Novel synthesis of nanosilver particles using plant active principle aloin and evaluation of their cytotoxic effect against Staphylococcus aureus

ObjectiveTo develop a reliable, eco-friendly and easy process for the synthesis of silver nanoparticles using aloin, the active principle of medicinal plant ‘Aloe vera’ and to evaluate antimicrobial activity against Staphylococcus aureus (S. aureus), a causative organism of most of the diseases in livestock and to standardize the level of safety of synthesized silver nanoparticles.MethodsCharacterization using UV-vis spectrophotometry, DLS technique, FT-IR and SEM. Tube dilution method was carried out to evaluate the MIC of the compound against S. aureus. MTT assay was performed to evaluate the level of safety of nanoparticles.ResultsUV-vis absorption spectrum showed a maximum absorption around 200 nm for aloin mediated silver nanoparticles (ANS). The size of the particles as measured by DLS technique was 67.8 nm. The results of FT-IR analysis indicated the involvement of hydroxyl, carboxyl, amine and nitrile groups in the synthesis and stabilization of aloin mediated silver nanoparticles. SEM images showed that ANS with cubical, rectangular, triangular and spherical morphology and measured sizes of the agglomerated nanoparticles are in a range of 287.5 to 293.2 nm, however the average size of an individual particle is estimated to be approximately 70 nm. The compound (ANS) showed a MIC of 21.8 ng/mL against S. aureus and showed an in vitro spleenocyte viability of more than 80% at the highest concentration of 87.5 mg/L per well.ConclusionsAloin consists of functional groups which reduced Ag+ ions to Ag° ions and helped in synthesis of silver nanoparticles. The synthesis process has further enhanced the antimicrobial activity of nanosilver. The compound is also proved to be safe at the level many times higher than the MIC.