AUTHOR=Bernardo Wagner Luis de Carvalho , Boriollo Marcelo Fabiano Gomes , Tonon Caroline Coradi , da Silva Jeferson Júnior , Oliveira Mateus Cardoso , de Moraes Fernando Cruz , Spolidorio Denise Madalena Palomari 

TITLE=Biosynthesis of silver nanoparticles from Syzygium cumini leaves and their potential effects on odontogenic pathogens and biofilms

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.995521

DOI=10.3389/fmicb.2022.995521

ISSN=1664-302X

ABSTRACT=<p>This study analyzed the antimicrobial and antibiofilm action and cytotoxicity of extract (HEScL) and silver nanoparticles (AgNPs-HEScL) from <italic>Syzygium cumini</italic> leaves. GC–MS, UV–Vis, EDX, FEG/SEM, DLS and zeta potential assays were used to characterize the extract or nanoparticles. Antimicrobial, antibiofilm and cytotoxicity analyses were carried out by <italic>in vitro</italic> methods: agar diffusion, microdilution and normal oral keratinocytes spontaneously immortalized (NOK-SI) cell culture. MICs of planktonic cells ranged from 31.2–250 (AgNPs-HEScL) to 1,296.8–10,375 μg/ml (HEScL) for <italic>Actinomyces naeslundii</italic>, <italic>Fusobacterium nucleatum</italic>, <italic>Staphylococcus aureus</italic>, <italic>Staphylococcus epidermidis</italic>, <italic>Streptococcus mutans</italic>, <italic>Streptococcus oralis</italic>, <italic>Veillonella dispar</italic>, and <italic>Candida albicans</italic>. AgNPs-HEScL showed antibiofilm effects (125–8,000 μg/ml) toward <italic>Candida albicans</italic>, <italic>Streptococcus mutans</italic> and <italic>Streptococcus oralis</italic>, and <italic>Staphylococcus aureus</italic> and <italic>Staphylococcus epidermidis</italic>. The NOK-SI exhibited no cytotoxicity when treated with 32.8 and 680.3 μg/ml of AgNPs-HEScL and HEScL, respectively, for 5 min. The data suggest potential antimicrobial and antibiofilm action of HEScL, and more specifically, AgNPs-HEScL, involving pathogens of medical and dental interest (dose-, time- and species-dependent). The cytotoxicity of HEScL and AgNPs-HEScL detected in NOK-SI was dose- and time-dependent. This study presents toxicological information about the lyophilized ethanolic extract of <italic>S. cumini</italic> leaves, including their metallic nanoparticles, and adds scientific values to incipient studies found in the literature.</p>