Biofouling causes huge economic loss and generates serious ecological issues worldwide. Marine coatings incorporated with antifouling (AF) compounds are the most common practices to prevent biofouling. With a ban of organotins and an increase in the restrictions regarding the use of other AF alternatives, exploring effective and environmentally friendly AF compounds has become an urgent demand for marine coating industries. Marine microorganisms, which have the largest biodiversity, represent a rich and important source of bioactive compounds and have many medical and industrial applications. This review summarizes 89 natural products from marine microorganisms and 13 of their synthetic analogs with AF EC₅₀ values ≤ 25 μg/mL from 1995 (the first report about marine microorganism-derived AF compounds) to April 2017. Some compounds with the EC₅₀ values < 5 μg/mL and LC₅₀/EC₅₀ ratios > 50 are highlighted as potential AF compounds, and the preliminary analysis of structure-relationship (SAR) of these compounds is also discussed briefly. In the last part, current challenges and future research perspectives are proposed based on opinions from many previous reviews. To provide clear guidance for the readers, the AF compounds from microorganisms and their synthetic analogs in this review are categorized into ten types, including fatty acids, lactones, terpenes, steroids, benzenoids, phenyl ethers, polyketides, alkaloids, nucleosides and peptides. In addition to the major AF compounds which targets macro-foulers, this review also includes compounds with antibiofilm activity since micro-foulers also contribute significantly to the biofouling communities.

Six new caryophyllene-based sesquiterpenoids named punctaporonins H–M (1–6), together with punctaporonin B (7) and humulane (8) were isolated from the fermentation broth of the sponge-derived fungus Hansfordia sinuosae. Their structures were determined by the extensive HRESIMS and NMR spectroscopic analysis, including the X-ray crystallographic data for the assignment of the absolute configurations of punctaporonins H–I (1–2). The isolated compounds were evaluated for antihyperlipidemic, cytotoxic and antimicrobial activities, and punctaporonin K (4) exhibited potent effects to reduce the triglycerides and total cholesterol in the intracellular levels.

The aim of this research is to explore the biological and chemical diversity of bacteria associated with a marine flatworm Paraplanocera sp., and to discover the bioactive metabolites from culturable strains. A total of 141 strains of bacteria including 45 strains of actinomycetes and 96 strains of other bacteria were isolated, identified and fermented on a small scale. Bioactive screening (antibacterial and cytotoxic activities) and chemical screening (ultra-performance liquid chromatography–mass spectrometry (UPLC-MS)) yielded several target bacterial strains. Among these strains, the ethyl acetate (EA) crude extract of Streptomyces sp. XY-FW47 fermentation broth showed strong antibacterial activity against methicillin-resistant Staphylococcus aureus ATCC43300 (MRSA ATCC43300) and potent cytotoxic effects on HeLa cells. The UPLC-MS spectral analysis of the crude extract indicated that the strain XY-FW47 could produce a series of geldanamycins (GMs). One new geldanamycin (GM) analog, 4,5-dihydro-17-O-demethylgeldanamycin (1), and three known GMs (2–4) were obtained. All of these compounds were tested for antibacterial, cytotoxic, and antifungal activities, yet only GM (3) showed potent cytotoxic (HeLa cells, EC₅₀ = 1.12 μg/mL) and antifungal (Setosphaeria turcica MIC = 2.40 μg/mL) activities. Their structure–activity relationship (SAR) was also preliminarily discussed in this study.

SUMMARY: Heated tobacco products (HTPs) are a recent category of tobacco products, with their relative safety compared to cigarette smoking and potential to help smokers to quit being two reasons why regulators may consider their market approval. Designed to heat tobacco rather than to burn in order to produce aerosol, different heating techniques are applied to commercial HTPs, which may result in differing aerosol formation. Therefore, each product requires separate assessment. This work focuses on a closed-end HTP (coded as HTP-A), which is electrically heated and designed to allow puffing air flow to bypass its tobacco section, resulting in reduced oxygen concentration within the tobacco section during heating and aerosol forming. To provide a preliminary aerosol chemistry and in vitro toxicological screening, this study assessed HTP-A against a commercial electrically heated HTP (IQOS ^TM , coded as HTP-B) and a 3R4F reference cigarette. Under Health Canada Intense (HCI) smoking regime, the levels of 9 regulatory priority toxicants in the aerosol of HTP-A were either reduced or comparable to those in HTP-B on a per-stick basis. Additionally, both HTPs showed significant reduction (greater than 90%) in comparison to those measured in mainstream smoke of 3R4F cigarette for these toxicants. Using a set of standard in vitro toxicological assays (Ames, Micronucleus and Neutral Red Uptake), the two HTPs showed no observable responses while significant toxicity responses were recorded for 3R4F’s total particulate matter. Based on these preliminary results, the novel closed-end HTP-A design may provide similar toxicological profiles to the comparator HTP-B. Further toxicological and clinical assessments are warranted to evaluate HTP-A’s potential for exposure or disease risk reduction. [Contrib. Tob. Nicotine Res. 32 (2023) 146–156]