title: Influence of sonication on the phenolic content and antioxidant activity of Terminalia catappa L. leaves.
abstract: OBJECTIVE
  This study was designed to evaluate the phenolic content and antioxidant activity of ethanolic extracts from T. catappa leaves obtained by different intervals of sonication.
  
  
  METHODS
  Three commonly used methods were followed to evaluate phenolic content and four in vitro methods like 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging assay, ferric reducing antioxidant potency (FRAP), and total antioxidant capacity assays for measuring the antioxidant activities. Antioxidant values of these assays were expressed in terms of milligrams vitamin C equivalent (VCE) antioxidant activities.
  
  
  RESULTS
  This study showed that extract obtained with 40 minutes of sonication possessed significant (P < 0.05) polyphenolic contents compared to 20 and 60 minutes sonication and control (24 hour maceration). Moreover, sonication of T. catappa leaf above 40 minutes was found to be unsuitable for extracting out phenolic contents. Even the results of antioxidant assays showed that 40 minutes of the sonicated extract exhibited significant (P < 0.05) VCE values compared to extracts obtained at different intervals of sonication and control.
  
  
  CONCLUSIONS
  In sonication extraction method 40 minutes is an ideal time to obtain extract enriched with high polyphenolic content with good antioxidant activity from T. catappa leaves.
authors.affiliation: Centre for Drug Research, Universiti Sains Malaysia, 118 00 Penang, Malaysia.
authors.forename: H V
authors.initials: HV
authors.lastname: Annegowda
authors.forename: L N
authors.initials: LN
authors.lastname: Anwar
authors.forename: M N
authors.initials: MN
authors.lastname: Mordi
authors.forename: S
authors.initials: S
authors.lastname: Ramanathan
authors.forename: S M
authors.initials: SM
authors.lastname: Mansor