[Optimization of extracting solutions of antibacterial molecules from Cenchritis muricatus (Gastropoda: Littorinidae)].

Introduction: marine mollusks are natural reservoirs of molecules with therapeutic potential for the treatment of infectious diseases, at a time when many antibiotic-resistant strains are being described.

Objective: to compare three solutions: 30 % acetic acid, 50 % methanol and saline-acid (NaCl 0.6 mol/L, 1 % HCl) according to their capacities to extract molecules with antimicrobial activity from the marine mollusk Cenchritis muricawus.

Methods: the three extraction solutions were used to process the biological material, and then, the obtained extracts were analyzed in terms of total protein concentration and the bacterial growth inhibition of Staphylococcus aureus and Escherichia coli strains by means of a turbidimetric bioassay using 96 well microplates in Luria-Bertani (LB) culture medium.

Results: the highest total protein concentration (7.8 microg/mL) was found in the C. muricatus extract from the saline-acid solution. Additionally, 200 microg/mL of total proteins from the extract caused significant growth inhibition (p< 0.001) of S. aureus (12.64 %) and E. coli (12.1 %) compared to the positive control of growth inhibition using chloramphenicol.

Conclusions: according to these results, the saline-acid solution proved to be more efficient in extracting molecules with antibacterial activity that are likely to be antimicrobial peptides from C. muricatus.