Green synthesis of well dispersed nanoparticles using leaf extract of medicinally useful adhatoda vasica nees


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Green synthesis of well dispersed nanoparticles using leaf extract of medicinally useful adhatoda vasica nees

  1. 1. 192 Micro and Nanosystems, 2012, 4, 192-198Green Synthesis of Well Dispersed Nanoparticles using Leaf Extractof Medicinally useful Adhatoda Vasica NeesV. Karthicka, V. Ganesh Kumara,*, T. Maiyalaganb, R. Deepaa, K. Govindarajua, A. Rajeswaria andT. Stalin Dhasaa Nanoscience Division, Centre for Ocean Research, Sathyabama University,Chennai - 600 119, Indiab School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive Singapore -639798 Abstract: Development of reliable method for the green synthesis of gold nanoparticles (AuNPs) using medicinally valued Adhatoda vasica Nees has been studied here. The color change and the Surface Plasmon Resonance (SPR) confirmed the formation of AuNPs. The biosynthesized AuNPs were characterized using UV-visible Spectroscopy (UV-vis), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDAX) and Transmission Electron Microscopy (TEM) analysis. The nanoparticles synthesized were predominantly monodisperse, stable spherical in nature with well-defined dimensions of size ranging from 22 to 47 nm. The crystalline nature of the synthesized particles was also evident by the X-ray diffraction analysis.Keywords: Adhatoda vasica, Gold nanoparticles, Biosynthesis, Electron Microscopy, Diffraction.INTRODUCTION Adhatoda vasica Nees, a malabar nut tree belonging to the family Acanthaceae is native of South Asia and is Nanobiotechnology combines biological principles with exclusively studied for its active components likephysical and chemical procedures to generate nano-sized quinazoline alkaloids, vasicine, vasicinone, deoxyvasicine,particles with well defined functions. Particles of oxyvasicinine, maiontone and other essential oils. The plantinterestingly small size make the field of drug delivery more parts have been traditionally used for curing diseases likeinteresting and effective. Synthesizing gold particles stomatitis, asthma and bronchititis [10]. The compound(AuNPs) with medicinal applications is the recent trend in 73/602 an alkaloid isolated from the leaves and roots of A.the field of nanobiotechnology. The surface availability of vasica is a structural analogue of vasicinone which showsnanoparticles for binding/reactivity of other species on them appreciable antiallergic activity in mice, rats and guinea pigsis an important function as it is synthesized in different [11]. Synthesis of AuNPs using medicinally useful plantsstructures like nanorods, spheres, prims and hexagons. The [12, 13] is gaining more importance in therapeuticcontrolled growth of AuNPs of different morphologies and applications, where the reducing agent responsible for thethe various chemical mechanisms involved in the anisotropic reduction of chloroauric acid will have its own effect ongrowth were studied using different chemical procedures [1]. biological systems. In our previous work, we haveThe low toxicity effects of green synthesized AuNPs on demonstrated the use of antidiabetic potent plant Cassiabiological systems made researchers to synthesize it by auriculata for the synthesis of AuNPs [14]. Herein, we havebiological method rather by chemical means. Extensive used an antiallergic potent plant A. vasica for the synthesis ofstudies were done on AuNPs and its binding affinity towards AuNPs which may possess antiallergic effect on animals andnucleic acids and proteins in biological systems [2]. AuNPs that will be a welcoming outcome in the field of drughave been synthesized from various sources like plants [3], delivery.microbes [4], seaweeds [5] and microalgae [6]”. Sastry et al.,2007 have synthesized AuNPs using chitosan and showed MATERIALS USEDgood control on postprandial hyperglycemia which when Chloroauric acid (HAuCl4·3H2O) was obtained fromloaded with insulin [7] proved AuNPs to be an effective drug Loba Chemie, India was used as received. All other reagentscarrier. AuNPs can be used for the detection of nucleic acids used in the reaction were of analytical grade with maximumas Chandirasekar and co-worker have, 2011 synthesized purity. A. vasica Nees leaves were collected from forest areaAuNPs using bile salts and particles with different geometry of Vellore, Tamilnadu, India and was cleaned with tap waterwas achieved by varying the reducing agent concentration and double distilled water twice to remove the dust. Further,[8]. AuNPs have also been employed in the imaging of it is shade dried for a week at room temperature andcancer cells like AR42J pancreatic tumor cells by powdered for use.synthesizing it using laser ablation technique and reportedthat size of AuNPs plays a role in the intracellular uptake [9]. SYNTHESIS OF GOLD NANOPARTICLES For the preparation of A. vasica leaf extract, 4 g of*Address correspondence to this author at the Nanoscience Division, Centrefor Ocean Research, Sathyabama University,Chennai - 600 119, India; powdered leaves is taken in a conical flask along with 40 mLTel: +91 44 24500646; Fax: +91 44 24503308; E-mail: of distilled water. The flask is then placed in an orbital shaker for 4 h and then the extract is taken by filtering the 1876-4037/12 $58.00+.00 © 2012 Bentham Science Publishers
  2. 2. Green Synthesis of Well Dispersed Nanoparticles Micro and Nanosystems, 2012, Vol. 4, No. 3 193Fig. (1A). Aqueous extract of A. vasica (B) Chloroauric acid solution (C) Ruby red colour indicating the formation of gold nanoparticles.Fig. (2). UV-vis spectrum of the gold nanoparticles recorded immediately after synthesis (after 5 min).whole content using whatman No.1 filter paper. The filtrate 983/G detector double beam spectrophotometer. XRDis then stored in refrigerator for further use. The reaction is pattern of the A. vasica reduced AuNPs was carried out usingcarried out using different concentrations of plant extract and a Rich Seifert P3000 instrument operated at a voltage of 40finally optimized to a ratio of 1:10 (Extract: Chloroauric acid kV with Cu K radiations. SEM-EDAX was studied to checksolution). Further 3 mL of extract is added to 30 mL aqueous the surface morphology and elemental analysis of the AuNPssolution of chloroauric acid (10-3 M) and kept in an orbital using XL30 FESEM, Philips. TEM studies were carried outshaker at room temperature. Formation of AuNPs takes place by drop coating AuNPs onto carbon-coated TEM grids usingwithin 4 min, evident from the development of a stable ruby Philips color (Fig. 1) in the solution indicates the reduction ofAu3+ to Au0 with no color change further. The experiment was RESULTS AND DISCUSSION:repeated thrice to check the formation of AuNPs. The The formation of AuNPs is noted down by the colorsynthesized AuNPs are stable at a pH range of 3.6-9.1 showed change after the addition of aqueous extract to chloroauricno precipitation and color change for a period of 45 days. acid solution as illustrated in (Fig. 1). The formation and stability of metal nanoparticles in aqueous solution is studiedCHARACTERIZATION OF GOLD NANOPARTICLES using UV-vis spectrophotometer. The surface plasmon The UV-vis spectra were recorded using Thermo resonance (SPR) arising due to the oscillation of freeScientific Spectrascan UV 2700 with samples in quartz conduction electrons induced by the absorption ofcuvette. FT-IR of Perkin Elmer spectrophotometer was used electromagnetic field [15] as a absorption band with ato identify the possible groups responsible for the reduction maximum at 532 nm has been observed in the spectrumof chloroauric acid at a resolution of 4 cm-1 in the range of (Fig. 2). To identify the possible functional groups4000-450 cm-1 and the FT-IR spectrum was recorded by responsible for the reduction of chloroauric acid the FT-employing KBr pellet technique using Perkin Elmer model- IR spectrum is taken and the interaction of biomolecules have
  3. 3. 194 Micro and Nanosystems, 2012, Vol. 4, No. 3 Karthick et al.Fig. (3). FT-IR spectra of dried powder of (A) A. vasica extract (B) gold nanoparticles.been studied (Fig 3). The spectrum show a clear difference in or –COOH group might have stabilized the AuNPs.the functional group shifts. The peak seen at 3358 cm-1 The stretching of C=O can be observed in the spectrumcorresponds to the –OH or –COOH group which has shifted indicating the red shift from 1625 to 1675 cm-1. Theto higher wavelength 3687 cm-1 thus, implying that the –OH peak 1406 cm-1 corresponds to the –COO- also shows a shift
  4. 4. Green Synthesis of Well Dispersed Nanoparticles Micro and Nanosystems, 2012, Vol. 4, No. 3 195Fig. (4). Diffraction pattern of gold nanoparticles synthesized using A. vasica.Fig. (5A). SEM image shows the presence of bioorganic compounds involved in the reduction (B) EDAX showing strong signals for goldnanoparticles.
  5. 5. 196 Micro and Nanosystems, 2012, Vol. 4, No. 3 Karthick et al.Fig. (6A&B). TEM image taken at various magnifications showing gold nanospheres.which confirms the contribution of carboxylate groups in the constant with value from 0.9 to 1, is the wavelength of thereduction. In the spectrum aromatic resonances have not X-ray source, is the full width at half maximum (FWHM)been identified indicating the absence of aromatic groups in and is the Diffraction angle. From this equation, thethe stabilizing compounds. Thus by using FT-IR, it is particle size calculated was found to be 39 nm which isconcluded that –OH or –COOH, -C=O, -COO- groups has similar to the size observed in TEM image of the AuNPs.involved in the stabilization of AuNPs. The crystalline nature The surface morphology and the scale in which the size ofof AuNPs was examined using XRD where three diffraction the nanoparticle synthesized can be studied using the SEM.peaks were observed in the 2 range of 10º to 70º which can The presence of bioactive components responsible for thebe indexed as (111), (200) & (220) reflections of fcc (face reduction of the chloroauric acid to AuNPs was revealedcentered cubic) matches with Joint Committee on Powder using SEM imaging (Fig. 5A). The image confirms theDiffraction Standards (JCPDS No: 04-0784) revealing that presence bioorganic compounds which has stabilized thesynthesized AuNPs are composed of pure crystalline gold as AuNPs. The EDAX profile has showed strong signal forthere is no other peak found (Fig. 4). The XRD patterns gold atoms (Fig. 5B) and weak signals for chlorine, oxygen,obtained were similar to the results reported earlier on sodium and magnesium which implies that these signalsAuNPs [16]. The particle size of the AuNPs formed were might be from the biomolecules present in the aqueouscalculated using Debye-Scherrer equation extract. The morphology of the synthesized nanoparticles were determined by TEM image and shown in (Fig. 6A&B).D = K / cos For the analysis the image is taken in a random place on the Where D is the average crystalline domain size grid and the morphology is observed carefully. The particlesperpendicular to the reflecting planes, K the Scherrer as seen in TEM image are triangular and spherical in shape
  6. 6. Green Synthesis of Well Dispersed Nanoparticles Micro and Nanosystems, 2012, Vol. 4, No. 3 197Fig. (7). Possible mechanism for the reduction of chloroauric acid by bioactive compounds.with an average size of 38 nm with many similar sized REFERENCESparticles except a few. The uniformity in size is a welcoming [1] Grzelczak, M.; Juste, J.P.; Mulvaney, P.; Marza, L.M.L. Shaperesult in the green synthesis as in most of the cases the control in gold nanoparticle synthesis, Chem. Soc. Rev., 2008, 37,particle size varies with greater range which is a concern 1783-1791.when applied in a targeted drug for therapeutic applications. [2] Niemeyer, C.M. Nanoparticles, proteins, and nucleic acids:The particle shape usually observed in most of the green Biotechnology meets materials, Science, Angew. Chem. Int. Ed., 2001, 40, 4128-4158.synthesis is triangles and spheres and sometimes hexagon [3] Sharma, N.C.; Sahi, S.V.; Nath, S.; Parsons, J.G.; Torresdey,[14]. The synthesis of gold nanoprisms has been J.L.G.; Pal, T. Synthesis of plant-mediated gold nanoparticles anddemonstrated [17] using a plant Cymbopogon flexuosus and catalytic role of biomatrix-embedded nanomaterials, Environ. Sci.a very clear image of prism structures have been observed in Technol., 2007, 41, 5137-5142.TEM. The possible mechanism for the stabilization of [4] Shankar, S.S.; Ahmad, A.; Pasricha, R.; Sastry, M. Bioreduction of chloroaurate ions by geranium leaves and its endophytic fungusAuNPs is illustrated in (Fig. 7). However, finding the exact yields gold nanoparticles of different shapes, J. Mater. Chem.,chemistry involved in reduction and elucidating the capping 2003, 13, 1822-1826.agent need further substantiation. [5] Singaravelu, G.; Arockimary, J.S.; Kumar, V.G.; Govindaraju, K. A novel extracellular synthesis of monodisperse gold nanoparticlesCONCLUSION using marine alga, Sargassum wightii Greville, Colloids Surf., B 2007, 57, 97-101. In the present work, a simple and more rapid method to [6] Govindaraju, K.; Basha, S.K.; Kumar, V.G.; Singaravelu, G. Silver,procure gold nanospheres of monodisperse nature been gold and bimetallic nanoparticles production using single-cell protein (Spirulina platensis) Geitler, J. Mat. Sci., 2008, 43, 5115-displayed and its characterization has been discussed. In 5122.future, such rapid and eco-friendly method may help [7] Bhumkar, D.R.; Joshi, H.M.; Sastry, M.; Pokharkar, V.B. Chitosanresearchers to synthesize AuNPs using green synthesis than reduced gold nanoparticles as novel carriers for transmucosalchemical methods. The formation of AuNPs in the reaction delivery of insulin, Pharm. Res., 2007, 24, 1415-1426. [8] Chandirasekar S.; Dharanivasan, G.; Kasthuri, J.; Kathiravan, K.;indicates the presence of bioactive compounds in the plants Rajendiran, N. Facile synthesis of bile salt encapsulated goldwhich are present on the surface of the AuNPs. Such nanoparticles and its use in colorimetric detection of DNA, J. Phys.compound rich AuNPs can be further used in therapeutic Chem. C, 2011, 115, 15266-15273. [9] Sobhan, M.A.; Sreenivasan, V.K.A.; Withford M.J.; Goldys, E.M.applications and it may have antiallergeic activity if tested on Non-specific internalization of laser ablated pure golda suitable animal model. nanoparticles in pancreatic tumor cell, Colloids Surf., B, 2012, 92, 190-195.CONFLICT OF INTEREST [10] Srivastava, S.; Verma, R.K.; Subhash, M.M.G.; Singh, C.; Kumar, S. HPLC determination of vasicine and vasicinone in Adhatoda The author(s) confirm that this article content has no vasica with photo diode array detection, J. Liq. Chrom. & Rel.conflicts of interest. Technol., 2001, 24, 153-159. [11] Paliwa, J.K.; Dwivedi, A.K.; Singh, S.; Gutpa, R.C.ACKNOWLEDGEMENT Pharmacokinetics and in-situ absorption studies of a new antiallergic compound 73/602 in rats, Int. J. Pharm., 2000, 197, We thank DST-Nanomission, Government of India for its 213- support for the project (SR/NM/NS-06/2009) and [12] Philip, D.; Unni C. Extracellular biosynthesis of gold and silverthe management of Sathyabama University, Chennai for its nanoparticles using Krishna tulsi (Ocimum sanctum) leaf, Physicastanch support in research activities. E, 2011, 43, 1318-1322.
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