Paper Title
Biosynthesis And Characterization Of Silver Nanoparticles Using Catharanthus Roseus Aqueous Extract

The biosynthesis of nanoparticles has been proposed as a cost-effective and environmental friendly alternative to chemical and physical methods. The present study was aimed to synthesise and characterise Catharanthus roseus (C. roseus) silver nanoparticles (AgNPs). The extract were prepared by soaking the dried leaves of C. roseus in 40 ˚C water bath for 24 h or boiled for 5 min. The extracts at concentrations of 10% or 20% were mixed with various concentrations of AgNO3 solutions (1, 3, 5 and 10 mM). The characterisation of C. roseus-AgNPs was performed by ultraviolet-visible (UV-Vis) spectra analysis, transmission electron microscope (TEM), X-ray diffraction (XRD), zeta potential analysis, fourier transform infrared spectroscopy (FTIR), and Liquid Chromatography/Time-of-Flight ion trap Mass Spectrometry (LC/TOF-MS). The colour changes indicate the presence of AgNPs in the solution, resulting from the reduction of Ag+ ions into AgNPs. UV-Vis spectra analysis indicates that AgNPs at concentration of 5 mM AgNO3 and 10% extract has produced the highest surface plasmon resonance peak at approximately 450 nm of wavelength. The shape and size determined by TEM indicates that the AgNPs sizes were in the range of 20 to 50 nm (average size of 31 nm with spherical shape). The XRD analysis confirmed the face-centered cubic structure of AgNPs. Zeta potential analysis exhibited the value at -16.8 mV, suggesting high stability of AgNPs due to the capping of biomolecules present in the C. roseus aqueous extract. FTIR spectrum of C. roseus aqueous extract showed the absorption band at 3210.83 cm-1 (C-H stretch), 2934.11 (C-H bond), 1578.15 (N=O stretch), 1388.76 & 1314.89 (N=O bend), 1119.29 (C-O bond) and 729.94 (C-Cl bond). While, the FTIR spectrum of C. roseus-Agnps showed the absorption band at 2925.01 & 2924.97 (C-H bond), 1622.93 (C-C=C symmetric stretch), 1383.19 & 1384.13 (N-O bend), 1037.92/1038.76/1238.3/1117.2 (C-O bond), 3169.4 (O-H bond), 774.59 & 691.53 (C-Cl bond). LC/TOF-MS confirmed the presence of indole alkaloids which were vindolinine, tabersonine, catharanthine, serpentine, catharosine, vincristine, catharine, ajmalicine, vinleurosine, and vindolicine. The present findings have shown that the AgNPs have been successfully synthesised and contain anticancer compounds that responsible for its synthesis. Index Terms - Catharanthus roseus, characterisation, LC/TOF ion trap MS, silver nanoparticles