Bioactive compounds and antimicrobial activity of black currant (Ribes nigrum L.) berries and leaves extract obtained by different soil management system

Polyphenols compounds have been found in berries and leaves of black currant (Ribes nigrum L.) are known as agents acting preventively and therapeutically on the human organism. The effect of three soil management system (bare fallow, sawdust mulch and black plastic mulch) on the content of total anthocyanins, anthocyanin glycoside (delphinidin 3-glucoside, delphinidin 3-rutinoside, cyanidin 3-glucoside and cyanidin 3-rutinoside), flavonols (quercetin, myricetin and kaempferol), flavan-3-ols (catechin and epicatechin) and antimicrobial activity of seven black currant cultivars ('Ben Lomond', 'Ben Sarek', 'Titania', Cacanska Crna', 'Tiber' and 'Tsema') was investigated. Total anthocyanins content was determined using the single pH and pH differential method. High performance liquid chromatography (HPLC) was employed for the identification of the most abundant metabolites presented in berries and leaves extracts. Microbial properties of extracts were examined using eight selected indicator strains. Soil management systems and cultivars showed highly significant differences in the tested parameters. Berries showed a higher content in anthocyanins, flavonols and flavan-3-ols than leaves. Quercetin was the most abundant flavonol in berries and leaves, and epicatechin the most abundant flavan-3-ol. Comparative research on black currant cultivars and soil management systems suggests an important relationship between cultivars and soil management systems. Soil management systems had an effect on the contents anthocyanins and anthocyanin glycoside in extract leaves, but not in extract berries of black currant cultivars. On the other hand, soil management systems have a significant positive effect on the synthesis and accumulation of flavonols and flavan-3-ols in both berries and leaves. Furthermore, all extracts showed strong antimicrobial activity. These results suggest that berries and leaves of black currant cultivars which growing on different soil management systems may be used as a source of beneficial compounds in food and pharmaceutical industries.