[Research progress of liver injury induced by Polygoni Mulitiflori Radix]

A comprehensive investigation on the chemical changes of traditional Chinese medicine with classic processing technology: Polygonum multiflorum under nine cycles of steaming and sunning as a case study

The processing of traditional Chinese medicine (TCM) plays an important role in the clinical application, which usually has the function of "increasing efficiency and reducing toxicity". Polygonum multiflorum (PM) has been reported to induce hepatotoxicity, while it is believed that the toxicity is reduced after processing. Studies have shown that the hepatotoxicity of PM is closely related to the changes in chemical components before and after processing. However, there is no comprehensive investigation on the chemical changes of PM during the processing progress. In this research, we established a comprehensive method to profile both small molecule compounds and polysaccharides from raw and different processed PM samples. In detail, an online two-dimensional liquid chromatography coupled with quadrupole-orbitrap mass spectrometry (2D-LC/Q-Orbitrap MS) was utilized to investigate the small molecules, and a total of 150 compounds were characterized successfully. After multivariate statistical analysis, 49 differential compounds between raw and processed products were screened out. Furthermore, an accurate and comprehensive method for quantification of differential compounds in PM samples was established based on ultra-high performance liquid chromatography/Q-Orbitrap-MS (UHPLC/Q-Orbitrap-MS) within 16 min. In addition, the changes of polysaccharides in different PM samples were analyzed, and it was found that the addition of black beans and steaming times would affect the content and composition of polysaccharides in PM significantly. Our work provided a reference basis for revealing the scientific connotation of the processing technology and increasing the quality control and safety of PM.

Polygoni Multiflori Radix interferes with bile acid metabolism homeostasis by inhibiting Fxr transcription, leading to cholestasis

Objective: To explore the possible mechanisms of cholestasis induced by Polygoni Multiflori Radix (PM). Methods: Low and high doses of water extract of PM were given to mice by gavage for 8 weeks. The serum biochemical indexes of aspartate aminotransferase (AST), alanine aminotransferase (ALT), glutamyltransferase (GGT) alkaline phosphatase (ALP) and so on were detected in the second, fourth, sixth, and eighth weeks after administration. At the end of the eighth week of administration, the bile acid metabolic profiles of liver and bile were screened by high-performance liquid chromatography tandem triple quadrupole mass spectrometry (HPLC-QQQ-MS/MS). Liver pathological changes were observed by hematoxylin and eosin staining. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the mRNA transcription of the target genes and Western blotting (WB) was used to the detect target protein expression. Results: Biochemical tests results showed the values of ALP and GGT were two and three times greater than the normal values respectively, and the value of R was less than 2. Histopathology also showed that PM caused lymphocyte infiltration, a small amount of hepatocyte necrosis and nuclear fragmentation in mouse liver. The proliferation of bile duct epithelial cells was observed in the high group. These results indicated that PM may lead to cholestatic liver injury. HPLC-QQQ-MS/MS analysis with the multivariate statistical analysis revealed significant alterations of individual bile acids in liver and gallbladder as compared to those of the control group. RT-qPCR showed that the transcription of Fxr, Shp, Bsep, Bacs, Mdr2, and Ugt1a1 were downregulated and that of Cyp7a1, Mrp3, and Cyp3a11 was significantly upregulated in the treatment group. WB demonstrated that PM also markedly downregulated the protein expression of FXR, BSEP, and MDR2, and upregulated CYP7A1. Conclusion: PM inhibited the expression of FXR, which reduced the expression of MDR2 and BSEP, leading to the obstruction of bile acids outflow, and increased the expression of CYP7A1, resulting in an increase of intrahepatic bile acid synthesis, which can lead to cholestasis.

Comparative Studies on Multi-Component Pharmacokinetics of Polygonum multiflorum Thunb Extract After Oral Administration in Different Rat Models

The clinical use of Polygonum multiflorum Thunb (PM) has been restricted or banned in many countries, due to its hepatotoxic adverse effects. Its toxicity research has become a hot topic. So far, the pharmacokinetic studies of PM, focusing on prototype compounds such as 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG), emodin, and physcion, have been considered the main basis of pharmacodynamic material or of toxic effect. However, pharmacokinetic studies of its phase II metabolites have not yet been reported, mainly because the quantifications of such metabolites are difficult to do without the reference substance. In addition, pharmacokinetic studies on different pathological models treated with PM have also not been reported. On the other hand, toxic effects of PM have been reported in patients diagnosed with different liver pathologies. In the present work, a simultaneous quantitation method for eight prototypes components of PM and their five phase II metabolites has been performed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and used for the pharmacokinetic study of PM in two different liver pathological models in rats (normal, alpha-naphthylisothiocyanate (ANIT), and carbon tetrachloride (CCl₄)). The results showed that the main blood-entering components of PM are TSG, emodin, physcion, emodin-8-O-β⁃D⁃glucoside (E-Glu), physcion-8-O-β⁃D⁃glucoside (P-Glu), aloe-emodin, gallic acid, resveratrol and catechin, among which TSG, emodin, and catechin were primary metabolized in phase II, while resveratrol was converted to all phase II metabolites, and the others were metabolized as drug prototypes. Meanwhile, their pharmacokinetic parameters in the different models also exhibited significant differences. For instance, the AUC (0-∞) values of the TSG prototype and its phase II metabolites were higher in the ANIT group, followed by CCl₄ group and the normal group, while the AUC (0-∞) values of the emodin prototype and its phase II metabolites were higher in the CCl₄ group. To further illustrate the reasons for the pharmacokinetic differences, bilirubin metabolizing enzymes and transporters in the liver were measured, and the correlations with the AUC of the main compounds were analyzed. TSG and aloe-emodin have significant negative correlations with UGT1A1, BSEP, OATP1A4, OCT1, NTCP, MRP2 and MDR1 (p < 0.01). These data suggest that when the expression of metabolic enzymes and transporters in the liver is inhibited, the exposure levels of some components of PM might be promoted in vivo.