Comparative Phytochemical Profiling and Biological Activities of Two Asplenium ceterach L. Extracts

Methanol (ME) and dichloromethane (DCM) extracts of rustyback fern (Asplenium ceterach L.) sporophytes were analyzed for antioxidant properties by thin-layer chromatography (TLC)-based bioautography, using DPPH as the detection reagent, and were comparatively tested for their antimicrobial, antibiofilm, and cytotoxic activities. The bioautography assay indicated that the rustyback fern ME extract had significant antioxidant potential and moderate α-amylase activity compared to the DCM extract. Both extracts exhibited pronounced scavenging activity towards hydroxyl radicals, as well as antibacterial and antifungal potential against all tested strains, although to varying degrees. The Gram-negative Escherichia coli and Gram-positive Bacillus cereus were the most sensitive bacteria, while the most sensitive fungus was the yeast Candida krusei. Furthermore, the tested extracts showed notable capability to prevent Candida albicans biofilm establishment, with no significant difference between the two extracts examined and an inhibition range of 72–74%. Cytotoxic screening indicated the safety of the extracts even at high concentrations, up to 100 μg mL−1. The results of the present study highlight A. ceterach extracts as a significant source of bioactive compounds, supporting their potential use as potent antioxidants and for combating diseases caused by multidrug-resistant microorganisms.