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Aims: Protocatechuic acid (PCA) is a phenolic compound found in many antiviral Chinese herbal medicines. HNF4α and HNF1α, the members of hepatocyte nuclear factor (HNF) family, play an important regulatory role in the gene transcription of hepatitis B virus (HBV). Previous studies found that PCA inhibited HBV antigen secretion and HBV DNA replication in HepG2.2.15 cells, but its anti-HBV mechanism has not been fully understood. We aim to illustrate the anti-HBV mechanism of PCA., Materials and Methods: MTT was used to estimate cytotoxicity. The content of HBsAg or HBeAg was detected using an enzyme-linked immunosorbent assay kit. HBV DNA in cell-free culture media was detected by PCR kit. HNF1α and HNF4α mRNA expression was detected by real-time PCR. HNF1α, HNF4α and ERK1/2 protein expression was detected by western blotting and HBV promoter activity was tested by luciferase reporter assay., Key Findings: Our results demonstrated that PCA inhibited the gene transcription and protein translation of HNF1α and HNF4α in Huh7 and HepG2.2.15 cells, as well as the promoter activities of HBV X and preS1 in Huh7 cells transfected with the luciferase reporter plasmid of HBV promoter. Further study suggested that PCA induced the phosphorylation of extracellular-signal-related kinase (ERK) 1/2, and thereby inhibited HNF4α and HNF1α expression in HepG2.2.15 cells to exert its antiviral activity., Significance: To our knowledge, this study is the first to reveal the anti-HBV mechanism of PCA. Our results demonstrate that PCA inhibits HBV replication by activating ERK1/2 pathway and subsequently down-regulating HNF4α and HNF1α in HepG2.2.15 cells., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Amygdalin and its metabolites in rat urine were identified using liquid chromatography-electrospray ionization (ESI) tandem ion-trap mass spectrometry. The purified rat urine sample was separated using a reversed-phase C18 column with 10 mM sodium phosphate buffer (pH 3.1) containing 30% methanol as the mobile phase, amygdalin and its metabolites were detected by on-line mass detector in selected ion monitoring (SIM) mode. The identification of the metabolites and elucidation of their structure were performed by comparing the changes in molecular masses (DeltaM), retention times and MS(2) spectral patterns of metabolites with those of parent drug. At least seven metabolites and the parent drug were found in rat urine after i.v. injection of 100 mg/kg doses of amygdalin. Among them, six metabolites were reported for the first time.

A rapid, sensitive and specific liquid chromatographic-electrospray ionization (ESI) tandem ion trap mass spectrometric method has been developed for identification of dauricine and its metabolites in rat urine. Six healthy rats were administrated a single dose (100 mg/kg) of dauricine by oral gavage. The urine were sampled from 0 to 24 h and purified by using a C18 solid-phase extraction (SPE) cartridge, then the purified urine samples were separated on a reversed-phase C18 column using methanol/2 mmol/L ammonium acetate (70:30, v/v, adjusted to pH 3.5 with formic acid) as mobile phase and detected by an on-line MS detector. Identification and structural elucidation of the metabolites were performed by comparing their changes in molecular mass (Deltam) and full scan MS(n) spectra with those of the parent drug. At least eight metabolites (such as N-demethyl, dehydrogenate, demethoxyl, hydroxyl, glucuronide conjugated and sulfate conjugated metabolites) and the parent drug were found in rat urine.