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抗坏血酸(H_2A)的主要作用是防治坏血病。然而许多实验证明,抗坏血酸的缺乏与肿瘤的发生和发展有一定关联,大剂量使用抗坏血酸可以从一定程度上防治实验动物或人类肿瘤。其预防肿瘤作用可能是通过如下作用实现的。抗坏血酸作为一种强还原剂可以阻断食物及药物中亚硝酸盐与胺类生成致癌物亚硝酸铵;抗坏血酸氧化,特别是在有微量过渡金属离子,如Cu~(2+),Fe~(3+)存在下,生成各种活性氧对肿瘤细胞产生细胞毒作用。为了探讨抗坏血酸抗肿瘤的机理,首先要搞清其氧化,尤其是在过渡金属离子存在下的氧化机理。本文旨在研究生理条件下,二甘氨酰组氨酸(GGH)对Cu(Ⅱ)催化抗坏血酸氧化的抑制,检测反应中间体,并对该体系的抗肿瘤活性进行研究。
The main role of ascorbic acid (H_2A) is to prevent scurvy. However, many experiments have proved that the lack of ascorbic acid is associated with the occurrence and development of tumors. Ascorbic acid can prevent and treat experimental animals or human tumors to some extent. Its role in preventing the tumor may be achieved through the following actions. Ascorbic acid as a strong reducing agent can block nitrite and amines in food and medicine to generate carcinogenic ammonium nitrite; ascorbate oxidation, especially in the presence of trace transition metal ions such as Cu ~ (2 +), Fe ~ ( 3+) in the presence of various reactive oxygen species generated cytotoxic effect on tumor cells. In order to explore the anti-tumor mechanism of ascorbate, we must first understand its oxidation, especially in the presence of transition metal ions in the oxidation mechanism. The purpose of this paper is to study the inhibition of Cu (Ⅱ) catalyzed oxidation of ascorbic acid by diglycylglycine histidine (GGH) under physiological conditions. The reaction intermediates were detected and the anti-tumor activity of this system was studied.