Search

Aim. This study aimed to evaluate and quantify the antimicrobial activity of lyophilized fruit juice (BCLJ) and waste extract (BCLW) obtained from the black currant (Ribes nigrum L.) variety Čačanska crna. Materials and method. The study was conducted using four Gram (+) (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis) and five Gram (-) bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis, Proteus mirabilis, Enterobacter aerogenes) as well as one yeast (Candida albicans). Cyanidin-3-O-glucoside, delphinidin-3-O-rutinoside and delphinidin-3-Oglucoside present in black currant were used as standards, so the second aim was to determine their influence on the total antimicrobial activity. Results. The tested samples showed moderate antimicrobial activity. The inhibitory effect of BCLJ was shown on all Gram (+) bacteria (B. cereus, E. faecalis, S. aureus), apart from L. monocytogenes, for which the extracts were not effective. It was noted that BCLJ did not suppress the growth of Gram (-) bacteria. Black currant waste extract on the other hand was shown to be efficient on Gram (+) as well as on Gram (-) bacteria. The results of minimum inhibitory concentrations MIC (MFC) of BCLJ and BCLW were 100 mg/mL and MBC was higher than 100 mg. The MIC/MBC (MFC) of standards were 0.13 - 0.5 mg/mL. Conclusion. Results indicate that these black currant lyophilizates might be potentially used as antimicrobial agents.

Berries include a large number of species that are known for their nutritional and health benefits. Several studies have found that red currant has different biological properties, such as antiproliferative, anticancer, antimicrobial, anti-inflammatory, antidiabetic, and antioxidant. The aim of this study was to investigate the antimicrobial activity of lyophilized fruit juice (RPJL) and waste extract (RPWL) obtained from red currant (Ribes rubrum L.) variety Redpoll on different Gram-positive (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis, Proteus mirabilis, Enterobacter aerogenes) and one yeast (Candida albicans). The activity of dominant active compounds (ascorbic acid, quercetin and kaempferol) contained in red currants under the same conditions were also examined to determine their responsibility in the antimicrobial effect. Tested RPJL and RPWL showed moderate antimicrobial activity. The minimum inhibitory (MIC) and microbicidal concentrations (MBC/MFC) of RPJL and RPWL were 100 mg/ml and more than 100 mg/ml. RPJL and RPWL have the same effect on Gram (+) bacteria and the same MIC and MBC value. RPWL showed stronger antimicrobial effects on Gram (-) bacteria while the juice did not inhibit the growth of the Gram (-) bacteria at all. Standard solutions of ascorbic acid and quercetin showed strong inhibitory and microbicidal activity at lower concentrations than tested samples with the MIC/MBC (MFC) =2.5-10 mg/ml. Results showed that red currants could have potential applications as natural antimicrobial agents.