Dunaliella salina extract effect on diabetic rats: metabolic fingerprinting and target metabolite analysis

Abstract

Antioxidant therapy has been proposed to improve the oxidative stress status of diabetic patients. Natural products are a source of substances such as carotenoids, with known antioxidant properties with possible benefits on diabetes. Among them, Dunaliella salina is a microalga with high content in carotenoids that can be extracted via an environmentally clean process such as supercritical fluid extraction with CO2. Five doses of D. salina extract with in vitro antioxidant properties were intragastrically administrated to adult male streptozotocin (STZ) diabetic rats. Urine fingerprints of control and diabetic rats, both with and without treatment, were obtained by capillary electrophoresis with two different modes (normal polarity and MEKC and reverse polarity and CZE). When the profiles were submitted together to pattern recognition techniques they showed the effects of D. salina extract on this acute and short-term treatment animal model in a rapid, simple and cost-effective way without identifying a single marker. In order to have a further biochemical knowledge of the effect, after treatment, rats were sacrificed and blood and liver glutathione, as well as plasma glucose, triglycerides, cholesterol, total protein, urea, acetoacetate, 3-hydroxybutyrate, lactate, pyruvate and urate, TBARS and urine 8-isoprostane were analysed. Vitamin E in plasma and liver was also measured. Twenty-seven parameters were individually assessed, and both univariate statistics (mean comparison after 1W-ANOVA) and multivariate data analysis were performed. D. salina extract induced changes showed up by the multivariate analysis. Results of the treatment from most of the parameters can be considered beneficial for diabetic animals; although an increase in hyperglycemia and 8-isoprostane excretion when STZ treated animals received the extract was observed.