Antioxidant properties of food products containing lycopene are increased by the presence of chlorophyll

A diet based on the consumption of fresh fruits such as tomato has been associated with health protection and longevity, due to their nutraceutical value. The latter is influenced by the presence of antioxidant compounds such as vitamin C (ascorbic acid), vitamin E (tocopherol), carotenoids, flavonoids as well as phenolic acids. Indeed, these molecules are able to neutralize reactive oxygen species (ROS) and, for this reason, are worldwide recognized as beneficial for preventing human diseases among which cancer and cardiovascular pathologies. Lycopene is a natural pigment synthesized by photosynthetic plants and represents the most abundant carotenoid in tomatoes, being present in concentrations ranging from 9-150 mg/Kg depending on the variety. The increase in dietary lycopene has been associated to a decreased risk of chronic diseases and one of the possible mechanisms involved in this action is represented by its antioxidant activity. Lycopene as well as chlorophyll are lipophilic antioxidants, contributing to the antioxidant activity of tomato berries and leaves. However, the antioxidant activity of lipid extract from leaves was shown to be 45-70-fold higher than that from berries. This is because chlorophyll behaves as a fast lipophilic antioxidant (FLA), accounting for the 38% of FLA present in the lipid extract from leaves, whereas lycopene can be classified as a slow lipophilic antioxidant (SLA) responsible for the 40% of the antioxidant activity due to the slow fraction of the lipid extract from berries. Moreover, the presence of chlorophyll in a mixture containing lycopene increased the antioxidant activity compared to lycopene alone. The role of chlorophyll for human health, for example in reducing risk of colon cancer, is more and more recognized by scientific community and its presence in food products such as not-fully ripe berries could substantially increase their nutritional value, in combination with high concentrations of lycopene.