Adverse (geno)toxic effects of bisphenol A and its analogues in hepatic 3D cell model

Exposure of Bisphenols (BPA, BPB and BPC) in HepG2 Cells Results in Lysosomal Dysfunction and Lipid Accumulation

Nonalcoholic fatty liver disease poses a significant public health concern, as do the issues surrounding plastic usage. The bisphenols are reported to cause fat accumulation in the liver. However, literature is scanty about the effect of bisphenols on lysosomes or lysosomal functions. We predicted the interaction of bisphenols with lysosomal proteins available in the online databases using in silico tools. Molecular docking revealed that chosen Bisphenols interact with critical lysosomal proteins including lipid hydrolyzing enzymes. Following exposure of BPA, BPB and BPC to HepG2 cells fat accumulation and lysosomal functions were evaluated. Exposure to BPB and BPC results intracellular fat accumulation under experimental conditions like BPA. All three Bisphenols disturb lysosomal homeostasis perhaps by different mechanisms. Overall our results suggest that Bisphenols can also cause fat accumulation in liver by disturbing lysosomal homeostasis.

Effects of two typical organophosphate flame retardants on DNA damage of GT1-7 cells and relevant molecular mechanism

The tris (2-chloroethyl) phosphate (TCEP) and tri-n-butyl phosphate (TNBP) are two typical organophosphate esters (OPEs), which have estrogenic activity. However, fewer studies have been conducted on their genotoxicity and mechanisms. In this study, we evaluated the effects of TCEP and TNBP on cellular DNA damage in GT1-7 cells and examined the role of estrogen signaling in regulating DNA damage. The results showed that TCEP and TNBP significantly inhibited the cell viability and elevated intracellular reactive oxygen species (ROS) levels at higher exposure concentrations. TCEP and TNBP at test concentrations significantly increased comet tail length, comet tail DNA percentage (Tail DNA%), and Olive tail moment (OTM) values, indicating that TCEP and TNBP induced cellular DNA damage. In addition, TCEP and TNBP significantly upregulated the mRNA levels of target genes related to DNA damage-repair pathways, and elevated the expression of ataxia-telangiectasia mutated (ATM) and γ-H2AX proteins associated with DNA double-strand breaks. Furthermore, TCEP and TNBP significantly up-regulated the expression of membrane bound G-protein coupled estrogen receptor 1 (GPER) protein and increased the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2) at 10 µM. While the pretreatment of GPER1 inhibitor G15 and ERK1/2 inhibitor U0126 significantly inhibited the up-regulation of mRNA expression of the target genes associated with the DNA damage-repair pathways and decreased the DNA damage induced by TCEP and TNBP. These findings indicate that TCEP and TNBP activate GPER1/ERK1/2 signaling pathway which plays an important role in regulating DNA damage. The study will provide a novel insight into the genotoxicity mechanism of OPEs.

Comparative toxicity of eleven bisphenol analogs in the nematode Caenorhabditis elegans

Bisphenol analogs are widely used as industrial substitutes for Bisphenol A (BPA) and are included in water bottles, food containers, and receipts commonly encountered daily. However, there are currently no specific regulations on these substitute substances, and reports on their harmful effects are also lacking. In this study, we examined the toxicity of eleven bisphenol analogs, including BPAP, BPB, BPC, BPC2, BPE, BPG, BPM, BPP, BPPH, BPZ, and TBBPA at 1 mM concentration using the C. elegans model. Our findings revealed that several bisphenol analogs, most notably BPB, BPC, BPE, and BPG, significantly increased lethality in embryonic and L1 larval stages. Additionally, developmental delays were observed with BPAP, BPB, BPC, and BPG, with a reduced fraction of animals reaching adulthood. Regarding reproductive toxicity, we found that BPAP, BPB, BPC, BPC2, and BPG reduced egg production. Furthermore, exposure to the analogs significantly shortened the lifespan of C. elegans, particularly with BPAP, BPB, BPC, and BPG, raising concerns about their potential impact on aging. This study suggests their potential harmful effects on development, reproduction, and longevity.

Comprehensive assessment of the safety of bisphenol A and its analogs based on multi-toxicity tests in vitro

As substitutes for bisphenol A (BPA), bisphenol analogs (BPs) have raised concerns due to their frequent environmental detection and unclear safety. Here, the cytotoxicity, endocrine disruption, neurotoxicity, aryl hydrocarbon receptor (AhR) activity, and genotoxicity of nine BPs and BPA were evaluated in three types of cell lines. Over half of the tested BPs exhibited greater cytotoxicity than BPA, with IC50 values showing a linear correlation with LogKow (R²=0.69). All tested BPs exhibited at least one endocrine-disrupting effect, notably estrogenic, which was observable even at 0.01-0.1 μM. Importantly, BPAF and BPAP exposure had widespread endocrine-suppressing effects. Moreover, all BPs (except BPP) and BPA increased SH-SY5Y cells apoptosis at 1-10 μM. Only BPF and BPP significantly increased 7-ethoxyresorufin-O-deethylase levels, highlighting their notable effects on AhR activity. BPAF significantly induced DNA damage at 1.25 μM, whereas BPA, BPF, and BPP induced damage at 20, 25, and 25 μM, respectively. Finally, ToxPi, a weighted scoring system, was used to rank the comprehensive toxicity of BPs, with 7 of 9 BPs showing higher scores than BPA. Collectively, BPs generally exhibited stronger comprehensive toxicity compared with BPA, emphasizing the urgent need for further research to confirm their potential health implications.

Exposure to bisphenol S induces organ toxicity by disrupting oxidative and antioxidant defense system and blood physiology in Labeo rohita (Hamilton, 1822)

Bisphenol S is an emerging pollutant that is contaminating aquatic ecosystems and causing detrimental effects on aquatic organisms, especially fish. Therefore, the study was designed to evaluate the toxicity of bisphenol S (BPS) through genotoxic, biochemical, histopathological, and oxidative damage in the liver, gills, and kidneys of Labeo rohita fish. Fish were exposed to three different concentrations (400 µg/L, 800 µg/L, and 1000 µg/L) of BPS for 21 days. A significant (p ≤ 0.05) decline in antioxidant enzymatic activity of superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and peroxidase (POD) was observed in all tissues, whereas elevation in oxidative contents (TBARS and ROS) was observed. Comet analysis showed elevated olive tail moment and % of DNA damage. Light microscopy revealed several anomalies including cluster nuclei formation, damaged parenchyma cells, sinusoidal spaces, and melanomacrophage in the kidney, sinusoidal spaces, dilated hepatic vein, pyknotic nuclei, melanomacrophage, and cell necrosis in the liver and bone cell deformities, lamellar aneurysm, hyperplasia, and curved secondary gill lamellae in gills. Results of hematobiochemical analysis revealed a significant (p ≤ 0.05) increment in hematocrit, WBCs, cholesterol, blood glucose, triglycerides, AST, ALT, T3, TSH, T4, urea, and creatinine, whereas decline in RBCs, MCH, hemoglobin, proteins levels was observed. The results of the current study demonstrate that BPS has detrimental effects on the kidneys, gills, and liver. It interferes with normal functioning by inhibiting enzymatic activity, causing DNA damage, and disrupting the normal structure of vital organs. These effects make BPS toxic to fish, even at low concentrations.

Bisphenol A impairs oocyte maturation by dysfunction of cumulus cells

Bisphenol A (BPA) is a well-known environmental endocrine disruptor that has detrimental effects on reproduction. This study aimed to investigate whether BPA exposure could disrupt the function of cumulus cells and influence oocyte maturation and development. Porcine oocytes at the germinal vesicle stage were exposed to BPA for 44 h. The results revealed that BPA exposure led to dysfunction in cumulus cells by inhibiting meiotic division, inducing endoplasmic reticulum stress, and disrupting steroid synthesis. Furthermore, BPA exposure significantly increased reactive oxygen species and caused abnormal distribution of mitochondria in the oocytes. Notably, matured oocytes in the MII stage from the BPA-exposed groups showed significantly reduced development to the blastocyst stage, along with increased autophagy and apoptosis. These findings suggest that cumulus-oocyte complexes are sensitive to BPA exposure during the germinal vesicle stage, and the toxic effects of BPA on cumulus cells can severely inhibit oocyte and parthenogenetic embryos development.

BPAP induces autism-like behavior by affecting the expression of neurodevelopmental genes in Drosophila melanogaster

Bisphenol AP (BPAP), an environmental endocrine disruptor, may cause neurodevelopmental disorders affecting human health. Studies have shown that BPAP impacts hormone synthesis and metabolism, causes social behavior abnormalities, and induces anxiety-like behavioral impairments in mice. However, evidence for the neurobehavioral effects of BPAP is still lacking. Here, we examined the toxic effects of BPAP on neurodevelopment using a Drosophila model. We assessed the role of BPAP exposure in autism-like behavior and explored the underlying mechanisms. Our findings indicated that BPAP exposure reduced pupation and eclosion rates and delayed growth in Drosophila. Furthermore, BPAP exposure caused autism-like behaviors, characterized by increased grooming times and aberrant social interactions, along with abnormalities in locomotor activity, as well as learning and memory ability. Mechanistically, we found that BPAP decreases the number of neuroblasts (NBs) and mature intermediate neural progenitors (INPs) in the 3rd larval brain, impairing axon guidance in the mushroom body of the adult Drosophila brain. Additionally, our transcriptome analysis revealed that BPAP exposure alters the expression of neurodevelopment-related genes (Nplp3, sand, lush, and orco) and affects the estrogen signaling pathway (Hsp70Ab, Hsp70Bc, Hsp70Ba, and Hsp70Bb). These changes potentially explain the BPAP-induced autism-like behavior in Drosophila.

A critical review to identify data gaps and improve risk assessment of bisphenol A alternatives for human health

Bisphenol A (BPA), a synthetic chemical widely used in the production of polycarbonate plastic and epoxy resins, has been associated with a variety of adverse effects in humans including metabolic, immunological, reproductive, and neurodevelopmental effects, raising concern about its health impact. In the EU, it has been classified as toxic to reproduction and as an endocrine disruptor and was thus included in the candidate list of substances of very high concern (SVHC). On this basis, its use has been banned or restricted in some products. As a consequence, industries turned to bisphenol alternatives, such as bisphenol S (BPS) and bisphenol F (BPF), which are now found in various consumer products, as well as in human matrices at a global scale. However, due to their toxicity, these two bisphenols are in the process of being regulated. Other BPA alternatives, whose potential toxicity remains largely unknown due to a knowledge gap, have also started to be used in manufacturing processes. The gradual restriction of the use of BPA underscores the importance of understanding the potential risks associated with its alternatives to avoid regrettable substitutions. This review aims to summarize the current knowledge on the potential hazards related to BPA alternatives prioritized by European Regulatory Agencies based on their regulatory relevance and selected to be studied under the European Partnership for the Assessment of Risks from Chemicals (PARC): BPE, BPAP, BPP, BPZ, BPS-MAE, and TCBPA. The focus is on data related to toxicokinetic, endocrine disruption, immunotoxicity, developmental neurotoxicity, and genotoxicity/carcinogenicity, which were considered the most relevant endpoints to assess the hazard related to those substances. The goal here is to identify the data gaps in BPA alternatives toxicology and hence formulate the future directions that will be taken in the frame of the PARC project, which seeks also to enhance chemical risk assessment methodologies using new approach methodologies (NAMs).

Bisphenol AP inhibits mouse oocyte maturation in vitro by disrupting cytoskeleton architecture and cell cycle processes

Bisphenol A (BPA) is among the extensively researched environmental endocrine-disrupting chemicals (EDCs), and its utilization is restricted owing to the detrimental impacts it has on human health. Bisphenol AP (BPAP) is one of the alternatives to BPA, but the influence of BPAP on human health has not been elucidated. The objective of the current research was to determine the influence of BPAP exposure on the in vitro maturation of mouse oocytes and to explore its potential reproductive toxicity. BPAP exposure was found to inhibit polar body extrusion during mouse oocyte maturation, resulting in an arrest at the metaphase I stage of meiosis. Exposure to BPAP led to sustained activation of BubR1, preventing the degradation of both Securin and Cyclin B1. Mechanistically, BPAP exposure disrupts spindle assembly and chromosome alignment. Levels of acetylated α-tubulin were significantly elevated in BPAP-treated oocytes, reflecting decreased spindle stability. Exposure to BPAP also induced DNA damage and impaired DNA damage repair. In addition, BPAP exposure altered histone modification levels. In summary, this investigation suggests that exposure to BPAP can influence cytoskeletal assembly, interfere with cell cycle progression, induce DNA damage, alter histone modifications, and ultimately impede oocyte meiotic maturation. This investigation enhances understanding of the impact of bisphenol analogs on female gametes, underscoring that BPAP cannot be considered a reliable replacement for BPA.

Mitigating Dietary Bisphenol Exposure Through the Gut Microbiota: The Role of Next-Generation Probiotics in Bacterial Detoxification

Bisphenols, such as bisphenol A and its analogs, which include bisphenol S, bisphenol F, bisphenol AF, and tetramethyl bisphenol F, are chemical contaminants commonly found in food that raise serious health concerns. These xenobiotics can potentially have harmful effects on human health. The gut microbiota plays a crucial role in metabolizing and neutralizing these substances, which is essential for their detoxification and elimination. Probiotic supplementation has been studied for its ability to modulate the gut microbiota's composition and function, enhancing detoxification processes. Next-Generation Probiotics (NGPs) may exhibit better properties than traditional strains and are designed for targeted action on specific conditions, such as obesity. By modulating inflammatory responses and reducing the secretion of pro-inflammatory cytokines, they can significantly improve host health. Research on NGPs' ability to neutralize obesogenic bisphenols remains limited, but their potential makes this a promising area for future exploration. This review aims to understand the mechanisms of the chemical transformation of bisphenol through its interactions with the gut microbiota and the role of probiotics, particularly NGPs, in these processes. Understanding the interplay between bisphenols, gut microbiota, and NGPs may pave the way for strategies to counteract the negative health effects associated with daily and chronic exposure to bisphenols, which is crucial for food safety and consumer health protection.

A computational assay for identifying millet-derived compounds that antagonize the interaction between bisphenols and estrogen-related receptor gamma

The use of Bisphenol A (BPA) and its analogs in industries, as well as the products made from them, is becoming a significant concern for human health. Scientific studies have revealed that BPA functions as an endocrine disruptor. While some analogs of BPA (bisphenols) have been used for a longer time, it was later discovered that they are toxic, similar to BPA. Their widespread use ensures their presence in the environment, and thus, everyone is exposed to them. Scientific research has shown that BPA interacts with estrogen-related receptor gamma (ERRγ), affecting its normal function. ERRγ is involved in biological processes including energy metabolism and mitochondrial function. Therefore, continuous exposure to bisphenols increases the risk of various diseases. In our previous study, we observed that some analogs of BPA had a higher binding affinity to ERRγ compared to BPA itself and analyzed the amino acid residues involved in this interaction. We hypothesized that by antagonizing the interaction between bisphenols and ERRγ, we could neutralize their toxic effects. Taking into account the health benefits of millets and their toxin removal properties, virtual screening of millet-derived compounds was conducted along with prediction of their ADMET profiles. Top five candidates were prioritized for Density Functional Theory (DFT) calculations and further analyses. Long-term molecular dynamics simulation (1 µs) were utilized to evaluate their binding, stability, and antagonizing abilities. Furthermore, reevaluation of their binding energy was conducted using the MM-PBSA method. This study reports millet-derived compounds, namely, Tricin 7-rutinoside, Tricin 7-glucoside, Glucotricin, Kaempferol, and Setarin. These compounds are predicted to be potent competitive inhibitors that can antagonize the interactions between bisphenols and ERRγ. These compounds could potentially assist in the development of future therapeutics. They may also be considered for use as food supplements, although further investigations, including wet-lab experiments and clinical studies, are needed.

Exploring the safety of cannabidiol (CBD): A comprehensive in vitro evaluation of the genotoxic and mutagenic potential of a CBD isolate and extract from Cannabis sativa L

Cannabidiol (CBD), a naturally occurring cyclic terpenoid found in Cannabis sativa L., is renowned for its diverse pharmacological benefits. Marketed as a remedy for various health issues, CBD products are utilized by patients as a supplementary therapy or post-treatment failure, as well as by healthy individuals seeking promised advantages. Despite its widespread use, information regarding potential adverse effects, especially genotoxic properties, is limited. The present study is focused on the mutagenic and genotoxic activity of a CBD isolate (99.4 % CBD content) and CBD-rich Cannabis sativa L extract (63.6 % CBD content) in vitro. Both CBD samples were non-mutagenic, as determined by the AMES test (OECD 471) but exhibited cytotoxicity for HepG2 cells (∼IC50(4 h) 26 µg/ml, ∼IC50(24 h) 6-8 µg/ml, MTT assay). Noncytotoxic concentrations induced upregulation of genes encoding metabolic enzymes involved in CBD metabolism, and CBD oxidative as well as glucuronide metabolites were found in cell culture media, demonstrating the ability of HepG2 cells to metabolize CBD. In this study, the CBD samples were found non-genotoxic. No DNA damage was observed with the comet assay, and no influence on genomic instability was observed with the cytokinesis block micronucleus and the γH2AX and p-H3 assays. Furthermore, no changes in the expression of genes involved in genotoxic stress response were detected in the toxicogenomic analysis, after 4 and 24 h of exposure. Our comprehensive study contributes valuable insights into CBD's safety profile, paving the way for further exploration of CBD's therapeutic applications and potential adverse effects.

Sexual dimorphism in neurobehavioural phenotype and gut microbial composition upon long-term exposure to structural analogues of bisphenol-A

Bisphenol S (BPS) and Bisphenol F (BPF), the analogues of the legacy endocrine disrupting chemical, Bisphenol A (BPA) are ubiquitous in the environment and present in various consumer goods, and potentially neurotoxic. Here, we studied sex-specific responses of bisphenols on behavioural phenotypes, including their association with pro-inflammatory biomarkers and altered neurotransmitters levels, and the key gut microbial abundances. Neurobehavioural changes, using standard test battery, biochemical and molecular estimations for inflammatory cytokines, neurotransmitters, and oxido-nitrosative stress markers, gene expression analysis using qRT-PCR, H&E based histological investigations, gut permeability assays and Oxford Nanopore-based 16S-rRNA metagenomics sequencing for the gut microbial abundance estimations were performed. Bisphenol(s) exposure induces anxiety and depression-like behaviours, particularly in the male mice, with heightened pro-inflammatory cytokines levels and systemic endotoxemia, altered monoamine neurotransmitters levels/turnovers and hippocampal neuronal degeneration and inflammatory responses in the brain. They also increased gut permeability and altered microbial diversity, particularly in males. Present study provides evidence for sex-specific discrepancies in neurobehavioural phenotypes and gut microbiota, which necessitate a nuanced understanding of sex-dependent responses to bisphenols. The study contributes to ongoing discussions on the multifaceted implications of bisphenols exposure and underscores the need for tailored regulatory measures to mitigate potential health risks associated with them.

A combined in vitro-in silico method for assessing the androgenic activities of bisphenol A and its analogues

Interactions between endocrine-disruptor chemicals (EDCs) and androgen receptor (AR) have adverse effects on the endocrine system, leading to human reproductive dysfunction. Bisphenol A (BPA) is an EDC that can damage both the environment and human health. Although numerous BPA analogues have been produced as substitutes for BPA, few studies have evaluated their endocrine-disrupting abilities. We assessed the (anti)-androgenic activities of BPA and its analogues using a yeast-based reporter assay. The BPA analogues tested were bisphenol S (BPS), 4-phenylphenol (4PP), 4,4'-(9-fluorenyliden)-diphenol (BPFL), tetramethyl bisphenol F (TMBPF), and tetramethyl bisphenol A (TMBPA). We also conducted molecular docking and dynamics simulations to assess the interactions of BPA and its analogues with the ligand-binding domain of human AR (AR-LBD). Neither BPA nor its analogues had androgenic activity; however, all except BPFL exerted robust anti-androgenic effects. Consistent with the in vitro results, anti-androgenic analogues of BPA formed hydrogen bonding patterns with key residues that differed from the patterns of endogenous hormones, indicating that the analogues display in inappropriate orientations when interacting with the binding pocket of AR-LBD. Our findings indicate that BPA and its analogues disrupt androgen signaling by interacting with the AR-LBD. Overall, BPA and its analogues display endocrine-disrupting activity, which is mediated by AR.

Deciphering the mechanisms and interactions of the endocrine disruptor bisphenol A and its analogs with the androgen receptor

Bisphenol A (BPA) and its various forms used as BPA alternatives in industries are recognized toxic compounds and antiandrogenic endocrine disruptors. These chemicals are widespread in the environment and frequently detected in biological samples. Concerns exist about their impact on hormones, disrupting natural biological processes in humans, together with their negative impacts on the environment and biotic life. This study aims to characterize the interaction between BPA analogs and the androgen receptor (AR) and the effect on the receptor's normal activity. To achieve this goal, molecular docking was conducted with BPA and its analogs and dihydrotestosterone (DHT) as a reference ligand. Four BPA analogs exhibited higher affinity (-10.2 to -8.7 kcal/mol) for AR compared to BPA (-8.6 kcal/mol), displaying distinct interaction patterns. Interestingly, DHT (-11.0 kcal/mol) shared a binding pattern with BPA. ADMET analysis of the top 10 compounds, followed by molecular dynamics simulations, revealed toxicity and dynamic behavior. Experimental studies demonstrated that only BPA disrupts DHT-induced AR dimerization, thereby affecting AR's function due to its binding nature. This similarity to DHT was observed during computational analysis. These findings emphasize the importance of targeted strategies to mitigate BPA toxicity, offering crucial insights for interventions in human health and environmental well-being.

Are the BPA analogues an alternative to classical BPA? Comparison between 2D and alternative 3D in vitro neuron model to assess cytotoxic and genotoxic effects

BPA is used in a wide range of consumer products with very concern toxicological properties. The European Union has restricted its use to protect human health. Industry has substituted BPA by BPA analogues. However, there is a lack of knowledge about their impacts. In this work, BPA and 5 BPA analogues (BPS, BPAP, BPAF, BPFL and BPC) have been studied in classical SH-SY5Y and the alternative 3D in vitro models after 24 and 96 h of exposure. Cell viability, percentage of ROS, cell cycle phases as well as the morphology of the spheroids were measured. The 2D model was more sensitive than the 3D models with differences in cell viability higher than 60% after 24 h of exposure, and different mechanisms of ROS production. After chronic exposure, both models were more affected in comparison to the 24 h exposure. After a recovery time (96 h), the spheroids exposed to 2.5-40 µM were able to recover cell viability and the morphology. Among the BPs tested, BPFL>BPAF>BPAP and >BPC revealed higher toxicological effects, while BPS was the only one with lower effects than BPA. To conclude, the SH-SY5Y 3D model is a suitable candidate to perform more reliable in vitro neurotoxicity tests.

Single and multispecies microalgae toxicological tests assessing the impact of several BPA analogues used by industry

BPA is a hazard for human and environmental health and recently BPA was added to the Candidate List of substances of very high concern by European Chemical Agency (ECHA). In accordance with this proposal, the authorities have encouraged the replacement of BPA by BPA analogues; however, little is known about the impact of these compounds on the environment. Due to this situation five BPA analogues (BPS, BPAP, BPAF, BPFL and BPC) were chosen in order to study their effects on marine primary producers. Three marine microalgae species (Phaeodactylum tricornutum, Tetraselmis suecica and Nannochloropsis gaditana) were selected for single and multispecies tests concerning the ecotoxicological effects of these BPA analogues. Microalgae were exposed to BPs over 72 h at different dosages (5, 20, 40, 80, 150 and 300 μM). Responses such as: growth, ROS production, cell complexity, cell size, autofluorescence of chlorophyll a, effective quantum yield of PSII and pigment concentrations were assessed at 24, 48 and 72 h. The results revealed that BPS and BPA showed lower toxicity to microalgae in comparison with BPFL > BPAF > BPAP and >BPC for the endpoints studied. N. gaditana was the least sensitive microalgae in comparison to P. tricornutum and T. suecica. However, a different trend was found in the multispecies tests where T. suecica dominated the microalgae community in relation to N. gaditana and P. tricornutum. The results of this work revealed for first time that present day BPA analogues are a threat and not a safe substitute for BPA in terms of the marine phytoplanktonic community. Therefore, the results of their impact on aquatic organisms should be shared.

Fate of five bisphenol derivatives in Chlamydomonas mexicana: Toxicity, removal, biotransformation and microalgal metabolism

Bisphenols (BPs) are recognized as emerging contaminants because of their estrogenic properties and frequent occurrence in environmental matrices. Here, we evaluated the toxic effects of five common BPs on freshwater microalga Chlamydomonas mexicana and removal of the BPs by the alga. Bisphenols -AF (BPAF), -B (BPB), and -Z (BPZ) (96 h, EC50 1.78-12.09 mg·L-1) exhibited higher toxicity to C. mexicana compared to bisphenol -S (BPS) and -F (BPF) (96 h, EC50 30.53-85.48 mg·L-1). In contrast, the mixture of BPs exhibited acute toxicity (96 h, EC50 8.07 mg·L-1). After 14 days, C. mexicana had effectively removed 61%, 99%, 55%, 87%, and 89% of BPS, BPF, BPAF, BPB, and BPZ, respectively, at 1 mg L-1. The biotransformed products of all five BPs were analyzed using UHPLC QTOF, and their toxicity was predicted. All biotransformed products were observed to be less toxic than the parent compounds. The fatty acid composition of C. mexicana after exposure to the BP mixture was predominantly palmitic acid (34.14%), followed by oleic acid (18.9%), and γ-linolenic acid (10.79%). The results provide crucial information on the ecotoxicity of these five BPs and their removal by C. mexicana; the resulting biomass is a potential feedstock for producing biodiesel.

Degradation and toxicity of bisphenol A and S during cold atmospheric pressure plasma treatment

Bisphenols are widely recognised as toxic compounds that potentially threaten the environment and public health. Here we report the use of cold atmospheric pressure plasma (CAP) to remove bisphenol A (BPA) and bisphenol S (BPS) from aqueous systems. Additionally, methanol was added as a radical scavenger to simulate environmental conditions. After 480 s of plasma treatment, 15-25 % of BPA remained, compared to > 80 % of BPS, with BPA being removed faster (-k_t = 3.4 ms^-1, half-life = 210 s) than BPS (-k_t = 0.15 ms^-1, half-life 4700 s). The characterisation of plasma species showed that adding a radical scavenger affects the formation of reactive oxygen and nitrogen species, resulting in a lower amount of ˙OH, H₂O₂, and NO₂^- but a similar amount of NO₃^-. In addition, a non-target approach enabled the elucidation of 11 BPA and five BPS transformation products. From this data, transformation pathways were proposed for both compounds, indicating nitrification with further cleavage, demethylation, and carboxylation, and the coupling of smaller bisphenol intermediates. The toxicological characterisation of the in vitro HepG2 cell model has shown that the mixture of transformation products formed during CAP is less toxic than BPA and BPS, indicating that CAP is effective in safely degrading bisphenols.

Analogy or fallacy, unsafe chemical alternatives: Mechanistic insights into energy metabolism dysfunction induced by Bisphenol analogs in HepG2 cells

Bisphenol analogs (BPs) are widely used as industrial alternatives for Bisphenol A (BPA). Their toxicity assessment in humans has mainly focused on estrogenic activity, while other toxicity effects and mechanisms resulting from BPs exposure remain unclear. In this study, we investigated the effects of three BPs (Bisphenol AF (BPAF), Bisphenol G (BPG) and Bisphenol PH (BPPH)) on metabolic pathways of HepG2 cells. Results from comprehensive cellular bioenergetics analysis and nontarget metabolomics indicated that the most important process affected by BPs exposure was energy metabolism, as evidenced by reduced mitochondrial function and enhanced glycolysis. Compared to the control group, BPG and BPPH exhibited a consistent pattern of metabolic dysregulation, while BPAF differed from both, such as an increased ATP: ADP ratio (1.29-fold, p < 0.05) observed in BPAF and significantly decreased ATP: ADP ratio for BPG (0.28-fold, p < 0.001) and BPPH (0.45-fold, p < 0.001). Bioassay endpoint analysis revealed BPG/BPPH induced alterations in mitochondrial membrane potential and overproductions of reactive oxygen species. Taken together these data suggested that BPG/BPPH induced oxidative stress and mitochondrial damage in cells results in energy metabolism dysregulation. By contrast, BPAF had no effect on mitochondrial health, but induced a proliferation promoting effect on cells, which might contribute to the energy metabolism dysfunction. Interestingly, BPPH induced the greatest mitochondrial damage among the three BPs but did not exhibit Estrogen receptor alpha (ERα) activating effects. This study characterized the distinct metabolic mechanisms underlying energy metabolism dysregulation induced by different BPs in target human cells, providing new insight into the evaluation of the emerging BPA substitutes.

Combined Toxic Effects of BPA and Its Two Analogues BPAP and BPC in a 3D HepG2 Cell Model

Bisphenol A (BPA) is one of the most commonly used substances in the manufacture of various everyday products. Growing concerns about its hazardous properties, including endocrine disruption and genotoxicity, have led to its gradual replacement by presumably safer analogues in manufacturing plastics. The widespread use of BPA and, more recently, its analogues has increased their residues in the environment. However, our knowledge of their toxicological profiles is limited and their combined effects are unknown. In the present study, we investigated the toxic effects caused by single bisphenols and by the combined exposure of BPA and its two analogues, BPAP and BPC, after short (24-h) and prolonged (96-h) exposure in HepG2 spheroids. The results showed that BPA did not reduce cell viability in HepG2 spheroids after 24-h exposure. In contrast, BPAP and BPC affected cell viability in HepG2 spheroids. Both binary mixtures (BPA/BPAP and BPA/BPC) decreased cell viability in a dose-dependent manner, but the significant difference was only observed for the combination of BPA/BPC (both at 40 µM). After 96-h exposure, none of the BPs studied affected cell viability in HepG2 spheroids. Only the combination of BPA/BPAP decreased cell viability in a dose-dependent manner that was significant for the combination of 4 µM BPA and 4 µM BPAP. None of the BPs and their binary mixtures studied affected the surface area and growth of spheroids as measured by planimetry. In addition, all BPs and their binary mixtures studied triggered oxidative stress, as measured by the production of reactive oxygen species and malondialdehyde, at both exposure times. Overall, the results suggest that it is important to study the effects of BPs as single compounds. It is even more important to study the effects of combined exposures, as the combined effects may differ from those induced by single compounds.