Exploring Bioactivities and Peptide Content of Body Mucus from the Lusitanian Toadfish Halobatrachus didactylus

Identifying bioactive molecules from marine organisms is still vastly understudied. Fish remain an untapped source of bioactive molecules, even when considering species whose toxicity to other fish species has been noticed before. We assessed potential applications of crude body mucus of the Lusitanian toadfish (Halobratachus didactylus) and characterized its peptide fraction composition. Mucus samples from three individuals (two wild and one captive) revealed potential antioxidant, antihypertensive, and antimicrobial activities. For antioxidant activity, the best results of 2371 +/- 97 mu mol Trolox Equivalent/g protein for ORAC and 154 +/- 6 mu mol Trolox Equivalent/g protein for ABTS were obtained. For antihypertensive activity, the relevant inhibitory activity of ACE resulted in IC50 of 60 +/- 7 mu g protein/mL. Antimicrobial activity was also identified against the pathogenic bacteria Escherichia coli and Listeria monocytogenes. The peptide profile of the crude body mucus was obtained through size exclusion chromatography, with a conspicuous peak at ca. 800 Da. LC-MS/MS allowed the detection of the most probable peptide sequences of this dominant peptide. This is the first study where the bioactive potential of mucus from the Lusitanian toadfish is demonstrated. Peptides with such properties can be applied in the food and pharmaceutical industries.

Automated summary

Identifying bioactive molecules from marine organisms, particularly fish like the Lusitanian toadfish, can lead to the discovery of potential antioxidants, antihypertensives, and antimicrobial agents. The peptide fraction of the fish's body mucus was characterized, showing promising bioactive properties with potential applications in the food and pharmaceutical industries.