title: Enhanced DPPH radical scavenging activity and DNA protection effect of litchi pericarp extract by Aspergillus awamori bioconversion.
abstract: BACKGROUND
  Litchi (Litchi chinensis Sonn.) pericarp is a major byproduct which contains a significant amount of polyphenol. This study was designed to biotransformation litchi pericarp extract (LPE) by Aspergillus awamori to produce more bioactive compounds with stronger antioxidant activities.
  
  
  RESULTS
  The study exhibited that the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activities significantly (p < 0.05) increased from 15.53% to 18.23% in the water-extracted fraction and from 25.41% to 36.82% in the ethyl acetate-extracted fraction. Application of DNA cleavage assay further demonstrated the enhanced protection effect of the fermented phenolics on DNA damage. It is also noted that the water-extracted fraction of the fermented LPE possessed a much stronger capacity than the ethyl acetate-extracted fraction to prevent from damage of supercoiled DNA. Interestingly, it was found that some new compounds such as catechin and quercetin appeared after of A. awamori fermentation of LPE, which could account for the enhanced antioxidant activity.
  
  
  CONCLUSIONS
  The DPPH radical scavenging activity and DNA protection effect of LPE were increased by Aspergillus awamori bioconversion while some compounds responsible for the enhanced antioxidant activity were identified. This study provided an effective way of utilizing fruit pericarp as a readily accessible source of the natural antioxidants in food industry and, thus, extended the application area such as fruit by-products.
authors.affiliation: Key Laboratory of Plant Resource Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, People's Republic of China. ymjiang@scbg.ac.cn.
authors.forename: Sen
authors.initials: S
authors.lastname: Lin
authors.forename: Bao
authors.initials: B
authors.lastname: Yang
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
authors.forename: Guoxiang
authors.initials: G
authors.lastname: Jiang
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.forename: Xuewu
authors.initials: X
authors.lastname: Duan
authors.forename: Yueming
authors.initials: Y
authors.lastname: Jiang