Current Issue : October-December Volume : 2023 Issue Number : 4 Articles : 5 Articles
The inappropriate use of antimicrobials, along with environmental conditions, can lead to the emergence of resistant microorganisms. The use of phytopharmaceuticals and herbal medicines has a positive impact and represents a promising alternative. Psidium guajava extracts have been widely reported to have antimicrobial potential; however, studies reporting their activity against resistant bacterial strains are scarce. Because of the emerging resistance, the aim of this study was to analyze the antimicrobial capacity of the aqueous extract of guava leaves against wild-type and resistant bacterial strains. The aqueous extract obtained from the leaves of P. guajava was evaluated by HPLC for the content of total phenolics and tannins, antioxidant activity, and chemical composition. The antimicrobial activity of the extracts was analyzed by the disk diffusion and broth microdilution methods. The results of the chemical analysis of the extracts showed total phenolics content of 17.02 ± 6.87 mg/g of dry extract, total tannin content of 14.09 ± 1.20 mg of tannic acid equivalents/g of dry extract, and moderate antioxidant capacity with an EC50 value of 140 μg/mL. Flavonoids are the major compounds (rutin, hesperidin, and quercetin), followed by phenolic acids. Disk diffusion test results showed the presence of inhibition halos for Gram-positive bacteria (Staphylococcus aureus, sensitive and resistant; Staphylococcus pseudintermedius, sensitive and resistant; and Streptococcus spp., beta-hemolytic), while for Gram-negative bacteria (Escherichia coli, sensitive and resistant), there was no inhibition in the tested concentration range. The Minimal Inhibitory Concentration was 6.8 mg/mL for all Gram-positive strains evaluated. The present study demonstrated the antimicrobial activity of the aqueous extract of P. guajava against sensitive and resistant Gram-positive bacteria. The better antimicrobial activity found in the present study compared with previously reported activity should be highlighted and may be related to the higher concentration of total phenolics present in the tested extract. Moreover, the content of tannins found suggests a species with high quality that produces tannins. These new findings suggest an innovative profile regarding therapeutic resources that can be adopted to combat resistant microbial strains....
Antibiotics are often prescribed to treat infections caused by group B Streptococcus; however, inappropriate use of antibiotics can develop resistance. Because of this, the research was carried out with the aim of evaluating the in vitro effect of the hydroalcoholic extract of Caesalpinia spinosa (Molina) Kuntze known as Taya or Tara on the viability of β-hemolytic streptococci; an experimental investigation of increasing stimulation was carried out. The hydroalcoholic extract of C. spinosa pods was worked in concentrations of 250, 500, 750, and 1000 mg/mL, which were placed on filter paper discs to perform the sensitivity test following the Kirby–Bauer method. The greatest inhibition of bacterial viability was observed in the penicillin control group (GPT-01) followed by the TCT-04 group (hydroalcoholic Tara extract 1000 mg/mL). In addition, it was found that these groups are statistically different from the rest (p < 0.05), while the lowest bacterial inhibition was obtained for the erythromycin group and the TCT-01 group (250–1000 mg/mL). It was concluded that the hydroalcoholic extract of the pods of C. spinosa (Molina) Kuntze affects the viability of β-hemolytic streptococci associated with strep pharyngitis and that this antimicrobial activity is due to the presence of tannins, steroidal flavonoid, and alkaloids. Likewise, the tested concentrations of hydroalcoholic Tara extract were found to have better antibacterial activity than erythromycin (15 μg/mL) against β-hemolytic streptococci. These results are hopeful for the traditional or herbal medicine field. However, future in vivo research is needed to determine its effectiveness in humans....
Finding the ideal antimicrobial drug with improved efficacy and a safety profile that eliminates antibiotic resistance caused by pathogens remains a difficult task. Indeed, there is an urgent need for innovation in the design and development of a microbial inhibitor. Given that many promising antimicrobial peptides with excellent broad-spectrum antibacterial properties are secreted by some frog species (e.g., bombesins, opioids, temporins, etc.), our goal was to identify the antimicrobial properties of amphibian-derived dermorphin and ranatensin peptides, which were combined to produce a hybrid compound. This new chimera (named LENART01) was tested for its antimicrobial activity against E. coli strains K12 and R1–R4, which are characterized by differences in lipopolysaccharide (LPS) core oligosaccharide structure. The results showed that LENART01 had superior activity against the R2 and R4 strains compared with the effects of the clinically available antibiotics ciprofloxacin or bleomycin (MIC values). Importantly, the inhibitory effect was not concentration dependent; however, LENART01 showed a time- and dose-dependent hemolytic effect in hemolytic assays....
During the last two decades, new drug delivery strategies have been invented that have been able to solve microbial resistance against antibiotics. The goal of the current report was to assess the antimicrobial effects of nano-catechin gels against clinically isolated Porphyromonas gingivalis, one of the main causes of periodontal disease. Catechin-loaded chitosan nanoparticles were prepared by adding a catechin solution to a chitosan solution. Then, the mean particle size and the mean surface charge (zeta potential) of the nanoparticles were detected through photon correlation spectroscopy and zeta sizer, respectively. Nano-catechin gels (1000, 500, 250, 125, 62.5, and 31.2 μg/mL) were prepared, and the antimicrobial assay was performed against clinically isolated Porphyromonas gingivalis (P. gingivalis). The clinically obtained P. gingivalis isolates were obtained from periodontitis patients (N = 15). The consequences are specified as descriptive indices. The normality of data was detected by the Shapiro–Wilk test. Then, to compare the data between groups (with a p value < 0.05 as the significance level), SPSS software (version 22) was used via a Mann–Whitney U test. The results showed a nanometer particle size range and a positive zeta potential for the prepared nanoparticles. All the concentrations (1000, 500, 250, 125, 62.5, and 31.2 μg/mL) of nano-catechin gels showed sustained release patterns and were non-toxic against dental pulp stem cells as well. There were no significant differences between the minimal inhibitory concentrations (MICs) for nano-catechin gel (test group) and Chlorhexidine (control group) against 15 isolates (p > 0.05). Then, two groups showed similar antimicrobial effects. The similar antimicrobial activity of catechin nanoparticles and Chlorhexidine, as a potent antimicrobial agents, against clinically isolated P. gingivalis showed that catechin nanoparticles can be used as a potent antimicrobial material for the treatment of periodontal diseases in the near future....
In Saudi Arabia, Cymbopogon schoenanthus (L.) has been traditionally used to treat a variety of diseases. This study aimed to investigate the crude methanolic extract of Cymbopogon schoenanthus (L.) phytochemical, chemical composition, and antibacterial activity. Phytochemical analysis revealed the presence of tannins, poly-tannins, steroids, alkaloids, essential oils, terpenoids, and flavonoids. The presence of functional groups such as -COOH, -OH, -C=O, and CH2 was revealed via FTIR spectroscopy. 13C and 1H NMR (nuclear magnetic resonance) were used to determine the types and number of protons (hydrogen atoms) and their electronic states. Using an agar well diffusion assay, methanolic extract of Cymbopogon schoenanthus (L.) inhibited the growth of some foodborne pathogenic bacteria in zones ranging from 8 to 25 mm in diameter. The minimum inhibitory concentration (MIC) for Staphylococcus aureus was 12.5 mg/mL, whereas it was 25 mg/mL for Bacillus cereus, Klebsiella pneumoniae, and Escherichia coli. The time–kill assay revealed a sharp decline in Staphylococcus aureus and Klebsiella pneumonia after 2 h at a concentration of 150 mg/mL, while Bacillus cereus and Escherichia coli showed a gradual decline with constant concentrations of 75 to 150 mg/mL. The minimum bactericide concentration (MBC) value for Bacillus cereus, Staphylococcus aureus, and Escherichia coli was 50 mg/mL, while it was 25 mg/mL for Klebsiella pneumoniae. In conclusion, our study revealed that Cymbopogon schoenanthus (L.) methanolic extract has a significant antibacterial effect, suggesting that it could be used to treat various foodborne pathogens....
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