ANTIOXIDANT AND ANTIMICROBIAL ACTIVITY OF CUTTLEBONE CHITOSAN AGAINST Escherichia coli, Staphylococcus aureus AND Candida albicans

Abstract

The discovery of new antibiotics for infectious diseases has become challenging due to the rise of antimicrobial resistance.Meanwhile, chitosan has been considerably used in many branches of research. It has been discovered to have some good benefitsin medicals, pharmaceuticals, and food technologies. In this study, chitosan was prepared from the cuttlebone of Sepia sp. bychemical method and analyzed by using FT-IR spectrophotometer for the confirmed presence of its functional groups. Thereare three types of reactive functional groups in the chitosan which are the amino group and primary and secondary hydroxylgroup attached to the C-2, C-3, and C-6 positions respectively. Chitosan has a high cationic property due to the presence of itsamino group. The bacteriostatic activity of chitosan occurs due to its positive charge in acidic concentration that interacts withthe negatively charged residue of carbohydrates, lipids, and proteins located on the cell surface of bacteria. The antioxidantactivity was conducted using DPPH radical scavenging assay with a chitosan concentration ranging from 0.1 to 10 mg/mL anda hydrogen peroxide scavenging assay with a chitosan concentration ranging from 0.1 to 1.6 mg/mL. The antimicrobial activityof chitosan from cuttlebone was analyzed against two different bacterial strains (Escherichia coli & Staphylococcus aureus)and a fungal strain, Candida albicans by disc diffusion and minimum inhibitory concentration (MIC) method. The results showthat through the DPPH radical assay, the scavenging activity was 59.7% at the concentration of chitosan at 10mg/mL, whilethrough the hydrogen peroxide assay the scavenging activity was 56% at the concentration of chitosan at 1.6 mg/mL. Besides,this chitosan from Sepia sp. has concentration-dependent antimicrobial activity with higher antifungal activity compared toantibacterial activity against all tested organisms and may become a potential agent for antibiotic discovery