Prediction of acute fish toxicity (AFT) and fish embryo toxicity (FET) tests by cytotoxicity assays using liver and embryo zebrafish cell lines (ZFL and ZEM2S)

A novel integrated testing strategy (ITS) for evaluating acute fish toxicity with new approach methodologies (NAMs)

Acute fish toxicity (AFT) tests are performed in aquatic risk assessments of chemical compounds globally. However, the specific endpoint of in vivo AFT is based on the lethal concentration 50 (LC50), which is a serious challenge in terms of animal welfare. To support the 3Rs principle of replacing, reducing, and refining use of animals, integrated testing strategies (ITS) have recently been developed for environmental risk assessment. ITS efficiently integrates multiple types of information, especially new approach methodologies (NAMs), and further supports regulatory decision-making. Currently, an effective ITS framework for evaluating aquatic toxicity is lacking. Therefore, we aimed to develop a promising ITS for AFT using in silico, in vitro, and in vivo data. We established the ITS via in silico (OECD QSAR Toolbox 4.6), fish cell line acute toxicity (FCT), and fish embryo acute toxicity (FET) tests and then validated the NAMs with AFT testing. The NAM data were derived from the European Chemicals Agency (ECHA) dossier, toxicology databases, peer-reviewed research articles, and this study. For the first step in the ITS process, we aimed to design a high-throughput screening tool to identify non-toxic and toxic chemicals. We found that results of in silico, FCT, and FET tests alone were strongly correlated with AFT. Among the models, the in silico model was most suitable for identifying toxicants due to its high sensitivity and minimal animal use. Next, considering regulatory purposes and flexibility, we determined the predictive LC50 of toxic chemicals by pursuing a preference-dependent strategy, sequential testing strategy, and sensitivity-dependent strategy. All the strategies demonstrated a predictive power equal to or greater than 73%. In addition, to meet user preferences, our ITS approach has high flexibility and supports animal welfare and environmental protection. We have therefore developed multiple powerful, flexible, and more humane ITS methods for acute fish toxicity assessment by integrating NAMs.

Floral Fusion: Unravelling the Potent Blend of Ixora coccinea and Rhododendron arboreum for Health and Safety Benefits

OBJECTIVE

Ixora coccinea and Rhododendron arboreum are known for their traditional medicinal uses due to their diverse phytochemicals and pharmacological effects, which have attracted the interest of many researchers. This study aims to evaluate the antioxidant, anti-inflammatory, and cytotoxic effects of their combined extracts.

METHODS

In vitro antioxidant activity against reactive oxygen species (ROS) was measured using the ferric-reducing ability of plasma (FRAP), nitric oxide (NO), and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assays, while anti-inflammatory effects were assessed via the membrane stabilization method. Docking studies were performed to evaluate the interaction of phytochemicals - anthocyanins, quercetin, and ursolic acid, which are present in these plants - with nuclear factor kappa B (NF-κB), cyclooxygenase-1 (COX-1), and cyclooxygenase-2 (COX-2). Standard protocols were used to evaluate embryotoxicity using the brine shrimp model and cytotoxicity using the zebrafish model, which is crucial for determining safe clinical dosages.

RESULTS

The analysis revealed diverse bioactive compounds, including anthocyanins, quercetin, and ursolic acid. The formulation effectively inhibited ROS production at lower concentrations (inhibitory concentration 50%, or IC50 value ~2.8 µg/mL), indicating their potential for managing oxidative stress. Quercetin demonstrated the strongest interaction with all tested proteins, particularly NF-kB. Cytotoxicity and embryotoxicity assays revealed a dose-dependent effect (lethal concentration 50%, or LC50 value 82.4 µg/mL), with no adverse effects on developing embryos at the tested doses (5-80 µg/mL), suggesting the extracts are safe for clinical use, even during pregnancy.

CONCLUSION

The combined extracts of I. coccinea and R. arboreum exhibit potent antioxidant and anti-inflammatory effects without causing cytotoxic or embryotoxic effects, even at higher concentrations. This indicates their potential for safe clinical application in treating oxidative and inflammatory diseases.

Characterization, Mechanism, and Application of Dipeptidyl Peptidase III: An Aflatoxin B1-Degrading Enzyme from Aspergillus terreus HNGD-TM15

Aflatoxin B1 is a notorious mycotoxin with mutagenicity and carcinogenicity, posing a serious hazard to human and animal health. In this study, an AFB1-degrading dipeptidyl-peptidase III mining from Aspergillus terreus HNGD-TM15 (ADPP III) with a molecular weight of 79 kDa was identified. ADPP III exhibited optimal activity toward AFB1 at 40 °C and pH 7.0, maintaining over 80% relative activity at 80 °C. The key amino acid residues that affected enzyme activity were identified as H450, E451, H455, and E509 via bioinformatic analysis and site-directed mutagenesis. The degradation product of ADPP III toward AFB1 was verified to be AFD1. The zebrafish hepatotoxicity assay verified the toxicity of the AFB1 degradation product was significantly weaker than that of AFB1. The result of this study proved that ADPP III presented a promising prospect for industrial application in food and feed detoxification.

Enhancing photocatalytic tetracycline degradation through the fabrication of high surface area CeO2 from a cerium-organic framework

Water pollution is a global environmental issue, and the presence of pharmaceutical compounds, such as tetracyclines (TCs), in aquatic ecosystems has raised growing concerns due to the potential risks to both the environment and human health. A high surface area CeO2 was prepared via atmospheric thermal treatment of a metal-organic framework of cerium and benzene-1,3,5-tricarboxylate. The effects of calcination temperature on the morphology, structure, light absorption properties and tetracycline removal efficiency were studied. The best activity of the photocatalysts could be achieved when the heat treatment temperature is 300 °C, which enhances the photocatalytic degradation performance towards tetracycline under visible light. The resulting CeO2 particles have high capacity for adsorbing TCs from aqueous solution: 90 mg g-1 for 60 mg L-1 TCs. As a result, 98% of the initial TC can be removed under simulated sunlight irradiation. The cooperation of moderate defect concentration and disordered structure showed tetracycline removal activity about 10 times higher than the initial Ce-MOF. An embryotoxicity assessment on zebrafish revealed that treatment with CeO2 particles significantly decreased the toxicity of TC solutions.