Received: 07 Nov 2014 Revised and Accepted: 05 Dec 2014 ABSTRACT Objective: A novel, eco-friendly method of Nickel nanoparticles synthesis using aqueous extract of Desmodium gangeticum root (DG) has been reported in this study. Methods: Novel approach on synthesis of Ni nanoparticles using NiCl2 as precursor and aqueous extract of Desmodium gangeticum root as the reducing agent. Nanoparticles were characterized for its average size, morphology, functional moieties and thermal stability by UV-Visible spectrophotometry, X-Ray Diffractometry (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR) and Thermo Gravimetric Analysis (TGA) respectively. Cytotoxicity was also determined against LLC PK1 cell lines using LDH assay. Results: Less aggregate spherical shaped and mono-dispersed nanoparticles were synthesised whose size ranges from 20-30 nm in diameter. Nanoparticles were exhibit face centre cubic crystalline phase with an average size of ~23 nm which was obtained from XRD spectral pattern. Strong interaction between Desmodium gangeticum and nanoparticles was shown in TGA-thermogram. The reducing potential and total phenolic content of Ni nanoparticles was found to be same as that of Desmodium gangeticum. All the results were expressed as mean±SD of n = 4-6 independent assays, p<0.05, whose data were analysed using ANOVA. Conclusion: Biological activity of the nanoparticles and its toxicity was assessed and found to possess the good antioxidant and reduction potential with significant antibacterial activity and were nontoxic. Original Article DESMODIUM GANGETICUM ROOT AQUEOUS EXTRACT MEDIATED SYNTHESIS OF NI NANOPARTICLE AND ITS BIOLOGICAL EVALUATION SUDHASREE S, VAISHALI KRISHNA DOSS, SHAKILA BANU A, GINO A KURIAN* Vascular Biology Laboratory, School of Chemical and Biotechnology, SASTRA University, Thanjavur, Tamil Nadu. Email: ginokurian@hotmail.com Keywords: Green synthesis, Desmodium gangeticum, Ni Nanoparticles, Antimicrobial, DPPH, LLC PK1. INTRODUCTION Metal and Metal oxide nanoparticles are now becoming an active area of research especially in the field of regenerative medicine and drug delivery [1]. Ni and its oxide nanoparticles find its significant application in various research areas such as consumer products (batteries and electronics) [2], medical imaging [3], catalysis [4], magnetic storage [5], sensors [6], magnetic ink printing [7] and ferrofluidics [8]. In recent times, Ni nanoparticles have attracted researchers attention due to its high magnetic potential, high magnetoresistance, large coercivities and high Curie temperature. Ni nanoparticles were synthesized using different approaches such as metal evaporation-condensation [9], electrochemical methods [10], metal salt reduction [11], ultrasound irradiation [12], ultrasound spray pyrolysis [13], polyol methods [14] and neutral organometallic precursor decomposition [15]. Ni nanoparticles can be prepared in various shapes such as nanotubes [16], nano wires [17], nanorods, hollow spheres [18]and nanobelts [19.] In spite of its high yield and better efficiency obtained in conventional synthesis techniques, it has certain limits in terms of toxicity, time consumption, reliability and processing cost. An alternative approach to overcome these limitations is green synthesis involving the exploitation of reducing potential of biomolecules from plants, fungi and bacteria which pave the way for simplicity, economical, less toxicity and feasibility. The main concern in the synthesis of green nanoparticle is the use of reducing agent like NaBH4 [20] and N2H4, which are mainly involved in the chemical synthesis of nickel nanoparticles. All of these are highly reactive chemicals and pose potential environmental and biological risks. Here, the reducing property of aqueous extract of DG has been exploited for the biosynthesis of nanoparticles. Desmodium gangeticum (DG) from the Fabaceae family is found mainly in India, China, Africa and Australia. DG has very good medicinal values and thus being used in the Indian system of medicines since ancient times [22]. Desmodium gangeticum with properties like anti-inflammatory [23], anti-analgesic [24] and antioxidant activity [25]. It is found to be very effective against numerous disease conditions viz., jaundice, rheumatism, puerperal fever, paralysis, edema, filaria [26], ischemia reperfusion injury [27] and myocardial infarction [28]. Flavonoids, alkaloids and polyphenol compounds in plants plays a vital role in the preparation of nanoparticles due to its high reducing potential [29]. Pterocarpeniods, gangetin and desmodin, are the major chemical constituents of the Desmodium gangeticum root [30]. MATERIALS AND METHODS NiCl2, DPPH, Folin-Ciocalteu reagent, Na2CO3, K3 [Fe(CN)6], TCA (TriChloro Acetic acid) and ethanol were purchased from Sigma Aldrich, India. Muller Hinton agar and agar were purchased from HiMedia, India. LLC PK1 cell line was ordered from NCCS, Pune, India. All the chemicals were used as such without any further purification. Preparation of aqueous extract Desmodium gangeticum (Linn) DC. roots were collected from the botanical garden of St. Berchmans College, Changanassery, Kerala, India and authenticated by HOD, Botony department, SB college. The voucher of the specimen was kept for reference. The collected roots were washed thrice thoroughly with tap water and dried in the shade. Roots were cut into small pieces and grinded coarsely using pulveriser. Soxhelt extraction was carried out to obtain crude aqueous extract. The obtained sample is vapourized and lyophilized for the further purpose. Synthesis of Ni nanoparticles Ni nanoparticles were synthesized by the simple reduction method. NiCl2 solution and crude aqueous DG extract was mixed in three different ratio, 1:2, 1:5 and 1:10. The mixture was heated at 80 °C under thorough stirring for around 45 min till the colour of the solution turns from brown to grey. Thus prepared nanoparticles were dried, ground well and obtained the fine powder and were stored for further analysis. International Journal of Pharmacy and Pharmaceutical Sciences ISSN- 0975-1491 Vol 7, Supple 1, 2015 Innovare Academic Sciences