• Toxicological Research
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• v.22 no.4
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• pp.423-429
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• 2006

Recent reports on the photocarcinogenicity and photogerotoxicity of many compounds led to an increasing awareness for the need of a standard approach to test for photogenotoxicity. The comet assay has been recently validated as a sensitive and specific test system for the quantification of DNA damage. Thus, the objectives of this study are to investigate the utility of photo-comet assay for detecting photo-mutagens, and to evaluate its ability to predict rodent photo-carcinogenicity. Photo-comet assays were performed using L5178Y $Tk^{+/-}$ mouse lymphoma cells on five test substances (8-methoxypsoralen, chlorpromazine, lomefloxacin, anthracene and retinoic acid) that demonstrated positive results in photocarcinogenicity tests. For the best discrimination between the test substance-mediated DNA damage and the undesirable DNA damage caused by direct UV absorption, a UV dose-response of the cells in the absence of the test substances was firstly fnalized. Out of 5 test substances, positive comet results were obtained for chlorpromazine, lomefloxacin, anthracene and retinoic acid while 8-methoxypsoralen found negative. An investigation into the predictive value of this photo-comet assay for determining the photocarcinogenicity showed that photo-comet assay has relatively high sensitivity. Therefore, the photo-comet assay with mammalian cells seems to be a good and sensitive predictor of the photocarcinogenic potential of new substances.

• Korean Journal of Pharmacognosy
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• v.39 no.4
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• pp.300-304
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• 2008

The root of Astragalus membranaceus Bunge (Leguminosae) has been used in the Korean oriental medicine for strengthening the vital energy. UV irradiation has been suggested as a major cause of photo aging in skin. In order to investigate protective effects against UV induced cellular damage, Astragali Radix was extracted with 70% ethanol and dissolved in DMSO. The protective effect was detected by MTT assay, LDH assay, and Comet assay in immortalized human keratinocyte cell line, HaCaT cell system after UV irradiation. Astragli Radix 70% EtOH extract reduced UV induced cellular damage in cell survival, membrane integrity and DNA damage.