Antioxidative and Antimicrobial Activity of Anthocyanin-Rich Extracts from Fruits of Blackcurrant and Cherry

Anthocyanins are polyphenolic compounds found as natural pigments in various parts of plants. They possess antimicrobial and antioxidative properties. The aim of this study was: (1) to investigate the accumulation of anthocyanins in fruits of 'Joniniai', 'Ben Lomond' and 'Ben Tirran' blackcurrant cultivars, and in cherries 'Lotine', 'Pandy 301' and 'Vytenu zvaigzde'; (2) to evaluate the antioxidative activity of these extracts using a DPPH-binding assay; (3) to estimate the antimicrobial effect of anthocyanin-rich extracts from these fruits on growth of test gram-positive and gram-negative bacteria cultures using an agar diffusion method. Our results showed that fruits of blackcurrant accumulate 314-626 mg of anthocyanins per 100 g fresh weight, and fruits of cherry 156-220 mg/100 g fresh weight. The highest antioxidative activity (82%), according to free radical scavenging, was established in extracts from fruits of Lithuanian early ripening blackcurrant cultivar 'Joniniai', and from fruits of cherries 'Lotine' and 'Vytenu zvaigzde'. No direct dependence was found between anthocyanin quantity and antioxidative activity of extracts. The results of investigations of antimicrobial activity showed that anthocyanin-rich extracts from fruits of tested cherry cultivars suppressed effectively the growth of both gram-positive and gram-negative bacteria. However, gram-positive bacteria culture was more resistant to the anthocyanin-rich extracts from berries of blackcurrant cultivars. Furthermore, currant fruit extracts failed to suppress the growth of Ps. aeruginosa.