NGF and Parkinson disease: In vivo and in vitro tests have shown that 4-chloro-3,5-dimethoxybenzoic methyl ester and erinacine A stimulate nerve growth factor (NGF) synthesis and nerve regeneration in a Sprague–Dawley rat model and may be an important therapeutic element in alleviating the effects of neurodegenerative diseases, such as Parkinson’s and Alzheimer’s disease.