Design of nonsteroidal durassinosteroids

采用水稻叶片倾斜试验检测油菜素内酯的活性。按标准生物测定系统用不同浓度的化合物处理水稻品种后，用半圆形量角器测量叶片与叶鞘之间的夹角大小。用不同浓度的化合物处理后的角度与浓度作了关系图。在每一次测定中，分别以溶剂(DMSO)和高浓度油菜素内酯(10^&lt；-6&gt；M)作为阴性对照和阳性对照。根据各浓度-反应曲线，确定各化合物的半数有效浓度EC50&Gt；(M)，并以EC50&Gt；的倒数对数作为活性指数。使用这种方法，我们估计油菜素内酯、蓖麻酮和表油菜素内酯的可重复EC50和gt；值分别为9.14、8.08和8.28。油菜素内酯的活性顺序与…一致比之前报道的结果更多。该评价系统采用浓度-响应曲线估算50%有效浓度的优点是：1)平均值的标准误差小；2)无论实验条件如何，都能测定其恒定活度；3)能评价在测量中没有观察到的角超过标准角(通常为140度)的弱化合物的活度。利用该系统对昆虫蜕皮激素激动剂如蜕皮激素和二苯甲酰肼，哺乳动物激素如己烯雌酚和糖皮质激素，以及其他新合成的化合物如肟类和苯基苯甲醚化合物进行了筛选，但没有一种化合物是不起作用的。构建了20-羟基蜕皮酮和油菜素内酯的三维结构，并对它们在C-17位烷基链与甾体骨架D环之间的扭转角进行了比较。较少

The rice lamina inclination test was used to detect the brassinosteroid activity. After treating the rice cultivar with various concentration of compounds according to the standard bioassay system, the magnitude of the angle induced between the leaf and sheath was measured using semicircular protractor. The angles induced after treatments with various concentration of compounds were plotted against the concentrations. In each assay, both treatments with a solvent (DMSO) and a high concentration of brassinolide (10^<-6> M) were included as the negative and positive control, respectively. From each concentration-response curve, the 50% effective concentration EC_<50> (M) was determined for each compound, and the reciprocal logarithm of EC_<50> was used as the activity index. Using this method, we evaluated reproducible EC_<50> values for brassinolide, castasterone, and epibrassinolide to be 9.14, 8.08, and 8.28, respectively. The order of the activity of brassinosteroids is consistent wi … More th the previously reported results. The advantage of this evaluation system in which the concentration-response curve is adopted to estimate the 50% effective concentration is that 1) the standard error of averaged value is small, 2) the constant activity is able to be determined regardless of the experimental conditions, 3) the activity of weak compounds for which the angle exceeding the standard angle (usually 140 degree) is not observed in the measurement is able to be evaluated. With this bioassay system, insect molting hormone agonists such as ecdysone and dibenzoylhydrazines, mammalian hormones such as diethylstilbestrol and glucocorticoids, and other newly synthesized compounds such as oxime and phenyl benzyl ether compounds were screened, although none of compounds tested was not active. Three-dimensional (3-D) structures of 20-hydroxyecdysone and brassinolide were constructed and compared between them, which were different with respect to the torsion angle between alkyl chain at C- 17 position and D-ring of steroid skelton. Less