Investigation on the in vitro metabolism of bicyclol using liver microsomes, hepatocytes and human recombinant cytochrome P450 enzymes.

In vitro metabolism of bicyclol was studied using liver microsomes, hepatocytes and human recombinant cytochrome P450 enzymes. Liquid chromatography-benchtop orbitrap mass spectrometry technique was utilised to identify the metabolites.A total of 19 metabolites, including 5 new metabolites (M2, M3, M4, M5 and M16) were tentatively identified. Among these metabolites, M6&M8 (demethylenation), M9&M10 (demethylation) and M19 (glucuronidation) were the major metabolites.In glutathione (GSH)-supplemented liver microsomes, 5 new GSH conjugates were found and tentatively identified. The formation was assumed to be through demethylenation of methylenedioxyphenyl to form catechol derivatives, which further underwent oxidation to form ortho-quinone intermediates, reacting with GSH to form stable adducts.CYP3A4 and 2C19 were demonstrated to be the major enzymes responsible for the bioactivation of bicyclol.This study provided valuable information on the metabolic fate of bicyclol in liver microsomes and hepatocytes, and the bioactivation pathways were reported for the first time, which would be helpful for us to understand the potential drug-drug interactions and the possible side effect of this drug.

A high-resolution mass spectrometric method for identification and characterization of the in vitro metabolites of senkyunolide H.

RATIONALE: Ligusticum chuanxiong Hort is a well-known herb medicine that has been widely prescribed to treat cardiovascular diseases in China for hundreds of years. Senkyunolide H (SNH) is one of the major bioactive ingredients extracted from L. chuanxiong, and it displayed neuroprotective effects. To fully understand its mechanism of action, the metabolism needs to be investigated. METHODS: In vitro studies were conducted by incubating SNH with rat and human hepatocytes, and the metabolites were identified and characterized using liquid chromatography in combination with hybrid quadrupole Orbitrap mass spectrometry (LC-Orbitrap-MS). The structures of the metabolites were proposed by accurate mass analysis of respective precursor ions, indicative product ions, and elemental compositions. RESULTS: Under the current conditions, a total of 10 metabolites were identified, and among these metabolites, M3 and M4 were the most abundant metabolites both in rat and human hepatocytes. Our results demonstrated that hydroxylation, hydration, glucuronidation, and GSH conjugation were the primary metabolic pathways of SNH. CONCLUSIONS: The present study provides new information on the metabolism of SNH, which would help prospects of the disposition of SNH.

SOX4-induced upregulation of ARHGAP9 promotes the progression of acute myeloid leukemia.

Acute myeloid leukemia (AML) is the most common acute leukemia. Rho GTPase activating protein 9 (ARHGAP9) has been reported to be positively correlated with overall survival of AML patients, but the specific molecular function remains unclear. This study aims to further explore the functional role and the molecular mechanism of ARHGAP9 in AML cells. The expression level of ARHGAP9 in AML cells was measured using quantitative real-time PCR (qRT-PCR) and western blot. Cell transfection was performed to interfere ARHGAP9. CCK-8, flow cytometry and TUNEL assays were conducted to detect cell viability, cell cycle distribution and apoptosis, respectively. The binding relationship between SOX4 and ARHGAP9 promoter was verified using luciferase reporter assay and chromatin immunoprecipitation. The results showed that ARHGAP9 was upregulated in AML cells. Interference of ARHGAP9 greatly reduced cell viability and induced cell cycle arrest in G1 phase, accompanied with the reduction of Ki67, PCNA, cyclin D1, cyclin E1, CDK4 and CDK6. In addition, Interference of ARHGAP9 greatly promoted cell apoptosis, accompanied with the decreased protein expression of Bcl-2 and the increased protein expression of Bax, cleaved caspase 3 and cleaved caspase 9. Furthermore, SOX4 directly bound to ARHGAP9 promoter and regulated ARHGAP9 expression. In conclusion, this study suggested that ARHGAP9 interference exerted an anti-tumor effect through inhibiting cell proliferation, blocking cell cycle progression, and promoting cell apoptosis in AML cells. ARHGAP9 may serve as a novel therapeutic target for AML.