Topcu Zeki, Ozturk Bintug, Kucukoglu Ozlem, Kilinc Emrah
Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Ege University, 35100 Izmir, Turkey.
Z Naturforsch C J Biosci. 2008 Jan-Feb;63(1-2):69-74. doi: 10.1515/znc-2008-1-213.
DNA topoisomerases are important targets for cancer chemotherapy. We investigated the effects of a methanolic extract of Helichrysum pamphylicum on mammalian DNA topoisomerase I via in vitro plasmid supercoil relaxation assays. The extracts manifested a considerable inhibition of the enzyme's activity in a dose-dependent manner. We also performed a HPLC analysis to identify the flavonoid content of the H. pamphylicum extract and tested the identified flavonoids; luteolin, luteolin-4-glucoside, naringenin, helichrysinA and isoquercitrin, on DNA topoisomerase I activity. The measurement of the total antioxidant capacity of the flavonoid standards suggested that the topoisomerase inhibition might be correlated with the antioxidant capacity of the plant.
DNA拓扑异构酶是癌症化疗的重要靶点。我们通过体外质粒超螺旋松弛试验研究了淡黄蜡菊甲醇提取物对哺乳动物DNA拓扑异构酶I的影响。提取物对该酶的活性表现出显著的剂量依赖性抑制作用。我们还进行了高效液相色谱分析以鉴定淡黄蜡菊提取物中的黄酮类成分，并测试了所鉴定的黄酮类化合物（木犀草素、木犀草素-4-葡萄糖苷、柚皮素、蜡菊素A和异槲皮苷）对DNA拓扑异构酶I活性的影响。黄酮类标准品总抗氧化能力的测定表明，拓扑异构酶抑制作用可能与该植物的抗氧化能力相关。
