Antibacterial effects of gold nanoparticles functionalized with the extracted peptide from Vespa orientalis wasp venom.

The development of novel antimicrobial strategies is necessary because of the escalation of multidrug-resistant pathogens. Recently, antimicrobial peptides and their combination with nanoparticles were regarded as a promising tool to target drug-resistant pathogens. Herein, we evaluated antimicrobial efficacy of a peptide extracted from Vespa orientalis wasp venom and also its conjugation with gold nanoparticles. Nanoparticle conjugation measurement was done by evaluating the absorbance changes of the surface plasmon resonance band of gold nanoparticles at 555 nm. A significant increase in the antibacterial activity against gram negative and positive bacteria was obtained when the extracted peptide conjugated with gold nanoparticles. Finally, the results show that this new peptide-AuNps has the high practical potential for antibacterial activity and may provide an alternative therapy for bacterial infection.

Evaluation of 'green' synthesis and biological activity of gold nanoparticles using Tragopogon dubius leaf extract as an antibacterial agent.

Currently, the use of 'green' synthesised nanoparticles with environmentally friendly properties is considered a novel therapeutic approach in medicine. Here, the authors evaluated gold nanoparticles (AuNPs) conjugated with Tragopogon dubius leaf extract and their antibacterial activity in vitro and in vivo. Colour changes from yellow to dark brown and a peak at 560 nm on ultraviolet-visible spectroscopy confirmed the formation of nanoparticles. Additionally, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy analyses were performed to determine particle sizes and functional groups involved in gold reduction. Moreover, using standard micro-dilution and disc-diffusion assays against Klebsiella pneumoniae, Bacillus cereus, Escherichia coli, and Staphylococcus aureus, the antimicrobial properties of synthesised AuNPs were investigated. To confirm antibacterial activity, synthesised AuNPs were applied in a rat model on burn wounds infected with S. aureus, and the nanoparticles were as effective as tetracycline in bacterial reduction and wound healing. In conclusion, the synthesis of AuNPs with aqueous T. dubius extract was rapid, simple, and inexpensive, and the synthesised nanoparticles had significant antibacterial activity in vitro and in vivo.

In vitro ovicidal activity of Peganum harmala seeds extract on the eggs of Fasciola hepatica.

Peganum harmala seeds extract has been previously reported to have antimicrobial and other medicinal properties. The aim of this study was to evaluate the ovicidal activity of the methanolic extract of P. harmala seeds against the eggs of F. hepatica. The phenolic compounds of the methanolic extract of P. harmala seeds were identified by HPLC analysis. Catechin, rutin, p-Coumaric acid, chloregenic acid and hesperetin were found to be the major phenolic compounds. F. hepatica eggs were collected from the gall bladder of naturally infected sheep. The eggs were exposed to two concentrations of P. harmala seeds extract (1 and 3 mg/mL) for 24 and 48 h. To investigate the effect of the P. harmala seeds extract on the miracidial formation, the treated eggs were incubated at 28 °C for 14 days. The results indicated that F. hepatica eggs were susceptible to the methanolic extract of P. harmala seeds. Following 24 h exposure of the eggs to P. harmala seeds extract with concentrations of 1 and 3 mg/mL, the miracidial formation reduced to 5 and 2.2 % respectively (compared with 60 % for the control group). Following 48 h of exposure of the eggs to P. harmala seeds extract with 1 mg/mL concentration, the miracidial formation reduced to 0.5 %. In this exposure time, no miracidial formation was observed in the eggs exposed to P. harmala seeds extract with concentration of 3 mg/mL. Therefore, the results of this study indicated that P. harmala seeds extract has high ovicidal activity against the eggs of F. hepatica. Accordingly, this extract may have the potential flukicidal activity against the immature and mature F. hepatica.

In vitro antibacterial effect of wasp (Vespa orientalis) venom.

BACKGROUND: The emergence of antibacterial resistance against several classes of antibiotics is an inevitable consequence of drug overuse. As antimicrobial resistance spreads throughout the globe, new substances will always be necessary to fight against multidrug-resistant microorganisms. Venoms of many animals have recently gained attention in the search for new antimicrobials to treat infectious diseases. Thefore, the present study aimed to study the antibacterial effects of wasp (Vespa orientalis) crude venom. Two gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two gram-negative ones (Escherichia coli and Klesiella pneumonia) were compared for their sensitivity to the venom by determining the inhibition zone (Kirby-Bauer method) and minimum inhibitory concentration (MIC). A microbroth kinetic system based on continuous monitoring of changes in the optical density of bacterial growth was also used for determination of antimicrobial activity. RESULTS: The venom exhibited a well-recognized antimicrobial property against the tested bacterial strains. The inhibition zones were determined to be 12.6, 22.7, 22.4 and 10.2 mm for S. aureus, B. subtilis, E. coli and K. pneumonia, respectively. The corresponding MIC values were determined to be 64, 8, 64 and 128 µg/mL, respectively. The MIC50 and MIC90 values of the venom were respectively determined to be 63.6 and 107 µg/mL for S. aureus, 4.3 and 7.0 µg/mL for B. subtilis, 45.3 and 65.7 µg/mL for E. coli and 74.4 and 119.2 µg/mL for K. pneumonia. Gram-positive bacteria were generally more sensitive to the venom than gram-negative ones. CONCLUSIONS: Results revealed that the venom markedly inhibits the growth of both gram-positive and gram-negative bacteria and could be considered a potential source for developing new antibacterial drugs.

In vitro antibacterial effect of wasp (Vespa orientalis) venom

The emergence of antibacterial resistance against several classes of antibiotics is an inevitable consequence of drug overuse. As antimicrobial resistance spreads throughout the globe, new substances will always be necessary to fight against multidrug-resistant microorganisms. Venoms of many animals have recently gained attention in the search for new antimicrobials to treat infectious diseases. Thefore, the present study aimed to study the antibacterial effects of wasp (Vespa orientalis) crude venom. Two gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two gram-negative ones (Escherichia coli and Klesiella pneumonia) were compared for their sensitivity to the venom by determining the inhibition zone (Kirby-Bauer method) and minimum inhibitory concentration (MIC). A microbroth kinetic system based on continuous monitoring of changes in the optical density of bacterial growth was also used for determination of antimicrobial activity.

In vitro antibacterial effect of wasp (Vespa orientalis) venom

The emergence of antibacterial resistance against several classes of antibiotics is an inevitable consequence of drug overuse. As antimicrobial resistance spreads throughout the globe, new substances will always be necessary to fight against multidrug-resistant microorganisms. Venoms of many animals have recently gained attention in the search for new antimicrobials to treat infectious diseases. Thefore, the present study aimed to study the antibacterial effects of wasp (Vespa orientalis) crude venom. Two gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two gram-negative ones (Escherichia coli and Klesiella pneumonia) were compared for their sensitivity to the venom by determining the inhibition zone (Kirby-Bauer method) and minimum inhibitory concentration (MIC). A microbroth kinetic system based on continuous monitoring of changes in the optical density of bacterial growth was also used for determination of antimicrobial activity.