Characterization, Antioxidant, and Antibacterial Activity Silver Nanoparticle of Gelidium spinosum

Abstract

The purpose of this study was to characterize AgNP, and determine antioxidant and antibacterial activities. This research is exploratory descriptive research. The characterization method used PSA (Particle Size Analysis) and FTIR (Fourier Transform Infrared Spectroscopy). The antioxidant activity method uses the DPPH (1.1-diphenyl-2-picrylhydrazyl). The antibacterial activity test used the inhibition zone test with paper disc diffusion (Kirby and Bauer Method), the MIC test used the tube dilution method, and the MBC test used the total plate count method. The results of the research on PSA characterization showed that characterization AgNPs Gelidium spinosum has a size of 107.1 nm, while the FTIR results showed that AgNPs G. spinosum had 7 spectral peaks at wave numbers 466.37 and 534.83(-(CH2)n), 714.11 and 874.27 (C-H aromatic rings), 1035.43 (C-O alcohols, ethers, carboxylic acids, and esters), 1406.24 (C-H alkanes), 1644.42 (C=C alkenes), and 3323.07 (O-H hydrogen bonds in alcohols and phenols). The results of the antioxidant activity of AgNPs Gelidium spinosum an IC50 value of 18.34 ± 5,147 ppm, while the antibacterial inhibition zone test on the sample of AgNPs G. spinosum against E. coli was included in the strong category with an average value of the diameter of the inhibition zone 10.18 mm different from the others sample in the medium category. The results of the minimum inhibitory concentration (MIC) in G. spinosum AgNPs were 18.75 ppm, while the G. spinosum extract was 37.5 ppm. The result of the minimum bactericidal concentration (MBC) on AgNPs G. spinosum was 18.75 ppm, and the extract of G. spinosum is 37.5 ppm. Based on the results of this study AgNPs Gelidium spinosum had strong antioxidant and antibacterial activity against gram-positive and gram-negative bacteria.