Departamento de Química, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2340000, Chile.
Laboratory of Growth Regulators, Institute of Experimental Botany, The Czech Academy of Sciences, Palacký University, Šlechtitelů 27, 78371 Olomouc, Czech Republic.
Molecules. 2021 Feb 22;26(4):1173. doi: 10.3390/molecules26041173.
The metabolism of brassinosteroid leads to structural modifications in the ring skeleton or the side alkyl chain. The esterification and glycosylation at C-3 are the most common metabolic pathways, and it has been suggested that conjugate brassinosteroids are less active or inactive. In this way, plants regulate the content of active brassinosteroids. In this work, the synthesis of brassinosteroid 24-norcholane type analogs conjugated at C-3 with benzoate groups, carrying electron donor and electron attractant substituents on the aromatic ring, is described. Additionally, their growth-promoting activities were evaluated using the Rice Lamina Inclination Test (RLIT) and compared with that exhibited by brassinolide (used as positive control) and non-conjugated analogs. The results indicate that at the lowest tested concentrations (10-10 M), all analogs conjugated at C-3 exhibit similar or higher activities than brassinolide, and the diasteroisomers with configuration at C-22 are the more active ones. Increasing concentration (10 M) reduces the biological activities of analogs as compared to brassinolide.
油菜素内酯的代谢会导致环骨架或侧链烷基发生结构修饰。C-3 位的酯化和糖基化是最常见的代谢途径，有研究表明，轭合油菜素内酯的活性较低或没有活性。通过这种方式，植物可以调节具有活性的油菜素内酯的含量。在这项工作中，描述了具有苯甲酸盐基团的油菜素甾醇 24-降胆烷型类似物在 C-3 位的轭合，其在芳环上带有供电子和吸电子取代基。此外，还使用水稻叶片倾斜试验 (RLIT) 评估了它们的生长促进活性，并将其与油菜素内酯（用作阳性对照）和非轭合类似物进行了比较。结果表明，在所测试的最低浓度（10-10 M）下，所有在 C-3 位轭合的类似物的活性均与油菜素内酯相似或更高，并且 C-22 位构型为 的非对映异构体的活性更高。与油菜素内酯相比，增加浓度（10 M）会降低类似物的生物活性。
