Green synthesis of silver nanoparticles from Catharanthus roseus and its antibacterial properties

The antibiotics have been used since ages for treating pathogenic bacteria and fungus. However, biofilm formation and multi-drug resistance has compelled the scientific community to come up with an alternative antimicrobial agent that acts against pathogens without triggering microbial resistance. Our work has attempted to study the antimicrobial properties of silver nanoparticles synthesized from Catharanthus roseus leaves. The leaves were extracted and subjected to nanoparticle synthesis. The UV–Vis spectral analysis showed the peak at 392.4 nm. Scanning electron microscope showed well dispersed and spherical nanoparticles ranging from 20 to 30 nm. The Atomic Force Microscope further confirmed uniform distribution and size less than 100 nm. Fourier Transform Infra-Red indicated the presence of phenols, alcohols, alkenes and other functional groups. Zeta Potential revealed negative charge and Dynamic Light Scattering showed 0.290 polydispersity index. The antibacterial properties were seen best against Vibrio vulnificus ATCC 27562, Pseudomonas aeruginosa ATCC 27853 and Klebsiella pneumoniae subsp. pneumoniae ATCC 4352 with zone of inhibition of 21, 21 and 19 mm, respectively while 33 mm inhibition zone was seen in case of Candida albicans ATCC 10231. The nanoparticle and ampicillin synergistically act against Staphylococcus aureus ATCC 25923 strain and E. coli ATCC 25922 showing 15, 11 mm zone of inhibition, respectively. The hemo-compatibility and antibiofilm property make the silver nanoparticles safe for future In vivo studies. Further Methyl orange degradation proved that the nanoparticles have scope for future environment remediation and Bio-informatics tools helped to study drug-ability scope of secondary metabolites of C. roseus.