title: In vitro antimicrobial and antioxidant activities of seaweeds from hare island, Tuticorin coast of India.
abstract: OBJECTIVE
  To assess the antimicrobial and antioxidant activities from methanolic extracts of brown and red seaweeds.
  
  
  METHODS
  Padina tetrastromatica, Stocheopremum marginatum and Phorphyra sp. were evaluated by in vitro standard methods. In antimicrobial assay, P. tetrastromatica extract showed highest zone inhibition against E. coli and S. typhi. The S. marginatum extract exhibited the maximum zone inhibition against S. typhi, minimum against K. pneumonia. Phorphyra sp. extract showed higher sensitivity against T. mirabilis. The antioxidant activities of seaweeds were determined at different concentration of 100, 300 and 500 μg/mL.
  
  
  RESULTS
  In 1,1-diphenyl-2-picrylhydrazyl (DPPH) and total phenolic content assays, the S. marginatum extract was found the highest reducing power and the lowest showed by Phorphyra sp. and S. marginatum extracts. In the Linoleic acid peroxidation assay, the P. tetrastromatica extract showed the highest reducing power and minimum showed in S. marginatum extract. The Fourier-transform infrared spectra of the three seaweed extracts exhibited a strong broad, medium, weak and broadly-stretched peak at around 3,400 cm-1.
  
  
  CONCLUSIONS
  Our study indicates that the seaweeds are potential source for antimicrobial and antioxidant agents and further study will fulfill for the purification and structural characterization of the compounds.
authors.affiliation: Centre of Advanced Study in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, 608 502, Tamil Nadu, India, thangamjayam@gmail.com.
authors.forename: Sangappillai
authors.initials: S
authors.lastname: Thangaraj
authors.forename: Subramanian
authors.initials: S
authors.lastname: Bragadeeswaran
authors.forename: Nadarajah
authors.initials: N
authors.lastname: Srikumaran