Clinical studies show that diets rich in vegetables and fruit reduce the incidence of cardiovascular disease and cancers. Plants polyphenols are the most wide spread dietary antioxidants. Important components of the polyphenol family are stilbenes, that act as antioxidant in plant and protects against degenerative, age related diseases when supplied in human diet. The manipulation of plant secondary metabolism offers the opportunity to develop transgenic plants with increased health-promoting phytochemicals content. One such pathway with potential for manipulation is flavonoid metabolism where derivatives of cinnamic acid are converted to a wide array of phenolic compounds with various functions in plants. Overexpresssion of a grape stilbene synthase cDNA in tomato tissues caused plants to accumulate new compounds, not present in either wild type or vector transformed plants, which were identified as trans-resveratrol and trans-resveratrol-glucopyranoside by high-pressure liquid chromatography. The amount of trans-resveratrol and its piceid form was evaluated in the transgenic fruit. With the aim to verify the metabolic impairment, the amount of soluble phenolics and flavonoids, in both transgenic and wild type ripening fruits was compared and no dramatic variation in the profile synthesis of the metabolites was noted. Moreover, in transgenic tomato fruit cells, the redox regulation was not affected by the accumulation of a novel antioxidant molecule. The effect of resveratrol synthesis on the naturally present antioxidant pool was also analysed. In transgenic fruits increases in the levels of ascorbate and glutathione, the soluble antioxidants of primary metabolism, were found. Consistently, the total antioxidant activity was higher in transformed than in wild type fruits. In agreement with the increased antioxidant properties, the lipid peroxidation was lower in trasformed than in wild type fruits. The relevance of such trasformation strategy for increasing tomato fruit nutritional value is discussed.
Antioxidant metabolomic in transgenic tomato plants expressing grapevine stilbene synthase
G Giovinazzo;I Nicoletti;
2004
Abstract
Clinical studies show that diets rich in vegetables and fruit reduce the incidence of cardiovascular disease and cancers. Plants polyphenols are the most wide spread dietary antioxidants. Important components of the polyphenol family are stilbenes, that act as antioxidant in plant and protects against degenerative, age related diseases when supplied in human diet. The manipulation of plant secondary metabolism offers the opportunity to develop transgenic plants with increased health-promoting phytochemicals content. One such pathway with potential for manipulation is flavonoid metabolism where derivatives of cinnamic acid are converted to a wide array of phenolic compounds with various functions in plants. Overexpresssion of a grape stilbene synthase cDNA in tomato tissues caused plants to accumulate new compounds, not present in either wild type or vector transformed plants, which were identified as trans-resveratrol and trans-resveratrol-glucopyranoside by high-pressure liquid chromatography. The amount of trans-resveratrol and its piceid form was evaluated in the transgenic fruit. With the aim to verify the metabolic impairment, the amount of soluble phenolics and flavonoids, in both transgenic and wild type ripening fruits was compared and no dramatic variation in the profile synthesis of the metabolites was noted. Moreover, in transgenic tomato fruit cells, the redox regulation was not affected by the accumulation of a novel antioxidant molecule. The effect of resveratrol synthesis on the naturally present antioxidant pool was also analysed. In transgenic fruits increases in the levels of ascorbate and glutathione, the soluble antioxidants of primary metabolism, were found. Consistently, the total antioxidant activity was higher in transformed than in wild type fruits. In agreement with the increased antioxidant properties, the lipid peroxidation was lower in trasformed than in wild type fruits. The relevance of such trasformation strategy for increasing tomato fruit nutritional value is discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
