Development of a mechanism-based biomarker for Dioscorea bulbifera L. exposure and hepatotoxicity in rats

Covalent binding of Geniposide metabolites to hepatic proteins: A potential mechanism for its hepatotoxicity

Gardeniae fructus (GF) is a widely used traditional Chinese medicine; however, its application is limited due to the hepatotoxicity of its main active component, Geniposide (GE). To investigate the material basis and mechanisms of GE-induced hepatotoxicity. We utilized an in vitro gastrointestinal model to examine metabolic processes, conducted in vivo experiments to study GE's hepatotoxic effects and performed cellular experiments to verify toxic effects. Results indicated that GE-induced hepatotoxicity is associated with its metabolite Genipin (GP), with GP's hemiacetal structure being a key factor. Upon exposure of the C-1 hydroxyl group of GP, a covalent binding reaction occurs with amino acids. This reaction readily proceeds as a phase II conjugation with the amino group of lysine (LYS), resulting in the formation of genipin-lysine (GP-LYS) adducts. These adducts affect cellular oxidative stress and trigger cascading reactions leading to hepatotoxicity. Our findings not only highlight chemical structure as a crucial factor influencing toxicity but also advance the understanding of GE's toxic action mechanism. This study provides a foundation for guiding rational clinical use of GE and offers valuable insights for the development of novel GE-based pharmaceuticals.

Biochemical biomarkers for the toxicity induced by Traditional Chinese Medicine: A review update

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM) is widely used in China for disease treatment and has become a valuable resource for drug development due to its high efficacy and low risk of side-effects. However, growing toxicity reports has garnered significant global attention. A major challenge in addressing TCM-induced toxicity is lack of specific and sensitive biomarkers for diagnosing and predicting its toxicity. Identifying toxicological biomarkers reflecting TCM-induced toxicity is crucial for timely detection and intervention, and provides significant clues for elucidating the underlying toxic mechanism and key target.

AIM OF THE STUDY

This article aims to summarize and classify some potential toxicological biomarkers for side-effects induced by TCM and its contained phytochemical ingredients.

METHODS

The keywords "biomarkers", "traditional Chinese medicine", "Chinese herb", "phytochemical ingredient", "natural product", "toxicity", "hepatotoxicity", "nephrotoxicity", "cardiotoxicity" were used to collect relevant information from literature databases (including PubMed, Web of Science) up to October 2024.

RESULTS

Research has indicated that more sensitive and specific biomarkers are needed for reflecting TCM's side-effects. PA-protein adducts and AA-DNA adducts could be served as diagnostic biomarkers for hepatotoxicity and nephrotoxicity induced by TCM containing PA and AA, respectively. Multiple miRNAs like miRNA-122-3p, miRNA-5099, and miRNA-21-3p, as well as some endogenous metabolites such as hypoxanthine, choline, and L-valine could be potential biomarkers associated with TCM-induced hepatotoxicity, nephrotoxicity, and cardiotoxicity.

CONCLUSION

In this review, different research demonstrates that DNA/protein-adducts, noncoding RNAs, endogenous metabolites and so on show the potential to be new early-warning biomarkers for TCM-induced toxicity with high specificity and sensitivity.

Ameliorative Effect of Glycyrrhizic Acid on Diosbulbin B-Induced Liver Injury and Its Mechanism

This study aimed to clarify the protective effect of Glycyrrhizic acid (GL) against Diosbulbin B (DB) - induced liver injury in mice and investigate its mechanisms of action. A liver injury DB was established in mice through the oral administration of DB for 15 days. At the same time, GL was administered to the mice for treatment. After the experiment, the pharmacodynamics and mechanisms of GL in ameliorating DB-induced liver injury were explored using biochemical indexes, non-targeted metabolomics, targeted metabolomics, Western blotting analysis of protein expression, 16S rDNA sequencing, and Spearman correlation analysis. The results show reduced liver function indices and improved DB-induced hepatic pathological changes. It also attenuated DB-induced hepatic inflammation and oxidative stress. Hepatic metabolomics revealed that GL regulated ABC transporters and bile secretion. Targeted bile acid (BA) metabolomics and Western blotting demonstrated that GL improved DB-induced reduction in BA efflux by regulating FXR-mediated efflux transporters. Furthermore, analysis of 16S rDNA gene sequencing revealed that GL effectively restored the relative abundance of beneficial bacteria, reduced the relative abundance of harmful bacteria, and reinstated the structure of the intestinal flora. Additionally, correlation analyses between BA and intestinal flora indicated that Firmicutes, Bacteroidota, TDGA, DGA, UDGA, GDGA, THDGA, and HDGA could serve as major markers for DB-induced liver injury. In conclusion, GL significantly improved DB-induced liver injury by increasing the expression of Nrf2/FXR-BSEP/MRP2/P-gp/UGT1A1, promoting BA efflux, regulating intestinal flora, and alleviating inflammation and oxidative stress.

Mechanism-based cytotoxicity trend prediction of furan-containing pollutants present in a mixture

Human exposure to furan-containing pollutants (FCPs) has raised concerns due to their high risk of toxicity. A substantial number of approximately 8500 recorded compounds containing a furan ring exist which have been analytically or in biologically studied. A significant portion of these compounds is found in the everyday environments of individuals, particularly when ingested through food. Consequently, there is a need for a universal approach to rapidly predict the potential toxicity trends of FCPs. In this study, we developed a bromine labeling-based platform that combines LC-ICP-MS and LC-ESI-MS techniques to absolutely quantify FCP-induced protein adduction. The LC-ESI-MS approach facilitated the identification of FCP-derived protein adducts and optimized liquid chromatographic conditions for analyte separation. By employing a well-designed bromine-containing compound as a general internal standard, LC-ICP-MS-based technique enabled to absolutely assess bromine-labeled protein adduction. The protein adduction efficiencies of furan, 2-methylfuran, and 2,5-dimethylfuran were found to be 2.68, 2.90, and 0.37 molecules per 10,000 FCP molecules that primary hepatocytes received, respectively. Furthermore, we observed that 2-methylfuran exhibited the highest cytotoxicity, followed by furan and 2,5-dimethylfuran, which aligned with the order of their protein adduction. Thus, the protein adduction efficiency of FCPs could serve as a potential index for predicting their toxicity trends.

Investigation of the principle of concoction by using the processing excipient Glycyrrhiza uralensis Fisch. juice to reduce the main toxicity of Dioscorea bulbifera L. and enhance its main efficacy as expectorant and cough suppressant

ETHNOPHARMACOLOGICAL RELEVANCE

Dioscorea bulbifera L. (Rhizoma Dioscoreae Bulbiferae; RDB) is commonly used as an expectorant and cough suppressant herb but is accompanied by severe hepatotoxicity. Using the juice of auxiliary herbs (such as Glycyrrhiza uralensis Fisch. (Glycyrrhizae Radix et Rhizoma; GRR) juice) in concocting poisonous Chinese medicine is a conventional method to reduce toxicity or increase effects. Our previous study found that concoction with GRR juice provided a detoxifying effect against the major toxic hepatotoxicity induced by RDB, but the principle for the detoxification of the concoction is unknown to date.

AIM OF THE STUDY

The principle of concoction was investigated by using the processing excipient GRR juice to reduce the major toxic hepatotoxicity of RDB, and the efficacy of RDB as an expectorant and cough suppressant was enhanced.

MATERIALS AND METHODS

In this study, common factors (RDB:GRR ratio, concocted temperature, and concocted time) in the concoction process were used for the preparation of each RDB concocted with GRR juice by using an orthogonal experimental design. We measured the content of the main toxic compound diosbulbin B (DB) and serum biochemical indicators and performed pathological analysis in liver tissues of mice to determine the best detoxification process of RDB concocted with GRR juice. On this basis, the biological mechanisms of target organs were detected by Western blot and enzyme-linked immunosorbent assay at the inflammation and apoptosis levels. Further, the effects of RDB on expectorant and cough suppressant with GRR juice were evaluated by the conventional tests of phenol red expectorant and concentrated ammonia-induced cough. Lastly, the major compounds in the GRR juice introduced to RDB concoction were determined.

RESULTS

RDB concocted with GRR juice significantly alleviated DB content, serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase levels, and improved liver pathological damages. The best detoxification process was achieved by using an RDB:GRR ratio of 100:20 at 120 °C for 20 min. Further, RDB concocted with GRR juice down-regulated the protein levels of nuclear factor kappa B (NF-κB), cyclooxygenase 2 (COX-2), and Bcl-2 related X protein (Bax) in the liver and enhanced the expectorant and cough suppressant effects of RDB. Finally, liquiritin (LQ) and glycyrrhizic acid (GA) in the GRR juice were introduced to the RDB concoction.

CONCLUSION

Concoction with GRR juice not only effectively reduced the major toxic hepatotoxicity of RDB but also enhanced its main efficacy as an expectorant and cough suppressant, and that the rationale for the detoxification and/or potentiation of RDB was related to the reduction in the content of the main hepatotoxic compound, DB, the introduction of the hepatoprotective active compounds, LQ and GA, in the auxiliary GRR juice, as well as the inhibition of NF-κB/COX-2/Bax signaling-mediated inflammation and apoptosis.

Glycyrrhetinic acid ameliorates diosbulbin B-induced hepatotoxicity in mice by modulating metabolic activation of diosbulbin B

Exposure to diosbulbin B (DBB), the primary component of the herbal medicine Dioscorea bulbifera L. (DB), can cause liver injury in humans and experimental animals. A previous study found DBB-induced hepatotoxicity was initiated by CYP3A4-mediated metabolic activation and subsequent formation of adducts with cellular proteins. The herbal medicine licorice (Glycyrrhiza glabra L.) is frequently combined with DB used in numerous Chinese medicinal formulas in an effort to protect against DB-elicited hepatotoxicity. Importantly, glycyrrhetinic acid (GA), the major bioactive ingredient in licorice, inhibits CYP3A4 activity. The study aimed to investigate the protection of GA against DBB-induced hepatotoxicity and the underlying mechanism. Biochemical and histopathological analysis showed GA alleviated DBB-induced liver injury in a dose-dependent manner. In vitro metabolism assay with mouse liver microsomes (MLMs) indicated that GA decreased the generation of metabolic activation-derived pyrrole-glutathione (GSH) conjugates from DBB. Toxicokinetic studies demonstrated that GA increased maximal serum concentration (Cmax ) and area under the serum-time curve (AUC) of DBB in mice. In addition, GA attenuated hepatic GSH depletion caused by DBB. Further mechanistic studies showed that GA reduced the production of DBB-derived pyrroline-protein adducts in a dose-dependent manner. In conclusion, our findings demonstrated that GA exerted protective effect against DBB-induced hepatotoxicity, mainly correlated with suppressing the metabolic activation of DBB. Therefore, the development of a standardized combination of DBB with GA may protect patients from DBB-induced hepatotoxicity.

Ferulic acid prevents Diosbulbin B-induced liver injury by inhibiting covalent modifications on proteins

Diosbulbin B (DIOB) has been reported to cause serious liver injury. However, in traditional medicine, DIOB-containing herbs are highly safe in combination with ferulic acid (FA)-containing herbs, suggesting potential neutralizing effect of FA on the toxicity of DIOB. DIOB can be metabolized to generate reactive metabolites (RMs), which can covalently bind to proteins and lead to hepatoxicity. In the present study, the quantitative method was firstly established for investigating the correlation between DIOB RM-protein adducts (DRPAs) and hepatotoxicity. Then, we estimated the detoxication effect of FA in combination with DIOB and revealed the underlying mechanism. Our data indicated that the content of DRPAs positively correlate with the severity of hepatotoxicity. Meanwhile, FA is able to reduce the metabolic rate of DIOB in vitro. Moreover, FA suppressed the production of DRPAs and decreased the serum alanine/aspartate aminotransferase (ALT/AST) levels elevated by DIOB in vivo. Thus, FA can ameliorate DIOB-induced liver injury through reducing the production of DRPAs.