One approach for solving the problem of antibiotic resistance and bacterial persistence in biofilms is treatment with metals, including silver in the form of silver nanoparticles (AgNPs). Green synthesis is an environmentally friendly method to synthesize nanoparticles with a broad spectrum of unique properties that depend on the plant extracts used. AgNPs with antibacterial and antibiofilm effects were obtained using green synthesis from plant extracts of Lagerstroemia indica (AgNPs_LI), Alstonia scholaris (AgNPs_AS), and Aglaonema multifolium (AgNPs_AM). Nanoparticles were characterized by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) analysis. The ability to quench free radicals and total phenolic content in solution were also evaluated. The antibacterial activity of AgNPs was studied by growth curves as well as using a diffusion test on agar medium plates to determine minimal inhibitory concentrations (MICs). The effect of AgNPs on bacterial biofilms was evaluated by crystal violet (CV) staining. Average minimum inhibitory concentrations of AgNPs_LI, AgNPs_AS, AgNPs_AM were 15 ± 5, 20 + 5, 20 + 5 μg/mL and 20 ± 5, 15 + 5, 15 + 5 μg/mL against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, respectively. The E. coli strain formed biofilms in the presence of AgNPs, a less dense biofilm than the S. aureus strain. The highest inhibitory and destructive effect on biofilms was exhibited by AgNPs prepared using an extract from L. indica.

• Klíčová slova
• A. multifolium, A. scholaris, E. coli, L. indica, S. aureus, antimicrobial activity, nanoparticles, plant extracts, tropical plant,
• Publikační typ
• časopisecké články MeSH

Ginkgo biloba has long been used in traditional Chinese medicine. In this study, ginkgoneolic acid, a kind of compound extracted from G. biloba, was investigated for its effects on growth, acid production, adherence, biofilm formation, and biofilm morphology of Streptococcus mutans. The results showed that ginkgoneolic acid inhibited not only the growth of S. mutans planktonic cells at minimum inhibitory concentration (MIC) of 4 μg/mL and minimum bactericidal concentration (MBC) of 8 μg/mL but also the acid production and adherence to saliva-coated hydroxyapatite of S. mutans at sub-MIC concentration. In addition, this agent was effective in inhibiting the biofilm formation of S. mutans (MBIC(50) = 4 μg/mL), and it reduced 1-day-developed biofilm of S. mutans by 50 % or more at low concentration (MBRC(50) = 32 μg/mL). Furthermore, the present study demonstrated that ginkgoneolic acid disrupted biofilm integrity effectively. These findings suggest that ginkgoneolic acid is a natural anticariogenic agent in that it exhibits antimicrobial activity against S. mutans and suppresses the specific virulence factors associated with its cariogenicity.

• MeSH
• antibakteriální látky izolace a purifikace   farmakologie   MeSH
• bakteriální adheze účinky léků   MeSH
• biofilmy růst a vývoj   MeSH
• Ginkgo biloba chemie   MeSH
• kyseliny karboxylové metabolismus   MeSH
• mikrobiální testy citlivosti MeSH
• mikrobiální viabilita účinky léků   MeSH
• rostlinné extrakty izolace a purifikace   farmakologie   MeSH
• sliny mikrobiologie   MeSH
• Streptococcus mutans účinky léků   růst a vývoj   metabolismus   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH
• kyseliny karboxylové MeSH
• rostlinné extrakty MeSH