Antiurease Activity of Antibiotics: In Vitro, In Silico, Structure Activity Relationship, and MD Simulations of Cephalosporins and Fluoroquinolones.

Helicobacter pylori infection is widespread in 50% of the world's population and is associated with gastric ulcers and related disorders that ultimately culminate in gastric cancer. Levofloxacin-based, or clarithromycin-based, triple therapy is frequently used to inhibit the bacterial urease enzyme for the eradication of H. pylori. A comprehensive investigation based on the urease inhibitory profiles of antibiotics and their computational implications is lacking in the scientific literature. The present study was aimed specifically to determine the antiurease activities within the realms of cephalosporins and fluoroquinolones by in vitro methods supported with in silico investigations. The results demonstrate the jack bean urease inhibitory activity of cephalosporins, wherein cefadroxil, cefpodoxime, cefotaxime, and cefaclor displayed inhibitions (IC50 21.35 ± 0.64 to 62.86 ± 0.78 µM) compared with the standard thiourea (IC50 21.25 ± 0.15 µM). Among fluoroquinolones, levofloxacin, ofloxacin, and gemifloxacin (IC50 7.24 ± 0.29 to 16.53 ± 0.85 µM) unveiled remarkable inhibitory profiles. Levofloxacin and ofloxacin exhibited competitive inhibition against the said enzyme. Ciprofloxacin and moxifloxacin displayed weak urease inhibitions. During molecular docking studies, Asp362, Gly279, Arg338, Asn168, Asp223, Gln364, and Met366 were involved in hydrogen bonding in fluoroquinolones, and hydrogen bonding was established with Arg338, His248, Asn168 residues, and metal Ni601 and Ni602 of the enzyme. MD simulations and MMPBSA results demonstrated the existence of significant protein-ligand binding. Overall, these results warrant further investigations into the significance of these active molecules in relation to their inhibitory potential against the targeted urease enzyme.

Anti-enzymatic and DNA docking studies of montelukast: A multifaceted molecular scaffold with in vitro investigations, molecular expression analysis and molecular dynamics simulations.

Montelukast, an approved leukotriene receptor 1 (Cys-LT 1) antagonist with anti-inflammatory properties is used for the treatment of asthma and allergic rhinitis. In the present studies, montelukast was subjected to in vitro inhibitory assays followed by kinetic and in silico investigations. Montelukast demonstrated inhibitory activity against yeast α-glucosidase (IC50 44.31 ± 1.21 µM), jack bean urease (JB urease, IC50 8.72 ± 0.23 µM), human placental alkaline phosphatase (hPAP, IC50 17.53 ± 0.19 µM), bovine intestinal alkaline phosphatase (bIAP, IC50 15.18 ± 0.23 µM) and soybean 15-lipoxygenase (15-LOX, IC50 2.41 ± 0.13 µM). Kinetic studies against α-glucosidase and urease enzymes revealed its competitive mode of inhibition. Molecular expression analysis of montelukast in breast cancer cell line MCF-7 down-regulated AP by a factor of 0.27 (5 µM) compared with the 0.26 value for standard inhibitor levamisole (10 µM). Molecular docking estimated a binding affinity ranging -8.82 to -15.65 kcal/mol for the enzymes. Docking against the DNA dodecamer (ID: 1BNA) observed -9.13 kcal/mol via minor groove binding. MD simulations suggested stable binding between montelukast and the target proteins predicting strong inhibitory potential of the ligand. Montelukast features a chloroquinoline, phenyl ring, a cyclopropane group, a carboxylic group and a sulfur atom all of which collectively enhance its inhibitory potential against the said enzymes. These in vitro and computational investigations demonstrate that it is possible and suggested that the interactions of montelukast with more than one targets presented herein may be linked with the side effects presented by this drug and necessitate additional work. The results altogether suggest montelukast as an important structural scaffold possessing multitargeted features and warrant further investigations in repurposing beyond its traditional pharmacological use.

Phytochemical, enzymatic and biological studies of root extracts of Farsetia hamiltonii Royle.

Farsetia hamiltonii Royle is a medicinal plant of Cholistan desert, Pakistan, traditionally used for treating diabetes, oxidative stress, arthritis, fever, gastrointestinal and respiratory diseases. This study represents unprecedented phytochemical, enzymatic and biological properties of F. hamiltonii root extracts to prove floric uses. Evaluation of Phytochemical constituents was done by screening, total flavonoid, phenolic contents and gas chromatography-mass spectrometry. The phytochemical screening revealed the presence of glycosides, bounded anthraquinones, flavonoids, saponins, steroids, coumarins and diterpenes in root extracts. Eight compounds were identified in dichloromethane extract, whereas one compound was identified in methanol extract of root part of F. hamiltonii. The dichloromethane extract possesses significant lipoxygenase, chymotripsin and cholinesterase enzyme inhibition activities, whereas methanol extract possess lipoxygenase, alpha glucosidase, chymotrypsin and acetylcholinesterase enzyme inhibition activities. The antibacterial activity of methanol extract was significant against selected five microbial strains. Nine compounds were reported in root part of F. hamiltonii first time. The enzyme inhibition assays on anti-cholinesterase, anti-alpha glucosidase, antilipoxygenase, antichymotripsin and antibacterial activities were found significant for the extracts of root parts of F. hamiltonii. Therefore, results of this study justify folkloric therapeutic potential of F. hamiltonii root in treating diabetes, inflammations and infectious diseases.

Determination of nitrate in biological fluids by HPLC.

Nitrate is the stable product of nitric oxide, which is physiologically active radical, an immunomodulator and a neuromodulator; its quantification in biological fluids is important to study the physiological and biochemical nature. Therefore, the purpose of this study was to quantify nitrate in different biological fluids like serum, cerebrospinal fluid (CSF) and ascetic fluid (ASF) using HPLC technique. A new HPLC method for the estimation of nitrate in serum, CSF and ASF was developed using the mobile phase of 1.0mM each of Na2CO3 and NaHCO3 (1:1, v/v, pH 5 with H3PO4) at a flow rate of 1.0mLmin-1. Eluate was detected at 220nm with the retention time of nitrate 2.55 min. The LOD and LOQ values of nitrate were 0.03µgmL-1 and 0.098µgmL-1, respectively. Nitrate was eluted through SAX Hypersil column of 150 × 4.6mm, id, 5µm particle size. Run time was 10min. The method was validated according to the FDA guidelines and was found linear in the range of 0.39 to 50µgmL-1 and CV was <3%, within limits of FDA guidelines. The method was used successfully for the estimation of nitrate in biological fluids like serum, CSF and ASF of 20 patients each. This is an alternate and reproducible method for the detection of nitrates in biological fluids.

Spectrophotometric method for the determination of Gemifloxacin mesylate in pure and tablet dosage form.

A spectrophotometric method for the determination of Gemifloxacin mesylate (GFX) is developed and validated according to ICH guidelines. GFX is a fluoroquinolone that is used in the treatment of pneumonia. The analysis of the pure drug was carried out at its λmax 270 nm. The method was linear from 0.5-5µg/mL, r(2) 0.999 and equation is 0.102-0.000. The % RSD for inter-day (0.969%) and intra-day (0.714%) assuring a good precision and accuracy was close to 100%. Limit of detection and Limit of quantification were 0.197 and 0.599µg/mL, respectively. The validation results and statistical data demonstrate that the method is accurate, sensitive, cost effective and reproducible and has an importance in quality assurance of GFX analysis. The developed method was proved suitable for analysis of GFX in the pure and tablet dosage forms without interference of excepients.

Anti-diabetic and spasmolytic potential of Farsetia hamiltonii Royle from Cholistan desert.

ETHNOPHARMACOLOGICAL RELEVANCE: Folk herbal practitioners of the Cholistan desert claim Farsetia hamiltonii Royle (Brassicaceae) to treat diabetes, oxidative damages, diarrhea, fever, and abdominal cramps. The aim of this study was to scientifically find the potential of Farsetia hamiltonii in treating diabetes and gastrointestinal diseases. MATERIALS AND METHODS: In vivo anti-diabetic activity of Farsetia hamiltonii was studied on alloxan induced diabetic rats to justify its traditional use. The in vitro antispasmodic activity on isolated tissues of rabbit jejunum was also evaluated. In addition, several enzyme inhibition studies (lipoxygenase, tyrosinase, acetylcholinesterase (AchE), carbonic II anhydrase and phosphodiesterase I) and antioxidant activity of plant extracts were also conducted. RESULTS: In vivo experiments, Farsetia hamiltonii methanol extract (300 mg/kg) significantly lowered the fasting blood glucose (107.6 ± 1.249 mg/dL up to 4th day) comparable to positive control (Glibenclamide) throughout the study period. The in vitro antispasmodic activity on isolated tissues of rabbit jejunum on methanol extract showed concentration dependent (0.01-0.3 mg/ml) relaxation of spontaneous contractions with EC50 value 0.011 µM and high K(+) (80 mM) induced contraction (0.01-0.1 mg/ml) with EC50 value 0.066 mg/ml. Farsetia hamiltonii DCM and methanol extracts exhibited some antilipoxygenase activities while tyrosinase, acetylcholinesterase (AchE), carbonic II anhydrase, phosphodiesterase I, and antioxidant activity of plant extracts were not significant. CONCLUSIONS: Our results validate the traditional use of Farsetia hamiltonii for the traditional therapeutic potential in treating diabetes and gastrointestinal diseases.