a1 School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
a2 Department of Biological and Physical Sciences, University of Southern Queensland, Toowoomba, QLD 4350, Australia
Anthocyanins, phenolic acids and carotenoids are the predominant phytochemicals present in purple carrots. These phytochemicals could be useful in treatment of the metabolic syndrome since anthocyanins improve dyslipidaemia, glucose tolerance, hypertension and insulin resistance; the phenolic acids may also protect against CVD and β-carotene may protect against oxidative processes. In the present study, we have compared the ability of purple carrot juice and β-carotene to reverse the structural and functional changes in rats fed a high-carbohydrate, high-fat diet as a model of the metabolic syndrome induced by diet. Cardiac structure and function were defined by histology, echocardiography and in isolated hearts and blood vessels; liver structure and function, oxidative stress and inflammation were defined by histology and plasma markers. High-carbohydrate, high-fat diet-fed rats developed hypertension, cardiac fibrosis, increased cardiac stiffness, endothelial dysfunction, impaired glucose tolerance, increased abdominal fat deposition, altered plasma lipid profile, liver fibrosis and increased plasma liver enzymes together with increased plasma markers of oxidative stress and inflammation as well as increased inflammatory cell infiltration. Purple carrot juice attenuated or reversed all changes while β-carotene did not reduce oxidative stress, cardiac stiffness or hepatic fat deposition. As the juice itself contained low concentrations of carotenoids, it is likely that the anthocyanins are responsible for the antioxidant and anti-inflammatory properties of purple carrot juice to improve glucose tolerance as well as cardiovascular and hepatic structure and function.
(Received January 07 2010)
(Revised May 05 2010)
(Accepted May 10 2010)
(Online publication July 12 2010)
Abbreviations: CRP, C-reactive protein; H (8 weeks or 16 weeks), high-carbohydrate, high-fat; HC, high-carbohydrate, high-fat+β-carotene; HP, high-carbohydrate, high-fat+purple carrot juice; NAFLD, non-alcoholic fatty liver disease