Abstract

The research aimed at determination of the antioxidant properties of extracts from leaves and fruits of apple tree and of chlorogenic acid and phloridzin, that is compounds contained in the extracts and held responsible for the properties. The very good antioxidant properties of apple fruit extracts have been known since long ago, though it is not yet known what is the antioxidant action of an apple leaf extract. In order to enquire about the antioxidant effect of the extracts with respect to erythrocyte membrane lipids, erythrocyte ghosts were oxidated in the presence of compounds contained in the extracts. The erythrocyte was treated as a model cells and its membrane as an example and model of the biological membrane. The degree of lipid oxidation was determined by using two methods: spectrophotometric and fluorimetric with the DPH-PA probe. Oxidation was induced with two agents: UVC radiation and AAPH radical. The results obtained indicate a strong antioxidant activity of the extracts and phenolic compounds, whose strength follows the sequence: chlorogenic acid > apple leaf extract » apple fruit extract > phloridzin. Thus the present work proves that the apple leaf extract possesses a very high antioxidant activity, which is almost equal to that of the apple fruit extract. In light of these result one can hope that the apple leaf extract may be used as an effective, natural antioxidant in the food, cosmetics and pharmaceutical industries.

Key words: Antioxidant activity, chlorogenic acid, phloridzin, relative fluorescence, vegetable polyphenols.