Antimicrobial activity of silver nanoparticles capped with crude extract of Garcinia zeylanica and garcinol

Abstract

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Objectives: Biosynthesis of stable silver nanoparticles (AgNPs) from Garcinia zeylanica crude aqueous extract and 95% pure garcinol and to investigate their antimicrobial activity. Methods: Five milliliters of crude aqueous extract of dried pericarp of Garcinia zeylanica and 0.05% (w/v) garcinol were added drop wise into 95 ml of 0.001M AgN03 solutions separately. pH of the solutions was adjusted to 7. The formation of AgNPs was confirmed by UV-Visible spectrophotometry. The antimicrobial activity of synthesized AgNPs was tested against Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923) and Candida albicans (ATCC 10231) by well diffusion method. Results: UV-Visible peaks indicated the presence of small (9.5nm) and large (40.3nm) AgNPs from Garcinia extract and medium sized (12.5 nm) AgNPs from garcinol and confirmed by Transmission Electron Microscopy (TEM). The colour changes observed in solutions ranged from straw color to reddish brown (small), greenish brown (large) and brown (medium) respectively. The mean zones of inhibition (ZOI) of small AgNPs against E. coli, P. aeruginosa, S. aureus and C. albicans were 12.6 mm, 13 mm, 11 mm, and 10.66 mm, respectively. Mean ZOI of large AgNPs against the above organisms were 11 mm, 10.66 mm, 10 mm and 10 mm, respectively. Mean ZOI of garcinol capped AgNPs (medium) against E. coli, P. aeruginosa, S. aureus and C. albicans were 11.33 mm, 10 mm, 10 mm, 12 mm respectively. Conclusions: G. zeylanica and garcinol were successfully used for biosynthesis of AgNPs. Antimicrobial activity of AgNPs decreased with their increasing particle size. G. zeylanica and garcinol capped AgNPs can be used as potential antimicrobial-hgents in future applications.