Pyridine

Carboxymethyl cellulose sodium salt (CMC) was obtained from Yuanye Biological Technology Co., Ltd. (Shanghai, China). ANIT and MT were purchased from Sigma-Aldrich (Merck KGaA; Darmstadt, Germany). ANIT was dissolved in olive oil and administered at a dose of 75 mg/kg body weight [1 ml ANIT solution in olive oil (75 mg/ml) per 100 g body weight] to induce liver injury with cholestasis (35 (link)). MT (100 mg/kg body weight) was resuspended in 1 ml of 0.25% CMC (20 (link)). Colorimetric assay kits were purchased to determine serum alkaline phosphatase (ALP; cat. no. A059-1), aspartate aminotransferase (AST; cat. no. C010-2), alanine aminotransferase (ALT; cat. no. C0009-2) and γ-glutamyl transpeptidase (GGT; cat. no. C017-1) levels. total bilirubin (TBIL; cat. no. C019-1), direct bilirubin (DBIL; cat. no. C019-2) and were detected by chemical oxidation assays. All assay kits were purchased from Nanjing Jiancheng Bioengineering Institute (Nanjing, China). Methanol, acetonitrile, methoxylamine hydrochloride, n-hexane, pyridine and N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS) were purchased from CNW Technologies GmbH (Düsseldorf, Germany). In addition, 2-chloro-l-phenylalanine was obtained from Shanghai Hengchuang Biotech Co., Ltd. (Shanghai, China). All other chemicals were of analytical grade and were purchased from commercial sources.

All utilized chemicals and solvents were of analytical or HPLC grade. Water, acetonitrile, methanol and formic acid were purchased from Thermo Fisher Scientific (Waltham, MA). Pyridine, methoxylamine hydrochloride (97%), n-hexane, and N, O-Bis(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS) were purchased from CNW Technologies GmbH (Düsseldorf, Germany). Chloroform was acquired from Titan Chemical Reagent Co., Ltd. (Shanghai, China), and L-2-chlorophenyl alanine from Shanghai Heng Chuang Bio Technology Co., Ltd. (Shanghai, China).