UV-B radiation: A powerful tool to modulate flavonoid metabolism in tomato fruits

Flavonoids are well known health-beneficial molecules due to their protective action against cancer, cardiovascular and age-related diseases. Therefore, considerable efforts are being made to increase their levels in fruits and vegetables, also because the overall consumption of plant food is still often below the recommended five serves per day. The suspicion of consumers about transgenic cultures, together with the prudent position adopted by many national governments, make it necessary to exploit alternative strategies. Among the different environmental-friendly approaches, changes of light environment is particularly promising because of the pivotal role played by light on some main biosynthetic processes. In this context, UV-B radiation is known to stimulate phenylpropanoid biosynthesis, through the control played at the level of some key enzymes as phenylalanine ammonia-lyase, chalcone synthase and isomerase, flavanone 3-hydroxylase and dihydroflavonol-4-reductase. The tomato fruit accumulates phenolics, especially flavonoids, in flesh and, mainly, in peel and can be considered as a "functional food", capable of providing additional physiological benefits. The limited caloric supply and the high content of minerals, vitamins, and antioxidant compounds, among which flavonoids, make the tomato fruit an ideal food which meets the basic nutritional requirements. © 2012 by Nova Science Publishers, Inc. All rights reserved.