Investigation of Biological Activity of Squamarina cartilaginea (With.) P. James Species Distributed in Türkiye

In this study, the methanol extract of Squamarina cartilaginea, a species distributed in Türkiye, was investigated for its antimicrobial, antioxidant, cytotoxic, and DNA protective effects. The chemical composition of the extract was elucidated through spectroscopic determination of total phenols, total flavonoids, and chromatographic quantification of usnic acid. Antimicrobial activity was assessed using the disk diffusion method, revealing a significant zone of inhibition with a diameter of 17.5 mm against M. luteus and S. aureus. The antioxidant activity was evaluated through scavenging activities against DPPH and ABTS radicals, demonstrating a concentration-dependent potent scavenging activity against ABTS radicals. Cytotoxic activity was determined using the MTT method on DU-145 (Human Prostate Cancer Cell Line) and Colo 205 (Human Colon Cancer Cell Line) cell lines. The extract exhibited strong cytotoxic activity against the Colo 205 cell line, with a viability percentage of 33.16±2.01 at a concentration of 3.906 µg/mL. Furthermore, the S. cartilaginea extract demonstrated DNA protective activity on pBR322 plasmid DNA against UV and H2O2 exposure.