Antibiotics Development and the Potentials of Marine-Derived Compounds to Stem the Tide of Multidrug-Resistant Pathogenic Bacteria, Fungi, and Protozoa

Abstract

As the search for new antibiotics continues, the resistance to known antimicrobial compounds continues to increase. Many researchers around the world, in response to antibiotics resistance, have continued to search for new antimicrobial compounds in different ecological niches such as the marine environment. Marine habitats are one of the known and promising sources for bioactive compounds with antimicrobial potentials against currently drug-resistant strains of pathogenic microorganisms. For more than a decade, numerous antimicrobial compounds have been discovered from marine environments, with many more antimicrobials still being discovered every year. So far, only very few compounds are in preclinical and clinical trials. Research in marine natural products has resulted in the isolation and identification of numerous diverse and novel chemical compounds with potency against even drug-resistant pathogens. Some of these compounds, which mainly came from marine bacteria and fungi, have been classified into alkaloids, lactones, phenols, quinones, tannins, terpenes, glycosides, halogenated, polyketides, xanthones, macrocycles, peptides, and fatty acids. All these are geared towards discovering and isolating unique compounds with therapeutic potential, especially against multidrug-resistant pathogenic microorganisms. In this review, we tried to summarize published articles from 2015 to 2019 on antimicrobial compounds isolated from marine sources, including some of their chemical structures and tests performed against drug-resistant pathogens.

Keywords: algae invertebrates.; antimicrobials; bacteria; drug-resistant; fungi; marine; natural products.

Figure 1

Flow chart of phases used to identify articles included in this review. Some of these articles were got using (marine (NOT military) OR marine natural products OR marine-derived) AND ((invertebrate OR sponge OR coral OR cnidarian OR arthropods OR echinoderms OR tunicates OR algae OR bryozoan)-associated (bacteria OR fungi OR algae))) ((drug-resistant OR multidrug-resistant) (bacteria OR fungi OR protozoa)) and careful insertion of (antibacterial OR antifungal OR antiprotozoal) and (oceans OR seas OR marshes OR bays OR shoreline OR estuaries OR deep sea OR coral reef OR coastal OR mangroves).

Figure 2

Structures of (A) Grincamycin L (1), and an angucycline derivative (2) [42]; (B) 3-methylpyridazine, indazol-4-one, 3,6,6-trimethyl-1-phthalazin-1-yl-1,5,6,7-tetrahydro- [43]; (C) Salinaphthoquinones B–D (2–4) [44]; (D) Echinomycin (quinomucin A) [45]; (E) 4-bromophenol [47].

Figure 3

Structures of (A) desertomycin G (1) [55]; (B) isatin [69]; (C) TM1: 1, 3-dione-5,5-dimethylcyclo-hexane (a), 2-enone-3hydroxy -5,5-dimethylcylohex (b), and that of TM2: 4H-1,3-dioxin-4-one-2,3,6-trimethyl (c) [7]; (D) GKK1032C (1) [95]; (E) penicilones A and B (1, 2) (azaphilones), brominated azaphilones (5, 6), penijanthinones A (7) [96], and (F) monomeric naphtho-γ-pyrones, peninaphones A–C (1–3) [97].

Figure 4

Structures of (A) physcion (3), dihydroauroglaucin (4), and isodihydroauroglaucin (6) [106]; and (B) dolabellane-type diterpenoids (1−3) and three new atranones (4) [110].