title: Protective Effect against Hydroxyl-induced DNA Damage and Antioxidant Activity of Radix Glycyrrhizae (Liquorice Root).
abstract: OBJECTIVE
  As a typical Chinese herbal medicine, Radix Glycyrrhizae (RG) possesses various pharmacological effects involved in antioxidant ability. However, its antioxidant has not been explored so far. The aim of the study was to investigate its antioxidant ability, then further discuss the antioxidant mechanism.
  
  
  METHODS
  RG was extracted by ethanol to obtain ethanolic extract of Radix Glycyrrhizae (ERG). ERG was then determined by various antioxidant methods, including DNA damage assay, DPPH assay, ABTS assay, Fe(3+)-reducing assay and Cu(2+)-reducing assay. Finally, the contents of total phenolics and total flavonoids were analyzed by spectrophotometric methods.
  
  
  RESULTS
  Our results revealed that ERG could effectively protect against hydroxyl-induced DNA damage (IC50 517.28±26.61μg/mL). In addition, ERG could scavenge DPPH· radical (IC50165.18±6.48μg/mL) and ABTS(+)• radical (IC507.46±0.07μg/mL), reduce Fe(3+) (IC50 97.23±2.88 μg/mL) and Cu(2+) (IC50 59.21±0.18 μg/mL). Chemical analysis demonstrated that the contents of total phenolics and flavonoids in ERG were 111.48±0.88 and 218.26±8.57 mg quercetin/g, respectively.
  
  
  CONCLUSIONS
  Radix Glycyrrhizae can effectively protect against hydroxyl-induced DNA damage. One mechanism of protective effect may be radical-scavenging which is via donating hydrogen atom (H·), donating electron (e). Its antioxidant ability can be mainly attributed to the flavonoids or total phenolics.
authors: School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China.
authors: Xican
authors: X
authors: Li
authors: Weikang
authors: W
authors: Chen
authors: Dongfeng
authors: D
authors: Chen
keywords: DNA oxidative damage; Liquorice root; Radical-scavenging; Radix Glycyrrhizae; Total flavonoids