Role of aqueous extract of Centella asiatica in synthesis of Nanosilver : A Green Approach 1
2
Naureen S. Khan , Ashwini K. Dixit and Rajendra Mehta
3
1
Dept. of Botany, Dr. C.V. Raman University, Kota, Bilaspur, (C. G) 495113 2 Dept. of Botany, Guru Ghasidas Vishwavidyalaya (A Central University) Bilaspur, (C.G) 495009 3 Dept. of Rural Technology, Guru Ghasidas Vishwavidyalaya (A Central University) Bilaspur, (C. G) 495009
Abstract Nanotechnology is a blazing and burning area of present day research due to the fabulous, fiery and terrific distinguishing properties of nanoparticles from their bulk counter parts. Nanoparticles are the key to this technology. They are called as the building block as they exhibit large surface to volume ratio from their heavier source. Due to this they are in great demand and a compulsive requirement in every sector of society. Channeling of Bio-nanotechnology through this broad area has offered a new path of Nano-particle synthesis. Following this stream green chemistry approach has brought a drastic change in present scenario because it offers a comparatively safer and productive output in terms of environmental condition and suitability of method execution, it offers an ecofriendly and energy saving way to get the NPs. Keeping in view the benefits of verdure synthesis, present fraction of research work comprises the phytofabrication of Ag NPs using Centella asiatica’s leaf extract as reducing and capping agent. The synthesized Ag NPs were characterized by UV-Vis Spectroscopy that confirms the formation of metallic nanoparticles by conferring the peak at (λmax) ~426nm Further, Transmission Electron Microscopy (TEM) and Nanoparticle Tracking analysis (NTA) were conducted to speculate the shape and size of phytosynthesized Ag NPs. The particles were found to be polydispersed spherical in nature with size distribution around 40±19nm. Also, the stability of Ag NPs was determined by Zeta sizer analysis which reveals negative zeta potential denoting negative surface charge (- 8.28 mV). Nanoparticles were found to be highly stable over a considerable period of time, which can be attributed to capping layer derived from reducing agent used to synthesize them. Keywords: Green synthesis, Ag NPs, Centella asiatica, Characterization.
Results and Discussion
Introduction Nanotechnology is the rapidly growing area of research. It basically involves multidisciplinary approach.
Visual Inference:
UV-Vis Spectroscopic Analysis:
Biology
Chemistry
Medical Industry
Pharmaceutical Industry BEFORE INCUBATION
NANO TECHNOLOGY
Physics
Chemical Engg
Agriculture
Properties of nanoparticles (a billionth of a meter) Ÿ Small size (1-100nm) Ÿ Large surface to volume ratio Ÿ Surface charge accounts for stability Ÿ Reactivity increases with the reduction in size.
Nanotechnology
NPs
NPs NPs NPs NPs
NPs
NPs NPs NPs
NPs
NPs
AFTER INCUBATION
UV-Vis spectra of synthesized AgNPs from aqueous leaf broth of Centella asiatica(L.) Urban λmax~426nm at both the concentrations.
Food and Beverages
Aqueous leaf broth of Centella asiatica (L.) Urban mixed in 1 mM solution of AgNO3 colour changes from orangish yellow to maroon red within 30 min. of incubation.
Cosmetics
Nanoparticle tracking analysis (NTA):
Zeta Sizer Analysis
Particle Size/Concentration NTA size-histogram of AgNPs synthesized from Centella asiatica leaf extract
Detected by Malvern Zetasizer 90 (ZS 90, USA). Zetasizer analysis denoting zeta potential of AgNPs synthesized from Centella asiatica leaf extract
Methods of nanoparticle synthesis: Top down Physical method
Hazardous
Bottom up Chemical method Biological method
Expensive
Eco-friendly Cost effective
Objective: Keeping in view, the afore mentioned facts present fraction of study was carried out to synthesize silver nanoparticle using the aqueous fresh leaves extract of Centella asiatica (L.) Urban.
Why this plant?
Transmission Electron Microscopy (TEM) Analysis: NERVOUS SYSTEM: Memory enhancing, neuroprotective. (Asiaticoside) CARDIOVASCULAR SYSTEM: Cardioprotective , reduced necrosis of mycocardium (Madecassoside) GASTROINTESTINAL SYSTEM: Gastric ulcer healing (Asiaticoside) INTEGUMENTARY SYSTEM: Effective in skin inflammation, eczema, atopic dermatitis, prevents hypertrophic scars (Asiaticoside)
Centella asiatica (L.) Urban. SYSTEMATIC POSITION Kingdom: Plantae Division: Tracheophyta Class: Magnoliopsida Order: Apiales Family: Apiaceae Genus: Centella L. Species: Centella asiatica (L.)Urban
LYMPHATIC & IMMUNE SYSTEM: In wound healing, improves chronic venous hypertension (Madecassic acid, terpenoids)
TEM micrographs of synthesized silver nanoparticles from aqueous leaf extract of Centella asiatica (L.)Urban.
Application of silver nanoparticles:
OTHER ACTIVITY: Antimicrobial, antioxidant, anxiolytic, anti viral, antipsoriatic, anti filarial, anti tubercular, anti leprotic, anti-hepatoma activity
Wound Healing property
Targeted drug delivery
Consumer products
Water purifier
Antibacterial agent
Food Packaging
BIOLOGICAL PROPERTIES EXHIBITED BY Centella asiatica (L.) Urban ON HUMAN BODY
Materials & Methods: a) Extraction of plant material:
Conclusions Phytochemicals(primary and secondary metabolites play a key role in NPs synthesis.) Fresh leaves of Centella asiatica were collected, washed and then crushed in mortar pestle. Extraction was carried out by Hot plate assisted method using DI water and filtrate was used for Ag NPs synthesis.
b) Synthesis of silver nanoparticle:
c) Purification
Merits of Phytonanofabrication: Ÿ Ideal reducing agent Ÿ Ideal capping agent Ÿ Energy efficient synthesis Ÿ Biocompatible Ÿ Non toxic Ÿ Easily conducted at room temperature and pressure. Ÿ Easy to sale up
Demerits of Phytonanofabrication: Ÿ In majority of cases, this technique yield polydispersed nanoparticles that confined its applicability to limited fields. Ÿ In the cocktail of plant extract uncertainty arises in confirming the actual chemical compound responsible for the reduction.
Acknowledgements: Different concentration of Centella asiatica
Incubated samples of Centella asiatica
Extracts were centrifuged and excess decanted
Dried in oven
References:
d) Characterization Absorbance was measured using UV-Vis spectroscopy (Systronic -2203)
Authors wish to acknowledge MANF- a grant by UGC for financial assistance. Sincere thanks to Prof. M. K. Rai, Head Dept. of Biotechnology, S.B.G.University, Amarawati and Dr. Chauhan, ITRC, Lucknow for their support.
Particle size determination was done by LM-20 UK Nanoparticle tracking analysis
Particle size determination was done by TEM (FEI Tecnai G2 Spirit Twin, Czech Republic)
Ÿ Gogoi SJ, and Gogoi B.2013.Green Synthesis of Nano Particles from Leaves of Ethno Medicinal Plants -A New Approach RJPBCS 4 (3):862-869. Ÿ Krishnaraj C, Jagan EG, Rajasekar S, Selvakumar P, Kalaichelvan PT, Mohan N. 2010. Synthesis of silver nanoparticles using Acalypha indica leaf extracts and its antibacterial activity against waterborne pathogens. Colloids Surf. B Biointerfaces 76, 50–56. Ÿ Khalil MMH, Ismail EH, El-Baghdady KZ, Mohamed D. 2014(Green synthesis of silver nanoparticles using olive leaf extract and its antibacterial activity) Arabian Journal of Chemistry 7: 1131–1139.