International Conference on African Development Issues (CU-ICADI) 2015 : Materials Teclmology Track Green Synthesis, Characterization of Silver Nanoparticles Using Canna indica and Senna occidentalis Leaf Extracts Akinsiku, A.A, Ajanaku, K.O., Adekoya , J.A Department of Chemistry, Covenant University, Canaan Land Nigeria anu.akinsiku@covenantuniversity.edu.ng Abstract- Green synthesis is now considered an alternative to chemical and physical synthetic procedures for nanoparticles by using sustainable and eco-friendly materials instead of harsh and toxic chemicals. This research aimed at synthesizing silver nanoparticles using locally- sourced leaf extracts of Canna indica and Senna occidentalis. The syntheses were monitored with double beam UV-Visible spectrophotometer. Aliquot samples were taken at time intervals (5, 10, 15, 20, 30 minutes) during bioreduction. Colour changes were observed in the process of Ostwald ripening in both syntheses. Again, excitation of surface plasmon resonance was obvious in the nanosilver formed by the biomass. Red shifting indicating particle size increase (400-430 nm), and blue shifting (350-380 nm) were evident in Canna indica and Senna occidentalis silver nanoparticles respectively. Energy dispersed analysis by X- ray (EDAX) indicated silver oxide peaks, and scanning electron microscopy (SEM) showed an amorphous phase of the nanoparticles as further proofs of nanosilver formation from both extracts. key words- Green synthesis, nanoparticles, nanosilver, Canna indica, Senna occidentalis, SEM, EDAX I. INTRODUCTION Researchers are now focused on the use of sustainability ideas that use green chemistry for bioremediation in all scientific fields; as this will eliminate complex synthetic routes. Metal nanoparticles are of various uses- catalytic, electronics, biology and biomedical material science, physics and environmental remediation. Hence, there is a need for the development of cheap and eco-friendly nanomaterials, as nanoparticles synthesis is still on the high cost side [ 1-8]. Consequently, use of benign materials and biomass in the synthesis of nanoparticles is gaining widespread acceptance. Microorganisms such as bacteria, actinomycetes, and fungi continue to be investigated in metal nanoparticles synthesis; the use of parts of whole plants in similar nanoparticles synthesis methodologies is an exciting possibility that is relatively unexplored and underexploited [9]. Even though gold nanoparticles are considered biocompatible, chemical synthesis methods may still lead to the presence of some toxic chemical 154 Dare , E.O Department of Chemistry, Federal University of Agriculture Abeokuta, Ogun State, Nigeria species adsorbed on the surface that may have adverse effects in medical applications. Synthesis ofnanoparticles using microorganisms or plants can potentially eliminate this problem by making nanoparticles more biocompatible. Using plants for synthesis of nanoparticles could be advantageous over other environmentally benign biological processes by eliminating the elaborate process of maintaining cell cultures. It can also be suitably scaled up for large-scale synthesis ofnanoparticles [9 , 10]. Hence, there is no need for hazardous chemica ls , high-energy and wasteful purifications [ 11]. In recent times, biodiversified plant extracts that are peculiar to Nigeria for the synthesis of silver nanoparticles (SNPs) were reported by Dare et al. , using the plant extracts of Afromomum melegue ta) , Anacardium occidentale linn, Capsicum chinense, Citrus aurantifolia, Ocimum gratissimum, Newbouldia la evis, Piper guineense, Psidum guajava, Gangronema latifolum), Telfairia occidentalis, Xylopia aethiopica) and Vernonia amygdalina [12]. Jha and Prasad also carried out nanoparticles synthesis using Eucalyptus hybrid [13]. Likewise, some selected alcoholic beverages [14] were employed for silver nanoparticles formation. Recently, researchers have discovered that phytochemicals present in the plant extracts are responsible for metal ion reduction and capping of the newly formed particles during their growth processes [15 , 16]. Alkaloids, flavonoids, terpenes etc. present in plants are good indicators for bioreduction process. However, Canna indica L. (Indian shot); the first plant considered for this research belongs to the family Carmaceae. Qualitative phytochemical analysis of Canna indica L. flower confirmed the presence of various alkaloids, carbohydrates, proteins, flavonoids, terpenoids, cardiac glycosides, steroids, tarmins, saponins, phlobatinins [17]. Hence, these qualities are positive indicators for nanosilver formation, as the alkanoids, terpenoids, and carbohydrates are responsible for the reduction of silver metal ion (Ag + to Ag 0 ), and capping of metal nanoparticles during nucleation and growth processes. The water extract of rhizomes of C. indica has been reported to have HIV -1 reverse transcriptase