Antimicrobial activity of different extracts obtained from Patagonian scallop (Zygochlamys patagonica)

Abstract

The excessive use of antibiotics in medicine, animal production, agriculture and food has contributed to the emergence of pathogens resistant to conventional antibiotics, making the search for new compounds from natural and safe sources necessary. Certain low molecular weight peptides with potential antimicrobial activity have high specificity for prokaryotic organisms and low or no toxicity to eukaryotes. Marine invertebrates are a tentative source for obtaining them, since they have a very effective innate immune system which is the first line of defense against bacteria, fungi and viruses. One way to obtain them is by extraction with different types of solvents, which allow maintaining the effector function of these molecules after their isolation. In this work, extracts with different solvents were obtained from Zygochlamys patagonica and yields were compared to those achieved by the isolation control method for peptides and proteins. Minimum inhibitory concentration (MIC) and antimicrobial activity were evaluated by determining the percentage of growth inhibition of all extracts obtained on Gram-positive and Gram-negative bacteria, and their efficacy was compared with a conventional antibiotic. MIC of the extracts from scallop tissues (without calluses) was 2.5 mg ml^-1, and their antimicrobial activity was comparable to that of a commercial broad-spectrum antibiotic. According to the results, it is recommended to use ethanol as an extraction method due to its lower toxicity and almost zero possibility of bacterial contamination during the process. The identification of these peptides could contribute to a future biotechnological application.