中文摘要：

采用微量热法研究中药蟾蜍中4种蟾蜍甾二烯类化合物（BD）对嗜热四膜虫BF5生长代谢的影响.在不同给药条件下,以表达热功率-时间曲线（热谱曲线）的特征参数生长速率常数（k）,最大产热功率（Pmax）和半数抑制浓度（IC50）为指标,对4种蟾蜍甾二烯类化合物干预嗜热四膜虫生长代谢程度进行客观的量化评价.结果表明：k和Pmax均随4种蟾蜍甾二烯类化合物浓度的增加而相应减小,且k与不同化合物的相应浓度间有良好的线性关系（r〉0.98）;华蟾毒精、蟾毒灵、蟾毒它灵和日蟾毒它灵的IC50分别为119.2、106.14、73.80和54.75μg·mL-1,即毒性效应大小顺序为日蟾毒它灵〉蟾毒它灵〉蟾毒灵〉华蟾毒精.初步构毒关系研究表明,在蟾蜍甾二烯结构母核C11上引入α-OH,C14上引入β-OH,C16上引入β-OAC以及C14与C15未发生脱水均可明显增加蟾蜍甾二烯对嗜热四膜虫BF5的毒性作用.

英文摘要：

The effects of various concentrations of toad bufanolide diene（BD） on the growth of Tetrahymena thermophila BF5 were investigated by means of a thermal activity monitor（TAM） system.The extent and duration of toxic effects on metabolism were evaluated by studying the growth rate constant（k）,maximum heat-output power（Pmax） and half inhibitory concentration（IC50）.Experimental results showed that the values of k and Pmax decreased as the concentrations of BD increased.Furthermore,the growth rate constant（k） was linked to the concentration of BD：rcinobufagin= 0.9910（IC50=119.2 μg·mL-1）;rbufalin=0.9923（IC50=106.14 μg·mL-1）;rbufotalin=0.9977（IC50=73.80 μg·mL-1）;rgamabufotalin=0.9923（IC50=54.75 μg·mL-1）.The sequence of toxicity for the four BDs was：gamabufotalinbufotalinbufalincinobufagin.The α-hydroxy group at C11,β-hydroxy group at C14,β-acetoxy at C16 and the non-dehydrolysis between C14 and C15 can possibly improve the toxicity of BD towards Tetrahymena thermophila BF5.