Panus giganteus (Berk.) Corner: Nutritional values and in vitro neurite outgrowth activity in rat pheochromocytoma cells

Background: Drugs dedicated to alleviate neurodegenerative diseases like Parkinson’s and Alzheimer’s have always been associated with debilitating side effects. Medicinal mushrooms which harness neuropharmacological compounds may be a promising avenue for protection against such diseases. Panus giganteus (Berk.) Corner has been consumed by the indigenous people in Peninsular Malaysia for many years. Domestication of this wild mushroom is gaining popularity but to our knowledge, medicinal properties reported for this culinary mushroom are minimal. Methods: The fruiting bodies of Panus giganteus were analysed for its nutritional values. Cytotoxicity of the mushroom aqueous and ethanolic extracts towards PC12, a rat pheochromocytoma cell line was assessed by using [3-[4,5-dimethythiazol-2-yl]-2,5-diphenyltetrazolium bromide] (MTT) assay. Neurite outgrowth stimulation assay was carried out with nerve growth factor (NGF) as control. To elucidate signaling mechanisms involved by mushroom extract-induced neurite outgrowth, treatment of specific inhibitor for MEK/ERK and PI3K signalling pathway was carried out. Results: The fruiting bodies of P. giganteus were found to have high carbohydrate, dietary fibre, potassium, phenolic compounds and triterpenoids. Both aqueous and ethanolic extracts induced neurite outgrowth of PC12 cells in a doseand time-dependant manner with no detectable cytotoxic effect. At day 3, 25 μg/ml of aqueous extract and 15 μg/ml of ethanolic extract showed the highest percentage of neurite-bearing cells, i.e. 31.7 ± 1.1% and 33.3 ± 0.9%; respectively. Inhibition treatment results