Assessment of Antioxidant, Antiproliferative and Proapoptotic Potential of Aqueous Extracts of Chroococcus sp. R-10

The rising incidence of cancer and the limitations of current therapeutic strategies underscore the urgent need to identify novel bioactive compounds for antitumor drug development. Cyanobacteria are widespread Gram-negative, photoautotrophic prokaryotes that have been recognized as an important source of biologically active secondary metabolites with vast potential for application in the fields of pharmaceutics. The aim of the present study was to analyze the phytochemical composition, antioxidant, and antitumor activities of low-temperature (LT) and high-temperature (HT) aqueous extracts of the cyanobacterium Chroococcus sp. R-10. Extracts were prepared and analyzed for phytochemical composition using UPLC-DAD, and antioxidant activity was tested via multiple assays. Antiproliferative effects were evaluated on human tumor cell lines, and the effects on cell cycle progression studied using flow cytometry. Fluorescence microscopy was employed to examine extract-induced cytomorphological changes in the treated cancer cells. UPLC-DAD analyses showed very similar chromatographic profiles of the extracts and identified glycogen as their main constituent. Both extracts displayed concentration-dependent antioxidant activity, with notable radical scavenging and ferric-reducing capacity. LT extract demonstrated higher phenolic content and antioxidant capacity. Both extracts reduced cell viability, particularly in MCF-7 and MDA-MB-231 breast carcinoma cell lines. Flow cytometry and fluorescent microscopy analyses revealed that the suppressed proliferative activity of the cancer cells was associated with a retardation of cell cycle progression and apoptosis induction. This study identifies Chroococcus sp. R-10 as a promising source of phytochemical compounds with pharmaceutical relevance and provides a rationale for further investigations to identify the primary bioactive constituents and elucidate their mechanisms of anticancer action.