Neuroprotective effects of extracts from American gingseng, ginkgo biloba and St. John's Wort on striatal dopaminergic neurons against 1-methyl-4-phenyl-1,2,4,6-tetrahydropyridine-induced toxicity

Abstract

Parkinson's disease is an idiopathic disease characterized by a depletion of neurotransmitter and loss of dopaminergic(DA) neurons in basal ganglia. It has been suggested that some herbal extracts, e.g. ginkgo biloba, can enhance the survival of injured CNS neurons. We examined the neuroprotective action of several herbal extracts, which have been standardized by ChemBioPrintTM(CV Technologies, Inc., Canada) procedure, on MPTP-induced neurotoxicity in striatal DA neurons. C57Bl/6N mice(6-9 months old) were given 4 i.p. injections of MPTP(10mg/kg, 2 hrs interval) on day 1. Animals were fed orally with either vehicle or different types of herbal extracts(AD-FX, Remember-FX, Menta-FX, Cold-FX, from CV Technologies, Inc., Canada) from day 1 to day 14, and were sacrificed on day 15. DA neurons in substantial nigra(SN) were visualized by tyrosine hydroxylase(TH) immunocytochemistry. TH-positive neurons were counted under light microscope. A reduction of 37% of DA neurons in SN was observed after MPTP treatment. Daily administration of Remember-FX(North Amercian Ginseng extract) rescued 77%(p<0.05) of the neurons from MPTP-induced neurotoxicity. However, other herbal extracts have no significant effect on the survival of the neurons. The result indicated that extracts of American ginseng could provide neuroprotective effects for the striatal dopaminergic neurons against MPTP-induced neurotoxicity. Sponsored by: The Hong Kong Society of Neuroscience. Supported by International Research and Development Program on Traditional Chinese Medicine and Natural Medicine, The University of Hong Kong