Antioxidants in Faculty Tomatoes

N. Kedar

            Antioxidants which are present in fruits and vegetables may help prevent cancer, arthritis and heart disease.  Tomatoes also provide an important source of human nutrition because of their widespread consumption in fresh and processed forms (1).  Research was performed at Harvard Medical School and other universities with yeast and mammals.  Plant polyphenols (including sirtuins and resveratrol) were found to block cancer formation, promotion and progression in animals.  Resveratrol has also been shown in numerous clinical trials to benefit heart disease and increasing HDL (beneficial) cholesterol.

            The scientists conclude that plant polyphenols increase the response to stressful conditions, decrease cancer and extend lifespan.  Most of the above experiments were performed with yeast and with mice, large scale experiments with humans (7) are planned for 2007 and the researchers stress that resveratrol is also active in human cells – suggesting a potential for lengthening life and preventing or treating aging-related diseases in humans (2).  It is also well known that coronary heart diseases (3) are low in southern France despite high intake of saturated fat – as a result of red wine consumption.  Also, the incidence of cancer is supposed to be low because of resveratrol (C₁₄H₁₂O₃) intake.

            The above materials are found in red wine, in vegetables (3) and peanuts.

            Nine commercial varieties of tomatoes – including Daniella – were tested in Spain for phenolic compounds, lycopene and antioxidant activity.  The phenolic compounds were characterized as flavonoids (quercetin, kaempferol and nargingenin) and hydroxycinnamic acids.  The antioxidant activity of tomato extracts varied with the tomato variety and the assay method used (4).  The antioxidant activity of tomatoes is discussed and the experimental methods are described.  The varieties are unknown in Israel except for Daniella.

            Commercial cooked tomato paste containing naringenin, one of the most abundant polyphenols in tomato, was tested in Italy for antioxidant activities (5).  The research demonstrated, that lycopene with polyphenols enhances antioxidant properties and the results support the hypothesis that tomato benefits could be attributed to a positive synergistic action in vivo between lycopene and other constituents such as naringenin.

            In a recent, most interesting study on antioxidants in tomato as a function of genotype, 12 tomato varieties were tested (6).  Among those varieties phenolic content was highest in the Israeli cherry cv 818, which is a cv. 139 type with added disease resistance, excellent taste and the ripening inhibitor gene nor.  The second best was cv. 124 BR cherry also containing the nor long shelf life gene.  In this study, phenolic content of the tomato peel was higher than the pulp.  Antioxidant activity of genotypes is given in Fig. 3 in paper 3.

            This research showed the high potential of our cherry varieties, containing high levels of antioxidants.

Our conclusions are:

Ø      There is little doubt that tomato polyphenols and lycopene have beneficial health effects.

Ø      Our cherry cvs., bred about 20 years ago, are high in polyphenols.

Ø      The new cherry cvs. 1335 and 1339 bred by Frida – as well as many new genetic types should be tested for polyphenol content.

Ø      The results will be important for human health – as well as for large scale marketing of fruits and seeds

Literature:

(1) Finely, J.W.  2005.  Proposed criteria for assessing the efficiency of cancer reducing by plant foods.  Ann. Bot. 95:1075-1096.

(2) Howiz et al.  2005.  Small molecule activators of sinuins extend Accharomyces cetevisiae        lifespan.  Nature 425:191-196.

(3) Renaud, S., de Largeril, M.  1992.  Wine, alcohol, platelets and the French paradox for coronary       diseases.  Lomet 339:1523-1526.

(4) Martinez-Valverde, I. et al.  2002.  Phenolic compounds, lycopene and antioxidant activity in       commercial varieties of tomato (Lycopersicum esculentum).  J. Sci. Food Agric. 82:323-330.

(5) Bugianesi, R. et al.  2002.  Naringenin from cooked tomato paste is bioavailable in men.  J. Nutr.       132:3349-3352.

(6) Binoy, G. et al. 2004.  Antioxidants in tomato (Lycopersicum esculentum) as a function of         genotype.   Food Chem.  84:45-51.

(7) Sinclair, D. and Komaroff, A.L.  2006.  Can we slow aging?  Newsweek 24: 57-59.