Phenolic Content and Antioxidant Activities of Fruit Extracts of Morus nigra L. (Moraceae) from Southeast Serbia

Purpose: To evaluate the content of phenolic compounds (flavonoids and anthocyanins) of Morus nigra L. fruit (black mulberry) as well as the antioxidant activities of its extracts. Methods: The contents of phenols, flavonoids and anthocyanins of the ethanol, ethanol-water (50/50, v/v) and water extracts of black mullbery were determined using spectrophotometric methods. Antioxidant assay was based on the measurement of 2,2-diphenyl-1-picrylhydrazyl (DPPH) absorbance at 517 nm caused by the reaction of DPPH with the test sample, and also on the measurement of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) absorbance at 734 nm caused by the reaction of ABTS with the test sample. Results: Spectrophotometric analysis indicates that the content of total phenol compounds in the extracts varied from 90.26 to 118.84 mg GAE/100 g of fresh mulberry fruit. The content of anthocyanins ranged from 114.83 to 128.68 mg of cyanidin-3-O-glucoside/100 g of fresh fruit (ff). The fruit extract (0.1 ml) showed high antioxidant activity with DPPH radical transformation value of 71.41 % in ethanol-water (50/50, v/v)) extract and good antioxidant activity (relative to trolox equivalent as standard) with ABTS of 55.43 % in the water extract. Conclusion: The high phenolic content and high antioxidant activity of black mulberry from Southeast Serbia underline the nutritive and phytomedicinal potentials of the fruit. Further studies are, however, required before the fruit extract can be exploited in the production of health foods and as an antioxidant carrier in the food and pharmaceutical industries.