title: Mangrove plant extracts: radical scavenging activity and the battle against food-borne pathogens.
abstract: OBJECTIVE
  The present study was carried out to evaluate the radical scavenging and antibacterial activity of methanolic leaf extracts of mangrove plants. 8 mangrove plants, which are used as folk medicine in various tropical countries, were collected in Pichavaram and Thondi, Tamil Nadu, India.
  
  
  METHODS
  The antioxidant properties of methanolic leaf extracts were assessed under in vitro conditions using different antioxidant tests, including DPPH, nitric oxide, hydrogen peroxide, hydroxyl radical scavenging assay, reducing power, ferrous ion chelating, and lipid peroxidation inhibition assay.
  
  
  CONCLUSIONS
  Of the 8 mangrove plants screened, Rhizophora mucronata (100 microg/ml) showed significantly higher (p < 0.05) activities for all antioxidant assays, and its IC50 values were 43.17, 116, 60.06, and 46.76 microg/ml for DPPH, hydrogen peroxide, nitric oxide, and hydroxyl radical scavenging activity, respectively. Butylated hydroxytoluene, ascorbic acid and alpha-tocopherol were used as positive controls. Methanolic extracts of R. mucronata were also found to be effective in protecting plasmid DNA against the strand breakage induced by hydroxyl radicals in a Fenton's reaction mixture. Moreover, the total phenolic content of R. mucronata (720.79 mg/gm of dry leaves) was very high and a strong positive correlation was observed between its phenolic content and its antioxidant activity. Methanolic leaf extracts of mangrove plants exhibited no antibacterial activity against seven food-borne pathogens studied.
authors.affiliation: Department of Biotechnology, Alagappa University, Karaikudi, Tamil Nadu, India.
authors.forename: Natarajan
authors.initials: N
authors.lastname: Suganthy
authors.forename: Periyanaina
authors.initials: P
authors.lastname: Kesika
authors.forename: Shanmugaiahthevar
authors.initials: S
authors.lastname: Karutha
authors.forename: Pandian
authors.initials: P
authors.lastname: Kasi
authors.forename: Pandima
authors.initials: P
authors.lastname: Devi
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects*; D053904:DNA Breaks, Single-Stranded / Q000187:drug effects; D005516:Food Microbiology; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D015227:Lipid Peroxidation; D000432:Methanol / Q000737:chemistry; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D029648:Verbenaceae / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D000975:Antioxidants; D016166:Free Radical Scavengers; D010636:Phenols; D010936:Plant Extracts; D000432:Methanol