Effects of White Rice, Brown Rice and Germinated Brown Rice on Antioxidant Status of Type 2 Diabetic Rats

Nur Hanisah Azmi,Siti Nor Asma Musa,Maznah Ismail,Mustapha Umar Imam

doi:10.3390/ijms131012952

Nur Hanisah Azmi, Siti Nor Asma Musa + Show 2 more

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https://doi.org/10.3390/ijms131012952

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Abstract

Oxidative stress is implicated in the pathogenesis of diabetic complications, and can be increased by diet like white rice (WR). Though brown rice (BR) and germinated brown rice (GBR) have high antioxidant potentials as a result of their bioactive compounds, reports of their effects on oxidative stress-related conditions such as type 2 diabetes are lacking. We hypothesized therefore that if BR and GBR were to improve antioxidant status, they would be better for rice consuming populations instead of the commonly consumed WR that is known to promote oxidative stress. This will then provide further reasons why less consumption of WR should be encouraged. We studied the effects of GBR on antioxidant status in type 2 diabetic rats, induced using a high-fat diet and streptozotocin injection, and also evaluated the effects of WR, BR and GBR on catalase and superoxide dismutase genes. As dietary components, BR and GBR improved glycemia and kidney hydroxyl radical scavenging activities, and prevented the deterioration of total antioxidant status in type 2 diabetic rats. Similarly, GBR preserved liver enzymes, as well as serum creatinine. There seem to be evidence that upregulation of superoxide dismutase gene may likely be an underlying mechanism for antioxidant effects of BR and GBR. Our results provide insight into the effects of different rice types on antioxidant status in type 2 diabetes. The results also suggest that WR consumption, contrary to BR and GBR, may worsen antioxidant status that may lead to more damage by free radicals. From the data so far, the antioxidant effects of BR and GBR are worth studying further especially on a long term to determine their effects on development of oxidative stress-related problems, which WR consumption predisposes to.

Highlights

Chronic hyperglycemia in type 2 diabetes promotes oxidative stress and diabetic complications [1], and may even be involved in pathogenesis of the disease [2]
Gamma-Aminobutyric Acid (GABA) was undetected in white rice (WR) while its content in brown rice (BR) was 0.09 ± 0.02 mg/g of BR
We evaluated the effect of the 70% ethanolic extracts of germinated brown rice (GBR), BR amd WR on the expression of catalase and SOD 2 genes to determine if any nutrigenomic mechanism was involved in BR or GBR’s antioxidant effects

Summary

Introduction

Chronic hyperglycemia in type 2 diabetes promotes oxidative stress and diabetic complications [1], and may even be involved in pathogenesis of the disease [2]. It causes diabetic retinopathy, neuropathy, nephropathy, and cardiovascular disease [1,3]. Neuropathy, nephropathy, and cardiovascular disease [1,3] These microvascular and macrovascular complications cause severe morbidity and significant mortality and could potentially be prevented if oxidative stress is reduced or reversed in type 2 diabetes. Alleviating oxidative stress is one way of lowering the risk of complications in diabetics In this way, the burden of the disease may be reduced

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