Synthesis, Electrochemistry, and Bioactivity of the Cyanobacterial Calothrixins and Related Quinones
Date
2004
Authors
Bernardo, Paul
Chai, Christina
Heath, Graham
Mahon, Peter
Smith, Geoffrey D
Waring, Paul
Wilkes, Bronwyn
Journal Title
Journal ISSN
Volume Title
Publisher
American Chemical Society
Abstract
The calothrixins are quinone-based natural products isolated from Calothrix cyanobacteria which show potent antiproliferative properties against several cancer cell lines. Preliminary mechanistic studies suggest that the biological mode of action of the calothrixins maybe linked to their ability to undergo redox cycling. In this study we compare the bioactivities of the calothrixins with those of structurally related quinones in order to identify the structural features in the calothrixins essential for biological activity. In particular, the reduction potentials of the calothrixins and some related quinones were measured electrochemically. Our studies indicate that while there is no direct correlation between the reduction potentials and biological activities of the studied compounds, in all cases quinones with EC50 values <1.6 μM undergo reduction to their respective semiquinones readily, with their E1/2 values being more positive than -0.5 V versus the standard hydrogen electrode (SHE).
Description
Keywords
Keywords: antineoplastic agent; benzocarbazoledione; calothrixin a; calothrixin b; carboquone; ellipticine derivative; menadione; quinone derivative; semiquinone; unclassified drug; antineoplastic activity; article; cancer cell culture; controlled study; Cyanobacte
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Source
Journal of Medicinal Chemistry
Type
Journal article