Related Experiment Video
Updated: Jul 8, 2026
Studying Chronic Exposure of Mice to Ultraviolet B Radiation
Published on: August 19, 2025
Green tea phenol extracts reduce UVB-induced DNA damage in human cells via interleukin-12
Agatha Schwarz1, Akira Maeda, David Gan
1Department of Dermatology, University Kiel, Kiel, Germany.
Abstract:
Green tea chemoprevention has been a focus of recent research, as a polyphenolic fraction from green tea (GTP) has been suggested to prevent UV radiation-induced skin cancer. Recently, it was demonstrated that GTP reduced the risk for skin cancer in a murine photocarcinogenesis model. This was accompanied by a reduction in UV-induced DNA damage. These effects appeared to be mediated via interleukin (IL)-12, which was previously shown to induce DNA repair. Therefore, we studied whether GTP induction of IL-12 and DNA repair could also be observed in human cells. KB cells and normal human keratinocytes were exposed to GTP 5 h before and after UVB. UVB-induced apoptosis was reduced in UVB-exposed cells treated with GTP. GTP induced the secretion of IL-12 in keratinocytes. The reduction in UV-induced cell death by GTP was almost completely reversed upon addition of an anti-IL-12-antibody, indicating that the reduction of UV-induced cell death by GTP is mediated via IL-12. The ability of IL-12 to reduce DNA damage and sunburn cells was confirmed in "human living skin equivalent" models. Hence the previously reported UV-protective effects of GTP appear to be mediated in human cells via IL-12, most likely through induction of DNA repair.
Insights
Green tea polyphenols (GTP) protect against UV radiation by inducing interleukin-12 (IL-12) in human cells. This mechanism enhances DNA repair and reduces UV-induced skin damage and cell death.
Area of Science:
- Dermatology
- Photobiology
- Molecular Biology
Background:
- Green tea polyphenols (GTP) show promise in preventing UV radiation-induced skin cancer.
- Previous studies in mice indicated GTP reduces skin cancer risk and DNA damage, potentially via interleukin-12 (IL-12).
Purpose of the Study:
- To investigate if GTP induces IL-12 and DNA repair in human cells.
- To confirm the role of IL-12 in mediating the UV-protective effects of GTP in human skin models.
Main Methods:
- Human keratinocytes and KB cells were treated with GTP before and after UVB exposure.
- Interleukin-12 (IL-12) secretion and UVB-induced apoptosis were measured.
- The effect of an anti-IL-12 antibody was assessed.
- Human living skin equivalent models were used to confirm DNA damage reduction.
Main Results:
- GTP significantly reduced UVB-induced apoptosis in human keratinocytes and KB cells.
- GTP stimulated IL-12 secretion in keratinocytes.
- Blocking IL-12 with an antibody reversed the protective effect of GTP against UV-induced cell death.
- IL-12 demonstrated the ability to reduce DNA damage and sunburn cells in skin models.
Conclusions:
- The UV-protective effects of green tea polyphenols (GTP) in human cells are mediated by the induction of interleukin-12 (IL-12).
- IL-12 likely enhances DNA repair mechanisms, thereby reducing UV-induced cellular damage and apoptosis.
- These findings support the chemopreventive potential of green tea against UV radiation-induced skin damage.
Related Concept Videos
01:35Mutations
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
01:38Nucleotide Excision Repair
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...