Clavulanic Acid Improves Memory Dysfunction and Anxiety Behaviors through Upregulating Glutamatergic Transporters in the Nucleus Accumbens of Mice Repeatedly Exposed to Khat Extract.

Khat (Catha edulis) is an evergreen shrub whose buds and leaves give a state of delight and euphoria when chewed. Cathinone, an amphetamine-like stimulant that is among the active ingredients in khat, is able to downregulate glutamate transporter subtype I (GLT-1). Neurobehavioral dysfunctions such as altered locomotor activity, anorexia, and nociception have been observed in animals exposed to cathinone. Interestingly, treatment with a ß-lactam antibiotic such as ceftriaxone, which upregulates GLT-1, normalizes cathinone-induced conditioned place preference, and alters repetitive movements in rats. However, little is known about the role of the glutamatergic system in memory dysfunction and anxiety-like behaviors in mice exposed to khat. We found here that clavulanic acid, a ß-lactam-containing compound and GLT-1 upregulator, would modulate the neurobehavioral changes, including memory impairment and anxiety-like behaviors, associated with repeated exposure of mice to khat. Our data supported that clavulanic acid could improve memory impairment and anxiety-like behaviors through upregulating GLT-1 in the nucleus accumbens (NAc), an effect abolished with a selective GLT-1 blocker. This upregulation was associated with restored glutamate/cystine antiporter expression in the NAc using a Western blotting assay. Cathine and cathinone were identified in khat extract using the gas chromatography technique. Our work provides preclinical insight into the efficacy of ß-lactam-containing compounds for the attenuation of neurobehavioral changes induced by khat exposure.

Potential Effect of Baobab's Polyphenols as Antihyperlipidemic Agents: In Silico Study.

Adansonia digitata L. is an African tree commonly called baobab. This tree is effectively used in traditional medicine to treat cardiovascular disorders. Hyperlipidemia is a well-known cardiovascular risk factor associated with the increased incidence of mortality worldwide. This study aimed to demonstrate the mechanism of baobab polyphenols in the activities of hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and pancreatic lipase as lipid metabolic enzymes. Molecular docking and an incentive for drug design showed that all the polyphenols in baobab bound to the proteins with higher affinity and a lower binding energy compared with simvastatin as the positive control (ΔG: from -5.5 kcal/mol to -6.5 kcal/mol). The same polyphenols exhibited a considerable binding affinity to pancreatic lipase (ΔG: from -7.5 kcal/mol to -9.8 kcal/mol) in comparison with the control and HMG-CoA reductase. Quercetin showed the best docking score from the selected Baobab polyphenols (ΔG = -9.8 kcal/mol). The root mean square deviation (RMSD) results indicated that stable epicatechin and quercetin complexes were demonstrated with HMG-CoA reductase, and other less stable complexes were developed using rutin and chlorogenic acid. Moreover, the analysis of the root mean square fluctuation (RMSF) simulation results was consistent with that of the RMSD. The RMSF value for all the baobab polyphenols, including the crystal control ligand, was kept between 0.80 and 8.00 Å, similarly to simvastatin, and less than 4.8 Å for pancreatic lipase. Chlorogenic acid, quercetin, epicatechin, and rutin had negative ΔG binding scores from highest to lowest. The same ligands displayed more negative ΔG binding scores than those observed in HMG-CoA reductase and crystal control ligand (methoxyundecyl phosphinic acid) in their simulation with pancreatic lipase. In conclusion, baobab polyphenols interact with HMG-CoA reductase and pancreatic lipase to inhibit their substrate binding and block their activity.

Molecular Dynamic Analysis of Carbapenem-Resistant Klebsiella pneumonia's Porin Proteins with Beta Lactam Antibiotics and Zinc Oxide Nanoparticles.

To prevent the rapidly increasing prevalence of bacterial resistance, it is crucial to discover new antibacterial agents. The emergence of Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae has been associated with a higher mortality rate in gulf union countries and worldwide. Compared to physical and chemical approaches, green zinc oxide nanoparticle (ZnO-NP) synthesis is thought to be significantly safer and more ecofriendly. The present study used molecular dynamics (MD) to examine how ZnO-NPs interact with porin protein (GLO21), a target of ß-lactam antibiotics, and then tested this interaction in vitro by determining the zone of inhibition (IZ), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC), as well as the alteration of KPC's cell surface. The nanoparticles produced were characterized by UV-Vis spectroscopy, zetasizer, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). In silico investigation was conducted using a variety of computational techniques, including Autodock Vina for protein and ligand docking and Desmond for MD simulation. The candidate ligands that interact with the GLO21 protein were biosynthesized ZnO-NPs, meropenem, imipenem, and cefepime. Analysis of MD revealed that the ZnO-NPs had the highest log P value (-9.1 kcal/mol), which indicates higher permeability through the bacterial surface, followed by cefepime (-7.9 kcal/mol), meropenem (-7.5 kcal/mol), and imipenem (-6.4 kcal/mol). All tested compounds and ZnO-NPs possess similar binding sites of porin proteins. An MD simulation study showed a stable system for ZnO-NPs and cefepime, as confirmed by RMSD and RMSF values during 100 ns trajectories. The test compounds were further inspected for their intersection with porin in terms of hydrophobic, hydrogen, and ionic levels. In addition, the stability of these bonds were measured by observing the protein-ligand contact within 100 ns trajectories. ZnO-NPs showed promising results for fighting KPC, represented in MIC (0.2 mg/mL), MBC (0.5 mg/mL), and ZI (24 mm diameter). To draw the conclusion that ZnO-NP is a potent antibacterial agent and in order to identify potent antibacterial drugs that do not harm human cells, further in vivo studies are required.

Age-associated global DNA hypermethylation augments the sensitivity of hearts towards ischemia-reperfusion injury.

Most pre-clinical studies in cardiac ischemia-reperfusion injury (I/R) are carried out in young or old animals, which does not cater to the adult age in humans who encounter I/R. Not many studies in the literature are available that emphasize the sensitivity of the adult heart to injury from the young heart, where there exist distinct alterations in DNA methylation and mitochondrial function that contribute to injury. In the present study, we utilized young (8 weeks old) and adult (24 weeks old) rat hearts to evaluate distinct DNA methylation alterations that contribute to I/R injury. The cardiac basal physiological activities in young and adult rat hearts were insignificantly changed from normal. But the DNA hypermethylation and expression level of mitochondrial genes were slightly higher in adult rat hearts. The consequential effect of these changes was measured in the I/R heart to understand its response to additional stress. Accordingly, we noted an increase in global DNA hypermethylation levels by 40% and 62% in young and adult I/R hearts, respectively, from their respective control. Subsequently, a decline in mitochondrial genes (ND1, ND4L, ND6, Cyt B, COX1, COX2, and ATP8) that regulate cardiac contractility was observed in adult I/R hearts. These changes, in turn, reduced hemodynamics (Rate pressure product) by 51% and 32% in adult and young I/R hearts, respectively, from their controls. Besides, the I/R-linked infarct size was higher in adult hearts (58%) than in young hearts (37%). Correlation analysis showed a significant negative correlation of global DNA methylation with the MT-ND1 expression (r = -0.7591), MFN2 expression (r = -0.8561) and cardiac RPP (r = -0.8015) in adult I/R hearts. Based on the above observations, we concluded that age promoted DNA methylation and deteriorated cardiac responsive ability to resist I/R injury.