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International Journal of Endocrinology
Volume 2014 (2014), Article ID 839095, 10 pages
http://dx.doi.org/10.1155/2014/839095
Research Article

Bixin and Norbixin Have Opposite Effects on Glycemia, Lipidemia, and Oxidative Stress in Streptozotocin-Induced Diabetic Rats

1Graduate Program on Pharmacology, Center of Health Sciences, Federal University of Santa Maria, 97105-900 Santa Maria, RS, Brazil
2Integrated Center for Laboratory Analysis Development (NIDAL), Department of Alimentary Technology and Science, Center of Rural Sciences, Federal University of Santa Maria, 97105-900 Santa Maria, RS, Brazil
3Department of Clinical and Toxicological Analysis, Center of Health Sciences, Federal University of Santa Maria, 97105-900 Santa Maria, RS, Brazil

Received 13 September 2013; Revised 3 December 2013; Accepted 9 December 2013; Published 30 January 2014

Academic Editor: Sandeep Singh

Copyright © 2014 Miguel Roehrs et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The present study investigated the effects of oral administration of annatto carotenoids (bixin (BIX) and norbixin (NBIX)) on glucose levels, lipid profiles, and oxidative stress parameters in streptozotocin (STZ)-induced diabetic rats. Animals were treated for 30 days in the following groups: nondiabetic control, diabetic vehicle, diabetic 10 mg/kg BIX, diabetic 100 mg/kg BIX, diabetic 10 mg/kg NBIX, diabetic 100 mg/kg NBIX, diabetic metformin, and diabetic insulin. Blood glucose, LDL cholesterol, and triglyceride levels were reduced in the diabetic rats treated with BIX. BIX treatment prevented protein oxidation and nitric oxide production and restored superoxide dismutase activity. NBIX treatment did not change most parameters assessed, and at the highest dose, it increased LDL cholesterol and triglycerides levels and showed prooxidant action (increased protein oxidation and nitric oxide levels). These findings suggested that BIX could have an antihyperglycemic effect, improve lipid profiles, and protect against damage induced by oxidative stress in the diabetic state. Because NBIX is a water-soluble analog of BIX, we propose that lipophilicity is crucial for the protective effect of annatto carotenoids against streptozotocin-induced diabetes.