Supriya Pramod Sawant and Vinda Manjramkar
Abstract
Fish epidermal mucus constitutes an essential component of innate immunity and contains diverse bioactive molecules with antimicrobial properties. While antimicrobial activity of mucus from freshwater and estuarine fishes has been widely documented, marine elasmobranch mucus remains comparatively underexplored. The present study reports a preliminary screening of antimicrobial activity of mucus extracts obtained from the shark Scoliodon (âMushiâ) against selected bacterial and fungal pathogens. Crude mucus was extracted using aqueous, alcoholic (absolute and 70% ethanol), and acidic (3% acetic acid) solvents. Antimicrobial activity was assessed using the disc diffusion method against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Salmonella typhi, Candida albicans, and Aspergillus niger. Zones of inhibition were recorded as qualitative indicators of antimicrobial activity. The acidic and alcoholic extracts demonstrated measurable antimicrobial activity against selected microorganisms. In contrast, crude and aqueous extracts exhibited inhibitory effects mainly against fungal species, with negligible or no activity against the bacterial strains tested. Notable variability was observed across experimental replicates, and solvent controls showed significant inhibitory effects. Considerable variability was observed across experimental runs, and solvent controls demonstrated substantial inhibitory effects. The findings suggest that shark mucus contains solvent-extractable compounds with preliminary antimicrobial potential. However, due to the absence of MIC determination and solvent-associated effects, the results should be interpreted as screening-level observations. Further standardized and quantitative studies are required to validate and characterize the antimicrobial components of Scoliodon mucus.