Radical-Scavenging Activity in vitro of Lemon Peel Fermented with Aspergillus saitoi and Its Suppressive Effect against Exercise-Induced Oxidative Damage in Rat Liver

Abstract

We prepared fermented lemon peel (FLP) with high antioxidative activity by fermentation of the lemon peel (LP) with Aspergillus saitoi. The antioxidative activity of LP and FLP was examined by the radical-scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) in vitro, and the suppressive effect against exercise-induced oxidative damage in rat liver. FLP exhibited higher radical-scavenging activity against DPPH than LP. The administration of LP and FLP prior to exercise significantly suppressed the increases in thiobarbituric acid-reactive substance caused by lipid peroxidation during exhaustive exercise, with FLP having a tendency of higher activity than LP. Moreover, FLP showed a significant suppressive effect of Ne-(hexanonyl)lysine content, a primary oxidative stress marker, which increases due to exhaustive exercise, whereas LP did not. The fermentation of LP with A. saitoi was thought to produce a high antioxidative activity. The high antioxidative activity of FLP was assumed to be related to the production of antioxidative flavonoids, as a hydroxyflavanone and aglycones, by the fermentation of lemon peel with Aspergillus saitoi.