Unexpected conversion of epinephrine into tetrahydroisoquinolines in a solution containing ascorbic acid.
作者:AKIRA SHIRAHATA、MASANORI YOSHIOKA、ZENZO TAMURA
DOI:10.1248/cpb.30.1352
日期:——
Degradation of 3H-epinephrine during incubation for 14 h at 37°C in a phosphate buffer, pH 7.0, containing ascorbic acid was observed in a study on the radioimmunoassay of epinephrine. Chromatographic separations of the products were carried out on a large scale. They were identified as 1, 2, 3, 4-tetrahydro-4, 6, 7-trihydroxy-2-methylisoquinoline (1) and 1, 2, 3, 4-tetrahydro-4, 7, 8-trihydroxy-2-methylisoquinoline (2). These products were synthesized from epinephrine and formaldehyde for the first time. Our results suggested that 3H-epinephrine reacted with formaldehyde generated through the oxidation of ascorbic acid by oxygen from air under the incubation conditions used above to yield 1 or 2. Care is clearly required in using ascorbic acid as an antioxidant in catecholamine studies.
在一项有关肾上腺素放射免疫测定的研究中,观察到 3H-epinephrine 在含有抗坏血酸的 pH 值为 7.0 的磷酸盐缓冲液中于 37°C 孵育 14 小时后发生降解。对产物进行了大规模的色谱分离。它们被鉴定为 1, 2, 3, 4-四氢-4, 6, 7-三羟基-2-甲基异喹啉(1)和 1, 2, 3, 4-四氢-4, 7, 8-三羟基-2-甲基异喹啉(2)。这些产物首次由肾上腺素和甲醛合成。我们的结果表明,在上述培养条件下,3H-肾上腺素与抗坏血酸被空气中的氧气氧化生成的甲醛发生反应,生成 1 或 2。在儿茶酚胺研究中使用抗坏血酸作为抗氧化剂显然需要谨慎。