Neuronal cell protection and acetylcholinesterase inhibitory effect of the phenolics in chestnut inner skin

Chestnut inner skin was known to contain various phenolics as a potential antioxidant, and 3 phenolics (catechin, epicatechin, and gallic acid) were isolated. The relative antioxidant capacity of 3 phenolics in vitamin C equivalent antioxidant capacity (VCEAC) evaluated by ABTS assay was in decreasing order as follows: gallic acid greater than catechin greater than epicatechin greater than vitamin C. Gallic acid showed the highest inhibitory effect against acetylcholinesterase (AChE) in a dose-dependent manner and competitive inhibition. However catechins presented neuroprotective effects on amyloid β-induced neurotoxicity by MTT, lactate dehydrogenase (LDH) release, and neutral red uptake assays. Considering above data, it was supposed that gallic acid, catechin, and epicatechin have various antiamnesic effect in neurodegenerative diseases such as Alzheimer's disease (AD). Therefore, it was strongly suggested that chestnut inner skin as phenolics-rich substance can be used in functional food supplement or pharmaceutical industry by utilization of wastage from valuable resources.