Extraction of Anthocyanins from Black Currants and In Vitro Testing for the Determination of Antioxidant Activity ^†

Abstract

Black currants have antioxidant, anti-inflammatory and chemoprotective properties. Anthocyanins, which are components of black currants, are powerful antioxidants that are able to inhibit the growth of tumor cells and induce apoptosis. In this context, our study was designed to investigate the antitumoral effects following exposure to the total ethanolic extract obtained from blackcurrant powder, rich in anthocyanins, on cervical cancer. The content of total phenolic compounds was analyzed using Folin-Ciocalteu reagent, and the concentration of anthocyanins was determined by HPLC. The in vitro characterization of the extracts included common tests to measure antioxidant capacity, cell viability and inflammation tests on HeLa cervix cells, and measure reduced glutathione level and catalase and glutathione S-transferase activities, as well as flow cytometry analysis to evaluate the cell cycle phases. Our study demonstrated that the extract with the highest concentration in anthocyanins (delphinidin and malvidin), with an antiproliferative capacity, was the one obtained after 48 h of extraction with ethanol, which induced a time- and dose-dependent decrease in cancer cell viability. An increase in enzyme activity of catalase and glutathione S-transferase was noted after the first 24 h of incubation, suggesting a tendency of the cells to counteract the oxidative stress induced by anthocyanins. Incubation of cells with blackcurrant extract resulted in cell cycle arrest in the G1 and sub-G1 phases after 24 and 72 h, respectively. These data support the antioxidant and antiproliferative efficiency of anthocyanins from black currants, which is valuable for further in vivo studies.