Qualitative Analysis of Drug-Containing Plasma and its Application to Quantitative Analysis and Pharmacokinetic Study of Zexie Decoction Using UPLC-MS/MS

Fuling-Zexie formula attenuates hyperuricemia-induced nephropathy and inhibits JAK2/STAT3 signaling and NLRP3 inflammasome activation in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Fuling-Zexie (FZ) formula, a traditional Chinese herbal prescription composed of Poria cocos (Schwan.) Wolf. (Poria), Pueraria lobate (Willd.) Howe. (Puerariae Lobatae Radix), Alisma orientale (Sam.) Julep. (Alismatis Rhizoma), and Atractylodes lancea (Thunb.) Dc. (Atractylodis Rhizoma), has been clinically used to ameliorate hyperuricemia (HUA) and its associated renal injury.

AIM OF STUDY

This study aims to explore the action and mechanism of FZ on renal inflammation and dysfunction caused by HUA.

MATERIALS AND METHODS

FZ was orally administered to rapid HUA mouse induced by potassium oxonate (PO) and hypoxanthine (HX) for 7 days. Serum levels of uric acid (UA), creatinine (CRE), blood urea nitrogen (BUN), xanthine oxidase (XOD), adenosine deaminase (ADA), alanine aminotransferase (ALT), aspartate aminotransferase (AST), urine levels of UA, CRE and urinary albumin were determined by biochemical assays. Serum levels of interleukin (IL)-1β and IL-6 were tested by ELISA. Hematoxylin-eosin and Masson staining were used to examine kidney and liver histopathological alterations. The expressions of renal glucose transporter 9 (GLUT9), ATP-binding cassette subfamily G member 2 (ABCG2), organic anion transporter 1 (OAT1), phospho-janus kinase 2 (p-JAK2), p-signal transducer and activator of transcription 3 (p-STAT3), suppression of cytokine signaling 3 (SOCS3), NLR family pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein (ASC), and cleaved-cysteinyl aspartate specific proteinase-1 (cleaved-Cas-1) were detected by western blots. The potential protein targets and pathways of FZ intervention on HUA were predicted by network pharmacology. The constituents in FZ aqueous extract were analyzed by UPLC-MS.

RESULTS

FZ reduced serum UA, CRE, BUN, and urinary albumin and increased urine UA, CRE levels in HUA mice. In addition, the treatment with FZ to HUA mice inhibited the elevated serum levels of XOD and ADA, and regulated renal urate transports including OAT1, GLUT9 and ABCG2. FZ also attenuated kidney inflammation and fibrosis and downregulated the expressions of IL-1β, p-JAK2, p-STAT3, SOCS3, IL-6, NLRP3, ASC, and cleaved-Cas-1. Thirteen compounds were identified in the FG, including L-phenylalanine, D-tryptophan, 3'-hydroxypuerarin, Puerarin, 3'-Methoxy Puerarin, Daidzin, Pueroside A, formononetin-8-C- [xylosyl (1→6)]-glucoside, Ononin, Alisol I 23-acetate, 16-oxo-alisol A, Alisol C and Alisol A.

CONCLUSION

FZ inhibits serum UA generation and promotes urine UA excretion as well as attenuates kidney inflammation and fibrosis in HUA mouse with nephropathy. The underlying mechanism of its action may be associated with suppression of the JAK2/STAT3 signaling pathway and NLRP3 inflammasome activation. This formula may offer a novel source for developing anti-HUA drugs.

The roles of serine hydrolases and serum albumin in alisol B 23-acetate hydrolysis in humans

Introduction: Alisol B 23-acetate (AB23A), a major bioactive constituent in the Chinese herb Zexie (Rhizoma Alismatis), has been found with multiple pharmacological activities. AB23A can be readily hydrolyzed to alisol B in mammals, but the hydrolytic pathways of AB23A in humans and the key enzymes responsible for AB23A hydrolysis are still unrevealed. This study aims to reveal the metabolic organs and the crucial enzymes responsible for AB23A hydrolysis in human biological systems, as well as to decipher the impact of AB23A hydrolysis on its biological effects. Methods: The hydrolytic pathways of AB23A in human plasma and tissue preparations were carefully investigated by using Q-Exactive quadrupole-Orbitrap mass spectrometer and LC-UV, while the key enzymes responsible for AB23A hydrolysis were studied via performing a set of assays including reaction phenotyping assays, chemical inhibition assays, and enzyme kinetics analyses. Finally, the agonist effects of both AB23A and its hydrolytic metabolite(s) on FXR were tested at the cellular level. Results: AB23A could be readily hydrolyzed to form alisol B in human plasma, intestinal and hepatic preparations, while human butyrylcholinesterase (hBchE) and human carboxylesterases played key roles in AB23A hydrolysis in human plasma and tissue preparations, respectively. It was also found that human serum albumin (hSA) could catalyze AB23A hydrolysis, while multiple lysine residues of hSA were covalently modified by AB23A, suggesting that hSA catalyzed AB23A hydrolysis via its pseudo-esterase activity. Biological tests revealed that both AB23A and alisol B exhibited similar FXR agonist effects, indicating AB23A hydrolysis did not affect its FXR agonist effect. Discussion: This study deciphers the hydrolytic pathways of AB23A in human biological systems, which is very helpful for deep understanding of the metabolic rates of AB23A in humans, and useful for developing novel prodrugs of alisol B with desirable pharmacokinetic behaviors.