Inhibitory Effects of Several Fluoroquinolones on Feline CYP1A and 3A in Hepatic Microsomes

In this study, the effects of several fluoroquinolones (FQs), such as Ciprofloxacin (CPFX);Orbifloxacin (OBFX);Norfloxacin (NFX);Ofloxacin (OFX);and Enerofloxacin (EFX) on activities of both Cytochrome P450 1A (CYP1A) and Cytochrome P450 3A (CYP3A) of feline microsomes by in vitro tests were studied. Ethoxyresorufin O-deethylation (EROD) and Midazolam 1' hydroxylation and 4-hydroxylation (MDZ1'H and MDZ4H) were analyzed by High Performance Liquid Chromatography (HPLC). All the FQs inhibited the reactions by a competitive or noncompetitive and irreversible manner. The inhibitory constants (Ki) were as followings: CYP1A;ranged from 0.12 to 1.23 mM for NFX, OBFX, EFX, CPFX, OFX and CYP3A, for MDZ1'H;ranged from 5.8 to 35 and MDZ4H;9 to 29 mM, respectively. As these values are higher by 24 to 200-times of given single clinical dose of serum levels after application of FQs. It indicates that if co-administrated with these FQs by reversible inhibitory manner, the inhibition of CYP1A and CYP3A effect on CYP1A and 3A actions is not very significant to cause drug interaction with above mentioned enzyme substrates. Out of the FQs tested, CPFX and NFX for CYP1A, and CPFX for CYP3A showed irreversible inhibitory effects (time-dependent), so it has been concluded that these drugs may cause drug-drug interaction by accumulation, when they are repeatedly administrated. Since EFX is biotransformed to CPFX by the liver, it could have the identical risk too.

The cytochrome P4501A1(CYP1A1)inhibitor bergamottin enhances host tolerance to multidrug-resistant Vibrio vulnificus infection

Purpose:Vibrio vulnificus (V. Vulnificus) infection is characterized by rapid onset, aggressive progression, and challenging treatment. Bacterial resistance poses a significant challenge for clinical anti-infection treatment and is thus the subject of research. Enhancing host infection tolerance represents a novel infection prevention strategy to improve patient survival. Our team initially identified cytochrome P4501A1 (CYP1A1) as an important target owing to its negative modulation of the body''s infection tolerance. This study explored the superior effects of the CYP1A1 inhibitor bergamottin compared to antibiotic combination therapy on the survival of mice infected with multidrug-resistantV. Vulnificus and the protection of their vital organs.Methods:An increasing concentration gradient method was used to induce multidrug-resistantV. Vulnificus development. We established a lethal infection model in C57BL/6J male mice and evaluated the effect of bergamottin on mouse survival. A mild infection model was established in C57BL/6J male mice, and the serum levels of creatinine, urea nitrogen, aspartate aminotransferase, and alanine aminotransferase were determined using enzyme-linked immunosorbent assay to evaluate the effect of bergamottin on liver and kidney function. The morphological changes induced in the presence of bergamottin in mouse organs were evaluated by hematoxylin and eosin staining of liver and kidney tissues. The bacterial growth curve and organ load determination were used to evaluate whether bergamottin has a direct antibacterial effect on multidrug-resistantV. Vulnificus. Quantification of inflammatory factors in serum by enzyme-linked immunosorbent assay and the expression levels of inflammatory factors in liver and kidney tissues by real-time quantitative polymerase chain reaction were performed to evaluate the effect of bergamottin on inflammatory factor levels. Western blot analysis of IκBα, phosphorylated IκBα, p65, and phosphorylated p65 protein expression in liver and kidney tissues and in human hepatocellular carcinomas-2 and human kidney-2 cell lines was used to evaluate the effect of bergamottin on the nuclear factor kappa-B signaling pathway. One-way ANOVA and Kaplan-Meier analysis were used for statistical analysis.Results:In mice infected with multidrug-resistantV. Vulnificus, bergamottin prolonged survival (p = 0.014), reduced the serum creatinine (p = 0.002), urea nitrogen (p = 0.030), aspartate aminotransferase (p = 0.029), and alanine aminotransferase (p = 0.003) levels, and protected the cellular morphology of liver and kidney tissues. Bergamottin inhibited interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α expression in serum (IL-1β:p = 0.010, IL-6:p = 0.029, TNF-α:p = 0.025) and inhibited the protein expression of the inflammatory factors IL-1β, IL-6, TNF-α in liver (IL-1β:p = 0.010, IL-6:p = 0.011, TNF-α:p = 0.037) and kidney (IL-1β:p = 0.016, IL-6:p = 0.011, TNF-α:p = 0.008) tissues. Bergamottin did not affect the proliferation of multidrug-resistantV. Vulnificus or the bacterial load in the mouse peritoneal lavage fluid (p = 0.225), liver (p = 0.186), or kidney (p = 0.637).Conclusion:Bergamottin enhances the tolerance of mice to multidrug-resistantV. Vulnificus infection. This study can serve as a reference and guide the development of novel clinical treatment strategies forV. Vulnificus.

Exploring the potential of functional polymer-lipid hybrid nanoparticles for enhanced oral delivery of paclitaxel

Most biopharmaceutics classification system(BCS)class IV drugs,with poor solubility and inferior permeability,are also substrates of P-glycoprotein(P-gp)and cytochrome P450(CYP450),leading to their low oral bioavailability.The objective of this study is to explore the potential of using functional polymer-lipid hybrid nanoparticles(PLHNs)to enhance the oral absorption of BCS IV drugs.In this paper,taking paclitaxel(PTX)as a drug model,PTX-loaded PLHNs were prepared by a self-assembly method.Chitosan was selected to modify the PLHN to enhance its mucoadhesion and stability.Three P-gp inhibitors(D-α-tocopherol polyethylene glycol 1000 succinate,pluronic P123 and Solutol RHS15)were incorporated into selected PLHNs,and a CYP450 inhibitor(the extract of VBRB,BC0)was utilized to jointly promote the drug absorption.Properties of all the PLHNs were characterized systemically,including particle size,zeta potential,encapsulation efficiency,morphology,stability,in vitro drug release,mucoadhesion,in situ intestinal permeability and in vivo systemic exposure.It was found mucoadhesion of the CS-modified PLHNs was the strongest among all the formulations tested,with absolute bioavailability 21.95%.P-gp and CYP450 inhibitors incorporation further improved the oral bioavailability of PTX to 42.60%,8-fold increase compared with that of PTX itself(4.75%).Taken together,our study might shed light on constructing multifunctional PLHNs based on drug delivery barriers for better oral absorption,especially for BCS IV drugs.

Discovery of Benzimidazole Derivatives as Novel Aldosterone Synthase Inhibitors:QSAR,Docking Studies,and Molecular Dynamics Simulation

Aldosterone synthase inhibitors can lessen the production of aldosterone in organisms,which effec-tively affecting the treatment of hypertension.A series of computational approaches like QSAR,docking,DFT and molecular dynamics simulation are applied on 40 benzimidazole derivatives of aldosterone synthase(CYP11B2)in-hibitors.Statistical parameters:Q^(2)=0.877,R^(2)=0.983(CoMFA)and Q^(2)=0.848,R^(2)=0.994(CoMSIA)indicate on good predictive power of both models and DFT’s result illustrates the stability of both models.Besides,Y-randomization test is also performed to ensure the robustness of the obtained 3D-QSAR models.Docking studies show inhibitors rely onπ-πinteraction with residues,such as Phe130,Ala313 and Phe481.Molecular dynamics simulation results further confirm that the hydrophobic interaction with proteins enhances the inhibitor’s inhibitory effect.Based on QSAR studies and molecular docking,we designed novel compounds with enhanced activity against aldosterone synthase.Furthermore,the newly designed compounds are analyzed for their ADMET proper-ties and drug likeness and the results show that they all have excellent bioavailability.