Protective effect of phenolics from Lonicera caerulea fruits against UVB-induced damage to HaCaT keratinocytes
As a screening barrier our skin is directly exposed to solar UV light (100–400nm), which is responsible for many adverse biological effects such as attack on the regulation pathways, alterations in differentiation, proliferation and apoptosis of skin cells. These changes may result in skin cancer development . Novel agents, mainly from natural sources, with UV-protective activities have been intensively studied. Lonicera caerulea L. (Caprifoliaceae) fruits contain several groups of phenolics including anthocyanins, flavonoids and phenolic acids. These compounds are strong antioxidants with the potential to protect ROS-mediated damage . In this study we tested the UVB protective activity of the phenolic fraction isolated from Lonicera caerulea fruits (PFLC).
Keratinocytes HaCaT, used as cell model, were i) pre-treated (1h) or ii) post-treated (4h) with PFLC (5–50mg/l) in serum-free medium. For irradiation a solar simulator SOL-500 (Dr. Hönle Technology, Germany) was used. The protective efficacy of PFLC was evaluated using the following parameters: ROS generation, DNA single strand breaks, caspase-3 activation and DNA fragmentation.
We found that UVB-induced ROS generation was obviously diminished in cells pre- and post-treated with PFLC. Application of PFLC suppressed DNA damage as well as apoptotic processes (caspase-3 activation and DNA fragmentation) in keratinocytes. Taken together our data suggest that PFLC prevent UVB caused alteration to human keratinocytes and may be beneficial as an active ingredient in dermatological preparations to protect UV-caused damage and/or support skin cell regeneration after UV exposure.
Acknowledgements: This work was supported by the grant of Grant Agency of the Czech Republic (303/07/P314), Ministry of Education of the Czech Republic (MSM 6198959216) and Ministry of Trade and Commerce (FT-TA3/024).
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