BIOFABRICATION OF SILVER NANOPARTICLES USING AQUEOUS LEAF EXTRACT OF MELIA DUBIA, CHARACTERIZATION AND ANTIFUNGAL ACTIVITY Original Article VASUDEVA REDDY NETALA 1 , VENKATA SUBBAIAH KOTAKADI 2 , SUKHENDU BIKASH GHOSH 3 ,PUSHPALATHA BOBBU 1 , VENKATESWARLU NAGAM 4 , SHARMA KK 5 , VIJAYA TARTTE 4* 1 Department of Biotechnology, Sri Venkateswara University, Tirupati, A. P. India, 2 DST-PURSE Centre, Sri Venkateswara University, Tirupati, A. P. India, 3 NABTD, DAE-BRNS, BARC, Mumbai, M. H. India, 4 Department of Botany, Sri Venkateswara University, Tirupati, A. P. India, 5 Received: 22 Aug 2014 Revised and Accepted: 22 Sep 2014 Department of Microbiology, SVIMS University, Tirupati, A. P. India. Email: tvijayasvu@yahoo.com ABSTRACT Objective: To investigate the bio-fabrication of silver nanoparticles (AgNPs) using aqueous leaf extract of Melia dubia (ALM) and test the antifungal activity of AgNPs against pathogenic fungi Aspergillus niger and Candida tropicalis. Methods: 10 ml of aqueous leaf extract of Melia dubia was added to 90 ml of 1 mM silver nitrate and incubated for 8h at room temperature. After incubation, the color change was observed from light yellow to dark brown. The synthesized AgNPs were characterized using UV-Vis spectroscopy, Fourier Transform Infra red spectroscopy (FTIR), Energy Dispersive X-ray Spectroscopy (EDX), Scanning Electron microscopy (SEM), X-ray diffraction analysis (XRD) and Atomic Force Microscopy (AFM). Antifungal activity against Aspergillus niger and Candida tropicalis was carried out by employing the disc diffusion method. Results: UV-Vis spectra confirmed the synthesis of AgNPs by showing characteristic peak between 380-450 nm*. FTIR spectra showed the functional groups possibly involved in the synthesis of AgNPs. EDX confirms the presence of elemental silver at 3 Kev. SEM and AFM showed the synthesized AgNPs were spherical in shape with size ranging between 20-40 nm*. XRD analysis revealed the crystalline nature of AgNPs with face centred cubic (FCC) lattice. AgNPs was found to be very effective against the tested pathogenic fungi A. niger and C. tropicalis and formed the inhibition zones 13.0 and 14.5 mm respectively. Conclusion: It is concluded that the bio-fabrication of AgNPs using aqueous leaf extract of Melia dubia was robust and rapid. The AgNPs were stable and proved to be excellent antifungal agents. Keywords: Melia dubia, Silver nanoparticles, FTIR, SEM, Antifungal activity. INTRODUCTION In the recent years, research on silver nanoparticles (AgNPs) has attracted many scientists a considerable attention due to their remarkable optical, electrical, magnetic and catalytic properties [1]. Due to these properties, AgNPs find several applications in different fields. AgNPs was employed in electrical batteries [2], polarizing filters, catalysts, sensors [3], drug delivery [4], DNA sequencing [5], anticytotoxic agents [6] and antimicrobial agents [7,8]. Many recent studies reported that AgNPs are proved to be excellent antifungal agents [9]. Many physical and chemical methods which include sonochemical assisted [10], thermal assisted [11], and polyol [12] processes were reported for the synthesis of AgNPs. But all of these methods involved the application of toxic, hazardous chemicals leading to environmental and health risks. By considering all these risks, researchers moved to biosynthetic approach. Biological approaches are simple, eco-friendly and rapid. Biological approaches includes plant extract mediated synthesis, microbial assisted and enzyme assisted synthesis. Microbial and enzyme mediated approaches are involved elaborate culturing processes, aseptic environment, while plant extract mediated synthesis does not involve all of these processes. AgNPs has been extensively synthesized using various plant extracts including Acalypha indica [13], Eucalyptus citriodora, Ficus bengalensis [14], Cissus quadrangularis [15], Cassia alata [16], Catharanthus roseus [17] and Andrographis paniculata [18]. In the present work, we have reported the bio-fabrication of AgNPs from the aqueous leaf extract of Melia dubia (ALM), an important medicinal plant belongs to the family Meliaceae. The characterization of biofabricated AgNPs was done to determine their formation, size, shape and crystalline nature by employing different spectroscopic methods which include UV-Vis spectroscopy, Fourier Transform Infra Red spectroscopy (FTIR), Scanning Electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), Atomic force microscopy (AFM) and X-ray diffraction (XRD) analysis. Antifungal activity of the biofabricated AgNPs was carried out to evaluate their biomedical importance. AgNPs were very effective against Aspergillus niger and Candida tropicalis MATERIALS AND METHODS Collection of plant material Leaves of Melia dubia were collected and authenticated by Taxonomist, Department of Botany, Sri Venkateswara University, Tirupati, A. P. India. The voucher specimen was deposited in the herbarium (VJ-0912). Preparation of aqueous leaf extracts Fresh leaves were washed with tap water and then with distilled water (DW) for 2-3 times. 10 g of leaves were weighed, cut into fine fragments, boiled in 100 ml of DW for 15 m at 60 º C, cooled to room temperature and then filtered. The filtrate named. Aqueous leaf extract (ALM) was used for the synthesis of AgNPs. Bio-fabrication of AgNPs Silver nitrate (AgNO3) was purchased from Molychem, India. 10 ml of ALM was added to 90 ml of 1 mM AgNO3 Characterization of AgNPs and incubated in a dark place at room temperature for about 8h. After incubation, the synthesis of AgNPs was initially observed visually and further detected by UV-Vis spectral analysis. UV-Vis analysis of AgNPs 1 ml of AgNPs solution was diluted with 10 ml of DW. An aliquot of this diluted sample was used for UV-Vis spectroscopic (Analytical International Journal of Pharmacy and Pharmaceutical Sciences ISSN- 0975-1491 Vol 6, Issue 10, 2014 Innovare Academic Sciences