Oxyberberrubine, a novel liver microsomes-mediated secondary metabolite of berberine, alleviates hyperuricemic nephropathy in mice.

BACKGROUND: Berberrubine (BRB), one of the major metabolites of berberine (BBR), exerts an anti-hyperuricemic effect even superior to BBR. Liver is an important location for drug transformation. Nevertheless, there are few studies on the bioactivities and metabolites of BRB. PURPOSE: We investigated whether oxyberberrubine (OBR), a liver metabolite of BRB, exerted urate-lowering and reno-protective effects in hyperuricemic mice. METHODS: Liver microsomes were used to incubate BRB for studying its biotransformation. We isolated and identified its new metabolite OBR, and investigated its anti-hyperuricemic and reno-protective effects. In this work, the hyperuricemic mice model was established by receiving potassium oxonate (PO) and hypoxanthine (HX) for 7 consecutive days. 1 h after modeling, different dosages of OBR (5, 10 and 20 mg/kg), BRB (20 mg/kg) or febuxostat (Fex, 5 mg/kg) were given mice by gavage. RESULTS: Results showed that OBR possessed potent anti-hyperuricemic and reno-protective effects in hyperuricemic mice. Serum uric acid (UA) level was lowered, and the activities of xanthine oxidase (XOD) as well as adenosine deaminase (ADA) in the liver were suppressed after treatment with OBR. Hepatic expressions of XOD were remarkably decreased at mRNA and protein levels by OBR treatment. In addition, OBR prominently alleviated renal injury, embodied in markedly reduced serum creatinine and blood urea nitrogen (BUN) levels, decreased inflammatory mediators (TNF-α, IL-1ß, IL-6 and IL-18) levels, mRNA expression of CYP27B1 and repairment of renal tissues damage. Besides, OBR down-regulated renal expression of urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), NOD-like receptor 3 (NLRP3), apoptosis-associated speck-like protein containing CARD (ASC), and caspase-1 at mRNA and protein levels. CONCLUSIONS: In short, our study indicated that OBR possessed superior anti-hyperuricemic and reno-protective effects, at least in part, through the inhibition of XOD, URAT1, GLUT9 and NLRP3 inflammasome signaling pathway in the kidney.

Hypouricemic and nephroprotective effects of palmatine from Cortex Phellodendri Amurensis: A uric acid modulator targeting Keap1-Nrf2/NLRP3 axis.

ETHNOPHARMACOLOGICAL RELEVANCE: Palmatine (Pal) is a major bioactive alkaloid originated from ancient Chinese herbal medicine Cortex Phellodendri Amurensis (CPA), which has long been applied to treat hyperuricemia (HUA)-related diseases. Pal possesses potent anti-inflammatory and anti-oxidant effects against metabolic diseases. However, its potential beneficial effect against PO (potassium oxonate)/HX (hypoxanthine)-induced HUA remains elusive. AIM OF THE STUDY: This study aimed to investigate the potential pharmacological effect and mechanism of Pal on PO/HX-induced HUA in mice. MATERIAL AND METHODS: A mouse model of HUA was established by co-administration of PO/HX once daily for 7 consecutive days. The HUA mice were orally given three doses (25, 50 and 100 mg/kg) of Pal daily for a week. Febuxostat (Feb, 5 mg/kg) was given as a positive control. At the scheduled termination of the experiment, the whole blood, liver and kidney were collected for subsequent analyses. The concentrations of uric acid (UA), creatinine (CRE) and blood urea nitrogen (BUN), and activities of adenosine deaminase (ADA) and xanthine oxidase (XOD) were evaluated. Histopathological alterations of the kidney were detected by H&E staining. The inflammatory and oxidative stress status was detected by assay kits. Additionally, key proteins involved in the urate transporter, Keap1-Nrf2 and TXNIP/NLRP3 signaling pathways were evaluated by immunohistochemistry and Western blotting. Finally, molecular docking was employed to probe the binding characteristics of Pal and target proteins Keap1, NLRP3, URAT1 and HO-1. RESULTS: Administration of Pal substantially decreased the elevated kidney weight, lowered UA, CRE and BUN levels, and attenuated abnormal histopathological alterations. Meanwhile, treatment with Pal also dramatically lowered hepatic XOD and ADA activities. Besides, Pal treatment effectively mitigated the renal inflammatory and oxidative stress markers. Further mechanistic investigation indicated Pal distinctly downregulated the protein levels of GLUT9 and URAT1, while up-regulated the expression levels of OAT1 and ABCG2. Pal also restored Nrf2 activation, promoted subsequent expression of anti-oxidative enzymes, and downregulated the expressions of TXNIP, NLRP3, apoptosis-associated speck-like (ASC), caspase-1, IL-1ß and IL-18. Molecular docking analysis also indicated Pal firmly bound with Keap1, NLRP3, URAT1 and HO-1. CONCLUSIONS: These findings indicated that Pal exhibited favorable anti-HUA effect via modulating the expressions of transporter-related proteins and suppressing XOD activity. Furthermore, Pal also alleviated HUA-induced kidney injury, which was at least partially related to restoring Keap1-Nrf2 pathway and inhibiting TXNIP/NLRP3 inflammasome. Our investigation was envisaged to provide experimental support for the traditional application of CPA and CPA-containing classical herbal formulas in the management of HUA-related diseases and might provide novel dimension to the clinical application of Pal.

Anti-Inflammatory Activation of Phellodendri Chinensis Cortex is Mediated by Berberine Erythrocytes Self-Assembly Targeted Delivery System.

Background: Berberine (BBR) is the primary active component of Phellodendri Chinensis Cortex (PCC), which has been traditionally used to treat inflammatory diseases. However, the discrepancy between its low bioavailability and significant therapeutic effect remains obscure. The purpose of this study was to explore the previously unsolved enigma of the low bioavailability of BBR and its appreciable anti-inflammatory effect to reveal the action mechanism of BBR and PCC. Methods: The quantitative analysis of BBR and its metabolite oxyberberine (OBB) in blood and tissues was performed using high-performance liquid chromatography to investigate the conversion and distribution of BBR/OBB mediated by erythrocytes. Routine blood tests and immunohistochemical staining were used to explore the potential relationship between the amounts of monocyte/macrophage and the drug concentration in erythrocytes and tissues (liver, heart, spleen, lung, kidney, intestine, muscle, brain and pancreas). To comparatively explore the anti-inflammatory effects of BBR and OBB, the acetic acid-induced vascular permeability mice model and lipopolysaccharide-induced RAW 264.7 macrophages were employed. Results: Nearly 92% of BBR existed in the erythrocytes in rats. The partition coefficient of BBR between plasma and erythrocytes (Kp/b) decreased with time. OBB was found to be the oxidative metabolite of BBR in erythrocytes. Proportion of BBR/OBB in erythrocytes changed from 9.38% to 16.30% and from 13.50% to 46.24%, respectively. There was a significant relationship between the BBR/OBB concentration in blood and monocyte depletion after a single administration of BBR. BBR/OBB was transported via erythrocytes to various tissues (liver, kidney, spleen, lung, and heart, etc), with the liver achieving the highest concentration. OBB exhibited similar anti-inflammatory effect in vitro and in vivo as BBR with much smaller dosage. Conclusion: BBR was prodominantly found in erythrocytes, which was critically participated in the biodistribution, pharmacokinetics, metabolism and target delivery of BBR and its metabolite. The anti-inflammatory activity of BBR and PCC was intimately associated with the metabolism into the active congener OBB and the targeted delivery to monocytes/macrophages mediated by the erythrocytes.

Oxyberberine, a novel HO-1 agonist, effectively ameliorates oxidative stress and inflammatory response in LPS/D-GalN induced acute liver injury mice via coactivating erythrocyte metabolism and Nrf2 signaling pathway.

Oxyberberine (OBB), a main gut-mediated metabolite of Phellodendron chinense Cortex (PC), exhibits prominent protective property against acute liver injury (ALI). Heme oxygenase-1 (HO-1) is a vital molecule in attenuating acute and chronic liver injury for its prominent anti-oxidative injury and anti-inflammation properties. The present study was performed to investigate the hepatoprotective role of OBB through HO-1 signaling pathway in lipopolysaccharide/D-galactosamine (LPS/D-GalN) induced ALI. Our results indicated that PC treatment improved survival rate and its metabolite OBB evidently improved histopathological deteriorations and liver function. Additionally, OBB dramatically ameliorated hepatic oxidative stress and inflammation. Besides, OBB exerted remarkable HO-1 agonistic activity, even be comparable to hemin (a HO-1 inducer), as evidenced by increased HO-1 level, carbon monoxide and bilirubin activities, which are the markers of erythrocyte metabolism. Moreover, OBB modulated the parameters of inflammation and oxidative stress through HO-1 dependent pathway. Beyond this, OBB also notably suppressed the translocation of p65, enhanced antioxidation defense genes expressions, promoted the degradation of Kelch-like ECH-associated protein 1 (Keap1) and the nuclear translocation of nuclear factor-erythroid-2-related factor 2 (Nrf2). In conclusion, OBB could be the principle active metabolite substance of PC and exert excellent hepatoprotective effects via inducing HO-1 through coactivation of erythrocyte metabolism and Nrf2/HO-1 pathway.

Protective Effects of Oxyberberine in 5-Fluorouracil-Induced Intestinal Mucositis in the Mice Model.

Berberine (BBR), a major active constituent of Rhizoma coptidis, was reported to exert beneficial effects on intestinal mucositis (IM) induced by 5-fluorouracil (5-FU). However, the bioavailability of BBR is extremely low, and its metabolites were perceived to contribute to its prominent pharmacological activities. Oxyberberine (OBB) is a gut metabolite of BBR, which has been reported to have a superior anti-inflammatory effect in experimental colitis. However, its anti-inflammatory effects against 5-FU-induced IM mice have not yet been investigated. Hence, the purpose of this study was to reveal the protective effects of OBB on IM induced by 5-FU and investigate its potential underlying mechanism. The IM mice model was induced by receiving 5-FU (60 mg/kg, i.p.) for five days. Meanwhile, BBR (50 mg/kg) and OBB (12.5, 25, and 50 mg/kg) were given prior to 30 min intraperitoneal injection of 5-FU for seven days. Results indicated that OBB ameliorated body weight loss, anorexia, diarrhea, and histopathological damage in 5-FU-induced IM mice. After OBB administration, the amounts of MDA, SOD, and GSH altered by IM were remarkably restored. OBB was also observed to dramatically decrease the levels of TNF-α, IL-8, IL-6, COX-2, and iNOS and promote the release of IL-10. Besides, OBB distinctly upregulated the mRNA expressions of PCNA, ZO-1, occludin, and mucin-1, which could improve intestinal homeostasis in IM mice. OBB also blocked the activation of the upstream TLR4/MyD88 signaling pathway, and then it inhibited the phosphorylation of the NF-κB and MAPK pathways. Importantly, compared with BBR, OBB displayed a superior therapeutic effect to BBR in alleviating 5-FU-induced IM mice. These results indicated that OBB has considerable potential to become a novel candidate drug against IM.