Effects Of Gut Microbiota On Bioaccessibility And Metabolic Transformation Of Triadimefon In Strawberry And Grape

Pesticide residues in fruits and vegetables have become more and more concerned about the quality and safety of agricultural products.Bioaccessibility is an important factor to accurately evaluate pesticide residue exposure risk.Gut microbiota has a strong ability to metabolize and transform natural products and environmental pollutants.After pesticide residues in fruits and vegetables are ingested into human gastrointestinal environment through dietary intake,what happens to metabolism and transformation under the action of gut microbiota?Which in turn affects its bioaccessibility?Little has been reported so far.In this study,triadimefon commonly used in strawberry and grape was used as the object to study the effect of gut microbiota on the bioaccessibility of triadimefon by using the in vitro gastrointestinal simulation method of SHIME,and to identify the main intestinal bacteria and their metabolites that affect the bioaccessibility of triadimefon.The results provided theoretical basis for scientific evaluation of dietary exposure risk of triadimefon in strawberry and grape species.The main research results are as follows:1.Confirmation of the method for residue analysis of triadimefon in simulated intestinal fluid of strawberry and grapeThe results of the addition and recovery of triadimefon in the simulated intestinal fluid of strawberry and grape showed that the average recoveries of triadimefon in the simulated intestinal fluid of strawberry were 96.61-106.16%with relative standard deviations(RSD)of 5.63-8.52%at the added concentrations of 0.1,1 and 5 mg/kg.The average recoveries of triadimefon in the simulated intestinal fluid ranged from 84.60%-96.70%with relative standard deviations(RSDs)of 0.56-6.97%.The correlation coefficient(r~2)was 0.9999 in the range of 0.1-10 mg/kg and the minimum limit of quantification(LOQ)was 0.02 mg/kg.It is suitable for the determination of triadimefon residues in simulated intestinal fluid of strawberry and grape.2.Effects of gut microbiota on the bioaccessibility of triadimefon pesticide residues in strawberry and grapeThe results showed that the gut microbiota had a time effect on the bioaccessibility of triadimefon in strawberry and grape.After 12 h digestion,the gut microbiota could reduce the bioaccessibility of triadimefon in strawberry by 58.5%.The results indicated that the influence of gut microbiota on the bioaccessibility was related to food substrate.3.Isolation and identification of main intestinal bacteria that affect the bioaccessibility of triadimefonA main strain of intestinal flora was isolated and purified by enrichment culture method,and was identified as Stenotrophomonas maltophilia(SM-3),which had significant effect on the bioaccessibility of triazolone(39.62-46.49%).The results showed that SM-3 had the most significant effect on triadimefon bioaccessibility(43.12%)when the p H value was 7.0,and the triadimefon bioaccessibility was negatively correlated with the bile salt concentration,and the bioaccessibility reached the lowest value(25%)when the bile salt concentration was0.03%.4.Identification of the metabolites of triadimefon in gut microbiota of strawberry and grapeUPLC-QTOF-MS was used to identify the metabolites of triadimefon under the action of gut microbiota.The results showed that the main metabolites of triadimefon under the action of gut microbiota were alcohol derivatives such as triadimenol,1-(4-chlorophenoxy)-3,3-dimethyl-2-butanol and p-phenol,and the metabolic pathway might be that gut microbiota caused the redox reaction,hydroxylation reaction and dehalogenation reaction of triadimefon to form the final product of p-phenol.However,the addition reaction of triadimefon to triadimefon only occurred under the action of the main intestinal bacteria SM-3.