ABSTRACT

An imbalance of prooxidants and antioxidants, which leads to oxidative stress, is now believed to be a key contributing factor in the manifestation of chronic diseases such as cardiovascular disease, hypertension, diabetes mellitus, and some forms of cancer. (1,2). Recent research has shown that populations consuming diets rich in fruits and vegetables have lower incidences of many chronic diseases (3-6), which has encouraged the use of diet as a complementary strategy for the management of these oxidative diseases (7-10). Fruits and vegetables are rich sources of phytochemicals and highly antioxidant vitamins, which are now believed to be responsible for these beneficial effects. The function of antioxidants from fruits and vegetables has been categorized into two types depending on their mode of action. First, oxidation of biological macromolecules such as nucleic acids, proteins, and lipids as a result of free radical damage (oxidative stress) has now been strongly associated with development of many physiological conditions which can manifest as disease (11-17). The protective effect of antioxidants from fruits and vegetables, therefore, is believed to be due to their direct involvement in neutralizing free radicals in biological systems and preventing oxidative damage to cellular systems (18).