Ohnmacht Stephan, Nava Phillip, West Ryan, Parker Robert, Atkinson Jeffrey
Department of Chemistry and Centre for Biotechnology, Brock University, 500 Glenridge Avenue, St. Catharines, Ont., Canada L2S 3A1.
Bioorg Med Chem. 2008 Aug 15;16(16):7631-8. doi: 10.1016/j.bmc.2008.07.020. Epub 2008 Jul 13.
The oxidative metabolism of tocopherols and tocotrienols by monooxygenases is a key factor in the plasma and tissue clearance of forms of vitamin E other than alpha-tocopherol. It is well known that a commonly ingested form of vitamin E, gamma-tocopherol, has greatly reduced plasma half-life (faster clearance) than alpha-tocopherol. The tocotrienols are metabolized even faster than gamma-tocopherol. Both gamma-tocopherol and alpha- and delta-tocotrienol possess intriguing biological activities that are different from alpha-tocopherol, making them potentially of interest for therapeutic use. Unfortunately, the fast clearance of non-alpha-tocopherols from animal tissues is a significant hurdle to maximizing their effect(s) as dietary supplements. We report here the design and synthesis of N-heterocycle-containing analogues of alpha-tocopherol that act as inhibitors of Cyp4F2, the key monooxygenase responsible for omega-hydroxylation of the side chain of tocols. In particular, an omega-imidazole containing compound, 1, [(R)-2-(9-(1H-imidazol-1-yl)nonyl)-2,5,7,8-tetramethylchroman-6-ol] had an ED(50) for inhibition of gamma-CEHC production from gamma-tocopherol of approximately 1 nM when tested in HepG2 cells in culture. Furthermore, feeding of 1 to mice along with rapidly metabolized delta-tocopherol, resulted in a doubling of the delta-tocopherol/alpha-tocopherol ratio in liver (P<0.05). Thus, 1 may be a useful adjuvant to the therapeutic use of non-alpha-tocopherols.
生育酚和生育三烯酚通过单加氧酶的氧化代谢是除α-生育酚之外的其他维生素E形式在血浆和组织中清除的关键因素。众所周知,维生素E的一种常见摄入形式γ-生育酚,其血浆半衰期比α-生育酚大大缩短(清除更快)。生育三烯酚的代谢甚至比γ-生育酚更快。γ-生育酚以及α-和δ-生育三烯酚都具有与α-生育酚不同的有趣生物活性,这使得它们在治疗用途上具有潜在的吸引力。不幸的是,非α-生育酚从动物组织中的快速清除是将它们作为膳食补充剂发挥最大效果的一个重大障碍。我们在此报告了含N-杂环的α-生育酚类似物的设计与合成,这些类似物可作为Cyp4F2的抑制剂,Cyp4F2是负责生育酚侧链ω-羟基化的关键单加氧酶。特别是,一种含ω-咪唑的化合物1,[(R)-2-(9-(1H-咪唑-1-基)壬基)-2,5,7,8-四甲基色满-6-醇],在培养的HepG2细胞中测试时,对抑制γ-生育酚产生γ-CEHC的ED(50)约为1 nM。此外,给小鼠喂食1并同时给予快速代谢的δ-生育酚,导致肝脏中δ-生育酚/α-生育酚的比例翻倍(P<0.05)。因此,1可能是治疗性使用非α-生育酚的一种有用佐剂。