Protective Effect of Highly Polymeric A-Type Proanthocyanidins from Seed Shells of Japanese Horse Chestnut (Aesculus turbinata BLUME) against Light-Induced Oxidative Damage in Rat Retina.

Tomoe Ishihara,Yotaro Matsuoka,Hideto Kimura,Akihiro Ohira,Sachiko Kaidzu,Yasurou Koyama

doi:10.3390/nu10050593

Abstract

Retinal tissue is exposed to oxidative stress caused by visible light. Light-damaged rat used in age-related macular degeneration (AMD) studies clarified that antioxidants decrease retinal light damage. Albino rats were exposed to 5000 Lux light for 12 h with oral administration of the polyphenolic compounds fraction (PF) from the seed shells of Japanese horse chestnut (30 mg/kg, 100 mg/kg, and 300 mg/kg body weight: BW). To evaluate the protective effects against light damage, electroretinograms (ERGs), the outer nuclear layer (ONL) thickness, the antioxidant activity of plasma, oxidized retinal lipids, and the detection of apoptosis were examined. To reveal their active compounds, PF were separated into an A-type proanthocyanidin (PAF) and a flavonol O-glycosides fraction. The protective effects of these fractions against light damage were compared by measuring the thickness of the ERGs and ONL. Compared with the negative control, the PF group (100 mg/kg and 300 mg/kg BW) significantly suppressed the decrease of the ERG amplitudes and ONL thickness. PF (300 mg/kg BW) induced the elevation of in vivo antioxidant activity, and the suppression of retinal lipid oxidation. PF administration also suppressed apoptotic cell death. The protective effects against light damage were attributable to the antioxidant activity of PAF. The light-induced damage of retinas was protected by oral administration of PF and PAF. Taken together, these compounds are potentially useful for the prevention of the disease caused by light exposure. Highlights: The protective effects of retinal damage by light exposure were evaluated using polyphenolic compounds from the seed shells of Japanese horse chestnut (Aesculus turbinata BLUME) as an antioxidant. Decreases in the electroretinographic amplitude and outer nuclear layer thickness were suppressed by the polyphenolic compounds of the seed shells. Polyphenolic compounds from the seed shells of Japanese horse chestnut inhibited the oxidation of retinal lipids. Highly polymeric A-type proanthocyanidin from the seed shells protected the rat retina from light exposure damage by inhibiting oxidative stress and apoptotic mechanisms.

Highlights

The seeds of the Japanese horse chestnut (Aesculus turbinata BLUME), which has been used as emergency food since antiquity, is an ingredient in rice cakes and rice balls
Nutrients 2018, 10, 593 that the seed shells of the Japanese horse chestnut, which is regarded as a waste byproduct, contain a large amount of polyphenolic compounds with different degrees of polymerization, i.e., highly polymeric A-type proanthocyanidins (PAFs) [1] and flavonol O-glycosides [2], which have antioxidant activity [1,2]
We examined the protective effect of polyphenolic compounds from seed shells of Japanese horse chestnut using a rat model of retinal light damage

Summary

Introduction

The seeds of the Japanese horse chestnut (Aesculus turbinata BLUME), which has been used as emergency food since antiquity, is an ingredient in rice cakes and rice balls. Nutrients 2018, 10, 593 that the seed shells of the Japanese horse chestnut, which is regarded as a waste byproduct, contain a large amount of polyphenolic compounds with different degrees of polymerization, i.e., highly polymeric A-type proanthocyanidins (PAFs) [1] and flavonol O-glycosides [2], which have antioxidant activity [1,2]. AMD is a progressive blinding disease with no cure at present. AMD in the United States alone, with a global prevalence of 170 million. AMD is thereby the leading cause of worldwide blindness [3]

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