First evidence of anticancer and antimicrobial activity in Mediterranean mesopelagic species

Abstract

Mesopelagic organisms form huge biomass aggregations, supporting important pelagic trophic webs and several top predators. Although some studies on the occurrence, biology and ecology of these organisms are available, to date there are no investigations on their potential use for anticancer and antimicrobial biotechnological applications. The aim of this study was to screen extracts of seven mesopelagic species for possible anticancer (Lung cell line A549, skin cell line A2058, liver cell line HepG2, breast cell line MCF7 and pancreas cell line MiaPaca-2) and antibacterial (Gram-negative bacteria Escherichia coli and Klebsiella pneumoniae, the Gram-positive bacteria methicillin resistant/ sensitive Staphylococcus aureus, and Mycobacterium tuberculosis) activities. Results showed that only two species were active, the lanternfish Myctophum punctatum and the Mediterranean krill Meganyctiphanes norvegica. In particular, M. punctatum showed strong activity against the A549 and MCF7 cells, while M. norvegica was more active against HepG2 cells. Regarding antibacterial assays, both species were active against methicillin resistant S. aureus. Fractionation and LC/MS dereplication of the fractions showed that the main compounds found in extracts of both species were EPA, DHA and ETA. For some of the detected compounds anticancer and/or antibacterial activity are already known, but this is the first time that such activities have been found for mesopelagic species. The mesopelagic zone, from "meso" meaning intermediate, represents a water layer of the ocean below the epipelagic and above the bathypelagic zones, at depths between 200 and 1000 m, that is characterized by increased hydrostatic pressure, diminished light, high inorganic nutrient concentrations and episodic food supply 1. A large number of marine organisms live in the mesopelagic zone, from bacteria to zooplankton and nekton, including species adapted to peculiar conditions, such as the twilight environment, inhabited by a myriad of bioluminescent and unique organisms 2-4. These organisms often form huge biomass aggregations, supporting important pelagic trophic webs and several top predators 5-8. In particular, due to their high density and wide diffusion, mesopelagic fish can be considered the most abundant vertebrates on earth 9. Studies on mesopelagic micronekton have been mainly focused on their distribution, biology and ecology as well as bioluminescent properties but studies related to their potential biotechnological applications are very rare. The reason is mainly due to high costs for their sampling, often requiring the planning of research cruises, the scarce scientific information on most species, and the very scarce available information on their genomes and transcriptomes. Few mesopelagic species are accidentally caught by fishing gear. However, in the Straits of Messina (central Mediterranean Sea), there is a recurrent phenomenon of stranding of mesopelagic organisms due to several factors. Tidal currents, lunar phases, winds and seasons influen...

Antimicrobial Lipids from Plants and Marine Organisms: An Overview of the Current State-of-the-Art and Future Prospects

“…Some of these reports have identified total lipid extracts as a potential source of bioactive compounds, lacking a sequential workflow of isolation, characterization, and purification of the metabolites responsible for the activity [99,143]. Although most of these studies used classical bioprospection methods to identify the bioactive compounds from marine species, others followed eco-friendly approaches by using fishing waste [141] or seafood by-products [144].…”

“…with activity against S. aureus and MRSA [164]. A recent study screening mesopelagic species as a source of potential antimicrobial compounds recognized the extracts of the lanternfish Myctophum punctatum and the Mediterranean krill Meganyctiphanes norvegica to inhibit the growth of MRSA, MSSA, and M. tuberculosis [141]. Extracts of both marine species were fractionated, and their composition was elucidated by LC-UV analysis.…”

“…Extracts of both marine species were fractionated, and their composition was elucidated by LC-UV analysis. EPA, 4,7,10,13,16,19-docosahexaenoate (DHA, 22:6 n-3) and 8,11,14,17-eicosatetraenoic (ETA, 20:4 n-3) acids were the most abundant components in the lipid fractions of both marine species [141]. The 14-methyl-5,9-pentadecadienoic FA from the phospholipid pool was isolated and identified in the gorgonian coral Eunicea succinea and it was active against S. aureus and E. faecalis [137].…”

“…Tropical biodiversity-rich benthic communities have been the most explored, thus the most fruitful in the identification of new potential antimicrobial compounds [ 137 , 138 , 139 ]. However, less conventional environments such as the Arctic ocean or mesopelagic communities have been started to be surveyed [ 140 , 141 ].…”

Chemical Defense in Marine Organisms

“…In addition to these defense molecules and enzymes, marine organisms are known to produce a great variety of compounds, unique in terms of diversity, structural and functional features, which have been shown to have defensive roles (the best known of which are marine toxins) [ 17 , 18 , 19 ]. In addition, several of these compounds have been tested for different bioactivities (e.g., anticancer, anti-inflammatory and antioxidant, as well as for the treatment of neurodegenerative diseases) and results have shown their potential for possible industrial applications [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. Several experiments and observations have focused on understanding defense strategies of marine organisms and the identification of new natural products by using various physiological, chemical, as well as -omics approaches [ 33 , 34 , 35 , 36 ].…”