Vol 9, Issue 1, 2016 ISSN - 0974-2441 COSTǧEFFECTIVE GREEN SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES FROM AVICENNIA ALBA BLUME LEAVES AND THEIR ANTIBACTERIAL ACTIVITY NAGABABU P, UMAMAHESWARA RAO V* Department of Botany and Microbiology, Acharya Nagarjuna University, Nagarjuna Nagar - 522 510, Guntur, Andhra Pradesh, India. Email: umrvanga@yahoo.co.in Introduction: )n recent years, green synthesis of silver nanoparticles ȋAgNPsȌ has gained much interest from chemists and researchers and also increasing commercial demand for nanoparticles due to their wide applicability in various areas such as electronics, catalysis, chemistry, energy, and medicine. Objective: )n the present study, AgNPs were synthesized from ͳ mM AgNO ͵ solution through the extract of Avicennia alba leaves. )t is a cost-effective and eco-friendly technique. The nature of AgNPs synthesized was analyzed by UV-visible spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy. The antibacterial potential of synthesized AgNPs was compared with that of standard antibiotic by agar well diffusion method. Results: The antibacterial activity results revealed that A. alba leaf AgNPs showed a significant zone of inhibition against the majority of tested bacteria than the streptomycin. Arthrobacter protophormiae and Proteus mirabilis were found to be two-fold sensitive to AgNPs of A. alba leaf than to positive control, streptomycin. Rhodococcus rhodochrous was found sensitive only to AgNPs but not to streptomycin. Other remaining sensitive bacteria exhibited more or less same susceptibility to AgNPs and streptomycin. Conclusion: AgNPs of A. alba leaf showed broad spectrum antibacterial activity and may be a good alternative therapeutic approach in future. Keywords: Green synthesis, Silver nanoparticles, Avicennia alba leaves, Fourier transform infrared spectroscopy, Scanning electron microscopy, Antibacterial activity. INTRODUCTION Nanotechnology is deals with nanometer sized objects. Nanomaterials, due to their small size, show unique and considerably changed physical, chemical, and biological properties compared to their macro scale counterparts [ͳ]. There are several methods for the preparation of silver nanoparticles ȋAgNPsȌ including electrochemical method, laser ablation, microwave irradiation, thermal decomposition, and sonochemical synthesis. The development of new chemical and physical methods for the preparation of nanoparticles may produce pure and well-defined nanoparticles. (owever, these methods are quite expensive and potentially hazardous to the environment. Due to this, recently the studies are focused toward eco-friendly methods such as green synthesis of AgNPs from natural sources such as plants and microorganisms have grabbed researchers’ focus. Moreover, this method has some advantages such as cost-effectiveness and in the process of production, it does not require high temperature, pressure, energy, and toxic chemicals. )n general, metallic nanoparticles are mostly prepared by noble metals such as silver, platinum, and gold [ʹ,͵]. Biologically synthesized gold and AgNPs could be of immense use in medical and biomedical textiles for their efficient antibacterial and antimicrobial properties and also in other applications such as spectrally-selective coatings for solar energy absorption and intercalation material for electrical batteries and also useful as optical receptors and as catalysts in chemical reactions [Ͷ]. Avicennia alba is a species of tropical mangrove belonging to the family Acanthaceae ȋFig. ͳȌ. )t is used for the treatment of several types of diseases such as sexual disorders, scabies, rheumatism, paralysis, snake bites, asthma, and ulcers [ͷ]. )n the present investigation, A. alba leaf aqueous extract was used to synthesize a simple, low-cost and green method of AgNPs. Prepared nanoparticles were characterized by UV/vis, Fourier transform infrared spectroscopy ȋFT)RȌ, and scanning electron microscopy ȋSEMȌ. The in vitro antimicrobial activity of AgNPs was assessed by green synthesized nanoparticles. METHODS Plant material and preparation of the extract Fresh Avicennia alba leaves were collected from Coringa mangrove forest, near Kakinada ȋAndhra PradeshȌ, )ndia. The collected leaves were washed and air dried in the shade and crushed by a mechanical grinder to obtain fine powder. ͳͷ g of this powder was added to ͳͲͲ ml of deionized water and boiled for ͳͷ minutes at ͸Ͳ°C. After cooling to room temperature, the extract was filtered using Whatman No.ͳ filter paper and stored at Ͷ°C for further analysis. Research Article Fig. 1: Avicennia alba plant Received: 24 November 2015, Revised and Accepted: 3 December 2015 ABSTRACT