The enantioselective effects and potential risks of paclobutrazol residue during cucumber pickling process

Effects and Potential Risks of Chiral Penflufen on Pickled Cowpea: Combined Microbiome and Metabolomics

Pesticide residues on vegetables may affect microbes and metabolites during the fermentation process, leading to effects and potential risks. Here, the enantioselective effects and potential risks of chiral penflufen on pickled cowpea were investigated by using microbiome and metabolomics analyses. Correlation analysis was conducted to construct bacterial-metabolite interaction networks. Penflufen enantiomers were degraded little during the fermentation process. Rac-penflufen treatment significantly decreased the relative abundance of Lactiplantibacillus while increasing Weissella, but the opposite effects were found in R- and S-penflufen treatments. These shifts were linked to content and functional changes of metabolites. R-/S-/Rac-penflufen upregulated rose aroma metabolites (e.g., β-damascenone), while R- and S-penflufen downregulated floral aroma metabolites (e.g., β-ionone, 2-nonenal) and green leaf aroma metabolites (e.g., (E)-2-hexenal). S-Penflufen reduced alcohols and increased esters more significantly, and altered a higher number of volatile organic compounds (VOCs) and chiral amino acids than R-penflufen, showing a greater risk to food flavor and nutritional quality.

Enantioselective Degradation and Processing Factors of Seven Chiral Pesticides During the Processing of Wine and Rice Wine

Chiral pesticides often undergo enantioselective degradation during food fermentation. In this study, the enantioselective fates of seven chiral pesticides during processing of wine and rice wine were investigated. The results revealed that R-metalaxyl, R-mefentrifluconazole and S-hexaconazole were preferentially degraded during wine processing with EF values of 0.57, 0.78, and 0.43, respectively, whereas S-metalaxyl and R-hexaconazole were preferentially degraded during rice wine processing with EF values of 0.44 and 0.54, respectively. Stereoselectivity was attributed to fermentative bacterial activity. The processing factor (PF) values for the five pesticides ranged from 0.04 to 0.34 during wine processing and from 0.02 to 0.29 during rice wine processing, suggesting that fermentation can mitigate pesticide exposure risks and ensure food safety. This study enhances our understanding of enantioselective fate of chiral pesticides during fermented food processing, provides guidance for the application of chiral pesticides, and enables the dietary risk of chiral pesticides in processed products to be assessed more accurately.

Novel herbicide flusulfinam: absolute configuration, enantioseparation, enantioselective bioactivity, toxicity and degradation in paddy soils

BACKGROUND

Flusulfinam, a novel chiral herbicide, effectively controls Echinochloa crusgalli and Digitaria sanguinalis in paddy fields, indicating significant potential for practical agricultural applications. However, limited information is available on flusulfinam from a chiral perspective. A comprehensive evaluation of the enantiomeric levels of flusulfinam was performed.

RESULTS

Two enantiomers, R-(+)- and S-(-)-flusulfinam, were separately eluted using a Chiralcel OX-RH column. The bioactivity of R-flusulfinam against the two was 1.4-3.1 fold that of Rac-flusulfinam against two weed species. R-flusulfinam toxicity to Danio rerio larvae and Selenastrum capricornutumwere was 0.8- and 3.0-fold higher than Rac-flusulfinam, respectively. Degradation experiments were conducted using soil samples from four Chinese provinces. The findings indicated that S-flusulfinam (half-life T1/2 = 40.8 days) exhibits preferential degradation than R-flusulfinam (T1/2 = 46.2-57.8 days) in the soils of three provinces. Under anaerobic conditions, soil from Anhui exhibited preferential degradation of R-flusulfinam (T1/2 = 46.2 days) over S-flusulfinam (T1/2 = 63 days). Furthermore, two hydrolysis products of flusulfinam (M299 and M100) are proposed for the first time.

CONCLUSION

The enantioselective bioactivity, toxicity and degradation of flusulfinam were investigated. Our findings indicate that R-flusulfinam is an extremely effective and low-toxicity enantiomer for the tested species. The soil degradation test indicated that the degradation of flusulfinam was accelerated by higher organic matter content and lower soil pH. Furthermore, microbial communities may play a crucial role in driving the enantioselective degradation processes. This study lays the groundwork for the systematic evaluation of flusulfinam from an enantiomeric perspective. © 2024 Society of Chemical Industry.

Dissipation Behavior and Dietary Risk Assessment of Thiamethoxam, Pyraclostrobin, and Their Metabolites in Home-Style Pickled Cowpea

In this study, the fate of two pesticides commonly used on cowpeas, thiamethoxam and pyraclostrobin, during the preparation of home-made pickled cowpeas was investigated using an improved QuEChERS method combined with UHPLC-MS/MS. Although pesticide residues were primarily distributed on cowpea samples, some were transferred to brine. The dissipation half-life of thiamethoxam on cowpea samples was significantly shorter than that of pyraclostrobin due to thiamethoxam's higher water solubility. Thiamethoxam demonstrated a half-life of 5.12 ± 0.66 days, whereas pyraclostrobin exhibited a longer half-life of 71.46 ± 7.87 days. In addition, the degradation half-lives of these two pesticides in the whole system (cowpea and brine) were 45.01 ± 4.99 and 70.51 ± 5.91 days, respectively. This result indicates that the pickling did not effectively promote the degradation of thiamethoxam and pyraclostrobin. The metabolite clothianidin of thiamethoxam was not produced throughout the pickling process, but the metabolite BF 500-3 of pyraclostrobin was detected in cowpea samples. The detection rates for thiamethoxam, pyraclostrobin, and BF 500-3 in the 20 market samples were 10%, 70%, and 45%, respectively. However, the risk quotient analysis indicated that the risk of dietary intake of thiamethoxam and pyraclostrobin in pickled cowpeas by Chinese consumers was negligible.

Enantioselective Behaviors of Chiral Pesticides and Enantiomeric Signatures in Foods and the Environment

Unreasonable application of pesticides may result in residues in the environment and foods. Chiral pesticides consist of two or more enantiomers, which may exhibit different behaviors. This Review intends to provide progress on the enantioselective residues of chiral pesticides in foods. Among the main chiral analytical methods, high performance liquid chromatography (HPLC) is the most frequently utilized. Most chiral pesticides are utilized as racemates; however, due to enantioselective dissipation, bioaccumulation, biodegradation, and chiral conversion, enantiospecific residues have been found in the environment and foods. Some chiral pesticides exhibit strong enantioselectivity, highlighting the importance of evaluation on an enantiomeric level. However, the occurrence characteristics of chiral pesticides in foods and specific enzymes or transport proteins involved in enantioselectivity needs to be further investigated. This Review could help the production of some chiral pesticides to single-enantiomer formulations, thereby reducing pesticide consumption as well as increasing food production and finally reducing human health risks.

Potential Risks of Tebuconazole during Wine Fermentation at the Enantiomer Level Based on Multiomics Analysis

The enantioselectivity and potential risks of tebuconazole enantiomers (R-tebuconazole and S-tebuconazole) in wine fermentation were investigated in this study using Cabernet Sauvignon grapes. Tebuconazole was mainly degraded during the alcoholic fermentation stage, and no obvious transformation between R-tebuconazole and S-tebuconazole was observed. Selective degradation between these two enantiomers occurred, with R-tebuconazole degrading faster than S-tebuconazole. The residual tebuconazole inhibits glucose metabolism and the unsaturated fatty acid formation in the wine fermentation system and inhibits gene expression in the late phase of Saccharomycetales, affecting its cell wall formation. Overall, the findings highlight that R-tebuconazole exhibited a higher risk than S-tebuconazole in these processes. These insights are potentially exploitable to understand chiral pesticides at the enantiomer level using multiomics technology in food-processing systems.

Large-scale fate profiling of butralin between cultivated and processed garlics for multi-risk estimations

Elaborating on the fate profiling and risk magnitude of butralin during large-scale applications was conducive to agroecosystems sustainability and dietary rationality. Occurrence, dissipation and concentration variation of butralin were elucidated from garlic cultivation to household processing by tracing UHPLC-MS/MS within 2 min, with regard to original depositions, half-lives, and terminal magnitude in typical origins of garlic. The processing factors (Pfs) of butralin were further clarified among washing, stir-frying and pickling of garlic crops, and pickling was the most effective way for butralin removal with a Pf of 0.092. A probabilistic model with Pfs was further introduced for the comprehensive risk estimations, by reduction factors of 3.1-10.9 from raw garlic crops to processed products. The short-term risks of butralin from green garlic were greater than those between garlic shoot and garlic, with the %ARfDs of 0.030 %-6.323 % from 50^th to 99.9^th percentiles. The long-term risks were inversely correlated to the age of the population, whose location in rural (%ADIs, 0.256 %-0.768 %) suffered more serious exposures than in urban (%ADIs, 0.231 %-0.699 %). High potential risk amplification should be continuously emphasized given the increasing applications and persistent fate of butralin, especially for vulnerable rural children.

Dissipation, metabolism, accumulation, processing and risk assessment of fluxapyroxad in cucumber and cowpea vegetables from field to table

Understanding the residue fate of fluxapyroxad is critical for food safety and human health. The present study profiled the dissipation, metabolism, accumulation, removal and risk assessment of fluxapyroxad in cucumbers and cowpeas from field to table. Greenhouse-field trials suggested that fluxapyroxad dissipated faster in cucumbers than in cowpeas, and M700F008 was the only detected metabolite at <LOQ-37.92 μg/kg. Fluxapyroxad accumulated in cucumbers (average residue accumulation value, 1: 2.21: 1.16) and cowpeas (1: 1.33: 1.05) after repeated spraying. Peeling, washing and parboiling could remove fluxapyroxad from cucumbers and cowpeas (PF range, 0.16-0.85); however, fluxapyroxad was partly concentrated by stir-frying (PF range, 0.36-1.41). Moreover, fluxapyroxad residues increased with increasing pickling time. Chronic and acute risk assessments revealed that dietary exposure to fluxapyroxad was within the acceptable levels from cucumber and cowpea consumption. Given high residue levels and their potential accumulation, fluxapyroxad should be continuously monitored and assessed in the future.

Degradation and chiral properties of metamifop during rice processing

Metamifop has been used to control gramineous weeds in paddy fields and may form residues in rice. In this study, the residue analysis method for metamifop and the metabolites was set up based on high-performance liquid chromatography-mass spectrometry and the chiral analysis method was also developed. The enantioselective degradation and residue of metamifop in rice processing were studied, and the major metabolites were monitored. The removal rate of metamifop by washing could reach 60.03%, while the loss in rice and porridge cooking was less than 16%. No decrease was found in fermentation into fermented grains, but metamifop was degraded in the process of rice wine fermentation with half-lives of around 9.5 days. N-(2-fluorophenyl)-2-(4-hydroxyphenoxy)-N-methylpropionamide and 6-chlorobenzo [d] oxazole-2 (3H)-one were found to be the major metabolites. This study reveals the enantioselective residue of metamifop in rice processing, which helps understand the potential risk in food consumption.

Widely targeted metabolite profiling of mango stem apex during floral induction by compond of mepiquat chloride, prohexadione-calcium and uniconazole

Background

Insufficient low temperatures in winter and soil residues caused by paclobutrazol (PBZ) application pose a considerable challenge for mango floral induction (FI). Gibberellin inhibitors SPD (compound of mepiquat chloride, prohexadione-calcium and uniconazole) had a significant influence on enhancing the flowering rate and yield of mango for two consecutive years (2020-2021). Researchers have indicated that FI is regulated at the metabolic level; however, little is known about the metabolic changes during FI in response to SPD treatment.

Methods

Here, ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS)-based widely targeted metabolomic analysis was carried out to assess the metabolic differences in the mango stem apex during different stage of mango FI (30, 80, 100 days after SPD/water treatment).

Results

A total of 582 compounds were annotated and 372 metabolites showed two-fold differences in abundance (variable importance in projection, VIP ≥ 1 and fold change, FC≥ 2 or≤ 0.5) between buds at 30, 80, 100 days after SPD/water treatment or between buds under different treatment. Lipids, phenolic acids, amino acids, carbohydrates, and vitamins were among metabolites showing significant differences over time after SPD treatment. Here, 18 out of 20 lipids, including the lysophosphatidylethanolamine (12, LPE), lysophosphatidylcholine (7, LPC), and free fatty acids (1, FA), were significantly upregulated from 80 to 100 days after SPD treatment comared to water treatment. Meanwhile, the dormancy release of mango buds from 80 to 100 days after SPD treatment was accompanied by the accumulation of proline, ascorbic acid, carbohydrates, and tannins. In addition, metabolites, such as L-homocysteine, L-histidine, and L-homomethionine, showed more than a ten-fold difference in relative abundance from 30 to 100 days after SPD treatment, however, there were no significant changes after water treatment. The present study reveals novel metabolites involved in mango FI in response to SPD, which would provide a theoretical basis for utilizing SPD to induce mango flowering.

Effects of Household Processing on Residues of the Chiral Fungicide Mandipropamid in Four Common Vegetables

The study aimed to detect the content of mandipropamid enantiomers in unprocessed and processed tomato, cucumber, Chinese cabbage, and cowpea samples and assess the health risks to Chinese consumers. Data showed that washing and soaking with an acidic solution reduced the mandipropamid residue from vegetable samples by 54.1-82.2%. The pickling process resulted in a 6.2-65.2% loss of mandipropamid from cucumber, Chinese cabbage, and cowpea samples. Peeling and juicing were the best removing techniques for mandipropamid residues in tomato and cucumber (removal rate (RR) value > 91%), and cooking for 5 min could effectively reduce the levels of mandipropamid in Chinese cabbage and cowpea (RR values of 81.4-99.7%). The values of processing factor for the processed vegetable samples are all less than one. No significant enantioselectivity of mandipropamid was found in the vegetables during processing. Health risk data showed that samples of four types of mandipropamid-contaminated vegetables were safe for consumption after processing.

Network Pharmacology Combined with Metabolomics Approach to Investigate the Toxicity Mechanism of Paclobutrazol

Paclobutrazol (PBZ) is a commonly used plant growth regulator (PGR) with good antibacterial activity. It has widespread applications in agricultural production. However, there is limited research reported on the potential risks of human health resulting from PBZ residues. In this study, using Sprague-Dawley rats, we carried out a systematic study on the hepatotoxicity and nephrotoxicity of PBZ in different doses (0.2, 0.5, and 1.0 g/kg). The metabolic profiles and network pharmacology were combined to construct a PBZ-endogenous substances-gene-hepatorenal diseases network to elucidate the underlying mechanism of PBZ's hepatorenal toxicity. At first, metabolomics analysis was done to investigate the metabolites and the related metabolic pathways associated with PBZ. Secondly, the network pharmacology approach was used in further exploration of the toxic targets. Additionally, molecular docking was carried out to investigate the interactions between PBZ and potential targets. The results indicated that PBZ showed obvious toxicity towards the liver and kidney of rats. The metabolomics analysis showed that PBZ mainly affected 4 metabolic pathways, including tryptophan metabolism, arachidonic acid metabolism, linoleic acid metabolism, and purine metabolism. Network pharmacology and molecular docking revealed that CYP1A2, CYP2A6, CYP2E1, MAOA, PLA2G2A, PTGS1, and XDH were critical targets for PBZ hepatorenal toxicity. This preliminary study revealed PBZ's hepatorenal toxicity and provided a theoretical basis for the rational and safe use of PBZ. Furthermore, it provided possible intervention targets for further research on how to avoid or reduce the damage caused by pesticides to the human body.

Enantioselective monitoring chiral fungicide mefentrifluconazole in tomato, cucumber, pepper and its pickled products by supercritical fluid chromatography tandem mass spectrometry

A fast, effective, and environmental-friendly method was developed for enantioseparation and analysis of mefentrifluconazole in vegetables based on supercritical fluid chromatography tandem mass spectrometry. The enantioselective behaviors of mefentrifluconazole enantiomers in tomato, cucumber, and pepper in the greenhouse, and pickled cucumber and pepper during processing were investigated. Mefentrifluconazole enantiomers could obtain baseline separation within 2 min. The average recoveries of all matrices ranged from 78.4% to 119.0%, with relative standard deviations less than 16.8% for two enantiomers. S-(+)-mefentrifluconazole was preferentially degraded in pepper, while there was no enantioselectivity in tomato and cucumber under field conditions. During processing, S-(+)-mefentrifluconazole was reduced preferentially than R-(-)-mefentrifluconazole in pickled cucumber and cucumber brine. Inversely, R-(-)-mefentrifluconazole degraded faster than S-(+)-mefentrifluconazole in pepper brine. But, no obvious enantioselectivity was observed in pickled pepper. The result of this study could contribute to a more accurate dietary risk assessment of mefentrifluconazole in vegetables and processed products.

Pesticide Residue Behavior and Risk Assessment in Celery after Se Nanoparticles Application

This study investigates pesticide levels in celery, and compares their degradation, dissipation, distribution, and dietary risk after spraying with selenium (Se) nanoparticles. Abamectin, imidacloprid, acetamiprid, thiamethoxam, and lambda-cyhalothrin were sprayed at 1.6, 6.8, 2.0, 1.0, and 0.7 g a.i. ha⁻¹ followed by a 2 g·ha⁻¹ Se nanoparticle application during the growing period. Thiamethoxam, abamectin, imidacloprid, lambda-cyhalothrin, and acetamiprid in celery degraded following a first order kinetic model after 2 g·ha⁻¹ Se nanoparticles application. With the exception of acetamiprid, the half-lives of thiamethoxam, abamectin, imidacloprid, and lambda-cyhalothrin were reduced from 2.4, 0.5, 1.2, 4.2 days without Se nanoparticles application to 1.4, 0.2, 0.9, 3.7 days with the addition of Se nanoparticles (2 g·ha⁻¹), respectively. The chronic dietary exposure risk probability (RQc) and the acute dietary exposure risk probability (RQa) of celery after Se nanoparticles application were within acceptable limits for consumption except for abamectin.

Paclobutrazol exposure induces apoptosis and impairs autophagy in hepatocytes via the AMPK/mTOR signaling pathway

Paclobutrazol (PBZ), one of the most widely used plant growth retardants in vegetables, fruits, and traditional Chinese medicine ingredients, exposes people to adverse events. In this study, HepaRG hepatocytes were cultured and exposed to PBZ (360 μM) in vitro to determine its mechanism. Results showed that PBZ exposure inhibited cell viability in a time- and dose-dependent manner and increased the oxidative stress and apoptosis ratio in HepaRG cells. These data revealed that the adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) has an important role in PBZ-induced cell apoptosis, which is mediated by impaired autophagy and blocked by the AMPK activator. In conclusion, PBZ exposure induces apoptosis and impairs autophagy in hepatocytes via the AMPK/mTOR signaling pathway.

Stereoselective behaviors of the fungicide triadimefon and its metabolite triadimenol during malt storage and beer brewing

The stereoselective behaviors of triadimefon (TF) and its metabolite triadimenol (TN) during barley storage and beer brewing were studied by supercritical fluid chromatography-tandem mass spectrometry to shed light on potential security risks. Matrix-matched calibration curves were constructed for barley and beer, with determination coefficients (r²) ≥ 0.9991. Average recoveries of 77.2-107.5 % and relative standard deviations within 15.0 % were observed. The degradation of the TF enantiomers during storage followed pseudo-first-order kinetics, and S-TF was degraded in preference to R-TF with the half-life ranges 18.5-36.5 d and 20.4-69.3 d, respectively. During beer brewing, the TF enantiomers (enantiomer fraction, 0.44-0.56) were selectively metabolized into TN stereoisomers (diastereomer fraction, 0.43-0.58). The total pesticide content of beer was 93.3 % lower than that of raw grain, whereby the TF content declined by up to 100 % and the TN stereoisomers were reduced by 35.1 %. The processing factors of all the brewing steps were less than one, illustrating that beer consumption is safer after its commercial processing. Furthermore, the TF enantiomers showed different behaviors upon fermentation by two yeast strains. Thus, this work is a useful reference for assessing the food safety risk posed by individual pesticide enantiomers and their contribution to environmental pollution.