Journal
EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS
Volume 81, Issue 2, Pages 346-350Publisher
ELSEVIER
DOI: 10.1016/j.ejpb.2012.03.002
Keywords
Hypericum perforatum; Reactive oxygen species; Minimal erythema dose; Ultraviolet erythema test; Infrared radiation; Electron spin resonance spectroscopy
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Funding
- Cassella-med GmbH
- Foundation of Skin Physiology
- Federal Land of Berlin within the Program to Promote Research, Innovation and Technologies (ProFIT) [10148423]
- European Fund for Regional Development (ERDF)
- Software AG Stiftung
- WALA Heilmittel GmbH
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Hyperforin, a major constituent of St. John's Wort (Hypericum perforatum, HP), provides anti-inflammatory, anti-tumor, and anti-bacterial properties. Previous studies have shown anti-oxidative properties of St. John's Wort extracts; however, its free radical scavenging activity in skin cells or skin has not been assessed in detail so far. Therefore, the free radical scavenging activity of hyperforin was tested in the H(2)DCFDA-assay in vitro in HaCaT keratinocytes irradiated with solar simulated radiation. Hyperforin (EC50 0.7 mu M corresponding to 0.42 mu g/ml) was much more effective compared to Trolox (EC50 12 mu g/ml) and N-acetylcysteine (EC50 847 mu g/ml) without showing phototoxicity. The radical protection factor of a cream containing 1.5% w/w of a hyperforin-rich HP extract was determined to be 200 x 10(14) radicals/mg, indicating a high radical scavenging activity. The cream was further applied ex vivo on porcine ear skin and significantly reduced radical formation after infrared irradiation. Finally, the UV-protective effect of the HP cream was tested on 20 volunteers in a randomized, double-blind, vehicle-controlled study. HP cream significantly reduced UVB-induced erythema as opposed to the vehicle. Occlusive application of HP cream on non-irradiated test sites did not cause any skin irritation. Taken together, these results demonstrate that hyperforin is a powerful free radical scavenger. (C) 2012 Elsevier B.V. All rights reserved.
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