The effects of tea extracts on proinflammatory signaling

Frank Pajonk¹ , Anja Riedisser² , Michael Henke² , William H McBride¹ and Bernd Fiebich³

¹Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1714, USA

²Department of Radiation Oncology, University Hospital of Freiburg, Germany

³Department of Psychiatry, University Hospital of Freiburg, Germany

author email corresponding author email

BMC Medicine 2006, 4:28doi:10.1186/1741-7015-4-28


Published:	1 December 2006

Abstract

Background

Skin toxicity is a common side effect of radiotherapy for solid tumors. Its management can cause treatment gaps and thus can impair cancer treatment. At present, in many countries no standard recommendation for treatment of skin during radiotherapy exists. In this study, we explored the effect of topically-applied tea extracts on the duration of radiation-induced skin toxicity. We investigated the underlying molecular mechanisms and compared effects of tea extracts with the effects of epigallocatechin-gallate, the proposed most-active moiety of green tea.

Methods

Data from 60 patients with cancer of the head and neck or pelvic region topically treated with green or black tea extracts were analyzed retrospectively. Tea extracts were compared for their ability to modulate IL-1β, IL-6, IL-8, TNFα and PGE₂release from human monocytes. Effects of tea extracts on 26S proteasome function were assessed. NF-κB activity was monitored by EMSAs. Viability and radiation response of macrophages after exposure to tea extracts was measured by MTT assays.

Results

Tea extracts supported the restitution of skin integrity. Tea extracts inhibited proteasome function and suppressed cytokine release. NF-κB activity was altered by tea extracts in a complex, caspase-dependent manner, which differed from the effects of epigallocatechin-gallate. Additionally, both tea extracts, as well as epigallocatechin-gallate, slightly protected macrophages from ionizing radiation

Conclusion

Tea extracts are an efficient, broadly available treatment option for patients suffering from acute radiation-induced skin toxicity. The molecular mechanisms underlying the beneficial effects are complex, and most likely not exclusively dependent on effects of tea polyphenols such as epigallocatechin-gallate.