Anti-Proteus Activity, Anti-Struvite Crystal, and Phytochemical Analysis of Sida acuta Burm. F. Ethanolic Leaf Extract

Antibacterial properties and urease suppression ability of Lactobacillus inhibit the development of infectious urinary stones caused by Proteus mirabilis

Infectious urolithiasis is a type of urolithiasis, that is caused by infections of the urinary tract by bacteria producing urease such as Proteus mirabilis. Lactobacillus spp. have an antagonistic effect against many pathogens by secreting molecules, including organic acids. The aim of the study was to determine the impact of Lactobacillus strains isolated from human urine on crystallization of urine components caused by P. mirabilis by measuring bacterial viability (CFU/mL), pH, ammonia release, concentration of crystallized salts and by observing crystals by phase contrast microscopy. Moreover, the effect of lactic acid on the activity of urease was examined by the kinetic method and in silico study. In the presence of selected Lactobacillus strains, the crystallization process was inhibited. The results indicate that one of the mechanisms of this action was the antibacterial effect of Lactobacillus, especially in the presence of L. gasseri, where ten times less P. mirabilis bacteria was observed, compared to the control. It was also demonstrated that lactic acid inhibited urease activity by a competitive mechanism and had a higher binding affinity to the enzyme than urea. These results demonstrate that Lactobacillus and lactic acid have a great impact on the urinary stones development, which in the future may help to support the treatment of this health problem.

Characterization, antibacterial, antioxidant, antidiabetic, and anti-inflammatory activities of green synthesized silver nanoparticles using Phragmanthera austroarabica A. G. Mill and J. A. Nyberg extract

Introduction

Diabetes mellitus is a chronic metabolic disorder that exhibited great expansion all over the world. It is becoming an epidemic disease adding a major burden to the health care system, particularly in developing countries.

Methods

The plant under investigation in the current study Phragmanthera austroarabica A. G. Mill and J. A. Nyberg is traditionally used in Saudi Arabia for the treatment of diabetes mellitus. The methanolic extract (200 mg/kg) of the plant and pure gallic acid (40 mg/kg), a major metabolite of the plant, as well as their silver nanoparticle formulae (AgNPs) were evaluated for their antidiabetic activity.

Results and Discussion

The results showed a decrease in body fat, obesity, an improvement in lipid profiles, normalization of hyperglycemia, insulin resistance, and hyperinsulinemia, and an improvement in liver tissue structure and function. However, the results obtained from AgNPs for both extract and the pure gallic acid were better in most measured parameters. Additionally, the activity of both the crude extract of the plant and its AgNPs were evaluated against a number of gram-positive, gram-negative bacteria and fungi. Although the activity of the crude extract ranged from moderate to weak or even non-active, the AgNPs of the plant extract clearly enhanced the antimicrobial activity. AgNPs of the extract demonstrated remarkable activity, especially against the Gram-negative pathogens Proteus vulgaris (MIC 2.5 μg/ml) and Pseudomonas aeruginosa (MIC 5 μg/ml). Furthermore, a promising antimicrobial activity was shown against the Gram-positive pathogen Streptococcus mutants (MIC 1.25 μg/ml).