Leishmaniasis these reasons, There is an urgent

Leishmaniasis is a serious health problem. It is caused by the protozoan parasites of the genus Leishmania that cause different clinical forms in human and animals. (Bates and Ashford, 2006; Lainson and Shaw, 2006). Leishmaniasis can present as a localized or disseminated cutaneous ulcers, visceral or mucocutaneous lesions.Visceral Leishmaniasis, also known as kala-azar, is usually an insidious, chronic disease among the inhabitants of endemic areas with high mortality. L. donovani, L. infantum and L. chagasi are the major species responsible for visceral leishmaniasis (Ryan 2004).Among several drugs used in the treatment of leishmaniasis, pentavalent antimonials, considered a gold standard in the treatment, are known to be very toxic to humans.( Berman JD et al., 1988; Seaton RA et al., 1999). Resistance to antileishmanial drugs has also been observed in some endemic foci. The current antileishmania drugs, have serious side effect, toxic, expensive and require long term hospitalization..(Croft SL et al.,2003) For these reasons, There is an urgent need fro development of new antileishmania drugs .( Ouellette M, Drummelsmith J et al., 2004; Sundar S et al., 2008).Nowadays, the interest in nanotechnological approaches in microbiology is growing very fast in all fields of the science. (Curtis A, et al., 2001) as the main motive is the expectation that nanoparticles will be able to be used in the treatment of various diseases. ( Angeli E, et al., 2008; Debbage P. 2009). In recent studies it was determined that through their unique properties, metal oxide nanoparticles possess effective antimicrobial activities ( Elechiguerra JL, et al., 2005) Above all, owing to their great chemical reactivity, nanoparticles are capable of producing reactive oxygen species (ROS), which have the ability to kill infectious agents. The antibacterial and antiviral behaviors of silver, silver ions, and silver-containing compounds have long been investigated ( Tokumaru T, et al., 1974; Oloffs A, et al., 1994). The catalytic oxidation caused by metallic silver and reactions with dissolved single-valent silver ions are thought to contribute to its bactericidal effects within bacterial cells. However, some bacteria have recently shown resistance to the action of silver compounds, comparable to resistance to traditional antibiotics.( Chopra I. 2007) On the other hand, promising results were recently reported with respect to the antimicrobial effect of nanoparticles by themselves or within composites.(Sondi I, et al., 2004). Several studies have reported that silver nanoparticles (Ag-NPs) showed high effectiveness ininactivating bacteria and viruses.( Shrivastava S., et al., 2007; Lara HH, et al., 2010). Moreover, very few studies were carried out to investigate the potential use of medicinal plants in treatment of parasitic diseases. Previous studies have showed that, the extracts of A. nilotica have a potent antileishmanial activity in vitro against L. donovani promastigotes and amastigotes. Conversion of silver ion to silver nanoparticles by different physical and chemical methods is well documented, but recently interest in using biomaterial for synthesis of nanoparticle is new line of science without adverse effect on the environment since no synthetic material will be used. Among the different organisms used for nanoparticle synthesis, plants are of particular interest in metal nanoparticle synthesis because of its advantage over other environmentally benign biological processes as it does not involve harmful chemicals and eliminates the elaborate process of maintaining cell cultures. Silver nanoparticles will be prepared from silver nitrate solution by adding special amount of target plant extract, conversion will appear firstly in term of colour conversion of the mixture and will be confirmed using different apparatus. Therefore, the aim of this study is to investigate in vitro antileishmanial effects of Ag-NPs using A. nilotica as a synthesizer on morphology and various cellular biological activities including growth, metabolic activity, proliferation, infectivity, and infection index of Leishmania donovani parasites both in the presence and in the absence of UV light, as the high toxicity and cost of the available drugs, compounded with the increasing frequency of drug resistant Leishmania species, underlies the necessity to develop new antileishmanial agents