Attenuation of UVA-induced damage to human keratinocytes by silymarin.

Abstract

BACKGROUND:

UV radiation from sunlight is a potent environmental risk factor in skin cancer pathogenesis. UVA is the major portion of UV light reaching the earth surface ( approximately 95%) and it is reported to lead to benign and malignant tumor formation. UVA-mediated cellular damage occurs primarily through the release of reactive oxygen species (ROS) and it is responsible for inflammation, immunosuppression, photoaging and photocarcinogenesis.

OBJECTIVE:

The aim of our study was to investigate the potency of silymarin, the polyphenol fraction from the seeds of Silybum marianum, to modulate UVA-induced oxidative damage to human keratinocytes.

METHODS:

Skin epidermal cell line HaCaT, extensively used for studying the influence of UV radiation, was chosen as an experimental model. Silymarin's effect on UVA-disrupted cell viability, proliferation, mitochondrial function, and intracellular ATP and GSH level was measured. Furthermore, silymarin's potency to reduce UVA-induced ROS generation, membrane lipid peroxidation, caspase-3 activation and DNA damage was monitored.

RESULTS:

Treatment of irradiated HaCaT (20 J/cm(2)) with silymarin (0.7-34 mg/l; 4h) resulted in concentration-dependent diminution of UVA-caused oxidative stress on all studied parameters. Silymarin application extensively reduced GSH depletion and ROS production as well as lipid peroxidation in irradiated cells. Formation of UVA-induced DNA single strand breaks and caspase-3 activity was also significantly decreased by silymarin.

CONCLUSION:

The results suggest that silymarin may be beneficial in the treatment of UVA-induced skin oxidative injury and inflammation. However, further studies especially whose using human systems are needed to determine efficacy of silymarin in vivo.

• Authors: Alena Svobodová, Adéla Zdarilová, Jana Malisková, Hana Mikulková, Daniela Walterová, Jitka Vostalová
• Journal: Journal of dermatological science (J Dermatol Sci) Vol. 46 Issue 1 Pg. 21-30 (Apr 2007) ISSN: 0923-1811 [Print] Netherlands
• PMID: 17289350 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antioxidants
• Silymarin

Topics

• Antioxidants (chemistry, pharmacology, toxicity)
• Apoptosis (drug effects, radiation effects)
• Cell Division (drug effects, radiation effects)
• Cell Line, Transformed
• Cell Survival (drug effects, radiation effects)
• DNA Damage (drug effects)
• Energy Metabolism (drug effects, radiation effects)
• Humans
• Keratinocytes (cytology, drug effects, metabolism)
• Oxidative Stress (drug effects, radiation effects)
• Silymarin (chemistry, pharmacology, toxicity)
• Ultraviolet Rays (adverse effects)