Juzeniene Asta, Grigalavicius Mantas, Ma Li Wei, Juraleviciute Marina
Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Montebello, N-0310 Oslo, Norway.
Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Montebello, N-0310 Oslo, Norway.
J Photochem Photobiol B. 2016 Feb;155:116-21. doi: 10.1016/j.jphotobiol.2016.01.001. Epub 2016 Jan 6.
Folic acid (FA) is the synthetic form of folate (vitamin B9), present in supplements and fortified foods. During ultraviolet (UV) radiation FA is degraded to 6-formylpterin (FPT) and pterin-6-carboxylic acid (PCA) which generate reactive oxygen species (ROS) and may be phototoxic. The aim of the present study was to investigate the production of ROS and phototoxicity of FA, FPT and PCA in skin cells during UVA exposure. The production of ROS and phototoxicity of FA, FPT and PCA were studied in the immortal human keratinocytes (HaCaT) and malignant skin cells (A431 and WM115) during UVA exposure. Increased ROS production and the photoinactivation of cells in vitro were observed during UVA exposure in the presence of FA, FPT and PCA. HPLC analysis revealed that 10 μM FA photodegradation was around 2.1 and 5.8-fold faster than that of 5 μM and 1 μM FA. Photodegradation of FA is concentration dependent, and even non-phototoxic doses of FA and its photoproducts, FPT and PCA, generate high levels of ROS in vitro. FA, FPT and PCA are phototoxic in vitro. The photodegradation of topical or unmetabolized FA during UV exposure via sunlight, sunbeds or phototherapy may lead to ROS production, to the cutaneous folate deficiency, skin photocarcinogenesis and other deleterious skin effects. Further studies are needed to confirm whether UV exposure can decrease cutaneous and serum folate levels in humans taking FA supplements or using cosmetic creams with FA.
叶酸（FA）是叶酸（维生素B9）的合成形式，存在于补充剂和强化食品中。在紫外线（UV）辐射下，FA会降解为6-甲酰蝶呤（FPT）和蝶呤-6-羧酸（PCA），它们会产生活性氧（ROS），可能具有光毒性。本研究的目的是调查在UVA照射期间皮肤细胞中FA、FPT和PCA的ROS产生及光毒性。在UVA照射期间，在永生化人角质形成细胞（HaCaT）和恶性皮肤细胞（A431和WM115）中研究了FA、FPT和PCA的ROS产生及光毒性。在存在FA、FPT和PCA的情况下，UVA照射期间观察到体外细胞中ROS产生增加和光灭活。高效液相色谱分析显示，10μM FA的光降解速度比5μM和1μM FA分别快约2.1倍和5.8倍。FA的光降解具有浓度依赖性，即使是非光毒性剂量的FA及其光产物FPT和PCA在体外也会产生高水平的ROS。FA、FPT和PCA在体外具有光毒性。在通过阳光、日光浴床或光疗进行紫外线照射期间，局部或未代谢的FA的光降解可能导致ROS产生、皮肤叶酸缺乏、皮肤光致癌作用和其他有害的皮肤影响。需要进一步研究以确认紫外线照射是否会降低服用FA补充剂或使用含FA化妆品乳膏的人的皮肤和血清叶酸水平。
