细胞体系和非细胞体系下对映-贝壳杉烷二萜化合物Rabdosin B对DNA损伤作用的研究

Study of the DNA damage induced by Rabdosin B(an ent-kuarene diterpenoid) in cell system and cell-free system

采用单细胞凝胶电泳法检测Rabdosin B在细胞体系下对人肝癌细胞HepG2 DNA的损伤作用,运用紫外光谱、圆二色谱和琼脂糖凝胶电泳法检测该化合物在非细胞体系下对小牛胸腺DNA空间结构的影响.结果表明,6～15μmol.L-1 Rabdosin B处理HepG2细胞24 h和48 h后,细胞DNA损伤率与对照组相比其差异极显著,并呈时间及浓度依赖性.在非细胞体系下,较低浓度（1～50μmol.L-1）Rabdosin B对小牛胸腺DNA有一定的损伤作用,表现为嵌插和解旋;而较高浓度（10～25 mmol.L-1）的Rabdosin B对pBR322 DNA有较强的切割作用.二萜化合物Rabdosin B对人肝癌细胞HepG2 DNA的损伤作用极可能是抑制HepG2细胞生长和启动细胞凋亡程序的直接诱因.

Single cell gel electrophoresis is used to study the effect of Rabosin B on DNA damage in the cell system of human liver cancer cells HepG2.Meanwhile,the ulatra violet spectra,circular dichroism spectra and agarose gel electrophoresis are used to detect the direct actions between the diterpenoid and the calf thymus DNA in cell-free system.The results show that the DNA damage increased in a time and dose-dependent manners after treatment of Rabdosin B（6-15μmol·L-1）for 24 h and 48 h.The certain degree DNA damage could be induced by Rabdosin B at low concentration（1~50μmol·L-1）on calf thymus DNA in the manners of intercalative and unwinding;at the high concentration（10~25 mmol·L-1）,Rabdosin B could cleave pBR322 DNA effectively.The DNA damage induce by Rabdosin B in HepG2 cells is mostly the direct motivation of the cell proliferation inhibition and apoptosis.