Characterization of fatty acids and antimicrobial activity of the methanol extract of Holothuria princeps (Holothuriida: Holothuriidae)

In recent decades, studies related to the search and characterization of bioactive molecules in marine organisms have increased exponentially, demonstrating the enormous wealth of secondary metabolites of diverse structural composition that cannot be found in organisms present in the terrestrial environment. A significant number of the new marine natural compounds discovered have contributed to solving some of the problems of humanity, mainly those related to human health. The purpose of this research is to evaluate the bactericidal and fungicidal activities of the methanolic extract of sea cucumber Holothuria princeps collect from the bay of Cispata in the Colombian Caribbean, in addition to chemically identifying its fatty acids. A methanolic extraction was performed from the collected biological material, by the cold maceration method. The extract obtained was fractionated using chromatographic techniques and the fatty acids were obtained, which were derivatized and identified by means of gas chromatography in coupling with mass spectrometry. The antibacterial and antifungal activities of the methanolic extract of Holothuria princeps was performed through the microdilution method against reference strains and clinical isolates. We found 16 fatty acids present in Holothuria princeps according to the analysis of their mass spectra. Antibacterial activity showed that Enterococcus faecalis was the most susceptible to the extract at low concentrations, while Pseudomonas aeruginosa was the highest at the higher concentrations. In antifungal treatment, the fungus with the highest inhibition was the clinical isolate of Candida albicans (blood sample). Taking into account previous studies in the genus Holothuria, it is considered that the environment plays a fundamental role in the presence and diversity of fatty acids. The evaluation of the antibacterial activity against reference strains of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae and Enterococcus faecalis demonstrated the existence of a considerable effect in the reduction of bacterial growth by the extracts applied, mainly at low concentrations (less than 1 000 ppm). On the other hand, the antifungal activity against the reference strain of Candida albicans and the clinical isolates of Candida albicans (blood sample) and Candida krusei (catheter sample), the extract showed that the best results were presented at higher concentrations (above 1 500 ppm). (author)