Photodegradation of cobalamins in aqueous solutions and in human blood
Photodegradation of cobalamins in aqueous solutions and in human blood
复制标题
DOI：
10.1016/j.jphotobiol.2013.03.001
复制
发表时间：
2013-05-05
影响因子：
5.4
通讯作者：
Nizauskaite, Zivile
中科院分区：
文献类型：
--
作者：
Juzeniene, Asta;Nizauskaite, Zivile
维生素B12（钴胺素）是正常红细胞形成、神经功能和DNA合成所必需的。钴盐溶液对光敏感，但尚未进行全面研究以比较不同钴盐在UVA暴露下的光稳定性。利用紫外吸收光谱法研究了四种钴胺（甲基钴胺（MeCbl）、腺苷钴胺（AdCbl）、羟钴胺（OHCbl）和氰钴胺（CNCbl））在水溶液（pH = 7.4）中的紫外光降解。研究了OHCbl在内源性光敏剂核黄素存在和不存在下的光降解。测定了4例银屑病患者夏季前后的血清维生素B12浓度。钴胺素的生物活性形式AdCbl和MeCbl在UVA暴露期间在几秒钟内转化为OHCbl。OHCbl是最稳定的钴胺素。然而，活性氧物质增加OHCbl的降解速率。我们对人类的初步研究表明，在挪威的夏季，血清维生素B12浓度没有受到显着影响。需要进一步的工作来确定维生素B12在生活在低纬度或使用日光浴床的人中的光稳定性。(C)2013爱思唯尔有限公司版权所有。
Vitamin B12 (cobalamin) is required for proper red blood cell formation, neurologic function, and DNA synthesis. Cobalamins in solutions are light sensitive, but no comprehensive study has been performed to compare the photostability of different cobalamins under UVA exposure. Their indirect photodegradation due to their antioxidant properties and their photostability in vivo have also not been studied so far.The photodegradation of four cobalamins (methylcobalamin (MeCbl), adenosylcobalamin (AdCbl), hydroxocobalamin (OHCbl) and cyanocobalamin (CNCbl)) under UVA exposure in aqueous solutions (pH = 7.4) have been investigated by absorption spectroscopy. The photodegradation of OHCbl in the absence and presence of the endogenous photosensitizer riboflavin was studied. Serum vitamin B12 concentrations before and after summer were measured in four patients with psoriasis.All studied cobalamins are photolabile. The biologically active forms of cobalamin, AdCbl and MeCbl, are converted to OHCbl within seconds during UVA exposure. OHCbl is the most stable cobalamin. However, reactive oxygen species increases the degradation rate of OHCbl. Our pilot study on humans demonstrates that serum vitamin B12 concentrations are not significantly affected during summertime in Norway. Further work is needed to determine vitamin B12 photostability in humans living at lower latitudes or using sunbeds. (C) 2013 Elsevier B.V. All rights reserved.