Intracellular biosynthesis of Au and Ag nanoparticles using ethanolic extract of Brassica oleracea L. and studies on their physicochemical and biological properties

In this present study, we reported broccoli （Brassica oleracea L.） as a potential candidate for the synthesis of gold and silver nanoparticles （NPs） in green chemistry method. The synthesized metal nanoparticles are evaluated their antimicrobial efficacy against different human pathogenic organisms. The physico-chemical properties of gold nanoparticles were analyzed using different analytical techniques such as a UV-Vis spectrophotometer, Field Emission Scanning Electron Microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and a Fourier Transform Infrared spectrophotometer. In addition, gold and silver NP antimicrobial efficacy was checked by disc diffusion assay. UV-Vis color intensity of the nanoparticles was shown at 540 and 450 nm for gold and silver nanoparticles respectively. Higher magnification of the Field Emission Scanning Electron Microscopy image shows the variable morphology of the gold nanoparticles such as spherical, rod and triangular shapes and silver nanoparticles were seen in spherical shapes. The average spherical size of the particles was observed in 24- 38 nm for gold and 30-45 nm for silver NPs. X-ray diffraction pattern confirmed the presence of gold nanopartides and silver nanoparticles which were crystalline in nature. Additionally, the functional metabolites were identified by the Fourier Transform Infrared spectroscopy. IR spectra revealed phenols, alcohols, aldehydes （sugar moieties）, vitamins and proteins are present in the broccoli extract which are accountable to synthesize the nanoparticles. The synthesized gold and silver NPs inhibited the growth of the tested bacterial and fungal pathogens at the concentration of 50 μg/mL respectively. In addition, broccoli mediated gold and silver nanoparticles have shown potent antimicrobial activity against human pathogens.

Studies on in-vitro antioxidant activity of marine edible seaweeds from the east coastal region of Peninsular Malaysia using different extraction methods

Objective:To determine the antioxidant activity of two edible marine seaweeds Eucheumacottonii and Padina sp..Methods:The two extraction methods such as conventional and soxhlet extraction were used to isolate the secondary metabolites using methanol as a solvent medium.Total phenolic content of crude seaweeds extract were analysed by standard FC method.The different antioxidant assays DPPH,ferric reducing antioxidant power and β-carotene bleaching assays confirmed the antioxidant activities.Results:with expressed higher total phenolic content in the seaweeds extract.Also β-carotene bleaching assay lower activity compare with BHT as reference control.Additionally IR spectra showed the phenolic related functional groups are present in the solvent extract.The phenolic related compounds are mainly responsible for higher rate of antioxidant activity.Conclusions:DPPH and ferric reducing antioxidant power assays showed the positive correlation higher phenolic contents than the Eucheuma cottonii.And also the soxhlet extraction showed higher yield and better radical scavenging activity compared to conventional method.Moreover the studies confirmed both seaweeds are an effective candidate for the control the free radical scavenging activity.