Intestinal microbiota-mediated serum pharmacochemistry reveals hepatoprotective metabolites of Platycodonis Radix against APAP-induced liver injury.

Abstract

The urgent need for new medications that regulate CYP2E1, CASP3, Nrf2, HO-1, TLR2, TLR4, STAT3, and NF-κB activities is paramount for the treatment of drug-induced liver injury (DILI), particularly from acetaminophen (APAP). Previous studies have suggested that platycosides of Platycodonis Radix exhibits hepatoprotective properties against APAP-induced liver injury (AILI), and their serum metabolites may be the effective agents. As the identify the serum metabolites of platycosides is a huge challenge, the mechanism whether platycosides exert effects through the serum metabolites regulating those targets still remain unclear. In this study, we propose a novel method termed intestinal microbiota-mediated serum pharmacochemistry (IMSP) to identify the serum metabolite profile of platycosides, using deglycosylated platycosides as template molecules. Our results identified a total of 44 prototype platycosides in the total platycosides fraction of Platycodonis Radix (PF). In rat serum, we identified 12 prototype platycosides and 45 metabolites derived from the 44 platycosides. Furthermore, our findings indicate that all 44 platycosides can enter the serum in the form of metabolites. The presence of these metabolites in serum is closely related to their oral bioavailability and the content of the prototypes. The in vivo animal experiments showed that the PF possessed significant anti-AILI effects and CYP2E1, CASP3, Nrf2, HO-1, TLR2, TLR4, STAT3, and NF-κB p65 regulation activities. And the in vitro cell experiments and molecular docking analyses further demonstrated that the hepatoprotective effects were mainly ascribed to the serum metabolites, which regulating targets of CYP2E1, CASP3, Nrf2, HO-1, TLR2, TLR4, STAT3, and NF-κB p65. Additionally, the activities of these metabolites are closely associated with their structures. In summary, the IMSP method significantly enhances the ability to identify platycoside metabolites in serum, reveals that all platycosides may contribute to anti-AILI activity through their metabolites, PF and some of these metabolites are promising candidate compounds for developing new medications with anti-AILI effects for the first time.