title: Antioxidant activity and total phenolic content of methanol extracts of Ixora coccinea.
abstract: OBJECTIVE
  To investigate the in vitro antioxidant activity of methanol extracts of Ixora coccinea L. (Rubiaceae) flower, leaf and stem.
  
  
  METHODS
  The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, total antioxidant capacity (TAC) and xanthine oxidase inhibition assay were carried out to evaluate the antioxidant potential of the extract. The IC(50) values were calculated for the DPPH and xanthine oxidase assays in order to evaluate the antioxidant efficiency of each of the I. coccinea extracts. The phenol contents were also determined.
  
  
  RESULTS
  I. coccinea flowers revealed the best antioxidant property, presenting much lower IC(50) value (6.6 mg/mL for DPPH assay). The flower extract showed a significantly higher antioxidant capacity compared to the other extracts. Furthermore, the highest phenolic content (polyphenols) was found in the flower extract (210.55 ± 6.31 µg GAE/mg extract). Moreover, I. coccinea extracts scavenged the superoxide radical generated by the xanthine/xanthine oxidase system. The xanthine oxidase inhibition activity was in the order of allopurinol > leaf > flower > stem with the percentage of inhibition ranged from 39.7% to 77.3% for the plant parts investigated. The highest phenolic contents (polyphenols) were found in the flower extracts (210.55 ± 6.31 µg GAE/mg extract).
  
  
  CONCLUSIONS
  I. coccinea could be considered as a potential source of natural antioxidant.
authors.affiliation: Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Kedah.
authors.forename: Angeline
authors.initials: A
authors.lastname: Torey
authors.forename: Sreenivasan
authors.initials: S
authors.lastname: Sasidharan
authors.forename: Lachimanan Yoga
authors.initials: LY
authors.lastname: Latha
authors.forename: Sivaramakrishnan
authors.initials: S
authors.lastname: Sudhakaran
authors.forename: Surash
authors.initials: S
authors.lastname: Ramanathan
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry*; D035264:Flowers / Q000737:chemistry; D016166:Free Radical Scavengers / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D035261:Plant Components, Aerial / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D059808:Polyphenols; D019666:Rubiaceae / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D016166:Free Radical Scavengers; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols