UGTs-mediated metabolic interactions contribute to enhanced anti-inflammation activity of Jinhongtang

Abstract

Ethnopharmacological relevanceJinhongtang, a traditional Chinese medicine (TCM) formula consisting of dry stems of Rheum palmatum L. (Polygonaceae) and Sargentodoxa cuneata (Oliv.) Rehder & E.H.Wilson (Lardizabalaceae) and whole plant of Taraxacum mongolicum Hand.-Mazz. (Asteraceae), is widely used for the treatment of infection diseases including severe sepsis and COVID-19. Aim of the studyThe present study aimed to explore the compatibility mechanism in the prescription of Jinhongtang based on the pharmacokinetic interaction. Materials and methodsCLP-induced sepsis mice and LPS-induced RAW264.7 cells were used to explore the anti-inflammatory effect of Jinhongtang and herbs in this clinical prescription. Pharmacokinetics of active components in Jinhongtang (Rhein, Emodin and Aloe emodin) was studied in rats. In vitro analysis of metabolic pathways and interactions mediated by metabolic enzymes were conducted using human liver microsomes (HLMs) and recombinant UGT isoforms. ResultsJinhongtang exhibited much more potent anti-inflammatory effect than its single herbs on CLP-induced sepsis mice and LPS-induced RAW264.7 cells. Next, the bioavailability of active ingredients (Rhein, Emodin and Aloe emodin) in R. palmatum was significantly improved through reduced metabolic clearance when co-administered with S. cuneata and T. mongolicum as Jinhongtang during the in vivo pharmacokinetic study, which presented the rational herbal compatibility mechanism. In detailed, the components in S. cuneata and T. mongolicum including Sargentodoxoside A, Chanitracin Ia, Quercetin and Luteolin inhibited the UGT1A9-mediated glucuronidation of active ingredients in R. palmatum, with Ki values of 2.72 μM, 1.25 μM, 2.84 μM and 0.83 μM, respectively. ConclusionT. mongolicum and S. cuneata, the adjuvant herbs of Jinhongtang, could reduce the metabolic clearance of key active components of R. palmatum, prolong their action time and further enhance their anti-inflammatory activity via inhibition of UGTs. Our findings provided deep insight for the rational compatibility of TCMs and useful guidance for the development of TCM formula.