Antioxidant and glycation inhibitory activities of gold kiwifruit, Actinidia chinensis

Oxidative stress has been postulated to contribute significantly to the accelerated accumulation of advanced glycoxidation endproducts (AGEs) in collagen, which is implicated in the process of skin aging. Effectiveness of Actinidia chinensis, commonly called gold kiwifruit, in counteracting skin aging was investigated. Firstly, primary crude 70% ethanolic extracts of whole A. chinensis, pulp, and rind were screened for their in vitro antioxidant activities and anti-glycation activity by using 1,1-diphenyl-2-picrylhydrazyl (DPPH), Ferric Reducing Antioxidant Power (FRAP) assay, and bovine serum albumin-derived glycation model. Result indicated that rind portion exhibited significantly (p<0.05) high antioxidant activity as well as high phenolic and flavonoid contents compared to those of pulp and whole A. chinensis. Thus, rind was selected for further fractionated with hexane, chloroform, ethyl acetate, and butanol. Among these solvent fractions, A. chinensis rind ethyl acetate (ACRE-E) had the greatest radical-scavenging activity and reducing power, comparable to standard antioxidant, vitamin C. Immunofluorescence staining was used to determine AGEs distribution in glycated collagen matrix. ACRE-E inhibited formation of 67% AGEs. High Performance Liquid Chromatography analysis revealed phenolic compound of ACRE-E as quercetin-3-rhamnoside. High antioxidant and anti-glycation activities of ACRE-E in glycated collagen model indicate its contribution to anti-aging process. A. chinensis rind, previously considered as a byproduct, may have potential as a low-cost raw material for cosmetic and pharmaceutical industries.