Brown S A, Sampathkumar S
Can J Biochem. 1977 Jul;55(7):686-92. doi: 10.1139/o77-099.
Bergapten and xanthotoxin, labelling in the methyl group wich carbon-14 or tritiated at three skeletal carbons, were administered to leaves of Heracleum lanatum and to cell cultures of Ruta graveolens. In all experiments xanthotoxin was the more efficient precursor of isopimpinellin, although bergapten was always incorporated to a measurable extent. Double-labelling experiments showed that both precursors, especially bergapten, underwent considerable demethylation (and presumably remethylation) before conversion to isopimpinellin. 5-Hydroxyxanthotoxin and 8-hydroxybergapten were both O-methylated by cell-free extracts of Ruta cells to isopimpinellin, in reactions mediated by discrete O-methyltransferases. 8-Hydroxy[Me-14C]bergapten was converted with a high degree of incorporation to isopimpinellin by Ruta cells in vivo, and it is suggested that the preference for the pathway via xanthotoxin may be due to more rapid hydroxylation of this substrate.
将标记有碳 -14 甲基或在三个骨架碳原子处用氚标记的补骨脂素和花椒毒素施用于绵毛独活叶片和芸香细胞培养物中。在所有实验中，尽管补骨脂素总是能在一定程度上被掺入，但花椒毒素是异茴芹素更有效的前体。双标记实验表明，两种前体，尤其是补骨脂素，在转化为异茴芹素之前都经历了相当程度的去甲基化（可能还有再甲基化）。5 - 羟基花椒毒素和 8 - 羟基补骨脂素在离散的 O - 甲基转移酶介导的反应中，都被芸香细胞的无细胞提取物 O - 甲基化为异茴芹素。8 - 羟基[甲基 - 14C]补骨脂素在体内被芸香细胞高度掺入地转化为异茴芹素，并且有人提出，对经由花椒毒素途径的偏好可能是由于该底物的羟基化更快。
