Search

Background: Irinotecan (CPT-11) is a first-line treatment for advanced colorectal cancer (CRC). Four components (baicalin, baicalein, wogonin, and glycyrrhizic acid) derived from Huangqin Decoction (HQD) have been proven to enhance the anticancer activity of CPT-11 in our previous study. Objective: This study aimed to determine the optimal combination of the four components for sensitizing CPT-11 as well as to explore the underlying mechanism. Methods: The orthogonal design method was applied to obtain candidate combinations (Cmb1-9) of the four components. The influence of different combinations on the anticancer effect of CPT-11 was first evaluated in vitro by cell viability, wound healing ability, cloning formation, apoptosis, and cell cycle arrest. Then, a CRC xenograft mice model was constructed to evaluate the anticancer effect of the optimal combination in vivo. Potential mechanisms of the optimal combination exerting a sensitization effect combined with CPT-11 against CRC were analyzed by targeted metabolomics. Results: In vitro experiments determined that Cmb8 comprised of baicalin, baicalein, wogonin, and glycyrrhizic acid at the concentrations of 17 μM, 47 μM, 46.5 μM and 9.8 μM respectively was the most effective combination. Importantly, the cell viability assay showed that Cmb8 exhibited synergistic anticancer activity in combination with CPT-11. In in vivo experiments, this combination (15 mg/kg of baicalin, 24 mg/kg of baicalein, 24 mg/kg of wogonin, and 15 mg/kg of glycyrrhizic acid) also showed a synergistic anticancer effect. Meanwhile, inflammatory factors and pathological examination of the colon showed that Cmb8 could alleviate the gastrointestinal damage induced by CPT-11. Metabolic profiling of the tumors suggested that the synergistic anticancer effect of Cmb8 might be related to the regulation of fatty acid metabolism. Conclusion: The optimal combination of four components derived from HQD for the synergistic sensitization of CPT-11 against CRC was identified. [ABSTRACT FROM AUTHOR]

A highly sensitive LC–MS/MS method for simultaneous detection of both simvastatin (SV) and simvastatin acid (SVA) in beagle plasma was developed and successfully applied to an absolute bioavailability study. Lovastatin (LV) was used as internal standard (IS). The analysis was performed using electrospray ionization and selective reaction monitoring in positive mode at m/z 441.0 → 325.0 for SV, 459.0 → 343.0 for SVA and 427.0 → 325.0 for the IS, respectively. The assay procedure involved a simple liquid–liquid extraction of SV, SVA and LV from beagle plasma into methyl tert‐butyl ether. Separation of SV, SVA and the IS was achieved on a Shim‐pack VP‐ODS column (150 × 2.0 mm, 5 μm) with a binary gradient solvent system of 0.1% formic acid in water and methanol (15:85, v/v) as the mobile phase. The method was validated over the range of 0.25–500 ng/ml for SV (r2 ≥ 0.9923) and 0.24–481.23 ng/ml for SVA (r2 ≥ 0.9987). The results of method validation for accuracy, precision, extraction recovery, matrix effect and stability were within the acceptance criteria. The values of absolute bioavailability of SV and SVA in beagles were 2.97 and 25.40%, respectively. It is the first study developed for the measurement of absolute bioavailability of SV and SVA acid in beagles. [ABSTRACT FROM AUTHOR]