Persistence and dissipation study of azoxystrobin, buprofezin, dinocap and hexaconazole on mango (Mangifera indica L.)

A smartphone-based supramolecular biosensor for portable and rapid detection of buprofezin in real food samples

Buprofezin (BUP) is an insect growth regulator widely used in agriculture to control hemipteran pests, particularly the melon aphid, Aphis gossypii, due to its efficiency and low toxicity. Although approved by the Chinese government, its maximum residue limit (MRL) in food is strictly regulated, and conventional techniques for detecting BUP have several limitations. Our study reports successful BUP detection using a supramolecular fluorescent probe DP@ALB, constructed with chalcone-based fluorescent dye DP and albumin as the host. The probe offers advantages such as low cost, visual signal output with high fluorescence color variation, rapid response, and high sensitivity. Additionally, portable test strips enable convenient on-site BUP detection and simplifying field monitoring of spiked real samples. The study achieves precise qualitative and quantitative BUP analysis in grape fruit, groundwater, and soil with satisfactory recoveries. Further, the biological applicability of sensor for the in vitro detection of BUP in L929 living cells was demonstrated. This research breakthrough overcomes the limitations of traditional analytical methods, offering an efficient and reliable approach for food and environmental monitoring and pesticide residue detection.

Interaction mechanism of a pesticide, Azoxystrobin with bovine serum albumin: Assessments through fluorescence, UV-Vis absorption, electrochemical and molecular docking simulation techniques

The current study's objective was to investigate how an antifungal pesticide Azoxystrobin (AZO) interacts with bovine serum albumin (BSA) under conditions that simulate a physiological medium (pH 7.4). This investigation was carried out using various experimental (UV-Vis absorption, steady-state fluorescence and 3-D fluorescence spectroscopies, and electrochemical) and theoretical (molecular docking and molecular dynamics simulations) methods. The fluorescence quenching data demonstrated that AZO caused fluorescence quenching in BSA, and this quenching process was attributed to the static quenching mechanism. By examining the fluorescence quenching of BSA at three different temperatures, it was determined that the binding constants for the AZO-BSA complexes were approximately 104 M-1 in magnitude, while the same magnitude of the binding constant was found by the electrochemical method. This indicates that the interaction between AZO and BSA was of moderate strength. This was further validated by the changes observed in the UV-Vis spectrum of BSA following the addition of AZO. The thermodynamic information, including ΔH and ΔS, revealed that the interaction forces primarily involved van der Waals forces as well as hydrogen bonds. The negative Gibbs free energy indicated that the reaction is spontaneous. In the theoretical investigation, the comparison highlights a remarkable consistency in how AZO interacts with the BSA active site over various time points. Hydrogen bonding and hydrophobic interactions consistently play a role in ensuring the stable and specific binding of the ligand. Moreover, the 3-D fluorescence spectral findings revealed alterations in the surrounding microenvironment of protein fluorophores when AZO binds. Upon analyzing the electrochemical data, it was observed that there was a consistent decrease in the peak currents of AZO when BSA was added to solutions containing AZO. The primary cause of this decrease in the peak currents was the reduction in the equilibrium concentration of AZO due to the addition of BSA. Furthermore, the formation of a non-electroactive complex between BSA and AZO, which impedes electron transport between AZO and the working electrode, accounts for these decreases. As a result, it can be said that the understanding of how AZO binds to BSA offers valuable insights that can be applied in the food, human health, and environment sectors.

An integrated approach for evaluating the interactive effects between azoxystrobin and ochratoxin A: Pathway-based in vivo analyses

Azoxystrobin (AZO) is a broad-spectrum strobilurin fungicide widely used in agriculture. However, its use increases the possibility of co-occurrence with mycotoxins such as ochratoxin A (OTA), which poses a significant risk to human health. Therefore, it is imperative to prioritize the evaluation of the combined toxicity of these two compounds. To assess the combined effects of AZO and OTA, the response genes and phenotypes for AZO or OTA exposure were obtained by utilizing Comparative Toxicogenomics Database, and Database for Annotation, Visualization and Integrated Discovery was used for GO and KEGG pathway enrichment analysis. In addition, we provided in-vivo evidence that AZO and OTA, in isolation and combination, could disrupt a variety of biological processes, such as oxidative stress, inflammatory response, apoptosis and thyroid hormone regulation under environmentally relevant concentrations. Notably, our findings suggest that the combined exposure group exhibited greater toxicity, as evidenced by the expression of various markers associated with the aforementioned biological processes, compared to the individual exposure group, which presents potential targets for the underlying mechanisms of induced toxicity. This study provides a novel methodological approach for exploring the mechanism of combined toxicity of a fungicide and a mycotoxin, which can shed light for conducting risk assessment of foodborne toxins.

Effect of Processing on Reduction in Chiral Pesticide Hexaconazole for Kiwifruit Juice

In this study, the residue levels of chiral pesticide hexaconazole during kiwifruit juice processing (peeling, homogenization, and sterilization) were investigated by using high-performance liquid chromatography (HPLC), and the dietary risk during these processes was also assessed. Hexaconazole was applied at dosages of 173.33 and 346.66 mg/L (recommended and double recommended dosage) in kiwifruit. In the peeling process, 87.7% to 89.2% of the residues were decreased after peeling. Levels of hexaconazole residues in homogenization and sterilization processes further increased from 0.49% to 24.3% and from 0.2% to 3.0%, respectively. Processing factors (PFs) for (+)- and (-)-hexaconazole after peeling, homogenization, and sterilization were 0.12, 0.88, 0.99 for low-dose treatment and 0.12, 0.87, 0.99 for high-dose treatment, respectively. The enantioselectivity of hexaconazole during these procedures was evaluated by enantiomeric fractions (EFs) values, which were around 0.5 throughout all the procedures, indicating that hexaconazole enantiomers had similar dissipation behaviors during kiwifruit juice processing. The RQc of hexaconazole in pre-peeling samples was significantly greater than 100% under two dosages, while the peeling process can notably decrease the values to an acceptable level. The results of this study could provide guidance for agriculture applications and kiwi commodity production to decrease the risk of hexaconazole residue.

Stereoselective Toxicokinetic and Distribution Study on the Hexaconazole Enantiomers in Mice

Hexaconazole (Hex) has been widely used in agricultural products, and its residues may pose a potential risk to human health. However, the metabolic behavior of Hex enantiomers in mammal organisms is still unknown, which is important for evaluating the differences in their toxicity. In this study, the distribution of S-(+)- and R-(-)-Hex in mice was detected by an ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS), and the mechanism differences in the toxicokinetic behavior were analyzed by molecular docking. Good linearities, accuracies, and precisions were achieved for S-(+)- and R-(-)-Hex, with recoveries of 88.7~104.2% and RSDs less than 9.45% in nine tissues of mice. This established method was then used to detect the toxicokinetic of Hex enantiomers in mice after oral administration within 96 h. The results showed that the half-lives of S-(+)- and R-(-)-Hex were 3.07 and 3.71 h in plasma. Hex was mainly accumulated in the liver, followed by the kidneys, brain, lungs, spleen, and heart. The enantiomeric fraction (EF) values of Hex enantiomers in most of the samples were below 1, indicating that S-(+)-Hex decreased faster than its antipode. The molecular docking showed that the binding of S-(+)-Hex with P450arom was much more stable than R-(-)-Hex, which verified the fact that S-(+)-Hex was prefer to decrease in most of the tissues. The results of this study could be helpful for further evaluating the potential toxic risk of Hex enantiomers and for the development and usage of its pure monomer.

Persistence evaluation of fluopyram + tebuconazole residues on mango and pomegranate and their risk assessment

The persistence of combination formulation of fluopyram 200 + tebuconazole 200-400 SC was evaluated across different agro-climates in India for the management of fungal diseases in two commercially important fruit crops, mango and pomegranate. The residues were extracted using quick easy cheap effective rugged and safe (QuEChERS) method and quantification was done on liquid chromatography-tandem mass spectrometry (LC-MS/MS). The fungicide degradation followed 1st-order kinetics and the half-lives were 2.9-6.4 days for mango, and 3.5-7.4 days for pomegranate for both the fungicides. On the basis of Organisation for Economic Co-operation and Development (OECD) maximum residue limit (MRL) calculation, 1.0 mg kg^-1 MRL was obtained for fluopyram while for tebuconazole, it was 0.5 mg kg^-1 on mango, at the pre-harvest interval (PHI) of 5 days. For pomegranate, the respective MRLs were 1.0 mg kg^-1 and 0.7 mg kg^-1 at PHI of 7 days. The dietary risk assessment study indicated that % acceptable daily intake (% ADI) and % acute reference dose (% ARfD) were much lower than 100; thus, the application of fluopyram and tebuconazole on mango and pomegranate is unlikely to present public health concern.

A liquid chromatographic method for determination of acetamiprid and buprofezin residues and their dissipation kinetics in paddy matrices and soil

The present study was conducted to investigate the residue status of two insecticides (acetamiprid and buprofezin) and their dissipation kinetics in three matrices viz. paddy grain, straw, and soil. The extraction procedure for residues of these two insecticides was executed using acetonitrile solvent. The analytical method was validated, which showed good linearity with the limit of quantification (LOQ) value of 0.01 and 0.02 mg kg^-1 for acetamiprid and buprofezin, respectively. The recovery range was 79.67-98.33 % concerning all the matrices in both the insecticides. Acetamiprid (20% SP) and Buprofezin (25% SC) were applied separately in the paddy field in two doses: single dose (recommended dose) and double dose along with untreated control throughout the experiment. Residue analysis of these two insecticides in paddy (grain and straw) and soil was accomplished employing high-performance liquid chromatography (HPLC) with ultraviolet (UV) detector and confirmed by ultra-performance liquid chromatography (UPLC) coupled with mass spectrometry (UPLC-MS/MS). The dissipation data showed that acetamiprid exhibited higher dissipation in comparison with buprofezin. However, their persistence was found slightly higher in soil. The dissipation dynamics in the rice and soil were discussed with biological half-lives of both the insecticides. Consumer risk assessment study was also made considering its fate to the consumers.

The discovery of combined toxicity effects and mechanisms of hexaconazole and arsenic to mice based on untargeted metabolomics

The high detected frequencies of hexaconazole (Hex) and arsenic (As) increased the probabilities of their co-existence in agricultural products. However, the combined toxicity effect and mechanism of action for these two pollutants were still unclear. In this study, an untargeted metabolomics method with ultra high performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS) was developed to monitor the changes of endogenous metabolites and metabolism pathways in mice liver. Our study revealed that significant differences in metabolomics profiles were observed after Hex, As, and Hex+As exposure for 90 d. Hex exposure altered 54 metabolites and 11 pathways significantly which were mainly lipid-related. For As exposure, 63 metabolites and 9 pathways were affected most of which were amino acid-related. Hex+As induced 93 metabolites changes with 34% was lipids and lipid-like molecules and 22% was organic acids and derivatives. Hex+As exposure shared the pathways that altered by Hex and As indicated that the interaction of Hex and As might be independent action. The results of this study could provide an important insight for understanding the mechanism of combined toxicity for Hex and As and be helpful for evaluating their health risk to human.

Effect of Processing on Residual Buprofezin Levels in Ginseng Products

This study determined residual buprofezin levels in fresh ginseng and evaluated their changes during processing. Supervised field trials were conducted at Yeongju, Geumsan, and Goesan, Korea. Buprofezin 12.5% EC was applied to 5-y ginseng in accordance with the Korean good agriculture practice (GAP). Samples were collected at 0, 7, 14, 21, and 30 d after the final application. On day 14 (GAP-equivalent preharvest date), the ginseng was processed to obtain dried and red ginseng. The average buprofezin concentrations on day 0 were 0.076 (Yeongju), 0.055 (Geumsan), and 0.078 mg kg^-1 (Goesan). Residual concentrations increased as ginseng was processed into dried and red ginseng. Residue levels in dried ginseng manufactured by hot air drying were higher than in red ginseng obtained by steaming, hot air, and sunlight drying. However, the absolute amount of pesticides decreased by approximately 20-30% as a result of calculating the reduction factor considering the dry yield and moisture content. Therefore, the residual concentration in processed products may vary depending on the processing method, and it is deemed necessary to consider the processing yield and moisture content when evaluating the safety of residual pesticides in dried processed products.