STRAND SCISSION IN DNA INDUCED BY CURCUMIN IN THE PRESENCE OF CU(II)

Curcumin, a naturally occurring phytochemical responsible for the colo ur of turmeric, has shown a wide range of pharmacological properties i ncluding anti-inflammatory, anti-tumour promoter and anti-oxidant effe cts. In this paper we show that in the presence of Cu(II), curcumin ca used breakage of calf thymus and supercoiled plasmid pBR322 DNA. The p roducts were relaxed circles with no detectable linear forms. Other me tal ions tested (Mg(II), Ca(II), Fe(LI) and Ni(II)) were ineffective o r less effective in the DNA breakage reaction. Cu(I) was shown to be a n essential intermediate by using the Cu(I)-specific sequestering reag ent neocuproine. The involvement of active oxygen species, such as H2O 2 and O-1(2) was established by the inhibition of DNA breakage by cata lase and azide. Curcumin is also able to directly produce O-2(-) and H 2O2 and in the presence of Cu(II), OH. is generated. Absorption spectr a of curcumin in the presence of DNA indicated that a complex is forme d between the two. The results are discussed in relation to the establ ished pro-oxidant activities of other known anti-oxidants. (C) 1998 El sevier Science Ireland Ltd.