Study On The Variation Of Nicotine Compounds Metabolism In Edible Fungi By Based On Mass Spectrometry Analysis

Nicotine compounds in edible fungi are common endogenous trace substances,but their contents are strictly controlled in export limit standards.The formation mechanism of nicotine compounds in edible fungi,especially the metabolic pathway,has not been clearly defined.In this study,nicotine compounds in different edible fungi and self-cultivated lentinus edodes are detected.In addition,the contour of endogenous metabolites in lentinus edodes is studied to analyze the relationship between nicotine compounds and metabolites,and the formation mechanism of nicotine substances in edible fungi is preliminarily discussed.The U3000-Q Exactive ultra high performance liquid chromatography-mass spectrometry instrument and AB SCIEX QTRAP 5500 LC/MS/MS ultra high performance liquid chromatography(HPLC)-mass spectrometry instrument,through optimizing the experiment conditions and sample preparation method,complete the methodology validation,including specificity,linearity,quantitative restrictions and detection limit,precision,recovery,and the matrix effect into account,conform to the requirements.The quantitative results of this method are accurate and reliable,with high sensitivity and short analysis time.It can be used for the analysis of 8 nicotine compounds in edible fungi.The analysis of nicotine content in different edible fungi shows that in 16 kinds of edible fungi,except for hydrogen-removing nicotine,the other 7 kinds of nicotine compounds are detected to different degrees.Nicotine,titin,nicotinoids and nicotyrine are high content and widely distributed.The components of edible fungi is significantly from one edible fungus to another.Cotinine content is positively correlated with bipyridine and nicotine content.Cotinine content is negatively correlated with neonicotine content.Nicotine content is positively correlated with pyridine or cotinine content.In different growth stages of lentinus edodes,except for nicotine reduction and nicotine removal,the other 6 nicotine compounds are detected to different degrees.The components are significantly different in different growth stages: bipyridine is the highest and cotinine is the second highest in the prophase and prophase of the fruiting body.At the later stage of fruiting body,the values of the three components are close,and the nicotinoids are slightly higher.With the growth period,bipyridine decreases gradually,cotinine increases slightly,and neonicotinoid increases.The cotinine content is positively correlated with pyridine.The content of nicotine is positively correlated with the content of nicotinoids and dienotinoids,and negatively correlated with the content of bipyridine.The content of bipyridine is negatively correlated with that of nicotinoids,dienotinoids and pyridine.The content of nicotinoids is positively correlated with that of diene-nicotinoids.Bipyridine is negatively correlated with most nicotinoids,while nicotine is positively correlated with most nicotinoids.Metabolomics based on UHPLC-QE MS technique is used to analyze the metabolic profile changes of lentinus edotus in different growth stages.The statistical analysis of metabolites shows that compared with the previous metabolites of the fruiting body,19 metabolites are up-regulated and 10 metabolites are down-regulated.The results of pathwayanalysis shows that metabolites are mainly related to some fatty acid metabolic enzymes.There are 10 metabolites that are up-regulated and 1 metabolite that is down-regulated.There are three main metabolic pathways,which are related to lipid metabolism,glucose metabolism and nucleotide.There are 31 different metabolites in the three growth stages.Metabolic pathways are mainly related to some growth metabolites such as amino acids,sugars and fat metabolism.The results of the correlation analysis between the metabolites of lentinus edodes and the metabolites of nicotine compounds shows that cotinine and bipyridines are positively correlated with the metabolites of organic acids,amino acids,fats,nucleic acids and sugars,and negatively correlated with the metabolites of fatty acids and amino acids.The metabolite networks of cotinine,pyridine,neonicotine and bipyridine are similar.Caffeine is positively correlated with cotinine and pyridine,but negatively correlated with bipyridine and nicotinoids,suggesting that the interconversion of these nicotine compounds might be related to caffeine.Through the study,accumulates 8 nicotinoids in 16 edible fungi,finds the relationship between the change rule of nicotinoids in lentinus edodes and different metabolites,preliminary explores the metabolic pathway and metabolic network of nicotinoids in lentinus edodes.