Radix Paeoniae Alba attenuates Radix Bupleuri-induced hepatotoxicity by modulating gut microbiota to alleviate the inhibition of saikosaponins on glutathione synthetase.

Radix Bupleuri (RB) is commonly used to treat depression, but it can also lead to hepatotoxicity after long-term use. In many anti-depression prescriptions, RB is often used in combination with Radix Paeoniae Alba (RPA) as an herb pair. However, whether RPA can alleviate RB-induced hepatotoxicity remain unclear. In this work, the results confirmed that RB had a dose-dependent antidepressant effect, but the optimal antidepressant dose caused hepatotoxicity. Notably, RPA effectively reversed RB-induced hepatotoxicity. Afterward, the mechanism of RB-induced hepatotoxicity was confirmed. The results showed that saikosaponin A and saikosaponin D could inhibit GSH synthase (GSS) activity in the liver, and further cause liver injury through oxidative stress and nuclear factor kappa B (NF-κB)/NOD-like receptor thermal protein domain associated protein 3 (NLRP3) pathway. Furthermore, the mechanisms by which RPA attenuates RB-induced hepatotoxicity were investigated. The results demonstrated that RPA increased the abundance of intestinal bacteria with glycosidase activity, thereby promoting the conversion of saikosaponins to saikogenins in vivo. Different from saikosaponin A and saikosaponin D, which are directly combined with GSS as an inhibitor, their deglycosylation conversion products saikogenin F and saikogenin G exhibited no GSS binding activity. Based on this, RPA can alleviate the inhibitory effect of saikosaponins on GSS activity to reshape the liver redox balance and further reverse the RB-induced liver inflammatory response by the NF-κB/NLRP3 pathway. In conclusion, the present study suggests that promoting the conversion of saikosaponins by modulating gut microbiota to attenuate the inhibition of GSS is the potential mechanism by which RPA prevents RB-induced hepatotoxicity.

An integrated strategy to study the combination mechanisms of Bupleurum chinense DC and Paeonia lactiflora Pall for treating depression based on correlation analysis between serum chemical components profiles and endogenous metabolites profiles.

ETHNOPHARMACOLOGICAL RELEVANCE: Bupleurum chinense DC-Paeonia lactiflora Pall (BCD-PLP) is a common clinical herb pair in traditional Chinese medicine (TCM) prescriptions commonly used to treat depression. However, its combination mechanisms with its anti-depressive effects remain highly unclear. AIM OF THE STUDY: Here, an effective strategy has been developed to study the combination mechanisms of Bupleurum chinense DC (BCD) and Paeonia lactiflora Pall (PLP) by integrating serum pharmacochemistry analysis, metabolomics technology, and molecular docking technology. MATERIALS AND METHODS: First, the depression model rats were replicated by the chronic unpredictable mild stress (CUMS) procedure, and the difference in the chemical composition in vivo before and after the combination of BCD and PLP was analyzed by integrating background subtraction and multivariate statistical analysis techniques. Then, UPLC/HRMS-based serum metabolomics was performed to analyze the synergistic effect on metabolite regulation before and after the combination of BCD and PLP. Further, the correlation analysis between the differential exogenous chemical components and the differential endogenous metabolites before and after the combination was employed to dissect the combination mechanisms from a global perspective of combining metabolomics and serum pharmacochemistry. Finally, the molecular docking between the differential chemical components and the key metabolic enzymes was applied to verify the regulatory effect of the differential exogenous chemical components on the differential endogenous metabolites. RESULTS: The serum pharmacochemistry analysis results demonstrated that the combination of BCD and PLP could significantly affect the content of 10 components in BCD (including 5 prototype components were significantly decreased and 5 metabolites were significantly increased) and 8 components in PLP (including 4 prototype components and 3 metabolites were significantly increased, 1 metabolite was significantly decreased), which indicated that the combination could enhance BCD prototype components' metabolism and the absorption of the PLP prototype components. Besides, metabolomics results indicated that the BCD-PLP herb pair group significantly reversed more metabolites (8) than BCD and PLP single herb group (5 & 4) and has a stronger regulatory effect on metabolite disorders caused by CUMS. Furthermore, the correlation analysis results suggested that saikogenin F and saikogenin G were significantly positively correlated with the endogenous metabolite itaconate, an endogenous anti-inflammatory metabolite; and benzoic acid was significantly positively correlated with D-serine, an endogenous metabolite with an antidepressant effect. Finally, the molecular docking results further confirmed that the combination of BCD and PLP could affect the activities of cis-aconitic acid decarboxylase and D-amino acid oxidase by increasing the in vivo concentration of saikogenin F and benzoic acid, which further enhances its anti-inflammatory activity and anti-depressive effect. CONCLUSIONS: In this study, an effective strategy has been developed to study the combination mechanisms of BCD and PLP by integrating serum pharmacochemistry analysis, multivariate statistical analysis, metabolomics technology, and molecular docking technology. Based on this strategy, the present study indicated that the combination of BCD and PLP could affect the activities of cis-aconitic acid decarboxylase and D-amino acid oxidase by increasing the concentration of saikogenin F and benzoic acid in vivo, which further enhances its anti-depressive effect. In short, this strategy will provide a reliable method for elucidating the herb-herb compatibility mechanism of TCM.

Studies on the Changes of Pharmacokinetics Behaviors of Phytochemicals and the Influence on Endogenous Metabolites After the Combination of Radix Bupleuri and Radix Paeoniae Alba Based on Multi-Component Pharmacokinetics and Metabolomics.

Radix Bupleuri-Radix Paeoniae Alba (RB-RPA) is a classic herb pair, which is commonly used to treat depression by soothing "liver qi stagnation" in the clinic. However, little is yet known concerning the combination mechanism of Radix Bupleuri (RB) and Radix Paeoniae Alba (RPA), their bioactive forms in vivo and the regulatory effects on the organism. The present study aimed to elucidate the changes in multi-component pharmacokinetics (PK) behavior after the combination of RB and RPA by a high-resolution full-scan mode of UPLC-HRMS method (a total of 38 components PK profiles were obtained, of which 23 components come from RB and 15 components come from RPA). Moreover, the metabolomics approach was used to analyze the dynamic response of endogenous metabolites intervened by RB-RPA, and the correlation between concentration-time curves of 38 components from RB-RPA and the dynamic response profiles of endogenous metabolites was characterized by Pearson correlation analysis. The results demonstrated that the combination of RB and RPA could significantly improve the bioavailability of five components in RB, and six components in RPA. Besides, metabolomics results indicated that a total of 21 endogenous metabolites exhibited time-dependent changes in response to the RB-RPA administration, of which 12 endogenous metabolites were significantly increased, and nine endogenous metabolites were significantly decreased. Furthermore, correlation analysis results indicated that the components with significantly improved bioavailability after combination such as saikogenin F, saikogenin G, albiflorin, methyl gallate, paeonimetabolin II were significantly positively correlated with picolinic acid, a metabolite with neuroprotective effect; saikogenin F, saikogenin G were significantly positively correlated with itaconic acid, a endogenous metabolite with anti-inflammatory activity; and albiflorin, paeonimetabolin II were significantly positively correlated with α-linolenic acid, a metabolite with strong protective actions on brain functions. These results indicated that the combination of RB and RPA can enhance each other's neuroprotective and anti-inflammatory activities. In this study, A novel and efficient strategy has been developed to analyze the influence of the combination of RB and RPA in vivo behaviors by combining multi-component pharmacokinetics with metabolomics, which was contributed to clarifying the scientific connotation of herb-herb compatibility.

Studies on the potential link between antidepressant effect of Xiaoyao San and its pharmacological activity of hepatoprotection based on multi-platform metabolomics.

ETHNOPHARMACOLOGICAL RELEVANCE: In traditional Chinese medicine (TCM) theory, depression is considered to be "liver qi stagnation", and relieving "liver qi stagnation" is regarded as an effective method for treating depression. Xiaoyao San (XYS) is a well-known TCM formula for the treatment of depression by relieving "liver qi stagnation". This formula consists of Radix Paeoniae Alba (Paeonia lactiflora Pall.), Radix Bupleuri (Bupleurum chinense DC.), Poria (Poria cocos (Schw.) Wolf), Rhizoma Atractylodis Macrocephalae (Atractylodes macrocephala Koidz.), Radix Angelicae Sinensis (Angelica sinensis (Oliv.) Diels), Radix Glycyrrhizae (Glycyrrhiza uralensis Fisch.), Rhizoma Zingiberis Recens (Zingiber officinale Roscoe) and Herba Menthae Haplocalycis (Mentha haplocalyx Briq.). AIM OF THE STUDY: Several studies have suggested that depression is associated with liver injury. XYS was a well-known TCM formula for the treatment of depression and liver stagnancy. However, it was still unknown whether the antidepressant effect of XYS is related to the pharmacological activity of hepatoprotection. The aim of this study was to elucidate the potential link between the antidepressant and hepatoprotective effect of XYS. MATERIALS AND METHODS: A depression rat model was established by the CUMS (chronic unpredictable mild stress) procedure. The antidepressant effect of XYS was assessed by the behavioral indicators, and the hepatoprotective effect of XYS was evaluated through biochemical assays. 1H-NMR and LC/MS-based liver metabolomics were performed to discover key metabolic pathways involved in the antidepressant and hepatoprotective effects of XYS. Further, the key pathway was validated using commercial kits. RESULTS: The results demonstrated that XYS pretreatment could significantly improve the depressive symptom induced by CUMS. More importantly, the results demonstrated that liver injury was observed in the CUMS model rats, and XYS had a hepatoprotective effect by reducing the activities of AST and ALT in serum, increasing the levels of SOD and GSH-Px and reducing the contents of MDA, IL-6, and IL-1ß in the liver. In addition, the NMR and LC/MS-based metabolomics results indicated that XYS improved 23 of the 35 perturbed potential liver biomarkers that were induced by CUMS. Among them, 9 biomarkers were significantly correlated with both depression and liver pathology, according to Pearson correlation analysis. Metabolic pathway analyses of these 9 biomarkers showed that glutamine and glutamate metabolism were the most important metabolic pathways. Furthermore, to verify glutamine and glutamate metabolism, the levels of glutamine and glutamate, and the activity of glutamine synthetase (GS) and glutaminase (GLS) were quantitatively determined in the liver by commercial kits, and these results were consistent with the metabolomics results. CONCLUSIONS: XYS could significantly improve the depressive and liver injury symptoms induced by CUMS. The metabolomics results indicate that the regulation of glutamine and glutamate metabolism to maintain the balance of ammonia and promote energy metabolism is a potential junction between the antidepressant and hepatoprotective effects of XYS.