Polyphenol oxidase(PPO) is a food enzyme which holds a very important place in the food industry mainly because of its impairing effects. This enzyme leads to the darkening of tissue when fruits are cut or any damage occurs which leads to the depreciation of nutritional value and food acceptability. It is not clear which roles this compound may have in cell metabolism. In plants, PPO contributes to defence mechanisms against pests and pathogens by producing toxic quinones that deter herbivory and inhibit microbial growth. In this report, the possible antifungal effects were examined. Analyses are carried out by properties of standard polyphenolic substances oxidized by PPO were assayed on Red delicious apple extract whose phenolics were previously isolated.