Freeze-dried jaboticaba peel powder improves insulin sensitivity in high-fat-fed mice

Abstract

The peel of the native Brazilian fruit jaboticaba is rich in anthocyanins, which are known for their anti-obesity effects in animal models. The aim of the present study was to evaluate the effects of freeze-dried jaboticaba peel powder (FDJPP) on a number of metabolic parameters in a model of diet-induced obesity. Mice (n 8 per group) were initially fed on a high-fat diet (HFD, 35 % w/w) for 4 weeks and then switched to a HFD supplemented with FDJPP (1, 2 or 4 % w/w) for an additional 6 weeks. Energy intake, weight loss, glucose tolerance, insulin resistance and lipid profile were determined, and the results were evaluated using ANOVA and Tukey's tests. The FDJPP exerted no protective effect on HFD-induced weight gain, hyperleptinaemia and glucose intolerance. However, the supplementation was effective to reduce insulin resistance, as evidenced in the insulin tolerance test, and subsequently confirmed by improved signal transduction through the insulin receptor/insulin receptor substrate-1/Akt/forkhead box protein pathway and by the attenuation of HFD-induced inflammation in the liver, verified by lower expressions of IL-1b and IL-6 and decreased phosphorylated IkB-a protein levels in all jaboticaba-treated mice. These results suggest that FDJPP may exert a protective role against obesity-associated insulin resistance.Key words: Jaboticaba: Obesity: Insulin resistance Obesity has reached epidemic proportions in the world, with substantial adverse consequences for human health (1) . A number of life-threatening diseases, such as type 2 diabetes mellitus, dyslipidaemia, CVD, hypertension and certain types of cancer, are associated with this condition (2) .Nutritional factors are known to play an important role in the development of a number of diseases. The recent changes in human lifestyle, with the introduction of high-fat/simple carbohydrate-rich diets, are amongst the most important factors leading to the increased prevalence of obesity. Conversely, epidemiological data suggest that increased consumption of fruits and vegetables are positively associated with the prevention of metabolic disorders, including obesity (3,4) . The ability of some vegetable-derived nutrients to reduce the risk of chronic diseases has been associated, at least in part, with the occurrence of bioactive non-nutrient compounds that are known to exert a wide range of biological activities (5,6) .Anthocyanins, which belong to the flavonoid class, are an example of such bioactive compounds. They constitute the largest and probably the most important group of watersoluble natural pigments responsible for the vivid blue, purple and red colour of many vegetables and fruits (7) . Many reports have shown that anthocyanin exhibits an array of pharmacological properties, such as anti-inflammatory and anticarcinogenic activities, as well as preventive effects on CVD and degenerative disease. The majority of research has focused on the antioxidant properties of these dietary polyphenols (8) . Furthermore, it has been shown that phenolic co...

Jaboticaba peel and jaboticaba peel aqueous extract shows in vitro and in vivo antioxidant properties in obesity model

“…Thus, the enzymatic inhibition can be a mechanism in the obesity regulation. In recent study, Dragano, Marques, Cintra, et al (2013) reported that despite the consumption of FJP added to the high-fat did not effected on mice weight gain, insulin resistance and modulated proteins associated with obesity, inflammation and diabetes were improved.…”

“…However, the consumption of freeze-dried foods as a source of anthocyanins added to high-fat diet has not shown effects on weight gain neither in body fat in animal models (Batista, Lenquiste, Cazarin, et al, 2014;DeFuria, Bennett, Strissel, et al, 2009;Dragano, Marques, Cintra, et al, 2013;Lenquiste, Batista, Marineli, et al, 2012;Prior, Wilkes, Rogers, Khanal, Wu, & Howard, 2010). The effects of phenolic compounds on obesity have been studied and its effect on weight gain and body mass are still divergent.…”

Dietary açai attenuates hepatic steatosis via adiponectin-mediated effects on lipid metabolism in high-fat diet mice

“…Among these compounds, anthocyanins have been considered particularly promising for the prevention of NAFLD (Valenti et al, 2013). The ability of anthocyanins to reduce the risk of chronic diseases has been linked to their antioxidant capacity; however, recent findings have suggested that anthocyanins may exert their beneficial effects by interacting with a wide range of molecular targets of intracellular signaling machinery (Dragano et al, 2013;Fernandes, Faria, Calhau, de Freitas, & Mateus, 2014) including key transcription factors that coordinate lipid metabolism, such as PPAR-α (Jia et al, 2013) and SREBP-1c (Hwang et al, 2011). Although there are many reports about the health benefits of anthocyanin-rich extracts, studies to test whether physiologically relevant doses of anthocyanins could exert such effects are lacking.…”

Effects of jaboticaba (Myrciaria jaboticaba) peel on blood glucose and cholesterol levels in healthy rats

“…The fibers from FJP (Table 1) could also be responsible to enhance hypoglycemic effect, acting in synergy with polyphenols from the peel (Kim et al, 2010). In addition, studies have shown that the intake of jaboticaba peel is related to an increased insulin sensitivity in liver and adipose tissue (Dragano et al, 2013;Lenquiste et al, 2012). Studies with polyphenol and fiber-rich meals corroborate this result: reduction in plasma glucose levels by 13.04% (Esteves et al, 2011).…”

“…In view of the increase in total cholesterol and LDL-cholesterol fractions in G2 and G3 groups, we may suppose that 2% FJP should represent an upper limit for dietary intake. Thus, even that other studies showed good results with the same doses (Dragano et al, 2013;Lenquiste et al, 2012), more investigations are necessary in order to elucidate the mechanisms that may cause undesirable effects.…”