1. Biosynthesis of Silver Nanoparticles Using Lavandula stoechas and an Enhancement of Its Antibacterial Activity with Antibiotics
- Author
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Zheng-Fei Yan, Pei Lin, and Chang-Tian Li
- Subjects
biology ,medicine.drug_class ,Chemistry ,Antibiotics ,Biomedical Engineering ,Bioengineering ,biology.organism_classification ,Antimicrobial ,medicine.disease_cause ,Applied Microbiology and Biotechnology ,Silver nanoparticle ,Penicillin ,Staphylococcus aureus ,medicine ,Food science ,Candida albicans ,Antibacterial activity ,Lavandula stoechas ,Biotechnology ,medicine.drug - Abstract
Silver nanoparticles (AgNPs) were successfully synthesized by different extracts of Lavandula stoechas, which have an antibacterial effect on pathogenic strains, such as Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus. Among them, AgNPs-E4 that synthesized by EtOAc extract (E4) have greater antibacterial activity than that by other extracts. The highest inhibition zone diameter (18.6 mm) appeared in C. albicans, at a dosage of 1,000 ppm AgNPs-E4. It was identified as optimal antibacterial AgNPs, which are spherical in shape with an average size at 35.5 nm and maximum absorbance peak at 525 nm. The combined use of penicillin G and AgNPs-E4 exhibited a significant synergistic inhibition effect on the growth of C. albicans, which could produce a maximum inhibition zone of about 21.0 mm. Synergism between antibiotics and AgNPs-E4 was greater than the sum of their individual effects on pathogenic strains. Also, vancomycin, tetracycline, and AgNPs-E4 have slight or no inhibition effect on Escherichia coli. But combined use of the above antibiotics and AgNPs-E4 could exhibit antibacterial activity against E. coli, and the inhibition zone achieved 14.5 and 12.6 mm, respectively, suggesting combined use was able to realize antibacterial effect from nonexistence to pass into existence. HPLC analysis revealed polyphenols were the main compositions of EtOAc extract (E4), such as oleanolic fruit-12-en-3-ol, 19-hydroxyl wusu ester, and lanolin-8-en-3-alcohol. These polyphenols might be particularly useful for the synthesis of antibacterial AgNPs. Therefore, AgNPs synthesized by EtOAc extract of L. stoechas have potential value as antimicrobial agents and also enhance the antibacterial activity of antibiotics by combined use.
- Published
- 2021
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