Planta Med 2010; 76(6): 589-594
DOI: 10.1055/s-0029-1240604
Pharmacology
Original Papers
© Georg Thieme Verlag KG Stuttgart · New York

Comparative Antioxidant, Prooxidant and Cytotoxic Activity of Sigmoidin A and Eriodictyol

Solomon Habtemariam1 , Ermias Dagne2
  • 1Medway School of Science, The University of Greenwich, Chatham Maritime, Kent, U. K.
  • 2Department of Chemistry, Addis Ababa University, Addis Ababa, Ethiopia
Further Information

Publication History

received August 28, 2009 revised –

accepted October 21, 2009

Publication Date:
25 November 2009 (online)

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Abstract

Sigmoidin A (SGN) is a prenylated flavanone derivative of eriodictyol (ERD) with reported moderate antioxidant, antimicrobial and anti-inflammatory activity. Since ERD and other structurally similar antioxidant phenolic compounds have been shown to induce prooxidative macromolecular damage and cytotoxicity in cancer cells, the comparative in vitro effects of these structural analogues on cancer cell viability and Cu(II)-dependent DNA damage were studied. In the presence of Cu(II) ions, both SGN and ERD (7.4–236 µM) caused comparable concentration-dependent pBR322 plasmid DNA strand scission. The DNA damage induced by SGN and ERD could be abolished by ROS scavengers, glutathione (GSH) and catalase as well as EDTA and a specific Cu(I) chelator neocuproine. Both ERD and SGN readily reduce Cu(II) to Cu(I) suggesting a prooxidative mechanism of DNA damage. In a cell free system, ERD and SGN did also show comparable radical scavenging activity. SGN was, however, by an order of magnitude more cytotoxic to cancer cells than ERD and this effect was significantly attenuated by GSH suggesting a prooxidative mechanism of cell death. A depletion of intracellular GSH level by SGN in cancer cells is also demonstrated.