Phytochemical and Antimicrobial Evaluation of Silver Nanoparticle from Methanolic Extract of Wild Lettuce -Lactuca taraxacifolia

Abstract

Studies in nanotechnology field have been improved throughout the world rapidly. The phytochemical and antimicrobial evaluation of wild lettuce methanolic extract was carried out and silver nanoparticle was investigated. Qualitative and quantitative phytochemical screening was carried out on the methanolic plant extract after extraction using standard methods and the biosynthesis of silver nanoparticle was done using wild lettuce methanolic extract. The phytochemical analysis of Lactuca taraxacifolia leaves showed that saponins were highly present (7.55%w/w) followed in order by alkaloids, terpenoids, tannins and flavonoids which was the least (0.37%w/w). Cardiac glycosides, phenols and anthraquinones were detected. The extract had antioxidant scavenging activity in dose dependent manner in which the highest DPPH and FRAP scavenging activity (58.31 and 7.58) was recorded at 1000 μg/L. The extract was able to bio-reduced silver nitrate for silver nanoparticle production. The agar-well diffusion bioassay was used to test the antimicrobial activity of plant extracts and AgNPs. The antibacterial activity of the nanoparticles ranged from 4.0 – 16.0 mm in which Escherichia coli had the highest susceptibility to the nanoparticle. It was also observed that the test pathogens used were all susceptible to both the plant extract and the nanoparticles. The anatogonistic potential of the nanoparticles was higher than that of the plant extract. The research proved that African wild lettuce leaf vegetables have significant amounts of important phytochemicals, antioxidant properties and can bio-reduce silver for the production of silver nanoparticles. The methanolic extract of the wild lettuce and the nanoparticle have varied antibacterial potential. Hence, regular consumption of this leafy vegetable should be considered due to its several compositions.