Oroxin B improves metabolic-associated fatty liver disease by alleviating gut microbiota dysbiosis in a high-fat diet-induced rat model

Metabolic-associated fatty liver disease (MAFLD) has become a common chronic liver disease, but there is no FDA-approved drug for MAFLD treatment. Numerous studies have revealed that gut microbiota dysbiosis exerts a crucial effect on MAFLD progression. Oroxin B is a constituent of the traditional Chinese medicine Oroxylum indicum (L.) Kurz. (O. indicum), which has the characteristics of low oral bioavailability but high bioactivity. However, the mechanism through which oroxin B improves MAFLD by restoring the gut microbiota balance remains unclear. To this end, we assessed the anti-MAFLD effect of oroxin B in HFD-fed rats and investigated the underlying mechanism. Our results indicated that oroxin B administration reduced the lipid levels in the plasma and liver and lowered the lipopolysaccharide (LPS), interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) levels in the plasma. Moreover, oroxin B alleviated hepatic inflammation and fibrosis. Mechanistically, oroxin B modulated the gut microbiota structure in HFD-fed rats by increasing the levels of Lactobacillus, Staphylococcus, and Eubacterium and decreasing the levels of Tomitella, Bilophila, Acetanaerobacterium, and Faecalibaculum. Furthermore, oroxin B not only suppressed Toll-like receptor 4-inhibitor kappa B-nuclear factor kappa-B-interleukin 6/tumor necrosis factor-α (TLR4-IκB-NF-κB-IL-6/TNF-α) signal transduction but also strengthened the intestinal barrier by elevating the expression of zonula occludens 1 (ZO-1) and zonula occludens 2 (ZO-2). In summary, these results demonstrate that oroxin B could alleviate hepatic inflammation and MAFLD progression by regulating the gut microbiota balance and strengthening the intestinal barrier. Hence, our study suggests that oroxin B is a promising effective compound for MAFLD treatment.

Oroxin B Attenuates Ovariectomy-Induced Bone Loss by Suppressing Osteoclast Formation and Activity

Background

Osteoclasts are the major players in bone resorption and have always been studied in the prevention and treatment of osteoporosis. Previous studies have confirmed that a variety of flavonoids inhibit osteoporosis and improve bone health mainly through inhibiting osteoclastogenesis. Oroxin B (OB) is a flavonoid compound extracted from traditional Chinese herbal medicine Oroxylum indicum (L.) Vent, exerts potent antitumor and anti-inflammation effect, but its effect on osteoclastogensis remains unknown.

Methods

We comprehensively evaluated the effect of OB on the formation and function of osteoclasts and the underling mechanism by bone marrow-derived macrophage in vitro. In vivo, we used mice ovariectomized model to verify the protective effect of OB.

Results

OB was found to inhibit osteoclast formation and bone resorption function in vitro, in a dose-dependent manner and the increased osteoclastic-related genes induced by RANKL (NFATc1, c-fos, cathepsin K, RANK, MMP9 and TRAP) were also attenuated following OB treatment. Mechanistical investigation showed OB abrogated the increased phosphorylation level of MAPK and NF-κB pathway, and diminished the expression of the vital transcription factors for osteoclastogenesis. OB also prevented ovariectomy (OVX)-induced bone loss by inhibiting osteoclast formation and activity in mice.

Conclusion

Our study demonstrated that OB may act as an anti-osteoporosis agent by inhibiting osteoclast maturation and attenuating bone resorption.

A comprehensive study of the metabolism of flavonoid oroxin B in vivo and in vitro by UHPLC-Q-TOF-MS/MS

Oroxin B, a flavonoid, is a major bioactive component form Oroxylum indicum (L.) Vent. with enormous anti-hepatoma effects. To data, the oroxin B metabolism studies remain underexplored. This study was designed to characterize oroxin B metabolism in vivo and in vitro by ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). Consequently, 30 metabolites in rats, 8 metabolites in liver microsomes and 18 metabolites in intestinal bacteria were identified, and 9 metabolites were recognized by comparison with standards. The biotransformation processes involved ketone, acetylation, loss of C₁₂H₂₀O₁₀, and loss of C₆H₁₀O₅. And baicalein and oroxin A were generated after loss of C₁₂H₂₀O₁₀, and loss of C₆H₁₀O₅, respectively, and further went through some other reactions, such as oxidation, methylation, internal hydrolysis, hydrogenation, loss of O, ketone, glycine conjugation, glucuronide conjugation and their composite reactions. The results provide valuable evidence for elucidation the potential mechanism of oroxin B pharmacological action, and offer reasonable guidelines for further investigations of oroxin B safety and efficacy.

Oroxin B Induces Apoptosis by Down-Regulating MicroRNA-221 Resulting in the Inactivation of the PTEN/PI3K/AKT Pathway in Liver Cancer

This study aims to investigate the anticancer effect of Oroxin B (OB) both in vitro and in vivo, and the molecular mechanism involved in microRNA-221 and the PI3K/Akt/PTEN pathway through modulation of apoptosis in Hepatocellular carcinoma (HCC). DEN-induced rats and HepG2 cells based on the microfluidic chip were employed, while the mRNA and protein expression of microRNA-221, PI3K, p-Akt and PTEN were evaluated by RT-PCR and Western blot analysis. Based on Microfluidic Chip and DEN-induced rat model, OB effectively exerts anti-liver cancer effect both in vitro and in vivo, and the expression of miR-221 in OB treated groups was significantly lower than that in the control group (** p < 0.01). The RT-PCR and Western blot results suggested the PI3K mRNA and protein in OB treated groups were both lower than those in control group and indicated the overexpression of PTEN. Therefore, OB effectively exerts anticancer effects by positively regulating the PTEN gene and then inactivating the PI3K/Akt signaling pathway through down-regulating the expression of the microRNA-221, thereby inducing apoptosis of liver cancer cells. This study offers a theoretical evidence for further development and clinical guidance of OB as an anti-tumor agent.

Evidence for the Involvement of COX-2/VEGF and PTEN/Pl3K/AKT Pathway the Mechanism of Oroxin B Treated Liver Cancer

Background

Oroxin B (OB) is one of flavonoids isolated from traditional Chinese herbal medicine Oroxylum indicum (L.) Vent. Recent studies suggest that flavonoids have obvious anti-liver tumors effect, but the precise molecular mechanism is still unclear.

Objective

The current study was performed to investigate the antitumor effects of OB on human hepatoma cell line SMMC-772 and explore the part of molecular mechanisms in this process.

Materials and Methods

MTT method, terminal deoxynucleotidyl transferase dUTP nick end labeling assay and flow cytometry were utilized to detect the inhibition of proliferation and the apoptosis after treating OB in of SMMC-7721 cells. The mRNA and proteins expressions of COX-2, vascular endothelial growth factor (VEGF), phosphatidylinositol-3-kinase (PI3K), p-AKT, and PTEN were measured by a real-time polymerase chain reaction and Western Blot method.

Results

The results showed that OB inhibited proliferation of SMMC-7721 cell in a dose-dependent manner, and induced its apoptosis. Moreover, OB unregulated PTEN and downregulated COX-2, VEGF, p-AKT, and PI3K.

Conclusion

Our results demonstrated that OB significantly inhibits proliferation and induce apoptosis, which may be strongly associated with the inhibiting COX-2/VEGF and PTEN/PI3K/AKT pathway signaling pathway in SMMC-7721 cells, OB potentially be used as a novel therapeutic agent for liver cancer.

SUMMARY

OB (Oroxin B) is one of the effective flavonoid components of traditional Chinese medicine O. indicum (L.)OB can inhibite the proliferation and promoted apoptosis of the human hepatoma cell line SMMC 7721OB plays a role of antitumor effect may to regulate COX 2/VEGF and PTEN/PI3K/AKT pathways directly or indirectly. Abbreviations used: OB: Oroxin B; MTT: 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide; COX-2: cyclooxygenase-2; PI3K: phosphatidylinositol 3 kinase; PTEN: Phosphatase and tensin homolog deleted on chromosome ten; VEGF: Vascular endothelial growth factor; RT-PCR: Reverse transcription polymerase chain reaction; DAPI: Diamidino 2 phenylindole; PBS: Phosphate buffer saline; FITC: Fluorescein isothiocyanate; PI: Propidium Iodide; RIPA: Radio immunoprecipitation assay lysis buffer; PMSF: Phenylmethanesulfonyl fluoride; PAGE: Polyacrylamide gel electrophoresis.