Comprehensive widely targeted metabolomics to decipher the molecular mechanisms of Dioscorea opposita thunb. cv. Tiegun quality formation during harvest.

Dioscorea opposita Thumb. cv. Tiegun is commonly consumed as both food and traditional Chinese medicine, which has a history of more than two thousand years. Harvest time directly affects its quality, but few studies have focused on metabolic changes during the harvesting process. Here, a comprehensive metabolomics approach was performed to determine the metabolic profiles during six harvest stages. Thirty eight metabolites with significant differences were determined as crucial participants. Related metabolic pathways including phenylalanine, tyrosine and tryptophan biosynthesis, stilbenoid, diarylheptanoid and gingerol biosynthesis, phenylpropanoid biosynthesis, flavonoid biosynthesis and tryptophan metabolism were the most active pathways during harvest. The results revealed that temperature has a significant impact on quality formation, which suggested that Dioscorea opposita thumb. cv. Tiegun harvested after frost had higher potential value of traditional Chinese medicine. This finding not only offered valuable guidance for yam production, but also provided essential information for assessing its quality.

Fate characteristics and risk identification of thifluzamide in buckwheat across China: Analytical method development, occurrence, and health assessment.

Elaborating on the fate tendency of thifluzamide (thiazole-amide fungicide) in buckwheat based on nationwide application is vital for grain security and human health based on nationwide application. A rapid and sensitive analytical method was developed to trace thifluzamide in buckwheat matrices using an ultrahigh-performance liquid chromatography-tandem triple quadrupole mass spectrometer (UHPLC-MS/MS), with a retention time of 2.90 min and limit of quantitation (LOQ) of 0.001 mg/kg. Thifluzamide could be stably stored for 84 d in buckwheat matrices under -20 °C under dark condition. The occurrence, dissipation and terminal magnitudes of thifluzamide were reflected by the primary deposition of 0.02-0.55 mg/kg, half-lives of 12-14 d, and highest residues of 0.41 mg/kg. The long-term risks (ADI%) of thifluzamide were 37.268 %-131.658 % in registered crops, and the risks for the rural population were significantly higher than those of the urban population. The unacceptable dietary risks of thifluzamide should be continuously emphasized for children aged 2-7 with an ADI% values of 100.750 %-131.658 %. A probabilistic model was further introduced to evaluate the risk discrepancy of thifluzamide in buckwheat, showing the risks in Tartary buckwheat (Fagopyrum tararicum Gaerth) were 1.5-75.4 times than that in sweet buckwheat (Fagopyrum esculentum Moench). Despite the low risks for dietary buckwheat, the high-potential health hazards of thifluzamide should be pay more attention given the increasing applications and cumulative effects.

Comprehensive effects of thiamethoxam from contaminated soil on lettuce growth and metabolism.

The second-generation neonicotinoid thiamethoxam, is prevalent in soils because of its extensive application and persistence. However, the comprehensive effects of thiamethoxam residue in soils on cultivated plants are still poorly understood. This study examined variations of growth state, physiological parameters, antioxidant activity, and metabolites in lettuce after thiamethoxam exposure; the removal effects of different washing procedures were also investigated. The results indicated that thiamethoxam in soils significantly increased the fresh weight, seedling height and chlorophyll content in lettuce, and also altered its lipid, carbohydrate, nucleotide and amino acids composition based on untargeted metabolomics. KEGG pathway analysis uncovered a disruption of lipid pathways in lettuce exposed to both low and high concentrations of thiamethoxam treatments. In addition, the terminal residues of thiamethoxam in lettuce were below the corresponding maximum residue limits stipulated for China. The thiamethoxam removal rates achieved by common washing procedures in lettuce ranged from 26.9% to 42.6%. This study thus promotes the understanding of the potential food safety risk caused by residual thiamethoxam in soils.

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 50th to 99.9th 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.

Occurrence and fate characteristics of isoproturon from garlic cultivation to household processing: Implication for human exposure.

The fate characteristics of isoproturon (IPU) from garlic cultivation to household processing was elucidated by a tracing UHPLC-MS/MS based on the favorable storage stability. The occurrence, pharmacokinetics dissipation and terminal magnitude of IPU were reflected by parameters including original deposition of 31-170 µg kg-1, half-lives of 11.5-19.4 d, and final concentrations of <1.0-250.6 µg kg-1. The processing factors of IPU were further clarified in terms of washing, stir-frying and pickling, with processing factors of 0.008-0.828. The chronic dietary risks (%ADI) were assessed as 1.516-5.242 %, whereas the short-term exposures from green garlic should be continuously emphasized over 99th percentile with unacceptable %ARfD of 147.144-5074.018 %. The acute and chronic risk magnitude significantly decreased by a factor 2.0-125.0 and 2.2-3.3 from raw garlic crops to processed products, respectively. What was noteworthy was the unacceptable acute risks of IPU from green garlic at 99.9th percentile even after a series of processing procedures.

Foxtail Millet Improves Blood Glucose Metabolism in Diabetic Rats through PI3K/AKT and NF-κB Signaling Pathways Mediated by Gut Microbiota.

Foxtail millet (FM) is receiving ongoing increased attention due to its beneficial health effects, including the hypoglycemic effect. However, the underlying mechanisms of the hypoglycemic effect have been underexplored. In the present study, the hypoglycemic effect of FM supplementation was confirmed again in high-fat diet and streptozotocin-induced diabetic rats with significantly decreased fasting glucose (FG), glycated serum protein, and areas under the glucose tolerance test (p < 0.05). We employed 16S rRNA and liver RNA sequencing technologies to identify the target gut microbes and signaling pathways involved in the hypoglycemic effect of FM supplementation. The results showed that FM supplementation significantly increased the relative abundance of Lactobacillus and Ruminococcus_2, which were significantly negatively correlated with FG and 2-h glucose. FM supplementation significantly reversed the trends of gene expression in diabetic rats. Specifically, FM supplementation inhibited gluconeogenesis, stimulated glycolysis, and restored fatty acid synthesis through activation of the PI3K/AKT signaling pathway. FM also reduced inflammation through inhibition of the NF-κB signaling pathway. Spearman's correlation analysis indicated a complicated set of interdependencies among the gut microbiota, signaling pathways, and metabolic parameters. Collectively, the above results suggest that the hypoglycemic effect of FM was at least partially mediated by the increased relative abundance of Lactobacillus, activation of the PI3K/AKT signaling pathway, and inhibition of the NF-κB signaling pathway.

Dissipation, residue, dietary, and ecological risk assessment of atrazine in apples, grapes, tea, and their soil.

Atrazine is one of the most used herbicides in China. It is a persistent organic pollutant but has been widely used on Chinese farmlands for a long time. To assess its dietary and ecological risks to human and environment, in this study, atrazine residues were extracted with acetonitrile and then plant samples were detected with gas chromatography coupled with mass spectrometry (GC-MS) and soil samples were determined with gas chromatography coupled with nitrogen-phosphorus detector (GC-NPD). The limit of quantification (LOQ) of the method was 0.01 mg/kg for all matrices. The recoveries ranged from 82.0 to 105.4% for plant samples and 75.6 to 85.6% for soil samples. The final residues of atrazine in all plant samples were lower than LOQ. Dietary risk assessment suggested that under good agricultural practices (GAP) conditions, intake of atrazine from apples, grapes, and tea would exhibit an acceptably low health risk on consumers. However, the final residues of atrazine in soil samples were <0.01-9.2 mg/kg, and the half-lives were 2.0-9.1 days. Based on the species sensitivity distribution (SSD) model, the potential affected fraction (PAF) of atrazine in soil samples ranges from 0.01 to 65.8%. Atrazine residues in 43.1% soil samples were higher than 0.11 mg/kg, which was the hazardous concentration for 5% of species (HC5) of atrazine in soil. These results suggested that the ecological risks of atrazine in apples, grapes, and tea garden soil would exhibit a high risk on environmental species even under the same GAP conditions. This study could provide guidance for comprehensive risk assessment of atrazine properly used in apple, grape, and tea gardens.

Response surface methodology for the enantioseparation of dinotefuran and its chiral metabolite in bee products and environmental samples by supercritical fluid chromatography/tandem mass spectrometry.

Tracing the enantiomers of dinotefuran and its metabolite in bee products and relevant environmental matrices is vital because of the high toxicity of their racemates to bees. In this study, a statistical optimization strategy using three-dimensional response surface methodology for the enantioseparation of dinotefuran and its metabolite UF was developed by a novel supercritical fluid chromatography/tandem mass spectrometry (SFC-MS/MS) technique. After direct evaluation of the chromatographic variables - co-solvent content, mobile phase flow rate, automated backpressure regulator pressure (ABPR), and column temperature - involved in the separation mechanism and assessment of the interactions among these variables, the optimal SFC-MS/MS working conditions were selected as a CO2/2% formic acid-methanol mobile phase, 1.9mL/min flow rate, 2009.8psi ABPR, and 26.0°C column temperature using an amylose tris-(3,5-dimethylphenylcarbamate) chiral stationary phase under electrospray ionization positive mode. Baseline resolution, favorable retention, and high sensitivity of the two pairs of enantiomers were achieved in pollen, honey, water, and soil matrices within 4.5min. Additionally, the parameters affecting the dispersive solid-phase extraction procedure, such as the type and content of extractant or purification sorbents, were systematically screened to obtain better extraction yields of the enantiomers. Mean recoveries were between 78.3% and 100.2% with relative standard deviations lower than 8.0% in all matrices. The limits of quantification ranged from 1.0µg/kg to 12.5µg/kg for the dinotefuran and UF enantiomers. Furthermore, the developed method was effectively applied to authentic samples from a market, an irrigation canal, and a trial field, and the enantioselective dissipation of dinotefuran and UF in soil was demonstrated.