An extract of Polygonum multiflorum protects against free radical damage induced by ultraviolet B irradiation of the skin

Braz J Med Biol Res. 2006 Sep;39(9):1181-8. doi: 10.1590/s0100-879x2006000900005.


Over the last decades, the incidence of ultraviolet B (UVB)-related skin problems has been increasing. Damages induced by UVB radiation are related to mutations that occur as a result of direct DNA damage and/or the production of reactive oxygen species. We investigated the anti-oxidant effects of a Polygonum multiflorum thumb extract against skin damage induced by UVB irradiation. Female SKH-1 hairless mice were divided into three groups: control (N = 7), distilled water- (N = 10), and P. multiflorum extract-treated (PM, N = 10) groups. The PM (10 g) was extracted with 100 mL distilled water, cryo-dried and 9.8 g was obtained. The animals received a topical application of 500 microL distilled water or PM extract (1, 2, 4, 8, and 16%, w/v, dissolved in distilled water) for 30 min after UVB irradiation (wavelength 280-320 nm, 300 mJ/cm(2); 3 min) of the dorsal kin for 14 days, and skin immunohistochemistry and Cu,Zn-superoxide dismutase (SOD1) activity were determined. SOD1 immunoreactivity, its protein levels and activities in the skin were significantly reduced by 70% in the distilled water-treated group after UVB irradiation compared to control. However, in the PM extract-treated groups, SOD1 immunoreactivity and its protein and activity levels increased in a dose-dependent manner (1-16%, w/v, PM extract) compared to the distilled water-treated group. SOD1 protein levels and activities in the groups treated with 8 and 16%, w/v, PM extract recovered to 80-90% of the control group levels after UVB. These results suggest that PM extract strongly inhibits the destruction of SOD1 by UV radiation and probably contains anti-skin photoaging agents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Topical
  • Animals
  • Antioxidants / therapeutic use*
  • Blotting, Western
  • Female
  • Mice
  • Mice, Hairless
  • Plant Extracts / therapeutic use
  • Polygonum / chemistry*
  • Radiation Injuries, Experimental / metabolism
  • Radiation Injuries, Experimental / prevention & control*
  • Skin / radiation effects*
  • Superoxide Dismutase / metabolism*
  • Superoxide Dismutase-1
  • Ultraviolet Rays / adverse effects*


  • Antioxidants
  • Plant Extracts
  • Sod1 protein, mouse
  • Superoxide Dismutase
  • Superoxide Dismutase-1