Phenolic Compounds in Fractionated Blackcurrant Leaf Extracts in Relation to the Biological Activity of the Extracts.

The aim of this study was to determine the relationship between antioxidant and anticancer properties of extracts from blackcurrant (Ribes nigrum L.) leaves and their fractions and chemical contents. Dried ethanolic extract was divided into three fractions using solid phase extraction: aqueous (F1), 40% MeOH (F2), and 70% MeOH (F3). Both the extract and the fractions were analyzed in terms of antiradical activity (DPPH• and ABTS+•), total phenolic compounds, and total flavonoids. The antitumor potential of the fractions was evaluated in vitro on human colorectal (HCT 116) and prostate (PC-3) cancer cells. Phenolics were identified using HPLC-QTOF-MS, and twelve compounds were quantified by HPLC-DAD. Finally, principal component analysis was carried out to assess the relationship between the tested factors. The results confirmed that blackcurrant leaves are a rich source of phenolics with high antioxidant activity and anticancer properties. It was demonstrated that the F2 fraction had the highest content of phenolics and the highest antiradical activity. Additionally, only this fraction showed cytotoxic activity against HCT 116 cells. It was confirmed that both the blackcurrant leaf extract and its fractions are a promising source of condensed active compounds and can be used as natural functional food additives.

Phenolic Composition, Mineral Content, and Beneficial Bioactivities of Leaf Extracts from Black Currant (Ribes nigrum L.), Raspberry (Rubus idaeus), and Aronia (Aronia melanocarpa).

Currently, the incidence of lifestyle diseases is increasing due to inappropriate nutrition and environmental pollution. To prevent these diseases, various groups of bioactive compounds are needed with a broad spectrum of action and without adverse side effects. Polyphenolic compounds are the most widely studied group of this type of compounds. They occur widely in plants, but their content depends on many factors, including the type of plant, climatic conditions, and the date of harvest. The spectrum of bioactivity of phenolic compounds is determined by their chemical structure, concentration, and interaction with other compounds. Traditional recipes have been studied to search for active plant ingredients. Leaves of shrubs and fruit trees were used in folk medicine as a panacea for many diseases and have been forgotten with time, but their benefits are now being rediscovered. In recent years, much new information about biological activity of phenolic compounds from berry bushes (black currant, raspberry, and aronia) was published. This was reviewed and discussed in this article. The mineral content of their leaves was also summarized because minerals constitute a significant component of plant infusions. It has been shown that high antioxidant and biological activity of leaf extracts results from the presence of active phenolic compounds, which occur in definitely higher amounts than in fruits. Therefore, the leaves of berry bushes seem to be a promising source of substances that can be used as replacements for synthetic agents in the treatment and prevention of lifestyle diseases.