Protective Effect of Free and Bound Polyphenol Extracts from Ginger (Zingiber officinaleRoscoe) on the Hepatic Antioxidant and Some Carbohydrate Metabolizing Enzymes of Streptozotocin-Induced Diabetic Rats

Mutiu Idowu Kazeem,Anofi Omotayo Tom Ashafa,Musbau Adewunmi Akanji,Musa Toyin Yakubu

doi:10.1155/2013/935486

Abstract

This study investigated the hepatoprotective effects of polyphenols from Zingiber officinale on streptozotocin-induced diabetic rats by assessing liver antioxidant enzymes, carbohydrate-metabolizing enzymes and liver function indices. Initial oral glucose tolerance test was conducted using 125 mg/kg, 250 mg/kg, and 500 mg/kg body weight of both free and bound polyphenols from Z. officinale. 28 day daily oral administration of 500 mg/kg body weight of free and bound polyphenols from Z. officinale to streptozotocin-induced (50 mg/kg) diabetic rats significantly reduced (P < 0.05) the fasting blood glucose compared to control groups. There was significant increase (P < 0.05) in the antioxidant enzymes activities in the animals treated with both polyphenols. Similarly, the polyphenols normalised the activities of some carbohydrate metabolic enzymes (hexokinase and phosphofructokinase) in the liver of the rats treated with it and significantly reduced (P < 0.05) the activities of liver function enzymes. The results from the present study have shown that both free and bound polyphenols from Z. officinale especially the free polyphenol could ameliorate liver disorders caused by diabetes mellitus in rats. This further validates the use of this species as medicinal herb and spice by the larger population of Nigerians.

Highlights

Diabetes is a chronic metabolic disorder which has been in existence since time immemorial and affects about 45% of the population worldwide [1]
The effects of administration of free and bound polyphenol extracts from Z. officinale on postprandial blood glucose of male Wistar rats are presented in Figures 1 and 2
The groups of diabetic rats treated with 500 mg/kg of both free and bound polyphenol extracts of Z. officinale, respectively, displayed most significant reduction (P < 0.05) at all periods tested in comparison to the diabetic control group

Summary

Introduction

Diabetes is a chronic metabolic disorder which has been in existence since time immemorial and affects about 45% of the population worldwide [1]. Its complications cause disability in its sufferers leading to frequent hospitalization and huge financial burden [2]. It is a “modern day epidemic” and is given attention as a worldwide public health problem. The number of people suffering from this disease globally is rising on a daily basis with an estimated 366 million people likely to be affected by the year 2030 as against 191 million estimated in 2000 [3]. The management of diabetes mellitus is considered a global problem and successful treatment is yet not available. Studies have shown that diabetes mellitus is related to oxidative stress, leading to an increased generation of free radicals (H2O2)

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