178,184,185].