Antioxidant rich grape pomace extract suppresses postprandial hyperglycemia in diabetic mice by specifically inhibiting alpha-glucosidase

<p>Abstract</p> <p>Background</p> <p>Postprandial hyperglycemia is an early defect of type 2 diabetes and one of primary anti-diabetic targets. Treatment of postprandial hyperglycemia can be achieved by inhibiting intestinal α-glucosidase, the key enzyme for oligosaccha...

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Main Authors: Hogan Shelly, Zhang Lei, Li Jianrong, Sun Shi, Canning Corene, Zhou Kequan
Format: Article
Language:English
Published: BMC 2010-08-01
Series:Nutrition & Metabolism
Online Access:http://www.nutritionandmetabolism.com/content/7/1/71
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author Hogan Shelly
Zhang Lei
Li Jianrong
Sun Shi
Canning Corene
Zhou Kequan
author_facet Hogan Shelly
Zhang Lei
Li Jianrong
Sun Shi
Canning Corene
Zhou Kequan
author_sort Hogan Shelly
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Postprandial hyperglycemia is an early defect of type 2 diabetes and one of primary anti-diabetic targets. Treatment of postprandial hyperglycemia can be achieved by inhibiting intestinal α-glucosidase, the key enzyme for oligosaccharide digestion and further glucose absorption. Grape pomace is winemaking byproduct rich in bioactive food compounds such as phenolic antioxidants. This study evaluated the anti-diabetic potential of two specific grape pomace extracts by determining their antioxidant and anti-postprandial hyperglycemic activities <it>in vitro </it>and <it>in vivo</it>.</p> <p>Methods</p> <p>The extracts of red wine grape pomace (Cabernet Franc) and white wine grape pomace (Chardonnay) were prepared in 80% ethanol. An extract of red apple pomace was included as a comparison. The radical scavenging activities and phenolic profiles of the pomace extracts were determined through the measurement of oxygen radical absorbance capacity, DPPH radical scavenging activity, total phenolic content and flavonoids. The inhibitory effects of the pomace extracts on yeast and rat intestinal α-glucosidases were determined. Male 6-week old C57BLKS/6NCr mice were treated with streptozocin to induce diabetes. The diabetic mice were then treated with vehicle or the grape pomace extract to determine whether the oral intake of the extract can suppress postprandial hyperglycemia through the inhibition of intestinal α-glucosidases.</p> <p>Results</p> <p>The red grape pomace extract contained significantly higher amounts of flavonoids and phenolic compounds and exerted stronger oxygen radical absorbance capacity than the red apple pomace extract. Both the grape pomace extracts but not the apple pomace extract exerted significant inhibition on intestinal α-glucosidases and the inhibition appears to be specific. In the animal study, the oral intake of the grape pomace extract (400 mg/kg body weight) significantly suppressed the postprandial hyperglycemia by 35% in streptozocin-induced diabetic mice following starch challenge.</p> <p>Conclusion</p> <p>This is the first report that the grape pomace extracts selectively and significantly inhibits intestinal α-glucosidase and suppresses postprandial hyperglycemia in diabetic mice. The antioxidant and anti-postprandial hyperglycemic activities demonstrated on the tested grape pomace extract therefore suggest a potential for utilizing grape pomace-derived bioactive compounds in management of diabetes.</p>
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spelling doaj.art-edeb1ddf0ded430d8df1aa5f871a0fe32022-12-22T03:27:44ZengBMCNutrition & Metabolism1743-70752010-08-01717110.1186/1743-7075-7-71Antioxidant rich grape pomace extract suppresses postprandial hyperglycemia in diabetic mice by specifically inhibiting alpha-glucosidaseHogan ShellyZhang LeiLi JianrongSun ShiCanning CoreneZhou Kequan<p>Abstract</p> <p>Background</p> <p>Postprandial hyperglycemia is an early defect of type 2 diabetes and one of primary anti-diabetic targets. Treatment of postprandial hyperglycemia can be achieved by inhibiting intestinal α-glucosidase, the key enzyme for oligosaccharide digestion and further glucose absorption. Grape pomace is winemaking byproduct rich in bioactive food compounds such as phenolic antioxidants. This study evaluated the anti-diabetic potential of two specific grape pomace extracts by determining their antioxidant and anti-postprandial hyperglycemic activities <it>in vitro </it>and <it>in vivo</it>.</p> <p>Methods</p> <p>The extracts of red wine grape pomace (Cabernet Franc) and white wine grape pomace (Chardonnay) were prepared in 80% ethanol. An extract of red apple pomace was included as a comparison. The radical scavenging activities and phenolic profiles of the pomace extracts were determined through the measurement of oxygen radical absorbance capacity, DPPH radical scavenging activity, total phenolic content and flavonoids. The inhibitory effects of the pomace extracts on yeast and rat intestinal α-glucosidases were determined. Male 6-week old C57BLKS/6NCr mice were treated with streptozocin to induce diabetes. The diabetic mice were then treated with vehicle or the grape pomace extract to determine whether the oral intake of the extract can suppress postprandial hyperglycemia through the inhibition of intestinal α-glucosidases.</p> <p>Results</p> <p>The red grape pomace extract contained significantly higher amounts of flavonoids and phenolic compounds and exerted stronger oxygen radical absorbance capacity than the red apple pomace extract. Both the grape pomace extracts but not the apple pomace extract exerted significant inhibition on intestinal α-glucosidases and the inhibition appears to be specific. In the animal study, the oral intake of the grape pomace extract (400 mg/kg body weight) significantly suppressed the postprandial hyperglycemia by 35% in streptozocin-induced diabetic mice following starch challenge.</p> <p>Conclusion</p> <p>This is the first report that the grape pomace extracts selectively and significantly inhibits intestinal α-glucosidase and suppresses postprandial hyperglycemia in diabetic mice. The antioxidant and anti-postprandial hyperglycemic activities demonstrated on the tested grape pomace extract therefore suggest a potential for utilizing grape pomace-derived bioactive compounds in management of diabetes.</p>http://www.nutritionandmetabolism.com/content/7/1/71
spellingShingle Hogan Shelly
Zhang Lei
Li Jianrong
Sun Shi
Canning Corene
Zhou Kequan
Antioxidant rich grape pomace extract suppresses postprandial hyperglycemia in diabetic mice by specifically inhibiting alpha-glucosidase
Nutrition & Metabolism
title Antioxidant rich grape pomace extract suppresses postprandial hyperglycemia in diabetic mice by specifically inhibiting alpha-glucosidase
title_full Antioxidant rich grape pomace extract suppresses postprandial hyperglycemia in diabetic mice by specifically inhibiting alpha-glucosidase
title_fullStr Antioxidant rich grape pomace extract suppresses postprandial hyperglycemia in diabetic mice by specifically inhibiting alpha-glucosidase
title_full_unstemmed Antioxidant rich grape pomace extract suppresses postprandial hyperglycemia in diabetic mice by specifically inhibiting alpha-glucosidase
title_short Antioxidant rich grape pomace extract suppresses postprandial hyperglycemia in diabetic mice by specifically inhibiting alpha-glucosidase
title_sort antioxidant rich grape pomace extract suppresses postprandial hyperglycemia in diabetic mice by specifically inhibiting alpha glucosidase
url http://www.nutritionandmetabolism.com/content/7/1/71
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AT lijianrong antioxidantrichgrapepomaceextractsuppressespostprandialhyperglycemiaindiabeticmicebyspecificallyinhibitingalphaglucosidase
AT sunshi antioxidantrichgrapepomaceextractsuppressespostprandialhyperglycemiaindiabeticmicebyspecificallyinhibitingalphaglucosidase
AT canningcorene antioxidantrichgrapepomaceextractsuppressespostprandialhyperglycemiaindiabeticmicebyspecificallyinhibitingalphaglucosidase
AT zhoukequan antioxidantrichgrapepomaceextractsuppressespostprandialhyperglycemiaindiabeticmicebyspecificallyinhibitingalphaglucosidase