Phytochemical composition, antioxidant and antimicrobial properties of raspberry fruit, pulp, and marc extracts

In this study, the phytochemical composition (total phenolics, total anthocyanins and ellagitannins) and antimicrobial properties of raspberry fruit, pulp, and marc extracts obtained with 80% methanol and 80% acetone from different plant cultivars were assessed. The extracts were also subjected to screening for their possible antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) assay. The content of total phenolics in berry pulp extracts varied from 20.4 to 35.5, in whole berry extracts from 43.6 to 83.1 and in berry marc extracts from 93.9 to 163.8 mg/g (dry weight of extract). The content of ellagitannins was higher by 63-80% in raspberry marc extracts than in pulp extracts. Raspberry fruit, pulp and marc extracts isolated with aqueous acetone possessed stronger antimicrobial activity than the corresponding extracts isolated with aqueous methanol. The highest inhibitory effect against the investigated Gram-positive bacteria and yeast strains was shown by the extracts isolated from raspberry marc and containing the highest concentrations of total phenolics and ellagitannins.