Original Paper Skin Pharmacol Physiol 2004;17:42–48 DOI: 10.1159/000074062 S S ki ki n Pharmacol ol ogy y Phys iol iol ogy and Photoprotection by Cichorium endivia Extracts: Prevention of UVB-Induced Erythema, Pyrimidine Dimer Formation and IL-6 Expression C.D. Enk a M. Hochberg a A. Torres b O. Lev c I. Dor c M. Srebnik b V.M. Dembitsky b a Department of Dermatology, Hadassah University Hospital, Ein Kerem; b Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Hebrew University of Jerusalem, and c Department of Environmental Science, Hebrew University of Jerusalem, Jerusalem, Israel Received: March 20, 2003 Accepted after revision: July 22, 2003 Dr. Claes D. Enk Department of Dermatology Hadassah University Hospital, Ein Kerem Jerusalem 91120 (Israel) Tel. +972 2 677 7111, Fax +972 2 671 3637, E-Mail enk@hadassah.org.il ABC Fax + 41 61 306 12 34 E-Mail karger@karger.ch www.karger.com © 2004 S. Karger AG, Basel 1660–5527/04/0171–0042$21.00/0 Accessible online at: www.karger.com/spp Key Words Cichorium W UVB irradiation W Pyrimidine dimer formation W Interleukin-6 W Photoprotection W Abstract In the gradual process of evolution, plants have devel- oped natural sun protecting substances that enable con- tinuous survival under direct and intense ultraviolet (UV) radiation. As part of our studies of plant-derived pig- ments that might constitute an alternative to convention- al sunscreens, we have tested the ethanolic extracts of roots, stalks, and inflorescences of populations of wild Cichorium endivia subsp. divaricatum (Asteraceae) in terms of protection against sunburn, and in prevention of UVB-induced pyrimidine dimer formation and IL-6 mRNA expression in the human keratinocyte cell line, HaCaT. Using ELISA technique for detection of pyrimi- dine dimers and RT-PCR for detection of IL-6, we found that the ethanolic extract of C. endivia roots absorbs radiation in the UVB spectrum and partially prevents induction of pyrimidine dimers and IL-6 expression. Ap- plication of the root extract on the skin prior to UVB irra- diation totally prevented erythema. Our findings suggest that C. endivia extracts might possess sun-protective qualities that make them useful as sunscreens. Copyright © 2004 S. Karger AG, Basel Introduction Cichorium endivia grows wild in the whole Mediterra- nean area. The leaves were already used in ancient times, predominantly for medicinal purposes. Roots and leaves of Cichorium spp. accumulate glucose and fructose, con- tain flavones and flavonol-glycosides, organic acids, ses- qui-terpene lactones, polyamines and sterols [1–7]. Plant-derived extracts are important sources for many biologically active compounds in medicine. The advan- tages of natural products are many: they exhibit high structural diversity and a broad variety of biological activ- ity, yet the often chemically complex structures can be obtained through simple extractions; if widely distribut- ed, they can be isolated in high quantities at a low cost. Based on their UV-absorbing activity, natural substances extracted from plants and lichens have recently attracted attention as source of potential sunscreen agents [8]. In the gradual process of evolution, plants have devel- oped natural sun protecting substances that enable con- tinuous survival under direct and intense ultraviolet (UV) radiation. The UV protecting systems of these species are much more advanced than those of mammals, since pho- tosynthetic organisms depend on solar irradiation as their primary source of energy, but at the same time must pro- vide mechanisms that can counteract the damaging ef-