Compound from Dried Tomatoes Is a Potent Anti-Cancer Agent

Cancer researchers have identified a compound in dried tomatoes that works together with the bright red carotenoid antioxidant lycopene to protect against prostate cancer.

Unlike other fruits and vegetables, where nutritional content such as vitamin C is diminished upon cooking, processing of tomatoes increases the concentration of bioavailable lycopene. Lycopene in tomato paste is four times more bioavailable than in fresh tomatoes. This is due to lycopene's hydrophobicity and to its tight binding to vegetable fibers. Thus, processed tomato products such as pasteurized tomato juice, soup, sauce, and ketchup contain the highest concentrations of bioavailable lycopene. Cooking and crushing tomatoes and serving in oil-rich dishes greatly increases assimilation from the digestive tract into the bloodstream.

In the current study, investigators at the University of Missouri (Columbia, MO, USA) examined dehydrated tomatoes for compounds that contribute to lycopene activity. One promising compound was the ketosamine FruHis.

The investigators fed Wistar-Unilever rats energy-balanced diets supplemented with tomato paste, tomato powder, or tomato paste plus FruHis; and then injected the animals with N-nitroso-N-methylurea and testosterone to induce development of prostate cancer. Results published in the June 1, 2008, issue of the journal Cancer Research revealed that the tomato paste/FruHis group had median survival time of 51 weeks as compared to the control group, where median survival time was 40 weeks. The proportions of dying rats with macroscopic prostate tumors in the control, tomato paste, tomato powder, and tomato paste/FruHis groups were 63% (12 of 19), 39% (5 of 13), 43% (6 of 14), and 18% (2 of 11), respectively. FruHis at a concentration greater than 250 µmol/L completely blocked DNA oxidative degradation in vitro, whereas neither ascorbate nor phenolic antioxidants from tomato were effective protectors.

"Processing of many edible plants through heating, grinding, mixing, or drying dramatically increases their nutrition value, including their cancer prevention potential. It appears that the greatest protective effect from tomatoes comes by rehydrating tomato powder into tomato paste,” said first author Dr. Valeri V. Mossine, assistant professor of biochemistry at the University of Missouri. "Before this study, researchers attributed the protective effect of tomatoes to ascorbic acid, carotenoids, or phenolic compounds.

FruHis may represent a novel type of potential dietary antioxidant. Experiments like these suggest that a combination of FruHis and lycopene should be investigated as a potential therapeutic anti-tumor agent, not just a prevention strategy.”


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