Antimicrobial activity of green bio-synthesized silver nanoparticles using extracts of Pittosporum senacia
Author(s): Gunness Deepshi, Lisa Ah-Shee-Tee, Haadiyah Hosany, Vishwakalyan Bhoyroo
Compared to traditional production method (chemical method), biological synthesis of nanoparticles tend to be cheaper since no chemical reducing agents are required, secondary metabolites easily reduced metal ions to nanoparticles in simple steps. The present study compared the antimicrobial activities of both chemically and biologically produced nanoparticles. Aqueous extract of Pittosporum senacia, an endemic medicinal plant, was used to produce silver nanoparticle. Sodium citrate was used as reducing agent in the chemical production of silver nanoparticle. Produced silver nanoparticles were then characterised using UV-Vis spectroscopy. Absorption peak were produced at 400 nm by both type of nanoparticles indicating their spherical nature. Peak at 600 nm was also observed for the biosynthesized nanoparticle denoting other shapes of nanoparticles or possible aggregation. Phytochemical test revealed the presence of saponins, carbohydrates and phenols that were responsible for the reduction and stabilisation of biosynthesized silver nanoparticle. The antimicrobial activities of both type of synthesized nanoparticle were tested against both Gram positive and Gram negative bacteria and a fungus. Excellent antimicrobial activities were recorded against Escherichia coli using both chemically and biologically synthesized silver nanoparticles, reporting inhibition zone of 20.0 ± 0.0 mm and 21.67 ± 1.15 mm respectively. No synergistic interaction was found between biologically synthesized nanoparticles and antibiotic, chloramphenicol. This study demonstrated that there was no significant difference in the antimicrobial properties of both type of nanoparticle and Pittosporum senacia leaves can be effectively used to synthesize silver nanoparticles.