Two novel 27-norergostanol steroids,panthogenins A(1) and B(2),possessing unusual rings E and F featuring a ketal moiety at C-25 were isolated from rhizomes of Dioscorea panthaica.Their structures and relative configurations were elucidated by extensive spectroscopic methods including 1D and 2D NMR techniques,and the structure of panthogenin A was further confirmed by X-ray crystallography.Both compounds showed potent in vitro insulin sensitizing activity.
以溴化乙锭(EB)为分子探针,生理pH=7.4环境下,分别采用荧光光谱法、化学热力学法和黏度法等手段研究了β-环糊精-4-苄氧基苯酚(β-CD-PBP)包合物与鲱鱼精DNA(hsDNA)的相互作用。利用摩尔比法测定β-环糊精(β-CD)与4-苄氧基苯酚(PBP)的包合比nβ-CD∶n PBP=1∶1,其包合常数K f=7.39×103L·mol-1。β-CD-PBP包合物与hsDNA的结合比n DNA∶nβ-CD-PBP=1∶9,结合常数为K300.15K=2.86×103L/mol,K310.15K=2.69×104L/mol。热力学函数Δr H mθ=1.44×105J/mol,Δr G mθ300.15K=-1.97×104J/mol,Δr S mθ=549.32 J/(mol·K),结果表明β-CD-PBP包合物与DNA作用是熵驱动,β-CD-PBP与hsDNA的作用方式为静电和部分嵌插的作用方式。
Two new eupodienone lignans, named gymnothelignan T(1) and gymnothelignan U(2) were isolated from the whole plants of endemicmedicinal plant of Gymnotheca chinensis(Saururaceae). The structures of the new compounds were elucidated by means of HRMS, 1D and 2D NMR. Compound 1 was tested for cytotoxic activity in HCT15, HCT116, A549, MCF-7 and HepG2 cells and exhibited no appreciable activity against these tested cell lines with IC50 values above 50 mmol/L.
