Objective To establish an analytical method for the simultaneous determination of 18 perfluoroalkyl compounds(PFCs)in tea leaves using a quick,easy,cheap,effective,rugged,and safe(QuEChERS)method for sample pretreatment combined with ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).Methods The target analytes—18 PFCs—included 13 carboxylic acid PFCs(perfluorobutanoic acid[PFBA],perfluoropentanoic acid[PFPeA],perfluorohexanoic acid[PFHxA],perfluoroheptanoic acid[PFHpA],perfluorooctanoic acid[PFOA],perfluorononanoic acid[PFNA],perfluorodecanoic acid[PFDA],perfluoroundecanoic acid[PFUdA],perfluorododecanoic acid[PFTrDA],perfluorotridecanoic acid[PFTeDA],perfluorotetradecanoic acid[PFHxDA],perfluorohexadecanoic acid[PFHpS],and perfluorooctadecanoic acid[PFODA])and 5 sulfonic acid PFCs(perfluorobutanesulfonic acid[PFBS],perfluorohexanesulfonic acid[PFHxS],perfluoroheptanesulfonic acid[PFHpS],perfluorooctanesulfonic acid[PFOS],and perfluorodecanesulfonic acid[PFDS]).The QuEChERS pretreatment parameters were systematically optimized using the response surface methodology.The tea leave samples were extracted with an 80%acetonitrile solution and subsequently purified by adding a mixed absorbent consisting of 20 mg N-propyl-ethylenediamine(PSA),210 mg graphitized carbon black GCB),and 60 mg octadecylsilane(C18).The supernatant was concentrated by nitrogen blowing and subsequently re-dissolved in 50%methanol-2 mmol/L ammonium acetate solution.The re-dissolved solution was injected into the UHPLC-MS/MS for analysis.The target analytes were separated on an ACQUITY UPLC BEH C18 column(2.1 mm×50 mm,1.7 μm).The mobile phases consisted of methanol(phase A)and 2 mmol/L aqueous ammonium acetate(phase B),with a gradient elution procedure.The total running time was 18 min.The mass spectrometry analysis was conducted using an electrospray ionization source in negative ionization mode and multi-reaction monitoring(MRM),with quantification performed using the internal standard curve method.The greenness of the analytical method was assessed using Analytical GREEnness calculator(AGREE)and the Analytical Eco-Scale method(AES).Results Under the optimized conditions,the limits of detection(LODs)and limits of quantification(LOQs)of the method were 0.005 7-1.23 ng/g and 0.019-4.09 ng/g,respectively.The average recoveries of most target compounds were 71.1%-117.9%,with relative standard deviations(RSDs)below 15%.The AGREE index of the method was 0.49,and the AES score was 76.At least one PFC was detected in each of the 132 tea leave samples,and the detection rate of carboxylic acid PFC was higher than that of sulfonic acid PFC.The highest detection rates were observed for PFBA at 97.74%,PFHpA at 93.23%,and PFOA at 92.24%.In contrast,PFHpS,PFUdA,PFDoA,PFHxDA,and PFODA were not detected in the samples.Conclusion The proposed method has the advantages of simplicity,rapidity and sensitivity,and is suitable for the analysis of PFCs in tea leaves.The method has high greenness with minimal impact on the operator and the environment.The widespread presence of PFC contamination in tea leaves available in the market warrants strengthened monitoring and regulatory control.

ObjectiveThe differential expression of microRNAs （miRNAs） between the active stage and the remission stage of ulcerative colitis （UC） was analyzed by bioinformatics method， and the regulatory relationship was constructed by screening the differentially expressed genes （DEGs）. The mechanism of Xizhuo Jiedu recipe in the treatment of UC was speculated and verified by animal experiments. MethodThe miRNAs data set of colonic mucosa tissue of UC patients was obtained from the gene expression database （GEO）， and the most differentially expressed miRNAs were screened by GEO2R， Excel， and other tools as research objects. TargetScan， miRTarbase， miRDB， STRING， TRRUST， and Matescape databases were used to screen key DEGs， predict downstream transcription factors （TFs）， gene ontology （GO）， and conduct Kyoto Encyclopedia of Genes and Genomes （KEGG） enrichment analysis. The key signaling pathways were selected for animal experiments. In animal experiments， the UC mouse model was prepared by making the mouse freely drink 2.5% dextran sodium sulfate （DSS）. Xiezhu Jiedu recipe and mesalazine were given by gavage for seven days， and the inflammatory infiltration of colonic mucosa was observed by hematoxylin-eosin （HE） staining. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression of miR-155-5p in colon tissue. Immunohistochemistry and Western blot were used to detect the protein expression levels of cytokine signal transduction inhibitor （SOCS1）， phosphorylated transcriptional signal transductor and activator 3 （p-STAT3）， phosphorylated Janus kinase 2 （p-JAK2）， and retinoic acid-associated orphan receptor-γt （ROR-γt）. The expression levels of transforming growth factor-β （TGF-β）， interleukin-17 （IL-17）， interleukin-6 （IL-6）， and interleukin-10 （IL-10） in serum were detected by enzyme linked immunosorbent assay （ELISA）. ResultThe GSE48957 dataset was screened from the GEO database， and miR-155-5p was selected as the research object from the samples in the active and remission stages. 131 DEGs were screened. The GO/KEGG enrichment analysis was closely related to biological processes such as positive regulation of miRNA transcription and protein phosphorylation， as well as signaling pathways such as stem cell signaling pathway， IL-17 signaling pathway， and helper T cell 17 （Th17） cell differentiation. The Matescape database was used to screen out 10 key DEGs， among which SOCS1 was one of the key DEGs of miR-155-5p. Further screening of the TFS of key DEGs revealed that STAT3 was one of the main TFs of SOCS1. The results of animal experiments showed that Xiezhu Jiedu Recipe could effectively down-regulate the mRNA expression of miR-155-5p and protein expression of p-STAT3， p-JAK2， and ROR-γt in colon tissue of UC mice and the expression of IL-17 and IL-6 in serum of UC mice， up-regulate the protein expression of SOCS1 and the expression of TGF-β and IL-10， increase the level of anti-inflammatory factors， and reduce inflammatory cell infiltration. ConclusionIt is speculated that Xizhuo Jiedu recipe may interfere with SOCS1 by regulating the expression of miR-155-5p in UC mice， inhibit the phosphorylation of STAT3， inhibit the differentiation of CD4⁺ T cells into Th17 cells， reduce the levels of pro-inflammatory factors （IL-17 and IL-6）， and increase the levels of anti-inflammatory factors （TGF-β and IL-10）. As a result， the inflammation of colon mucosa in UC mice was alleviated.