Antimicrobial Potential of the Crude Extracts and Peptide Fractions of Two Marine Molluscs: Tympanatonus fuscatus Var Radula (Linneaus) and Pachymelania aurita (Muller)

Abstract

Aims: This study was aimed at evaluating the antimicrobial potential of the alcohol and aqueous extracts as well as peptide fractions of T. fuscatus and P. aurita. Place and Duration of Study: Department of Microbiology, Obafemi Awolowo University, Ile-Ife, Nigeria. Methodology: The antimicrobial activity of the whole body aqueous and acetone-methanol extracts of T.fuscatus Var Radula and P.aurita, collected from the Niger-Delta region of Nigeria, were evaluated based on inhibition zone diameter using the agar well diffusion method against ten bacterial isolates and C. albicans. These organisms were further used in the TLC bioautography experiment. The peptide fraction from the organic extracts of both organisms was obtained by Molecular sieve chromatography on Sephadex LH20. Peaks obtained were pooled and further analysed on TLC. A simple contact TLC bioautographic procedure was used to detect the number of antibacterial and antifungal peptides present in the extracts of both T. fuscatus and P. aurita. Results: The aqueous extract of both T. fuscatus and P. aurita had no antimicrobial effect against the test microorganisms whereas the acetone-methanol extract showed broad-spectrum antibacterial activity against five bacterial isolates at the highest concentration (100 mg/ml). It also showed inhibition against C. albicans at this concentration (100 mg/ml). All the peptides exhibited bactericidal activity against the five test bacterial isolates and bacteriostatic activity against C. albicans. This activity was denoted by inhibition of growth in the region in which the peptides on the TLC plate made contact with the agar containing the isolates. Conclusion:  Further studies to effectively separate these peptide fractions into individual peptides and further investigate the antimicrobial activity of the individual peptides is required.