Saponins from Tribulus terrestris L. protect human keratinocytes from UVB-induced damage

J Photochem Photobiol B. 2012 Dec 5;117:193-201. doi: 10.1016/j.jphotobiol.2012.10.002. Epub 2012 Oct 23.

Abstract

Chronic exposure to solar UVB radiation damages skin, increasing the risk to develop cancer. Hence the identification of compounds with a photoprotective efficacy is essential. This study examined the role of saponins derived from Tribulus terrestris L. (TT) on the modulation of apoptosis in normal human keratinocytes (NHEK) exposed to physiological doses of UVB and to evaluate their antitumoral properties. In NHEK, TT saponins attenuate UVB-induced programmed cell death through inhibition of intrinsic apoptotic pathway. In squamous cell carcinomas (SCC) TT saponins do not make the malignant keratinocytes more resistant to UVB and determine an enhanced apoptotic response. The photoprotective effect of TT saponins is tightly correlated to the enhancement of NER genes expression and the block of UVB-mediated NF-κB activation. Collectively, our study shows experimental evidence that TT has a preventive efficacy against UVB-induced carcinogenesis and the molecular knowledge on the mechanisms through which TT saponins regulate cell death suggests great potential for TT to be developed into a new medicine for cancer patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / isolation & purification
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Apoptosis / radiation effects
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Cell Survival / radiation effects
  • DNA Repair / drug effects
  • DNA Repair / genetics
  • DNA Repair / radiation effects
  • Disease Progression
  • Epidermal Cells
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / radiation effects
  • Humans
  • Keratinocytes / cytology
  • Keratinocytes / drug effects*
  • Keratinocytes / metabolism
  • Keratinocytes / radiation effects*
  • NF-kappa B / metabolism
  • Pyrimidine Dimers / metabolism
  • Saponins / isolation & purification
  • Saponins / pharmacology*
  • Signal Transduction / drug effects
  • Signal Transduction / radiation effects
  • Skin Neoplasms / etiology
  • Skin Neoplasms / pathology
  • Skin Neoplasms / prevention & control
  • Tribulus / chemistry*
  • Ultraviolet Rays / adverse effects*

Substances

  • Antineoplastic Agents
  • NF-kappa B
  • Pyrimidine Dimers
  • Saponins