Ecological and Pharmacological Activities of Antarctic Marine Natural Products

Abstract

Antarctic benthic communities are regulated by abundant interactions of different types among organisms, such as predation, competition, etc. Predators are usually sea stars, with omnivorous habits, as well as other invertebrates. Against this strong predation pressure, many organisms have developed all sorts of defensive strategies, including chemical defenses. Natural products are thus quite common in Antarctic organisms with an important ecological and pharmacological potential. In this paper, the chemical defenses of the Antarctic organisms studied during the ECOQUIM and ACTIQUIM projects, as well as their pharmacological potential, are reviewed. For the ecological defenses, predation against the sea star Odontaster validus is analyzed and evaluated along depth gradients as well as considering the lifestyle of the organisms. For the pharmacological activity, the anticancer, anti-inflammatory, and antibacterial activities tested are evaluated here. Very often, only crude extracts or fractions have been tested so far, and therefore, the natural products responsible for such activities remain yet to be identified. Even if the sampling efforts are not uniform along depth, most ecologically active organisms are found between 200 and 500 m depth. Also, from the samples studied, about four times more sessile organisms possess chemical defenses against the sea star than the vagile ones; these represent 50 % of sessile organisms and 35 % of the vagile ones, out of the total tested, being active. Pharmacological activity has not been tested uniformly in all groups, but the results show that relevant activity is found in different phyla, especially in Porifera, Cnidaria, Bryozoa, and Tunicata, but also in others. No relationship between depth and pharmacological activity can be established with the samples tested so far. More studies are needed in order to better understand the ecological relationships among Antarctic invertebrates mediated by natural products and to fully explore their pharmacological potential.

Marine Based Natural Products: Exploring the Recent Developments in the Identification of Antimicrobial Agents

“…spitzbergensis . Several bioactive metabolites have been isolated from cold‐water bryozoans (moss animals, phylum Ectoprocta) including compound 8 [32] . This is the first record of bioactive metabolites from a genus of Tegella .…”

“…Several bioactive metabolites have been isolated from cold-water bryozoans (moss animals, phylum Ectoprocta) including compound 8. [32] This is the first record of bioactive metabolites from a genus of Tegella. Compounds 8-11 were reported to have antimicrobial activity, with minimum inhibitory concentrations (MIC) as low as 6.25 μg/mL against Staphylococcus aureus.…”

Bacteria Associated with Marine Benthic Invertebrates from Polar Environments: Unexplored Frontiers for Biodiscovery?

“…Finally, as it is well known, bioprospecting is regulated by various international law regimes worldwide. It has considerable scientific and economic repercussions, and includes the research and discovery of bioactive compounds with a potentially high value for human and environmental health [109][110][111][112]. It must be pointed out that, in the case of Antarctica, the exploitation of biological resources must follow the directions within the Antarctic Treaty, which includes a number of ethical principles to be followed for all activities in this region to preserve Antarctic life.…”

Marine Pharmacology in 2016–2017: Marine Compounds with Antibacterial, Antidiabetic, Antifungal, Anti-Inflammatory, Antiprotozoal, Antituberculosis and Antiviral Activities; Affecting the Immune and Nervous Systems, and Other Miscellaneous Mechanisms of Action

“…In 2016-2017 several reviews covered general and/or specific areas of marine preclinical pharmacology: (a) marine pharmacology and marine pharmaceuticals: new marine natural products and relevant biological activities published in 2016 and 2017 [330,331]; chemistry and biology of guanidine natural products [332,333]; biological properties of secondary metabolites from sea hares of Aplysia genus [334]; alkynyl-containing peptides of marine cyanobacteria and molluscs [335]; bioactive cyanobacterial secondary metabolites for health [336]; biological active metabolites from marine-derived myxobacteria [337]; antimicrobial metabolites from the marine bacteria genus Pseudoalteromonas [338]; marine natural products from marine-derived Penicillium fungi [339]; biological activity of secondary metabolites from marine-algal-derived endophytic fungi [340]; pharmacological potential of fucosterol from marine algae [341]; pharmacological activities of Antarctic marine natural products [342]; bioactive acetylated triterpene glycosides from Holothuroidea in the past six decades [343]; terpenoids from octocorals of the genus Pachyclavularia [344]; bioactive marine natural products from sponges of the genus Hyrtios [345]; secondary metabolites from the marine sponge genus Phyllospongia [346]; discovery strategies of bioactive compounds synthetized by nonribosomal peptide synthetases and type-1 polyketide synthase derived from marine microbiomes [347]; developing natural product drugs: supply problems and how they have been overcome [348]; the global marine pharmaceutical pipeline in 2020: U.S. Food and Drug Administration-approved compounds and those in Phase I, II and III of clinical development http://marinepharmacology.midwestern.edu/clinPipeline.htm; (b) antimicrobial marine pharmacology: antimycobacterial metabolites from marine invertebrates [349]; antimicrobials from cnidarians [350]; (c) antiprotozoal and antimalarial marine pharmacology: natural products in drug discovery against neglected tropical diseases [351]; antimycobacterial natural products from marine Pseudopterogorgia elisabethae [352]; (d) immuno-and anti-inflammatory marine pharmacology: marine natural products inhibitors of neutrophil-associated inflammation [353]; (e) cardiovascular and antidiabe...…”