Zaidi R, Hadi S M
Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, India.
Biochem Int. 1992 Dec;28(6):1135-43.
Gossypol, a polyphenolic binaphthyl dialdehyde found in cotton seeds, is a dietary mutagen and a potential male contraceptive. We have earlier shown that in the presence of Cu(II) gossypol causes strand breakage in double stranded DNA and that active oxygen species are involved in this reaction. In this paper we present experiments to suggest that gossypol may be oxidised by Cu(II) to a gossypol radical that may directly react with DNA. Changes in absorption spectrum and fluorescence emission spectrum of gossypol indicated that it binds to both double stranded and single stranded DNA. Gossypol and Cu(II) were shown to form a charge transfer complex that decayed in an oxygen independent reaction. The rate of DNA degradation by gossypol-Cu(II) complex was found to be the same both in the presence and absence of molecular oxygen.
棉酚是一种存在于棉籽中的多酚类联萘二醛，它是一种膳食诱变剂，也是一种潜在的男性避孕药。我们之前已经表明，在铜离子（II）存在的情况下，棉酚会导致双链DNA链断裂，并且活性氧物种参与了这一反应。在本文中，我们展示了一些实验，表明棉酚可能被铜离子（II）氧化成棉酚自由基，该自由基可能直接与DNA反应。棉酚吸收光谱和荧光发射光谱的变化表明，它能与双链和单链DNA结合。棉酚和铜离子（II）形成了一种电荷转移复合物，该复合物在不依赖氧气的反应中衰变。发现棉酚-铜离子（II）复合物降解DNA的速率在有分子氧和无分子氧的情况下是相同的。
