Synthetic Phenolic Antioxidants Research Articles

Electrochemical strategies for determination of tert-butyl hydroquinone (TBHQ) in food samples

AbstractTert-butyl hydroquinone (TBHQ) is a member of the synthetic phenolic antioxidant family that prevents the formation of free radicals and prevents radicals from damaging cells by trapping them. In addition, TBHQ is widely preferred as an additive in foods and vegetable oils because of its low cost and high chemical stability. TBHQ is not only a food preservative but is also frequently used as a stabilizer to prevent auto-polymerization in cosmetics, biodiesel, pharmaceuticals, coating products, and different application areas. TBHQ has been shown to cause diseases, such as DNA damage, carcinogenesis, and cell apoptosis, when administered at high doses. Excessive consumption of TBHQ causes adverse effects, such as stomach tumors, liver damage, and underdevelopment of the reproductive system. Different analytical methods have been used to detect TBHQ in food samples. The most important of these methods are traditional analytical methods such as chromatographic and spectrophotometric methods. However, these methods have basic shortcomings such as high analysis costs, long pre-processing, expensive equipment, need for many organic solvents, requiring expertise, and long detection times. In recent years, electrochemical sensors have attracted attention in the scientific world owing to their high sensitivity, fast analysis time, portability, low cost, and convenience of miniaturization. This review discusses electrochemical studies performed to date for the determination of TBHQ in food samples. The methods used in these studies have been evaluated in a wide range of aspects, such as the electrode, working range, detection limits, and analytical applications.

Prevalence of synthetic phenolic antioxidants in food contact materials from China and their implications for human dietary exposure through take-away food

The application of disposable tableware has increased substantially in recent times due to the rapidly growing food delivery business in China. Synthetic phenolic antioxidants (SPAs) are widely used in food contact materials (FCMs) to delay the process of oxidation; however, their compositions, concentrations, and potential health hazards remain unclear. Therefore, FCMs comprised of five materials obtained from 19 categories (n=118) in China were analyzed for SPAs concentrations. FCMs have been found to contain a variety of SPAs, with ∑SPAs concentrations ranging from 44.18 to 69485.12μg/kg (median: 2615.63μg/kg). The predominant congeners identified in the sample include 2,4-di-tert-butylphenol (2,4-DTBP), 2,6-di-tert-butylphenol (2,6-DTBP), and 2,6-di-tert-butyl-p-benzoquinone (BHT-Q) with a median concentration of 885.75, 555.45 and of 217.44μg/kg, respectively. Milky tea paper cups, instant noodle buckets, milky teacups, and disposable cups showed high levels of SPAs. 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (AO 2246) was predominantly detected in polyethylene and polyethylene terephthalate-based products. The migration test identified disposable plastic cups and bowls as the predominant FCMs and 2,4-DTBP as the dominant SPA. The exposure risk of SPAs decreased with age. In children, the estimated daily intake of ∑SPAs from FCMs was determined to be 17.56ng/kg body weight/day, which was 8.3 times higher than that of phthalic acid esters. The current findings indicate the potential ingestion risk of SPAs during the daily life application of multiple FCM categories. Environmental ImplicationSynthetic phenolic antioxidants (SPAs) are widely used as anthropogenic antioxidants that are not covalently attached to the substrates. The packaging of food in China annually involves a large number of hundreds of millions of plastic containers; this combination may increase the risk of SPAs exposure. Hundreds of millions of plastic containers would also contribute significantly to environmental pollution and produce packaging waste. Prior investigations have revealed the toxicity influence and prolonged predicted half-lives of SPAs and associated transformation products in air, water, soil, and sediments. The presence and migration rates of SPAs in food contact materials must be investigated immediately.

Ubiquity of Synthetic Phenolic Antioxidants in Children's Cerebrospinal Fluid from South China: First Evidence for Their Penetration across the Blood-Cerebrospinal Fluid Barrier.

Synthetic phenolic antioxidants (SPAs) and relevant transformation products (TPs) are potentially neurotoxic pollutants to which humans are widely exposed. However, their penetration behavior across the brain barrier and associated exposure to the central nervous system (CNS) remain unknown. This study is the first to investigate a wide range of 30 SPAs and TPs, including emerging SPAs, in matched serum and cerebrospinal fluid (CSF) samples from children in Guangzhou, China. Sixty-two children of either sex aged <14 years with nonbloody CSF and complete clinical information were included. The findings demonstrated the ubiquitous occurrence of many SPAs and TPs, particularly BHT, 2,4-di-tert-butylphenol (DBP), AO 1010, AO 1076, BHT-Q, and BHT-quinol, not only in serum but also in the CSF. Median total concentrations of SPAs and TPs were up to 22.0 and 2.63 ng/mL in serum and 14.5 and 2.11 ng/mL in CSF, respectively. On calculating the penetration efficiencies across the blood-CSF barrier (BCSFB) (RCSF/serum, CCSF/Cserum) for selected SPAs and TPs, their RCSF/serum values (median 0.52-1.41) were highly related to their physicochemical properties, indicating that passive diffusion may be the potential mechanism of BCSFB penetration. In addition, the RCSF/serum values were positively correlated with the barrier permeability index RAlb (AlbuminCSF/Albuminserum), indicating that barrier integrity is an important determinant of BCSFB penetration. Overall, these results will improve our perception of human internal exposure to SPAs and lay a solid foundation for assessing the risk of CNS exposure to various SPAs.

8-OHdG mediates the association of co-exposure to fifty-five typical endocrine-disrupting chemicals with renal function: a cross-section investigation in Southern Chinese adults.

Individual typical endocrine-disrupting chemicals (EDCs), including organophosphate triesters (OPEs), parabens, triclosan (TCS), bisphenols, benzophenones (BPs), phthalates (PAEs), and synthetic phenolic antioxidants (SPAs), are associated with renal dysfunction. However, the combined effects and underlying mechanisms of mixed EDC exposure on renal function remain unclear. Two hundred ninety-nine adult participants were enrolled in the cross-sectional survey conducted in Guangzhou, China. Urinary levels of 7 OPEs, 6 parabens, TCS, 14 bisphenols, 8 BPs, 15 PAEs, 4 SPAs, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were determined, and estimated glomerular filtration rate (eGFR) was served as the outcome index. We found elevated levels of diphenyl phosphate (DPP), bisphenol A (BPA), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono-butyl phthalate (MBP) showed dose-responsive associations with eGFR decline, However, nonlinear associations were observed for bis(2-butoxyethyl) hydrogen phosphate (BBOEP), TCS, 4-hydroxybenzophenone (HBP), mono-n-pentyl phthalate (MnPP), and mono-benzyl phthalate (MBzP). The quantile-based g-computation model demonstrated that a quartile increase in the EDC mixture corresponded to a 0.383-SD decrease (95% CI - 0.658 ~ - 0.108, P = 0.007) in eGFR. Notably, BPA was identified as the primary contributor to this effect. Moreover, 8-OHdG mediated the eGFR decline associated with EDC mixtures with a mediation proportion of 25.49%. A sex-modified effect was also observed (P = 0.004), indicating that exposure to the mixture of EDC was linked to more pronounced renal dysfunction in females. Our novel findings suggest that exposure to a typical mixture of EDCs is associated with renal dysfunction in the general adult population of Southern China. Furthermore, 8-OHdG may play a role in the pathogenesis of EDC mixture-related renal dysfunction.

In situ formation of a deep eutectic solvent for liquid-liquid microextraction of synthetic phenolic antioxidants in edible oil

A simple and ecofriendly liquid-liquid microextraction (LLME) method was developed for the extraction of synthetic phenolic antioxidants (SPAs, e.g. tert-butyl hydroquinone (TBHQ) and butylated hydroxyanisole (BHA)) in edible oil. Compared with time-consuming and cumbersome off-line prepared deep eutectic solvent (DES), the in-situ formulated DES allowed to directly add DES components into sample matrix, making the sample preparation procedure greatly simplified. Preliminary experiment indicated that the DES made of 1:2 (molar ratio) tetrabutylammonium chloride (TBAC) and acetic acid (AA) was suitable for the extraction of SPAs. Under the optimized conditions, by combining with HPLC, the in-situ DES-LLME-HPLC method showed satisfactory detection limits (0.7−1.3 μg/L), precisions (RSDs≤5.0%), enrichment factors (20.8−22.0), recoveries (89.2%–103.6%), and linearity over 5−500 μg/L (TBHQ) and 10−500 μg/L (BHA) (R2 ≥ 0.9991). In addition, the method displayed acceptable matrix effect and robustness. Hence, it is promising for the extraction and determination of SPAs in real edible oil.

A preliminary understanding of the relationship between synthetic phenolic antioxidants and early pregnancy loss: Uncovering the potential molecular mechanisms

Mounting evidence suggests that environmental pollutants may affect reproductive health, potentially leading to adverse outcomes like pregnancy loss. However, it remains unclear whether exposure to synthetic phenolic antioxidants (SPAs) correlates with early pregnancy loss (EPL). This study explores SPA exposure's link to EPL and its potential molecular mechanisms. From 2021 to 2022, 265 early pregnant women (136 serum and 129 villus samples) with and without EPL were enrolled. We quantified 17 SPAs in serum and chorionic villus, with AO1010, AO3114, BHT, AO2246, and BHT-Q frequently being detected, suggesting their ability to cross the placental barrier. AO1135 showed a positive relationship with EPL in sera, indicating a significant monotonic dose-response relationship (p-trend <0.001). BHT-Q exhibited a similar relationship with EPL in villi. Inhibitory effects of BHT-Q on estradiol (E2) were observed. Molecular docking revealed SPA-protein interactions involved in E2 synthesis. SPA-induced EPL might occur with specific serum levels of AO1135 and certain villus levels of AO1010, BHT-Q, and AO2246. BHT-Q emerges as a potential biomarker for assessing EPL risk. This study provides insights into understanding of the exposure to SPAs and potential adverse outcomes in pregnant women.

The hidden diet: Synthetic antioxidants in packaged food and their impact on human exposure and health

Synthetic antioxidants (AOs) are commonly used in everyday items and industrial products to inhibit oxidative deterioration. However, the presence of AOs in food packaging and packaged foods has not been thoroughly documented. Moreover, studies on human exposure to AOs through skin contact with packaging or ingesting packaged foods are limited. In this study, we analyzed twenty-three AOs—including synthetic phenolic antioxidants (SPAs) and organophosphite antioxidants (OPAs)—along with six transformation products in various food samples and their packaging materials. We found AOs in food products at concentrations ranging from 1.30 × 103 to 1.77 × 105 ng/g, which exceeded the levels in both outer packaging (6.05 × 102–3.07 × 104 ng/g) and inner packaging (2.27 × 102–1.09 × 105 ng/g). The most common AOs detected in foodstuffs were tris(2,4-di-tert-butylphenyl) phosphate (AO168O), butylated hydroxytoluene (BHT), and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (AO1076), together constituting 95.7 % of the total AOs found. Our preliminary exposure assessment revealed that dietary exposure—estimated at a median of 2.55 × 104 ng/kg body weight/day for children and 1.24 × 104 ng/kg body weight/day for adults—is a more significant exposure route than dermal contact with packaging. Notably, four AOs were identified in food for the first time, with BHT making up 76.8 % and 67.6 % of the total BHT intake for children and adults, respectively. These findings suggest that food consumption is a significant source of BHT exposure. The estimated daily intakes of AOs via consumption of foodstuffs were compared with the recommended acceptable daily intake to assess the risks. This systematic investigation into AOs contributes to understanding potential exposure and health risks associated with AOs in packaged foods. It emphasizes the need for further evaluation of human exposure to these substances.

Assessing developmental neurotoxicity of emerging environmental chemicals using multiple in vitro models: A comparative analysis

Newly synthesized chemicals are being introduced into the environment without undergoing proper toxicological evaluation, particularly in terms of their effects on the vulnerable neurodevelopment. Thus, it is important to carefully assess the developmental neurotoxicity of these novel environmental contaminants using methods that are closely relevant to human physiology. This study comparatively evaluated the potential developmental neurotoxicity of 19 prevalent environmental chemicals including neonicotinoids (NEOs), organophosphate esters (OPEs), and synthetic phenolic antioxidants (SPAs) at environment-relevant doses (100 nM and 1 μM), using three commonly employed in vitro neurotoxicity models: human neural stem cells (NSCs), as well as the SK-N-SH and PC12 cell lines. Our results showed that NSCs were more sensitive than SK-N-SH and PC12 cell lines. Among all the chemicals tested, the two NEOs imidaclothiz (IMZ) and cycloxaprid (CYC), as well as the OPE tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), generated the most noticeable perturbation by impairing NSC maintenance and neuronal differentiation, as well as promoting the epithelial-mesenchymal transition process, likely via activating NF-κB signaling. Our data indicate that novel NEOs and OPEs, particularly IMZ, CYC, and TDCIPP, may not be safe alternatives as they can affect NSC maintenance and differentiation, potentially leading to neural tube defects and neuronal differentiation dysplasia in fetuses.

A simple molecularly imprinted electrochemical sensor for determination of propyl gallate in food samples

Propyl gallate (PG), a prevalent synthetic phenolic antioxidant found in food products, has generated considerable apprehension owing to its potential adverse impacts on human health. Therefore, as a result of the current inquiry, an innovative electrochemical sensor with improved sensitivity and selectivity for PG detection has been created. Under optimal conditions, the manufactured sensor exhibits the capability to identify PG within a broad range from 0.01 μM to 5 μM and from 5 μM to 1000 μM with a limit of detection (LOD) of 6 nM, demonstrating exceptional levels of reproducibility, repeatability, stability, and selectivity. The sensor demonstrated successful detection of PG in edible oils and mayonnaise, with good recoveries ranging from 98.44 % to 101.37 %.

Degradation of Butylated Hydroxyanisole by the Combined Use of Peroxymonosulfate and Ferrate(VI): Reaction Kinetics, Mechanism and Toxicity Evaluation.

Butylated hydroxyanisole (BHA), a synthetic phenolic antioxidant (SPA), is now widely present in natural waters. To improve the degradation efficiency of BHA and reduce product toxicity, a combination of peroxymonosulfate (PMS) and Ferrate(VI) (Fe(VI)) was used in this study. We systematically investigated the reaction kinetics, mechanism and product toxicity in the degradation of BHA through the combined use of PMS and Fe(VI). The results showed that PMS and Fe(VI) have synergistic effects on the degradation of BHA. The effects of operational factors, including PMS dosage, pH and coexisting ions (Cl-, SO42-, HCO3-, K+, NH4+ and Mg2+), and different water matrices were investigated through a series of kinetic experiments. When T = 25 °C, the initial pH was 8.0, the initial BHA concentration was 100 μM, the initial concentration ratio of [PMS]0:[Fe(VI)]0:[BHA]0 was 100:1:1 and the degradation rate could reach 92.4% within 30 min. Through liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) identification, it was determined that the oxidation pathway of BHA caused by PMS/Fe(VI) mainly includes hydroxylation, ring-opening and coupling reactions. Density functional theory (DFT) calculations indicated that •OH was most likely to attack BHA and generate hydroxylated products. The comprehensive comparison of product toxicity results showed that the PMS/Fe(VI) system can effectively reduce the environmental risk of a reaction. This study contributes to the development of PMS/Fe(VI) for water treatment applications.

Fe(VI) oxidation of synthetic phenolic antioxidants: Kinetics, influencing factors, transformation mechanism and toxicity

Synthetic phenolic antioxidants (SPAs) have been commonly used in industrial and domestic products to prevent the adverse effects of oxidants such as oxygen. However, attention to the removal of SPAs is scarcely attracted. In this paper, the removal kinetics, influencing factors, transformation mechanisms and toxicity in Fe(VI) oxidation of 18 SPA congeners were investigated in detail. Results showed that propyl gallate (PG), butylated hydroxyanisole (BHA), and tert-butylhydroquinone (TBHQ) had the highest reactivities with Fe(VI), while the reaction rate constant (kapp) value of 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate (UV120) was the lowest (221.3 M−1 s−1). A robust quantitative structure–activity relationship (QSAR) model between kapp and molecular structural descriptors of SPAs was established. The energy gap between the lowest unoccupied molecular orbital (ELUMO) and the highest occupied molecular orbital (EHOMO) was a vital parameter to determine the removal efficiencies of the SPA congeners. Furthermore, the numbers of oxygen atoms and alkyl groups in SPA structures also determined their reactivities with Fe(VI) to some extent. In addition, aqueous 2,6-di-tert-butyl-4-methylphenol (BHT, a representative of SPAs) could be efficiently removed with the increased amount of oxidant, and decreased substrate concentration and slightly alkaline conditions. Seventeen intermediates were identified, and oxidation routes including H-abstraction, single- and double-oxygen(s) transfer, and coupling were deduced. However, H-abstraction inevitably led to the generation of BHT-Q with higher toxicity than parent. These findings provide novel insights into the production and removal of SPA analogs.

Green Synthesis of Gold Nanoparticles Using Peach Extract Incorporated in Graphene for the Electrochemical Determination of Antioxidant Butylated Hydroxyanisole in Food Matrices.

Butylated hydroxyanisole (BHA) is a synthetic phenolic antioxidant widely used in various food matrices to prevent oxidative rancidity. However, its presence has been associated with liver damage and carcinogenesis in animals. Thus, an electrochemical sensor was built using a composite of gold nanoparticles synthesized in peach extract (Prunus persica (L.) Batsch) and graphene. Peach extract served as a reducing and stabilizing agent for gold nanoparticles, as a dispersing agent for graphene, and as a film former to immobilize the composite on the surface of a glassy carbon electrode. The gold nanoparticles were characterized using spectroscopic and microscopic techniques, and the electrodes were electrochemically characterized using electrochemical impedance spectroscopy and cyclic voltammetry. The sensor provided higher current responses and lower charge transfer resistances compared to the unmodified glassy carbon electrode. Under the established optimized working conditions (0.1 mol L-1 Britton-Robinson buffer, pH 4.0, and differential pulse voltammetry), the calibration curve exhibited a linear range from 0.2 to 9.8 µmol L-1, with a detection limit of 70 nmol L-1. The proposed sensor represented a sensitive and practical analytical tool for the accurate determination of BHA in mayonnaise samples.

Eco-friendly miniaturized kapok-fiber supported liquid-phase extraction coupled with gas chromatography-flame ionization detector for high-throughput edible oil preparation and low-cost determination of synthetic antioxidants

The addition of synthetic phenolic antioxidants can effectively delay or prevent oxidation of edible oils. However, excessive use of these antioxidants can have negative impacts, which emphasizes the importance of accurate analysis methods to determine their presence in edible oils. Given the large number of food samples involved in regulatory purposes, there is a need to develop high-throughput and cost-effective detection methods for routine analysis. However, the existing methods are not suitable, indicating a need for further improvement. This study presents a technique that combines miniaturized-kapok fiber-supported liquid-phase extraction (mini-KF-SLE) with gas chromatography-flame ionization detection (GC-FID) to determine synthetic antioxidants like 3-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxytoluene, and tert-butylhydroquinone in edible oils. The mini-KF-SLE device consists of 20mg of kapok fibers placed in a 1mL pipette tip attached to a pipette. The extraction procedure involves three simple steps: loading the oil sample (150mg), adding the extractant (150µL of ACN), and eluting the extractant by applying air pressure using a pipette. The developed mini-KF-SLE-GC-FID method shows satisfactory quantitation ability (R2>0.99) and detection limits of 0.4–0.5µg/g. Moreover, the relative standard deviations for all analytes were below 9.2%, indicating good precise of the method for routine analysis. The proposed method also exhibits excellent environmental friendliness, as evidenced by three widely recognized metrics. Overall, the mini-KF-SLE-GC-FID method provides a convenient, low-cost, environmentally friendly, and easy to automate alternative for routinely determining synthetic antioxidants in edible oils.

Synthetic Antioxidants as Contaminants of Emerging Concern in Indoor Environments: Knowns and Unknowns.

Synthetic antioxidants, including synthetic phenolic antioxidants (SPAs), amine antioxidants (AAs), and organophosphite antioxidants (OPAs), are essential additives for preventing oxidative aging in various industrial and consumer products. Increasing attention has been paid to the environmental contamination caused by these chemicals, but our understanding of synthetic antioxidants is generally limited compared to other emerging contaminants such as plasticizers and flame retardants. Many people spend a significant portion (normally greater than 80%) of their time indoors, meaning that they experience widespread and persistent exposure to indoor contaminants. Thus, this Perspective focuses on the problem of synthetic antioxidants as indoor environmental contaminants. The wide application of antioxidants in commercial products and their demonstrated toxicity make them an important family of indoor contaminants of emerging concern. However, significant knowledge gaps still need to be bridged: novel synthetic antioxidants and their related transformation products need to be identified in indoor environments, different dust sampling strategies should be employed to evaluate human exposure to these contaminants, geographic scope and sampling scope of research on indoor contamination should be broadened, and the partition coefficients of synthetic antioxidants among different media need to be investigated.

“Cocktail” of environmental chemicals and early reproductive outcomes of IVF: The insight from paternal and maternal exposure

BackgroundHumans are exposed to various chemicals, including organophosphate esters (OPEs), phthalates (PAEs), and phenols. The effects on early reproductive outcomes of in vitro fertilization (IVF) remain unclear. MethodsWe recruited 192 women and 157 men who underwent IVF treatment. A total of forty-nine urinary chemicals were detected, including six OPEs, fifteen PAEs, six parabens, two chlorophenols, nine bisphenols, five benzophenones, and six synthetic phenolic antioxidants. We examined the individual and joint effects of parental chemical exposure on early reproductive outcomes. ResultsWe found that certain chemicals were associated with early reproductive outcomes in Poisson regression models. For example, urinary diphenyl phosphate was negatively associated with high-quality embryos in both female (β: −0.12, 95%CI: −0.17, −0.07) and male partners (β: −0.09, 95%CI: −0.15, −0.03). A negative association was found between mixed chemicals and high-quality embryos in Bayesian kernel machine regression, weighted quantile sum regression (β: −0.34, 95%CI: −0.60, −0.07), and quantile-based g-computation model (β: −0.69, 95%CI: −1.34, −0.05) among female partners. Paternal mixture exposure was not associated with early reproductive outcomes. ConclusionsOur results indicated that increased exposure to environmental chemicals was associated with adverse early reproductive outcomes of IVF, especially female partners.

Synthetic antioxidant TS-13 reduces doxorubicin cardiotoxicity

The antitumor antibiotic doxorubicin, a representative of a large group of anthriacyclines, is widely and quite effectively used to treat patients with malignant neoplasms. The aim of this study was to study the effect of TS-13, a synthetic phenolic antioxidant and an activator of the antioxidant-responsive element redox-sensitive signaling system Keap1/ Nrf2/ARE, on the functional parameters of an isolated rat heart after a course of doxorubicin administration. Material and methods. Male Wistar rats (n = 24) were divided into three groups: control (n = 10), doxorubicin group (n = 7) (3 weekly intraperitoneal injections of doxorubicin solution at a cumulative dose of 15 mg/kg) and doxorubicin + TS-13 (n = 7) (administration of doxorubicin according to a similar scheme, TS-13 solution with drinking water). On the 21st day after the start of the experiment, the cardioprotective effect of TS-13 was assessed on the ex vivo model of perfusion of the heart isolated according to Langendorff. Coronary flow, heart rate (HR), pressure in the left ventricle (myocardial contractility) were recorded as parameters of myocardial functional activity; the integral indicator of myocardial contractility (working capacity) was calculated as the product of HR and pressure in the left ventricle. Results and discussion. The general toxic effect of doxorubicin was manifested in a significant decrease in rat body weight (by 21 %), the administration of TS-13 reduced the cachectic effect of the cytostatic. Doxorubicin worsened heart work by all studied parameters (coronary flow, HR, myocardial contractility and integral index of contractility); the effect persisted throughout the entire perfusion period (40 min). Animals treated with intraperitoneal injections of doxorubicin and TS-13 per os lost weight to a lesser extent, the functional activity of isolated hearts improved significantly – coronary flow, pressure in the left ventricle, and working capacity increased. Conclusions. Since, as we have shown earlier, TS-13 administration not only does not cancel, but even potentiates the antitumor activity of doxorubicin, the results obtained indicate the promise of using TS-13 as an adjuvant therapy for malignant neoplasms, enhancing the antitumor effect of the cytostatic and leveling its side effects, including cardiotoxicity.

Developmental and neurobehavioral toxicity of 2,2′-methylenebis(6-tert-butyl-4-methylphenol) (antioxidant AO2246) during the early life stage of zebrafish

Background2,2′-Methylenebis (4-methyl-6-tert-butylphenol) (AO2246) is a synthetic phenolic antioxidant extensively used in food packaging bags and cosmetics. Recently, AO2246 was detected with unexpectedly high concentrations in plasma and breast milk samples from pregnant and lactating women. Hence, it is essential to conduct a thorough investigation to evaluate the detrimental effects of AO2246 on biota. ObjectiveTo investigate the developmental and behavioral toxicity of AO2246 in zebrafish, as well as the molecular mechanisms underlying these effects. MethodsZebrafish embryos were exposed to AO2246 at concentrations ranging from 0.05 to 10 μM for up to 6 days postfertilization (dpf). Hatching rate, survival rate, heart rate, and body length were measured. Locomotor behavioral and electrophysiologal analyses were performed. Two fluorescence-labeled transgenic zebrafish lines (endothelium-Tg and macrophage/microglia-Tg) were employed. RNA sequencing was carried out. ResultsAO2246 has a 96-hour LC50 value of 3 μM. The exposure of AO2246 resulted in a significant reduction in both hatching rate and heart rate. Analysis of locomotor behavior demonstrated that larvae exposed to AO2246 doses exceeding 2 μM exhibited a significant decrease in both total distance and mean velocity. Electrophysiological recordings demonstrated a noteworthy reduction in spike activity at a concentration of 3 μM, relative to control conditions. The administration of AO2246 at 3 μM elicited morphological reactivity and immune alteration of the midbrain microglia in the macrophage/microglia-transgenic zebrafish line, indicating a potential contribution of neurological disorders to behavioral defects. RNA sequencing analysis revealed altered gene expression profiles at high AO2246 concentrations, particularly the dysregulation of pathways associated with neuronal function. ConclusionsThe present study demonstrates that AO2246 exposure elicits developmental and neurobehavioral toxicity in zebrafish larvae. Specifically, exposure to AO2246 was found to cause disturbances in neuronal electrophysiological activity and neurological disorders, which ultimately led to the impairment of locomotor behavior in zebrafish larvae.

Synthetic phenolic antioxidants evoked hepatoxicity in grass carp (Ctenopharyngodon idella) through modulating the ROS-PI3K/mTOR/AKT pathway: Apoptosis-autophagy crosstalk.

Synthetic phenolic antioxidants (SPAs) are an environmental concern due to their persistence nature and bioaccumulation. However, the hepatoxicity and mechanisms of SPAs in aquatic organisms remain poorly understood. In this study, grass carp were exposed to two representative SPAs (BHA and BHT) at environmentally relevant levels (0.1 μM) for 30 days. We observed that BHA and BHT exposure significantly increased the levels of serum aminotransferase (ALT) and aspartate aminotransferase (AST) in grass carp, accompanied by mild inflammatory cell infiltration and irregularity in the shape of hepatocytes. Dihydro ethylenediamine staining showed that BHA and BHT exposure resulted in elevated levels of superoxide levels, accompanied by increased antioxidant enzyme activities (T-AOC, SOD, CAT, GSH-PX) and MDA levels, which is suggestive of oxidative stress responses in the liver of grass carp. Besides, BHA and BHT could dock into the pocket of phosphatidylinositol 3-kinases (PI3K) and thereby inhibiting PI3K/mammalian target of rapamycin (mTOR)/protein kinase B (AKT) signaling cascades. Meanwhile, our results clarified that BHA and BHT could promote autophagosome production and increase the expression of key autophagy proteins, likely due to inhibition of PI3K/mTOR/AKT signaling pathway. Moreover, BHA and BHT could induce apoptotic process by upregulating the expression of Bax, Caspase3 and Caspase8 and downregulating Bcl2 expression. Notably, BHT exhibited more hepatoxicity on the indicators of the apoptosis and oxidative stress than BHA. In summary, our findings demonstrated that BHA and BHT exposure could induce liver damage induced via regulating ROS/PI3K-mediated autophagic hyperactivation, which is a crucial step in triggering hepatocyte death. This study provides novel insight into the potential mechanisms underlying liver damage caused by BHA and BHT in aquatic organisms, and offers a new theoretical basis for ecological risk assessment of SPAs.

Ce(IV)-coordinated organogel-based assay for on-site monitoring of propyl gallate with turn-on fluorescence signal

Propyl gallate (PG) is a commonly used synthetic phenolic antioxidant in foodstuffs and industrial products. Due to the potential health risk of PG, rapid and on-site detection in food and environment samples are important to guarantee human health. Herein, we demonstrated rapid monitoring of PG by a fluorescence turn-on strategy based on a specific fluorogenic reaction between PG and polyethyleneimine (PEI). Specifically, Ce4+ with oxidase-mimicking activity oxidized PG to its oxides, which then reacted with PEI through the Michael addition to generate the fluorescent compound. The proposed fluorogenic reaction had good specificity for PG, which could distinguish PG from other phenolic antioxidants and interferences. Furthermore, portable and low-cost organogel test kits were prepared using poly(ethylene glycol) diacrylate for quantitative and on-site detection of PG via a smartphone-based sensing platform. The organogel-based assay detection limit was 1.0 μg mL–1 with recoveries ranging from 80.2% to 106.2% in edible oils and surface water. Suitability of the developed assay was also validated by high-performance liquid chromatography. Our study provides an effective fluorescent approach to rapid, specific, and convenient monitoring of PG, which is useful for diminishing the risk of PG exposure.

Novel macromolecular synthetic phenolic antioxidants in sludge on a national scale in China: Their distribution, potential transformation products, and ecological risk

To fulfill the growing demand for retarding the oxidation of polymers and minimizing their migration from various products, new macromolecular synthetic phenolic antioxidants (SPAs) have emerged in the market. There is a concern that these SPAs may be released into wastewater streams during their manufacturing and use, eventually ending up in wastewater treatment plants (WWTPs). Nevertheless, information regarding the occurrence of these SPAs in sludge, particularly on a national scale, is scarce. In this study, several macromolecular SPAs and their transformation products (TPs) were investigated in sludge samples from 45 Chinese municipal WWTPs. All 14 analytes were detected in the sludge samples, among which, 12 analytes were first reported in sludge. 2,4,6-tri-tert-butylphenol (AO246) and 2 macromolecular SPAs, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (AO1010) and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (AO1076), were the most dominant SPAs, with geometric mean (GM) concentrations of 547, 212, and 35.2 ng/g dw, respectively. Two TPs, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoic acid (fenozan) and 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHT-COOH), were found in some sludge samples (48.9–71.1 %) with GM of 45.5 and 12.8 ng/g dw, respectively. By using LC-Q-TOF-MS/MS analysis, we tentatively identified previously unknown TPs of 10 macromolecular SPAs in sludge. This suggests that there are still unclear mechanisms modulating the transformation of these SPAs, which underscores the complexity of their fate. Additionally, using the freshwater photobacteria Vibrio qinghaiensis sp.-Q67 (Q67) as model organism, the acute and chronic EC50 of the 14 analytes were assessed for ecological risk assessment. By considering toxicity data obtained from algae, daphnia, and fish collected or predicted from various databases, we found that these analytes, including their mixture at low detected concentrations, pose risks to aquatic systems that should not be disregarded. Overall, the current study provides a comprehensive overview of novel SPAs and their TPs in sludge, offering valuable insights for investigating their environmental behavior, fate, and risks.