Pharmacokinetic properties of trifolirhizin, (-)-maackiain, (-)-sophoranone and 2-(2,4-dihydroxyphenyl)-5,6-methylenedioxybenzofuran after intravenous and oral administration of Sophora tonkinensis extract in rats

Systematic analysis of chemical profiles of Sophorae tonkinensis Radix et Rhizoma in vitro and in vivo by UPLC-Q-TOF-MSE

Sophorae tonkinensis Radix et Rhizoma (S. tonkinensis) has been recorded as a "poisonous" Chinese herbal medicine in Chinese Pharmacopoeia 2020. The clinical reaction reports of S. tonkinensis indicated its neurotoxicity, there exists still dispute about its toxic substances. At present, there is no report on the blood and brain prototype research of S. tonkinensis. Most studies focused on alkaloids, and less on other compounds. Moreover, the constituents absorbed into the blood and brain were rarely investigated so far. In this study, a rapid and efficient qualitative analysis method was established by UPLC-Q-TOF-MS^E to characterize S. tonkinensis ingredients and those entering into the rat body after oral administration. A total of 91 compounds were identified in S. tonkinensis, of which 28 were confirmed by the standards. 30 and 19 prototypes were also firstly identified in rat blood and brain, respectively. It was found that except for alkaloids, most flavonoids were detected in the rat body and distributed in the cerebrospinal fluid, suggesting that flavonoids may be one of the important toxic or effective substances of S. tonkinensis, which provides new clues and data for clarifying its toxicity or efficacy of the medical plant.

Integrated metabolomics and network pharmacology strategy for ascertaining the quality marker of flavonoids for Sophora flavescens

Traditional Chinese medicines (TCMs) have been widely used in Asian countries for thousands of years due to their supreme quality and good clinical efficacy. However, the increasing demand for TCMs in recent decades warrants effective quality control methodology to avoid clinical problems. Therefore, comprehensive quality evaluation systems should be established for ensuring TCM's quality, in terms of chemical components, as well as bioactivity for identifying quality markers in TCM and developing suitable analytical methods for quality control. In this study, we selected Sophora flavescens (S. flavescens) as the research object and developed a novel integrated strategy combining metabolomics and network pharmacology to explore the quality markers. Firstly, we determined the targeted metabolomic profiles of seventy-four batches of S. flavescens (aged from 1 to 6 years) by UHPLC/QE-MS. Six potential markers were successfully screened, quantified and reverse-verified as the most influential effective compounds by UHPLC/QE-MS and multivariate statistical analysis. Secondly, the network of "components-targets-pathways" was constructed, and the pharmacological activities of six potential markers were predicted. Finally, we determined the anti-tumor activity of six flavonoids (kurarinone, norkurarinone, kuraridin, kushenol N, trifolirhizin, and genistein) as the quality markers for Sophora flavescens, evaluated their pharmacokinetic profiles and reviewed their existing pharmacological researches. Thus, integrated metabolomics and network pharmacology technology were applied for the effective discovery of quality markers of Chinese material medica.

Lack of Correlation between In Vitro and In Vivo Studies on the Inhibitory Effects of (‒)-Sophoranone on CYP2C9 is Attributable to Low Oral Absorption and Extensive Plasma Protein Binding of (‒)-Sophoranone

(‒)-Sophoranone (SPN) is a bioactive component of Sophora tonkinensis with various pharmacological activities. This study aims to evaluate its in vitro and in vivo inhibitory potential against the nine major CYP enzymes. Of the nine tested CYPs, it exerted the strongest inhibitory effect on CYP2C9-mediated tolbutamide 4-hydroxylation with the lowest IC₅₀ (K_i) value of 0.966 ± 0.149 μM (0.503 ± 0.0383 μM), in a competitive manner. Additionally, it strongly inhibited other CYP2C9-catalyzed diclofenac 4′-hydroxylation and losartan oxidation activities. Upon 30 min pre-incubation of human liver microsomes with SPN in the presence of NADPH, no obvious shift in IC₅₀ was observed, suggesting that SPN is not a time-dependent inactivator of the nine CYPs. However, oral co-administration of SPN had no significant effect on the pharmacokinetics of diclofenac and 4′-hydroxydiclofenac in rats. Overall, SPN is a potent inhibitor of CYP2C9 in vitro but not in vivo. The very low permeability of SPN in Caco-2 cells (P_app value of 0.115 × 10⁻⁶ cm/s), which suggests poor absorption in vivo, and its high degree of plasma protein binding (>99.9%) may lead to the lack of in vitro–in vivo correlation. These findings will be helpful for the safe and effective clinical use of SPN.