Seaweed symbionts reveal treasure trove of potential drug compounds

In a recently published study, Dr Marine medicineScientists review the natural bioactive compounds produced by the marine macroalgae-associated Bacillus and their pharmacological properties.

Study: Natural products and pharmacological properties of the marine macroalgae symbiotic Bacillusota (Firmicutes).. Image credit: Created with assistance from DALL·E 3

Background

Marine macroalgae serve as a rich source of novel bioactive compounds with potential pharmacological properties. However, unlike bioactive compounds produced by terrestrial microorganisms, few studies have evaluated the chemical and biological properties of marine microorganisms.

Marine macroalgae or seaweeds host a wide range of bacterial species. The relationship between host algae and symbionts, such as bacteria or other microorganisms, depends on the type of nutrients provided by the host. Bacterial symbionts produce metabolites needed by their host, as well as antimicrobial and antifouling agents, which protect the host from harmful organisms and substances.

Bacillota has been identified as a bacterial phylum commonly associated with marine macroalgae. Furthermore, bacillota usually consist of gram-positive bacteria.

Bacillota use more than 9% of their genome to encode biosynthetic gene clusters and produce novel bioactive compounds belonging to different chemical classes including terpenes, polyketides, non-ribosomal peptides, lasso peptides, bacteriocins, thiopeptides, lantins.

Metabolites produced by bioactive bacillota

Marine macroalgae serve as a rich source of bioactive bacillota. Cultivation of the marine macroalgae-associated Bacillota in laboratory settings has produced several bioactive compounds, most of which are polyketides.

Macrolides are polyketide macrocyclic lactones with various ring shapes. These highly oxygenated polyenes exhibit a broad spectrum of antibacterial effects against pathogenic bacteria.

A total of 25 macrolides have been identified from the marine macroalga-associated Bacillota, including derivatives of macrolactin, bavalactone, elansolid, dificidin and macrobrevin. Apart from their antibacterial properties, these macrolides are known to have anticancer, antidiabetic, anti-inflammatory and neuroprotective properties.

Various novel derivatives of heterocyclic and aliphatic esters have been isolated from the macroalga Bacillota. Some compounds isolated from B. subtilis of Sargassum myriosystem Include pyranyl benzoate analogs, which are synthesized by Claisen condensation, dehydration, and ketoreduction pathways.

B. amyloliquefaciens isolated from Padina gymnospora, a brown alga, produces polyketides through the polyketide synthase-1 gene cluster. Other polyketide synthase-1 gene products include heterocyclic esters that are secondary metabolites of red alga-isolates. b. amyloliquefaciens

Furanoterpenoids (terpenoids) isolated from macroalgae Bacillotab. Subtilis red algae) exhibit antimicrobial and anti-inflammatory properties. However, these compounds are known to cause toxicity in humans by forming reactive electrophilic intermediates that can bind to and damage cellular macromolecules.

Amicoumacins are derivatives of dihydroisocoumarins produced by bacterial non-ribosomal peptide synthetase gene clusters. These compounds are known to have antibacterial, anti-ulcer, anti-inflammatory and cytotoxic properties.

Pharmacological properties of metabolites obtained from the macroalgae Bacillota

Bacillus Marine Bacillota species associated with macroalgae are the most common. These species use more than 7% of their genome to produce bioactive compounds with antimicrobial properties.

Compounds isolated from the macroalga bacillota exhibit potent antimicrobial effects against pathogenic bacteria that infect humans. Dificidin analogs isolated from red alga-related B. amyloliquefaciens Exhibits the highest antimicrobial effect against a broad spectrum of pathogenic bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis.

Similarly, isolated from compounds B. velegensis of Laurencia papillosa (red algae) exhibits antimicrobial effects against MRSA and Vibrio hemolyticus. Each of these compounds exhibits antimicrobial effects at micromolar concentrations.

Apart from their antimicrobial properties, the anti-inflammatory, antioxidant, antidiabetic, anti-hypercholesterolemic, anti-hyperglycemic and cytotoxic properties of extracts and fractions of the macroalgae Bacillota have been extensively studied.

in vitro Studies have reported antifungal activity of a volatile fraction B. amyloliquefaciens isolated from Zonaria turnforti. Similarly, an acetone extract Bacillus A species isolated from a brown algae has been shown to exert cytotoxic effects against colon cancer cells.

Significance

The marine macroalgae-associated Bacillusota is a rich source of novel bioactive compounds with diverse pharmacological properties. To date, only a small fraction of marine macroalgae populations have been studied. in vitro And in silico Antibacterial bioassays for their bacillus chemical constituents.

However, for the discovery of novel therapeutic agents from the macroalgae Bacillota, alive Studies using different animal models are needed to evaluate the safety, bioavailability and therapeutic efficacy of compounds derived from bacillota. Expanding the bioactivity profiles of these novel compounds beyond their well-known antibacterial properties requires more diverse biopursuits.