Characterization of silver nanoparticles by green synthesis method using Pedalium murex leaf extract and their antibacterial activity

Abstract

Nano-biotechnology has emerged as an important division of nanotechnology. One of the important aspects in the field of nanotechnology is the development of a more consistent process for the synthesis of nanomaterials more than a range of size (with good monodispersity) and chemical composition (Rai et al. 2011 ). Noble metal nanoparticles have been gaining a lot of significance in the past few years due to their applicability in the field of physics, chemistry, medicine, biology and material science (Yokohama and Welchons 2007 ). Metal nanoparticles have a high specific surface area and surface atoms, because of their outstanding physicochemical characteristics, including optical, catalytic, electronic, magnetic and antibacterial properties. Synthesis of metal nanoparticles is enormous due to their potential applicability in different areas such as electronics, chemistry, energy, and medicine development (Saxena et al. 2012 ). Metal nanoparticles, particularly noble metals, have been studied mainly because of their strong optical absorption in the visible region caused by the group excitation of the free electron gas (Mohamed et al. 2000 ). The silver nanoparticles have a large area of interest as they have a large number of applications: nonlinear optics, spectrally selective coating for solar energy absorption, biolabeling, intercalation materials for electrical batteries as optical receptors, catalyst in chemical reactions, antibacterial materials, chemically stable materials and good electrical conductors (Zargar et al. 2014 ; Sharma et al. 2009 ). They are ahead of time the interest of researchers for their novel method for synthesis of silver nanoparticles. Silver is well known for possessing an inhibitory result toward many bacterial strains and microorganisms commonly present in medical and industrial processes (Jiang et al. 2004 ). The general method of synthesizing silver nanoparticles in chemical reduction is as colloidal dispersions in water or organic solvents (Sharma et al. 2009 ). The green synthesis method utilizes nontoxic chemicals, eco-friendly solvent and renewable materials (Raveendran et al. 2003 ). In the medical field, silver and silver nanoparticles have broad applications, especially in skin ointments and creams to avoid infection of burns and open wounds (Duran et al. 2005). Ag nanoparticles have been synthesised by different physical and chemical approaches viz., chemical reduction, microemulsion/reverse micelles, electrochemical reduction and photochemical reduction. Many biological approaches of green synthesis have been reported till date using plant leaf extracts from Alternanthera sessilis (Niraimathi et al. 2013 ), Morinda citrifolia (Sathishkumar et al. 2012 ), Mukia scabrella (Prabakar et al. 2013 ), Iresine herbstii (Dipankar and Murugan 2012 ), Tribulus terrestris (Gopinath et al. 2012 ), Azadirachta indica (Khan et al. 2012 ), Cycas circinalis, Ficus amplissima, Commelina benghalensis , Lippia nodiflora (Johnson and Prabu 2015 ), Ocimum sanctum (Garima Singhal et al. 2011 ) and Aloe vera (Medda et al. 2014 ). Pedalium murex ( P. murex ) is a member of the sesame family, Pedaliaceae. It is found in different parts of the world such as tropical Africa, Sri Lanka, India, Mexico and Pakistan (Rajashekar et al. 2012 ). It has been usually used for the treatment of puerperal diseases, as digestive tonics and in the treatment of ulcers, fevers, wounds, other ailments and general debility. Naturally, we were tempted to verify the wisdom of the local community in using these plants as herbal drugs. The plant is sweet, cooling, mucilaginous, diuretic and anti-inflammatory and used to treat digestive, carminative, tonic and puerperal affections, spermatorrhea, spasmodic affections, amenorrhea, dysmenorrhea, vitiated conditions of pita, inflammation and general debility. A decoction of leaves is given in cases of gonorrhea, while that root is said to be antibilious. The whole plant of P. murex is used as a remedy to cure stomachache, headache, diarrhea, dysentery, cough and cold, intestinal infections, etc. So far, there has been no report on the green synthesis of nanoparticles using Pedalium murex leaves extract. The presently investigate the synthesis of silver nanoparticles from Pedalium murex extract and ascertain their characterization.