花椰菜是时下流行的蔬菜,多吃有益。可是你知道吗,花椰菜其实还有更重要的作用。美国科学家近日研究发现,花椰菜的一种提取物能够帮助人体预防太阳紫外线伤害,从而降低患皮肤癌的风险。相关论文10月23日在线发表于美国《国家科学院院刊》(PNAS)上。
紫外线照射和许多化学物质会对人体DNA造成氧化伤害,并可能导致癌症。研究人员一直在寻找多种方法来激活人体内的天然抗氧化剂,以分解这些会对人体造成伤害的氧化因子。
之前在小鼠身上进行的研究发现,花椰菜中含有的异硫氰酸盐(sulforaphane)能帮助减少紫外线照射造成的炎症。在最新的研究中,美国约翰·霍普金斯大学的药理学家Paul Talalay和同事让六个志愿者背部接受不同量的紫外线照射,其中有些志愿者使用了花椰菜提取物作为防护,另一些则没有。研究人员在不同的照射间隔测量了志愿者产生的皮肤红块,以确定细胞损伤的程度。结果发现,如果在紫外线照射前三日每天都使用花椰菜提取物,在照射后,细胞损伤平均会下降37%。
Talalay说,这表明异硫氰酸盐能够帮助细胞抵御伤害,所以含有异硫氰酸盐成分的药膏能够降低因紫外线照射而患皮肤癌的风险。
美国罗切斯特大学的皮肤病专家Francisco Tausk表示,世界上患皮肤癌的人数正在不断增加,此次研究将可能对改善这一状况发挥重要作用。
美国达特默斯医学院的药理学家Michael Sporn认为,这一研究对于进行器官移植的患者也将发挥作用,这些患者往往因服用免疫抑制药物而增加患皮肤癌的风险。同时,此次研究还清楚地说明,化学预防(chemoprevention)能对人体发挥作用,值得继续研究。(科学网 梅进/编译)
(《国家科学院院刊》(Proceedings of the National Academy of Sciences),10.1073/pnas.0708710104,Paul Talalay,Albena T. Dinkova-Kostova)
原始出处:
Published online before print October 23, 2007
Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0708710104
Sulforaphane mobilizes cellular defenses that protect skin against damage by UV radiation
Paul Talalay,, Jed W. Fahey,, Zachary R. Healy, Scott L. Wehage, Andrea L. Benedict, Christine Min, and Albena T. Dinkova-Kostova,¶
Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, ¶Division of Clinical Pharmacology, Department of Medicine, School of Medicine, and Department of International Health, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, MD 21205
Contributed by Paul Talalay, September 13, 2007 (sent for review September 10, 2007)
Abstract
UV radiation (UVR) is a complete carcinogen that elicits a constellation of pathological events, including direct DNA damage, generation of reactive oxidants that peroxidize lipids and damage other cellular components, initiation of inflammation, and suppression of the immune response. Recent dramatic increases in the incidence of nonmelanoma skin cancers are largely attributable to higher exposure of an aging population to UVR. Therefore, the development of cellular strategies for intrinsic protection of the skin against the deleterious effects of UVR is imperative. Here we show that erythema resulting from UVR is a comprehensive and noninvasive biomarker for assessing UVR damage and can be precisely and easily quantified in human skin. Topical application of sulforaphane-rich extracts of 3-day-old broccoli sprouts up-regulated phase 2 enzymes in the mouse and human skin, protected against UVR-induced inflammation and edema in mice, and reduced susceptibility to erythema arising from narrow-band 311-nm UVR in humans. In six human subjects (three males and three females, 28–53 years of age), the mean reduction in erythema across six doses of UVR (300–800 mJ/cm2 in 100 mJ/cm2 increments) was 37.7% (range 8.37–78.1%; P = 0.025). This protection against a carcinogen in humans is catalytic and long lasting.
erythema | nicotinamide:quinone oxidoreductase 1 | skin tumor | chemoprotection