Antioxidant and prebiotic effects of a beverage composed by tropical fruits and yacon in alloxan-induced diabetic rats

Abstract The aim of this study was to evaluate the antioxidant and prebiotic effect of a beverage composed by tropical fruits and yacon in alloxan-induced diabetic rats. To obtain the beverage, a Response Surface Methodology was used, with concentration of yacon extract (x1) and the sweetener (x2) added to a mixture of tropical fruits as independent variables, and the sensorial acceptance as response. The optimized beverage showed higher values for antioxidant capacity, measured by ABTS, FRAP and DPPH assays. Thus, the fructooligosaccharides content (2.32 ± 0.65 g FOS/100 g), total phenolic (126.83 ± 9.48 mg gallic acid equivalent/100 g) and ascorbic acid (171.64 ± 7.31 mg/100 g) shows that the beverage contains high levels of these bioactive compounds. In addition, the beverage was tested in vivo, using male Wistar rats, divided into five groups (control, non-treated diabetic, and diabetic treated with 100, 200 or 400 mg of lyophilized beverage/kg/day). The results showed a promotion of the growth of lactobacilli in cecal material and an increase in catalase activity in the liver, in a dose-dependent manner, showing the prebiotic and antioxidant effects of the beverage in the diabetic model.摘要 本研究旨在评估一款由热带水果与菊薯（yacon）制成的饮品对四氧嘧啶诱导的糖尿病大鼠的抗氧化与益生元功效。为制备该饮品，本研究采用响应面法（Response Surface Methodology），以菊薯提取物添加量（x₁）与甜味剂添加量（x₂）作为热带水果混合体系的自变量，以感官接受度作为响应指标。经优化的饮品抗氧化能力更优，通过ABTS、FRAP及DPPH三种抗氧化检测方法验证。该饮品的低聚果糖（fructooligosaccharides, FOS）含量为2.32±0.65 g FOS/100 g，总酚含量为126.83±9.48 mg 没食子酸当量/100 g，抗坏血酸含量为171.64±7.31 mg/100 g，表明其富含上述生物活性成分。此外，本研究以雄性Wistar大鼠开展体内实验，将其分为5组：对照组、未处理糖尿病组，以及分别以100、200、400 mg冻干饮品/千克体重/日的剂量给药的糖尿病治疗组。实验结果显示，该饮品可呈剂量依赖性地促进盲肠内容物中乳杆菌的增殖，并提升肝脏过氧化氢酶活性，证实其在糖尿病模型中具备益生元与抗氧化功效。