Antiinflammatory effects of a red orange extract in human keratinocytes treated with interferon‐gamma and histamine

Red oranges are an important component of the so‐called Mediterranean diet and they have been used by traditional medicine for their health protective properties, particularly to heal sore throat and cough, suggesting an interesting antiinflammatory activity. The purpose of this study was to evaluate the antiinflammatory activity of a red orange (Citrus sinensis varieties: Moro, Tarocco, Sanguinello) complex (ROC), characterized by high levels of anthocyanins, flavanones, hydroxycinnamic acids and ascorbic acid, on the human keratinocyte line NCTC 2544 exposed to interferon‐gamma (IFN‐γ) and histamine. The expression of immunomodulatory membrane molecules such as inter‐cellular adhesion molecule‐1 (ICAM‐1) by Western blot analysis, and the release of chemokines such as monocyte chemoattractant protein‐1 (MCP‐1) and interleukin‐8 (IL‐8) through ELISA kits, were determined. ICAM‐1 modulates the permanence and activation of T lymphocytes in the epidermis. MCP‐1 is a specific chemoattractant for monocytes and dendritic cells. IL‐8 is important for the recruitment of both neutrophils and T lymphocytes. Addition of ROC at different concentrations together with IFN‐γ and histamine induced a dose‐dependent inhibition of ICAM‐1 expression and MCP‐1 and IL‐8 release. ROC shows interesting antiinflammatory properties in human keratinocyte cells NCTC 2544. This natural complex could have a topical employment and mitigate the consequences of some skin pathologies. Copyright © 2009 John Wiley & Sons, Ltd.