Protective effects of green tea extracts on photoaging and photommunosuppression

Skin Res Technol. 2009 Aug;15(3):338-45. doi: 10.1111/j.1600-0846.2009.00370.x.

Abstract

Objectives: This study aimed to investigate whether the sunscreen-containing 2-5% green tea extracts (GTEs) protect ultraviolet irradiation (UVR)-induced photoaging and photoimmunosuppression.

Materials and methods: Twenty volunteers were exposed to repetitive solar-simulated UVR (ssUVR) on the upper back at a dosage of 1.5 minimal erythema doses (MED) per day for four consecutive days. Thirty minutes before each UVR and 6, 24, and 48 h after the last UV exposure, the products containing vehicle, and 2-5% GTEs were applied onto five sites on the dorsal skin, respectively. The skin biopsies were obtained 72 h after the last UVR. The thickness of the stratum corneum and epidermis was measured under the microscope and the expression of cytokeratins (CK)-5/6, CK16, metalloproteinases (MMP)-2, MMP-9, and the CD1a(+) Langerhans cells (LCs) were determined using immunohistochemistry.

Results: Our results showed that UVR substantially induced cutaneous erythema, thickening of the epidermis, overexpression of CK5/6, CK16, MMP-2, MMP-9, and depletion of CD1a(+) LCs. The sunscreens containing different concentrations of GTEs conferred significant protection against the photoaging and photoimmunology-related biological events. Interestingly, the protective effects were not parallel to the concentrations of GTEs, with 2% and 3% GTEs showing the most efficacious photoprotection.

Conclusions: GTEs-containing sunscreens have potential photoprotective effects on UVR-induced photoaging and photoimmunosuppression.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aging / drug effects*
  • Aging / immunology*
  • Camellia sinensis / chemistry*
  • Cytokines / immunology
  • Dose-Response Relationship, Drug
  • Erythema / etiology*
  • Erythema / immunology
  • Erythema / prevention & control*
  • Female
  • Humans
  • Plant Extracts / administration & dosage*
  • Radiation-Protective Agents / administration & dosage
  • Solar Energy
  • Treatment Outcome
  • Ultraviolet Rays / adverse effects*

Substances

  • Cytokines
  • Plant Extracts
  • Radiation-Protective Agents