Synthesis and biological activity of 3′-chloro, -bromo, and -iodoabscisic acids, and biological activity of 3′-fluoro-8′-hydroxyabscisic acid
作者:Sho Arai、Yasushi Todoroki、Satomi Ibaraki、Yoshikazu Naoe、Nobuhiro Hirai、Hajime Ohigashi
DOI:10.1016/s0031-9422(99)00444-6
日期:1999.12
(+)-3'-Chloro, -bromo and -iodoabscisic acids were synthesized, and their biological activities and metabolism were examined, as well as that of (+)-3'-fluoroabscisic acid. This was in order to estimate the effects of altered electron density at the C-2' position of abscisic acid on both biological activity and metabolic stability. The biological activities of (+)-3'-chloro acid bromoabscisic acids were similar to, or higher than, those of(+)-abscisic acid in four bioassays, while (+)-3'-iodoabscisic acid was more potent in two bioassays and less potent than (+)-abscisic acid in the other two bioassays. The biological activities of 3'-haloabscisic acids seem to be dependent on the 3'-halogens, but not on the electron density at C-2'. The metabolism of(+)3'-haloabscisic acids to ca. 50% of their original levels in the media of rice cell suspension culture was similar to that of(+)abscisic acid. Metabolites from (+)-3'-chloro, -bromo and -iodoabscisic acids were not found in the culture media and cells, while (+)-3'-fluoroabscisic acid gave (+)-3'-fluoro-8'-hydroxyabscisic acid as a stable metabolite. (+)-3'-fluoro-8'- hydroxyabscisic acid showed biological activities lower than (+)-3'-fluoroabscisic acid, but higher than (-)-3'alpha-Fluorophascsic acid. These findings suggested that the biological activity of (+)-8'-hydroxyabscisic acid is intermediate between those of (+)abscisic acid and (-)-phaseic acid. Abscisic acid may be inactivated in a stepwise manner by metabolism in plants. (C) 1999 Elsevier Science Ltd. All rights reserved.
(+)-3'-氯、-溴和-碘脱落酸被合成,并对其生物学活性和代谢进行了研究,同时也研究了(+)-3'-氟脱落酸的这些性质。这是为了评估脱落酸分子中C-2'位置电子密度变化对其生物学活性和代谢稳定性的影响。在四种生物测定中,(+)-3'-氯、-溴脱落酸的生物活性与(+)-脱落酸相当,或高于后者;而(+)-3'-碘脱落酸在两种生物测定中表现出更强的活性,在另外两种测定中则活性较低。3'-卤代脱落酸的生物活性似乎取决于3'位的卤素,而不是C-2'位的电子密度。在水稻细胞悬浮培养液中,(+)-3'-卤代脱落酸的代谢程度(约降至原浓度的50%)与(+)-脱落酸相似。来自(+)-3'-氯、-溴和-碘脱落酸的代谢产物未在培养液和细胞中检出,而(+)-3'-氟脱落酸产生(+)-3'-氟-8'-羟基脱落酸作为一种稳定的代谢产物。(+)-3'-氟-8'-羟基脱落酸的生物活性低于(+)-3'-氟脱落酸,但高于(-)-3'α-氟法尼酸。这些结果表明,(+)-8'-羟基脱落酸的生物活性介于(+)-脱落酸和(-)-法尼酸之间。脱落酸可能通过植物代谢以逐步的方式被失活。© 1999 Elsevier Science Ltd. 保留所有权利。