The research, published in Molecular Nutrition & Food Research, suggests that an extracted compound, 9-oxo-octadecadienoic (9-oxo-ODA) works to reduce blood lipid levels and restore ‘normal’ fat metabolism in the liver, which could in turn be of benefit in preventing the onset of vascular diseases linked to high blood lipids – such as atherosclerosis.
Fractioned extracts of tomatoes containing the 9-oxo-ODA compound were shown increase the expression of specific genes involved in fatty acid oxidation and suppress the accumulation of triglycerides in mouse liver tissue. The researchers said that their findings are the first to identify such a compound from tomato.
“These findings suggest that tomatoes containing 9-oxo-ODA activating PPARα are valuable for ameliorating abnormalities of lipid metabolism associated with obesity and diabetes,” said the researchers, led by Dr Teruo Kawada, from Kyoto University.
Kawada and his colleagues noted that abnormally high levels of lipids in the blood (known as dyslipidemia) is one of the major direct risk factors for arteriosclerosis and cirrhosis.
The Kyoto-based scientists explained that tomatoes, which are one of the most common crops worldwide, and are known to contain many beneficial compounds that are suggested to improve abnormalities of lipid metabolism. They added that previous studies have shown dietary intake of tomatoes to be associated with a reduced risk of chronic diseases, such as cardiovascular diseases, cancer, and type-2 diabetes. In many instances the potential benefits of the fruit have been linked to the lycopene content.
However, the authors said that the molecular mechanism underlying such effects of tomato on lipid metabolism remain unclear.
They noted that it is commonly accepted that PPARα (peroxisome proliferator-activated receptor alpha) is one of the most important targets for reducing abnormalities of lipid metabolism.
“In this study, we focused on the activation of PPARα, and attempted to identify a new anti-dyslipidemia compound that activates PPARα in tomato,” said the researchers.
To identify such active compounds, the researchers screened fractions of tomato extracts for its ability to bind to PPARα.
They found that one fraction, identified as containing 9-oxo-ODA, significantly increased PPARα activity, and reported that in mice the 9-oxo-ODA fraction significantly increased the expression levels of PPARα target genes which are involved in fatty acid oxidation.
Furthermore, they observed that 9-oxo-ODA-containing fraction blocked the accumulation of triglycerides in liver tissue.
In addition to testing the effects of the active fraction in mice, the scientists attempted to classify any compounds in the fraction, identifying a single active compound in the fraction.
“In this study, we identified an active fraction, [which contained the compound 9-oxo-ODA], activating PPARα in the Furikoma tomato, and this study is the first to identify such a fraction from tomato,” said the researchers.
“Finding a compound which helps the prevention of obesity-related chronic diseases in foodstuffs is a great advantage to tackling these diseases,” said Kawada.
The researchers concluded that 9-oxo-ODA may be a potent activator of PPARα, and suggested that as such may reduce abnormalities of lipid metabolism in the liver. Although they said that further investigation is needed to investigate the in vivo effects of 9-oxo-ODA.
Source: Molecular Nutrition & Food Research
Published online ahead of print, doi: 10.1002/mnfr.201000264
“9-oxo-10(E),12(E)-octadecadienoic acid derived from tomato is a potent PPAR α agonist to decrease triglyceride accumulation in mouse primary hepatocytes”
Authors: Y.I. Kim, S. Hirai, H. Takahashi, T. Goto, C. Ohyane, T. Tsugane, et al.