Samar Zuhair Alshawwa

The development of bacterial resistance is an increasing global concern that requires discovering new antibacterial agents and strategies. Bacterial quorum sensing (QS) systems play important roles in controlling bacterial virulence, and their targeting could lead to diminishing bacterial pathogenesis. In this context, targeting QS systems without significant influence on bacterial growth is assumed as a promising strategy to overcome resistance development. This study aimed at evaluating the anti-QS and anti-virulence activities of the β-adrenoreceptor antagonist propranolol at sub-minimal inhibitory concentrations (sub-MIC) against two Gram-negative bacterial models Pseudomonas aeruginosa and Serratia marcescens. The effect of propranolol on the expression of QS-encoding genes was evaluated. Additionally, the affinity of propranolol to QS receptors was virtually attested. The influence of propranolol at sub-MIC on biofilm formation, motility, and production of virulent factors was conducted. The outcomes of the propranolol combination with different antibiotics were assessed. Finally, the in vivo protection assay in mice was performed to assess propranolol’s effect on lessening the bacterial pathogenesis. The current findings emphasized the significant ability of propranolol at sub-MIC to reduce the formation of biofilms, motility, and production of virulence factors. In addition, propranolol at sub-MIC decreased the capacity of tested bacteria to induce pathogenesis in mice. Furthermore, propranolol significantly downregulated the QS-encoding genes and showed significant affinity to QS receptors. Finally, propranolol at sub-MIC synergistically decreased the MICs of different antibiotics against tested bacteria. In conclusion, propranolol might serve as a plausible adjuvant therapy with antibiotics for the treatment of serious bacterial infections after further pharmacological and pharmaceutical studies.

The accumulation of body fat due to an imbalance between calorie intake and energy expenditure is called obesity. Metabolic syndrome increases the risk of heart disease, type 2 diabetes, and stroke. The purpose of this study was to determine the effect of Jatropha tanjorensis (J.T.) and Fraxinus micrantha (F.M.) leaf extracts on high-fat diet-induced obesity in rats. Normal control, high-fat diet (HFD) control, orlistat standard, and test groups were created using male Albino Wistar rats (n = 6 per group) weighing 190 ± 15 g. Except for the control group, all regimens were administered orally and continued for 6 weeks while on HFD. Evaluation criteria included body weight, food intake, blood glucose, lipid profile, oxidative stress, and liver histology. High-Performance Thin Layer Chromatography (HPTLC) analysis was performed using a solvent system (7:3 hexane: ethyl acetate for sitosterol solution and Jatropha tanjorensis extracts and 6:4 hexane: ethyl acetate: 1 drop of acetic acid for esculetin and Fraxinus micrantha extracts). There were no deaths during the 14 days before the acute toxicity test, indicating that aqueous and ethanolic extracts of both J.T. and F.M. did not produce acute toxicity at any dose (5, 50, 300, and 2000 mg/kg). The ethanolic and aqueous extracts of J.T. and F.M. leaves at 200 and 400 mg/kg/orally showed a reduction in weight gain, feed intake, and significant decreases in serum glucose and lipid profile. As compared to inducer HFD animals, co-treatment of aqueous and ethanolic extract of both J.T. and F.M. and orlistat increased the levels of antioxidant enzymes and decreased lipid peroxidation. The liver’s histological findings showed that the sample had some degree of protection. These results indicate that ethanolic samples of J.T. have antidiabetic potential in diabetic rats fed an HFD. The strong antioxidant potential and restoration of serum lipid levels may be related to this. Co-treatment of samples JTE, JTAQ, FME, FMAQ and orlistat resulted in an increase in antioxidant enzymes and reduction in lipid peroxidation as compared to inducer HFD animals. We report, for the first time, on using these leaves to combat obesity.