A water soluble extract from Uncaria tomentosa (Cat's Claw) is a potent enhancer of DNA repair in primary organ cultures of human skin

Phytother Res. 2006 Mar;20(3):178-83. doi: 10.1002/ptr.1827.


Cat's Claw (Uncaria tomentosa) water extracts, essentially free of oxindole alkaloids, have been shown to possess a broad spectrum of biological activity including DNA repair enhancement and antiinflammatory properties. These two biological mechanisms are key molecular targets to develop treatments that protect skin exposed to ultraviolet light from the sun. Because C-Med-100, a Cat's Claw water extract, is the only documented natural source of components that can up-regulate simultaneously both DNA repair and antiinflammation, its ability to modulate DNA repair in human skin organ cultures was undertaken. For this purpose skin cultures were treated with or without 5 mg/mL C-Med-100, irradiated with 0-100 mJ/cm2 UVB, and microscopically analysed for necrosis as well as the level of pyrimidine dimers using immunofluorescent TT-dimer antibody staining. The data clearly demonstrated that co-incubation with C-Med-100 reduced skin cell death from UV exposure, and this protection was accounted for by a concomitant increase in DNA repair. Based on these results, it was concluded that C-Med-100 was a natural plant extract worthy of further consideration as a sunscreen product.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cat's Claw / chemistry*
  • Cells, Cultured
  • DNA Repair / drug effects*
  • Esters
  • Fluoroimmunoassay / methods
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Necrosis / pathology
  • Organ Culture Techniques
  • Phytotherapy*
  • Plant Bark / chemistry
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology*
  • Plant Extracts / toxicity
  • Pyrimidine Dimers / analysis
  • Pyrimidine Dimers / metabolism
  • Quinic Acid / analysis
  • Skin / drug effects*
  • Skin / radiation effects
  • Sunscreening Agents / chemistry
  • Sunscreening Agents / pharmacology*
  • Sunscreening Agents / toxicity
  • Ultraviolet Rays / adverse effects
  • Uncaria / chemistry
  • Uncaria / toxicity


  • C-MED-100
  • Esters
  • Plant Extracts
  • Pyrimidine Dimers
  • Sunscreening Agents
  • Quinic Acid