Antioxidant Properties of Selected African Vegetables, Fruits and Mushrooms: A Review

Abstract

Africa is blessed with vast amount of vegetables, fruits and mushrooms which are consumed for their nutrients or for their medicinal purposes. In recent years these vegetables, fruits and mushrooms have been shown to possess valuable antioxidants of great nutritional and therapeutic values. Antioxidants are substances which when present at low concentration compared to those of an oxidizable substrate [1] significantly delay or prevent the oxidation of that substrate. They are capable of preventing or attenuating damages such as lipid peroxidation, oxidative damage to membranes, glycation of proteins and inactivation of enzymes caused by free radicals. There are several evidences that show that oxidative stress resulting from reactive oxygen species including free radicals such as hydroxyl (OH. ), superoxide (O2.- ), nitric oxide (NO. ), nitrogen dioxide (NO2.- ), peroxyl (ROO. ) and non free radical like hydrogen peroxide and singlet oxygen play an important role in the development of several pathological conditions such as lipid peroxidation, protein oxidation, DNA damage and cellular degeneration. These have been implicated in the aetiology of these pathological conditions related to cardiovascular diseases, diabetes, inflammatory diseases, cancer, Alzheimer and Parkinson disease, monogolism, ageing process and perhaps dementia [2,3-4, 5] .