Antioxidant activity of selected parts of Prunus domestica L. harvested at two ripening stages

Abstract Introduction: Oxidative stress caused by an excess of reactive oxygen species (ROS) is the main reason behind many civilization diseases. The fruits and leaves of Prunus domestica L. contain antioxidants such as vitamins, polyphenols (including flavonoids) and organic acids. The aim of the study was to evaluate the antioxidant activity and total polyphenol content of extracts of leaves and fruits of the plum harvested in 2 ripening phases. Materials and methods: Antioxidative activity was measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) – ABTS methods, and total polyphenol content by Folin–Ciocalteu technique. Extracts in 40%, 70% and 96% (v/v) of ethanol as well as 99.8% (v/v) methanol were used. Ultrasound-assisted extraction was applied for 15, 30 and 60 min. Results: The antioxidant potential of the extracts, measured by DPPH method, was highest for leaf methanolic extracts of plum harvested before ripening (3.83 ±0.01 mg trolox/g of raw material), while for the ABTS method, highest activity was found in the fruit peel extract in methanol (12.89 ±0.04 mg trolox/g raw material). The highest polyphenol levels (5.89 ±0.16, 6.06 ±0.09 and 5.76 ±0.13 mg gallic acid/g raw material) were found in the extracts of leaves harvested at fruit ripening stage, prepared in 70% (30 and 60 min) ethanol and 40% ethanol (60 min), respectively. Conclusion: The alcohol based extracts from the leaves and fruit of Prunus domestica L. were characterized by high anti-oxidant potential, which suggests the possibility of their use as a valuable source of antioxidants. Ethanol seems to be the most appropriate extractant.