作者:Osamu Negishi、Kenji Sugiura、Yukiko Negishi
DOI:10.1021/jf901204m
日期:2009.11.11
(14)C-Labeled phenylalanine, 4-coumaric acid, 4-hydroxybenzaldehyde, 4-hydroxybenzyl alcohol, ferulic acid, and methionine were applied to disks of green vanilla pods 3 and 6 months after pollination (immature and mature pods), and the conversion of these compounds to vanillin or glucovanillin was investigated. In mature green vanilla pods, radioactivities of 11, 15, 29, and 24% from (14)C-Iabeled phenylalanine, 4-coumaric acid, ferulic acid, and methionine, respectively, were incorporated into glucovanillin within 24 h. In the incorporation processes of methionine and phenylalanine into glucovanillin, some of the (14)C labels were also trapped by the unlabeled ferulic acid. However, (14)C-labeled 4-hydroxybenzaldehyde and 4-hydroxybenzyl alcohol were not converted to glucovanillin. On the other hand, in immature green vanilla pods radioactivities of the above six compounds were not incorporated into glucovanillin. Although 4-coumaric acid, ferulic acid, 4-hydroxybenzaidehyde, and 4-hydroxybenzyl alcohol were converted to the respective glucose esters or glucosides and vanillin was converted to glucovanillin, their conversions were believed to be from the detoxication of the aglycones. These results suggest that the biosynthetic pathway for vanillin is 4-coumaric acid -> -> ferulic acid -> -> vanillin -> glucovanillin in mature vanilla pods.
(14)C-标记的苯丙氨酸、4-香豆酸、4-羟基苯甲醛、4-羟基苯乙醇、阿魏酸和甲硫氨酸被分别应用于授粉后的绿兰香荚切片(3个月和6个月后,即未成熟和成熟荚),并研究了这些化合物转化为香兰素或糖苷香兰素的情况。在成熟的绿兰香荚中,分别来自14C标记的苯丙氨酸、4-香豆酸、阿魏酸和甲硫氨酸的11%、15%、29%和24%的放射性在24小时内被整合入糖苷香兰素。在甲硫氨酸和苯丙氨酸整合入糖苷香兰素的过程中,部分14C标记也被无标记的阿魏酸捕捉。然而,14C标记的4-羟基苯甲醛和4-羟基苯乙醇并未转化为糖苷香兰素。另一方面,在未成熟的绿兰香荚中,上述六种化合物的放射性并未被整合入糖苷香兰素。虽然4-香豆酸、阿魏酸、4-羟基苯甲醛和4-羟基苯乙醇分别转化为相应的葡萄糖苷或糖苷,而香兰素转化为糖苷香兰素,但这些转化被认为源自苷元的解毒作用。这些结果表明,成熟兰香荚中的香兰素生物合成途径为:4-香豆酸 → 阿魏酸 → 香兰素 → 糖苷香兰素。