Invitro evaluation of antioxidant, antimicrobial, anticancer activities and characterisation of brassica oleracea. var. bortrytis. l synthesized silver nanoparticles

TLDR: In this paper, the free radical scavenging potential, antimicrobial activity of the nanoparticles against different human pathogens and its cytotoxic activity against MCF-7 breast cancer cell line.

Abstract: Objective: Vegetable mediated synthesis of nanoparticles is a green chemistry approach that links Nanotechnology and Biotechnology. The present study is focussed on the biosynthesis of silver nanoparticles using aqueous fresh Cauliflower floret extract and to investigate the free radical scavenging potential, antimicrobial activity of the nanoparticles against different human pathogens and its cytotoxic activity against MCF-7 breast cancer cell line. Methods: It was found that aqueous silver ions when treated with aqueous extract of fresh Cauliflower floret are reduced in solution there by leading to the formation of silver nanoparticles under optimum conditions at pH 6. The formation of silver nanoparticles was indicated by the colour change from colourless to reddish brown. Biosynthesized nanoparticles was characterised using several techniques, viz- UV-Vis spectroscopy, FT-IR, XRD, TEM, SEM and EDAX analysis. The free radical scavenging potential was measured by DPPH assay, antimicrobial activity against four microorganisms was tested using disc diffusion method and cytotoxcity of the nanoparticles was determined against MCF-7 cell line at different concentrations by MTT assay. Results: Water soluble antioxidant constituents present in the Cauliflower floret extract were mainly responsible for the reduction of silver ions to nanosized Ag particles. UV-Vis spectral analysis showed silver Surface Plasmon Resonance band at 425nm. The presence of active proteins and phenolic groups present in the biomass before and after reduction was identified by FT-IR. The presence of elemental silver was characterised by EDS. The crystalline morphology and size of the nanoparticles were determined by TEM, SEM, and X-ray diffraction studies which showed the average size of the nanoparticles in the range 40 –50nm, as well as revealed their FCC structure. The biologically synthesized nanoparticles efficiently inhibited pathogenic organisms such as Klebsiella Pneumonia, Staphylococcus Saprophyticus and E. Coli. The biosynthesized nanoparticles might serve as a potent antioxidant as revealed by DPPH assay. Further these nanoparticles efficiently showed reduced viability and increased cytotoxicity on MCF-7 breast cancer cell line in a dose dependent manner. Conclusion: The present investigation revealed that the fresh aqueous Cauliflower floret extract are capable of producing silver nanoparticles extra cellularly through green synthesis and the reduction process was proved to be good, competent, convenient, easy to handle and considered ecofriendly as an alternative route to physical and chemical methods. The biosynthesized nanoparticles are quite stable in aqueous solution for a month without any sign of precipitation.