Enantioselectivity Study Of Chiral Triazole Fungicides On Metabolic Disturbance In Fusarium Graminearum And HepG2 Cells

43%of currently registered pesticides are chiral,and the most of them are applied as racemic mixture that composed of two or more enantiomers which differ in their effects,environmental behavior,toxicity and biotransformation.Generally,in the racemic mixture,one may exhibit more bioactivity while the others may not as effective yet can cause unnecessary environment burden.In the method of enantioselective evaluation of chiral pesticides,metabolomic analysis based on nuclear magnetic resonance?NMR?technology stands out with its unique advantages.Fusarium head blight?FHB?is one of the most severe worldwide cereal crop diseases,and among the fungicides,the most promising are triazole fungicides with broad spectrum,high efficiency and low toxicity.Triticonazole?TRZ?and metconazole?MEZ?are two relatively new triazole fungicides which are still sold as racemates with potential environmental problems.At present,the chiral studies of TRZ and MEZ are still in their infancy.Herein,to select high-efficient and low-toxic TRZ and MEZ enantiomers,we have constructed target and non-target organism model,and researched the bioactivities and toxicities of the two fungicides respectively.What's more,1H-NMR-based metabonomic analysis was used on the medium samples from Fusarium graminearum and HepG2 cells to assess the enantioselective disturbance of MEZ and TRZ to target and non-target organisms.Our major works and achievements can be divided into the following parts:?1?The 96-wells micro bioassay was used to reveal the enantioselective bioactivity of TRZ and MEZ enantiomers.Our results indicated that TRZ and MEZ have obvious enantioselective bioactivity,and the R-TRZ and?1R,5R?-MEZ have stronger antifungal activities.Then,metabolomic analysis of Fusarium graminearum showed that MEZ have enantioselectivity in disturbing ethanol metabolism,amino acid metabolism and glucose metabolism.TRZ could interfere with the ethanol metabolism,lipid metabolism and amino acid metabolism with obvious enantioselectivity.In general,?1R,5R?-MEZ and R-TRZ have a stronger ability in disturbing Fusarium graminearum metabolism.?2?Cytotoxicity experiments on non-target cells HepG2 showed that both TRZ and MEZ in 10^-4 M can produce significant toxic effects,but there are no significant differences between the two enantiomers.The results based on 1H-NMR analysis showed that the two enantiomers of MEZ can interfere with 9 metabolites of cells,classified as amino acid metabolism,glucose metabolism,and lipid metabolism.Furthermore,pathway analysis showed that there were 2 metabolic pathways have been disturbed by?1S,5S?-MEZ and 3 pathways by?1R,5R?-MEZ.In general,?1R,5R?-MEZ showed stronger metabolic disturbance ability on amino acid metabolism.11metabolites were perturbed after exposed to TRZ enantiomers,involved in amino acid metabolism,glucose metabolism,and lipid metabolism.The pathway analysis showed that R-TRZ and S-TRZ disturbed 3 same metabolism pathways and two different ones.What's more,R-TRZ could perturb the glucose metabolism more strongly.In conclusion,?1R,5R?-MEZ and R-TRZ are efficient enantiomers with stronger metabolic disturbance ability of Fusarium graminearum.The metabolism of HepG2can be disturbed by both TRZ and MEZ enantiomers.Although the efficient enantiomers could perturb HepG2 cells metabolism more strongly,the metabolic perturbation effect of the inefficient enantiomers should also attract sufficient attention.In view of environmental safety,comprehensive consideration should be given to the use of?1R,5R?-MEZ and R-TRZ in place of the racemates,for the purpose of improving the effect of FHB control,reducing the pesticide load and the adverse effects to non-target organisms.All in all,our research will help us better understand the enantioselectivity of chiral pesticides and provide a reference for the development of green pesticides.