Strand scission in DNA by Gossypol and Cu(II): Role of Cu(I) and oxygen-free radicals
✍ Scribed by Zaidi, Rana ;Hadi, S. M.
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 784 KB
- Volume
- 7
- Category
- Article
- ISSN
- 0887-2082
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✦ Synopsis
Gossypol, a polyphenolic binaphthyl dialdehyde found in cotton seeds, is a dietary mutagen and a potential male contraceptive. In the presence of CdII), gossypol caused breakage of supercoiled plasmid pBR322 DNA. The products were relaxed circles or a mixture of these and linear molecules. Other metal ions tested [Ni(II), Co(II), Mn(II), and Fe(1I)I were ineffective or less effective in the DNA breakage reaction. In the case of gossypol-Cu(I1) mediated cleavage, Cu(1) was shown to be an essential intermediate by using the Cu(1) sequestering reagent bathocuproine. By us- ing job plots, it was established that in the absence of DNA, eight Cu(I1) ions can be reduced by one gossypol molecule. The involvement of active oxygen species, such as singlet oxygen and H,O,, was established by the inhibition of DNA breakage by catalase and by sodium aide. It was further shown that gossypol is capable of directly producing H202.