Marine biofouling is the undesired accumulation of organic molecules, microorganisms, macroalgae, marine invertebrates, and their by-products on submerged surfaces. It is a serious challenge for marine vessels and the oil, gas, and renewable energy industries, as biofouling can cause economic losses for these industries. Natural products have been an abundant source of therapeutics since the start of civilisation. Their use as novel anti-fouling agents is a promising approach for replacing currently used, harmful anti-fouling agents. Anthraquinones (AQs) have been used for centuries in the food, pharmaceutical, cosmetics, and paint industries. Citreorosein and emodin are typical additives used in the anti-fouling paint industry to help improve the global problem of biofouling. This study is based on our previous study, in which we presented the promising activity of structurally related anthraquinone compounds against biofilm-forming marine bacteria. To help uncover the anti-fouling potential of other AQ-related structures, 2194 compounds from the COCONUT natural products database were analysed. Molecular docking analysis was performed to assess the binding strength of these compounds to the LuxP protein in Vibrio carchariae. The LuxP protein is a vital binding protein responsible for the movements of autoinducers within the quorum sensing system; hence, interrupting the process at an early stage could be an effective strategy. Seventy-six AQ structures were found to be highly docked, and eight of these structures were used in structure-based pharmacophore modelling, resulting in six unique pharmacophore features.

Bacteria belonging to the phylum Actinobacteria are a very good source of antibiotics, and indeed dominate the current clinical antibiotic space. This paper reports Mutactimycin AP, a new compound belonging to an anthracycline-type family of antibiotics, isolated from a Saccharothrix sp. This actinobacterial strain was isolated from the rhizosphere of lupine plants growing in the extreme hyper-arid Atacama Desert. Structural characterization was carried out using electrospray ionization-mass spectrometry (ESI-MS) and NMR spectroscopy in combination with molecular modelling. The compound was tested against the ESKAPE pathogens, where it showed activity against MRSA and five strains associated with bovine mastitis, where it showed activity against Enterococcus pseudoavium and Staphylycoccus Aureus subsp. Aureus.

Mpox is a globally prevalent disease that has triggered multiple epidemics over the past few decades, leading to moderate rates of hospitalisation and mortality. Recently, it has re-emerged in several countries, including the Democratic Republic of Congo, and appears to be spreading at an unprecedented pace. The disease is caused by zoonotic double-stranded DNA viruses. Due to its similarities with smallpox, distinguishing between the two can be challenging, though the smallpox vaccine typically provides immunity against Mpox. At the time of writing, no approved treatment for Mpox exists; however, several promising candidates have demonstrated the ability to inhibit viral replication, including resveratrol—a polyphenolic compound found in red wine. This study employs molecular docking and molecular dynamics simulations to assess the effectiveness and stability of nine resveratrol analogues. Additionally, 2D and 3D pharmacophore models were developed for the highest-ranked docked compounds, leading to a composite pharmacophore. A structure–activity relationship analysis was also conducted using these top-performing compounds. The findings suggest that two compounds— (9) [1,1'-biphenyl]-3,4',5-triol and (11) {3-hydroxy-5-[2-(4-hydroxyphenyl)ethenyl]phenyl}oxidanesulfonic acid—exhibit strong binding affinity, with compound 11 potentially forming a stable complex with the thymidylate kinase of the vaccinia virus. Graphical abstract

Fungi represent a prolific source of structurally diverse secondary metabolites, yet the extent to which culture conditions reshape the metabolic profile and functional bioactivity remains incompletely understood. In this exploratory study, ten fungal strains belonging to genera Penicillium and Aspergillus were cultivated in Yeast Extract Sucrose (YES) and Czapek Yeast Autolysate (CYA) media and analysed using untargeted LC-HRMS metabolomics. The objective of this study was to evaluate how culture medium influences metabolic profiles and to investigate medium-dependent metabolic variation and its relation to cytotoxic, antibacterial, and antifungal activities. Global metabolic profiling revealed moderate but statistically significant medium-associated metabolite variation, with discriminant metabolites predominantly enriched under CYA conditions. Putative structural annotation suggested patterns consistent with differential regulation of isoprenoid-derived sterols, terpenoids, alkaloid-like metabolites, and aromatic polyketides. While antimicrobial activities displayed a heterogeneous, strain-dependent pattern with limited correlation to individual metabolites, cytotoxic activity co-varied with metabolite composition in OPLS regression modelling. Sterols and terpenoid-related features emerged as major contributors to cytotoxicity. Given the absence of biological replication and the limited sample size inherent to this pilot study, all findings should be considered hypothesis-generating and interpreted within an exploratory framework. These results suggest that nutrient composition influences biosynthetic pathway activation while functional outcomes remain strongly dependent on strain-specific metabolic capacity. This work provides a systematic framework and targeted hypothesis for future investigations into condition-dependent fungal chemical diversity in natural product discovery.

The Atacama Desert is an unexplored habitat with interesting possibilities for natural product chemistry due to the adaptations employed by microorganisms to survive the extreme salinity and high UV radiation present. Several soil samples were collected over the course of a few years in locations across the desert from which microorganisms were isolated. This paper reports on the isolation and structural characterisation, using LC-MS, and 1D and 2D NMR, of a new diketopiperazine that came from one of the fungi isolated from the Atacama Desert.