Antioxidant and Antibacterial Properties of Methanolic Extract of Green Seaweed Chaetomorpha linum From Gulf of Mannar: Southeast Coast of India

Background: Plants are an essential and integral part of complementary and alternative medicine due to their ability to generate secondary metabolites that are used to restore health and treat many diseases. Objectives: The aim of the present study was to determine the antioxidant and antibacterial activities of the green seaweed Chaetomorpha linum. Materials and Methods: The antioxidant and antimicrobial activities of C. linum from the Mandapam coastal region of the Gulf of Mannar, on the southeast coast of India, were examined based on the free radicalscavenging activity of the 1, 1-diphenyl-2-picryl- hydrazyl radical (DPPH), ferrous reducing antioxidant property (FRAP), and total phe- nolic content in the methanolic extract. The antibacterial properties of the methanolic extract of C. linum were tested against pathogenic bacterial strains, including Staphylococcus aureus, Bacillus cereus, Escherichia coli, Proteus mirabilis, Klebseilla pneumoniae, and Salmonella typhimurium, by cup-plate agar diffusion method. Results: The DPPH scavenging activity was equivalent to an IC 50 value of 9.8 μg/mL ascorbic acid. The total phenolic content was 672.3 mg/g gallic acid equivalent, and the IC 50 value by FRAP assay was 8.2 μg/mL. The C. linum extract showed significant activity against the majority of bacteria, comparable with standard antibiotics. Conclusions: C. linum has potential as a natural antioxidant and a natural source of antimicrobials against many microbes.