北京早园竹叶有机提取物对细胞DNA断裂损伤的保护与修复作用

Protecting and Repairing Effect of Extract of North Ph.Praecox Leaves on DNA Damage in CHO-K1 Cells

目的探讨北京早园竹叶提取物对H2O2诱导的中国仓鼠卵巢细胞（CHO-K1）DNA损伤的保护与修复作用。方法采用乙醇-水溶液超声辅助提取方法制备竹叶粗提物，经SP825大孔树脂吸附分离，分别以10％，30％，60％的乙醇水溶液洗脱得到不同成分的提取液，并用高效液相色谱（HPLC）定性分析早园竹叶提取物的主要活性成分；采用单细胞凝胶电泳法（SCGE）检测25～400μg／ml H2O2对CHO—K1细胞的DNA损伤作用以及不同组分竹叶提取物在25～50μg／ml浓度下抗H2O2诱导DNA损伤的保护与修复作用。结果竹叶总提物中含有C-黄酮苷类和酚酸类两类活性物质，经SP825大孔树脂纯化后，10％乙醇洗脱成分主要成分为酚酸类物质，30％乙醇洗脱成分中主要为C-黄酮苷类物质。H2O2具有明显的DNA链断裂作用，导致彗星尾长明显增加。全组分、10％组分、30％组分在6．25μg／ml浓度下对H2O2诱导的CHO—K1细胞DNA损伤的修复作用最强，且30％组分的修复作用最明显。在12．5μg／ml下预防H2O2诱导的CHO-K1细胞DNA损伤作用最强，其保护作用均以全组分为明显，由此说明C-黄酮类活性成分在抗遗传毒性作用中起重要作用。结论一定浓度的早园竹叶提取物对H2O2诱导的CHO-K1细胞DNA损伤具有保护与修复作用。

Objective To investigate the preventive and repairing effect of extract of bamboo （North Ph. Praecox） leaves on DNA damage in Chinese hamster ovary cell-K1 （CHO-K1）. Methods The crude extracts of North Ph. praecox leaves were prepared by ethanol-aqueous solution with ultrasonic-assisted extraction. The extracts were further purified and isolated by SP825 resin column, then eluted by 10%,30% and 60% ethanol and analyzed qualitatively by HPLC. The DNA damage effect of 25-400 μg/ml H2O2 and the protective and repaired effects of 25-400 μg/ml leaf extracts in different components on CHO-K1 DNA injury by H2O2 were determined by the single cell gel electrophoresis （comet）assay. Results C-glycosides and phenolic acids were detected in crude extracts. After purified by SP825 resin column chromatograph, the main components of 10% ethanol eluent was phenolic acids, and C-glycosides was the main ingredients of 30% ethanol eluent. No C-glycosides and phenolic acids were found in 60% ethanol eluent. H2O2 showed a significant effect on DNA damage, with dose dependent manner, for CHO-K1 cells and DNA tail length showed significant difference, compared with negative control. At concentration of 6.25 μg/ml, crude extracts, 10% ethanol eluent and 30% ethanol eluent had strong repairing DNA damage effect on CHO-K1 cells, and the effect of 30% group was the most obvious. In addition, three groups showed strong anti-DNA damage function to CHO-K1, and protecting effect of crude extracts was the most strong. The results suggest that C-glycosides ingredients play an important role in antigenotoxicity in extract Conclusion The extract of bamboo leaves has an antagonism to the DNA damage induced by H2O2 in CHO-K1.