ABSTRACT
Diterpenoid lactones (DLs), a group of furan-containing compounds found in Dioscorea bulbifera L. (DB), have been reported to be associated with hepatotoxicity. Different hepatotoxicities of these DLs have been observed in vitro, but reasonable explanations for the differential hepatotoxicity have not been provided. Herein, the present study aimed to confirm the potential factors that contribute to varied hepatotoxicity of four representative DLs (diosbulbins A, B, C, F). In vitro toxic effects were evaluated in various cell models and the interactions between DLs and CYP3A4 at the atomic level were simulated by molecular docking. Results showed that DLs exhibited varied cytotoxicities, and that CYP3A4 played a modulatory role in this process. Moreover, structural variation may cause different affinities between DLs and CYP3A4, which was positively correlated with the observation of cytotoxicity. In addition, analysis of the glutathione (GSH) conjugates indicated that reactive intermediates were formed by metabolic oxidation that occurred on the furan moiety of DLs, whereas, GSH consumption analysis reflected the consistency between the reactive metabolites and the hepatotoxicity. Collectively, our findings illustrated that the metabolic regulation played a crucial role in generating the varied hepatotoxicity of DLs.
ABSTRACT
Neobavaisoflavone is one of flavonoids of traditional Chinese medicine Psoralea corylifolial. It has numerous biological properties such as antibacterial, anti-inflammatory, anti-cancer, and anti-osteoporosis effects. This paper aimed to investigate the absorption mechanism of neobavaisoflavone in Caco-2 cell monolayer model. The analyte and osalmide were separated on Thermo Syncronis C18 column with methanol-0.1% formic acid solution (90∶10) as the mobile phase, at a flow rate of 0.2 mL•min⁻¹. The concentration of neobavaisoflavone was determined in eletrospray ionization(ESI) positive ion mode with osalmide as an the internal standard. The effects of time, concentration, P-gp inhibitor verapamil, MRP-2 inhibitor MK-571 and BCRP inhibitor Ko143 on the absorption of neobavaisoflavone were investigated. According to the results, neobavaisoflavone showed a good linearity within the concentration of 10-2 000 μg•L⁻¹, and the results of its specificity, matrix effect, extraction recovery, precision, accuracy and stability all met the requirements. In the Caco-2 cell monolayer model, the transport volume of neobavaisoflavone was correlated positively with the time and concentration. The ER values of 15, 30, 50 μmol•L⁻¹ neobavaisoflavone were 1.64, 1.94,0.99, respectively. As compared with the control group, all of verapamil hyduochloride, MK-571 and Ko143 could promote the transportation of neobavaisoflavone, and the effect was more obvious in verapamil hyduochloride and Ko143. The absorption of neobavaisoflavone may be mainly of active transport in Caco-2 cell monolayer model, and also involve passive transport. Excretion mechanism of intestinal transport protein may be also involved.