Abstract
Photosensitising properties of four naturally occurring anthraquinones, viz., erythroglaucin (ERG), teloschistin (TEL), 1-hydroxy-2-methylanthraquinone (HYQ) and 1-methoxy-2-hydroxyanthraquinone (MEQ) are studied. Photogeneration of singlet oxygen was monitored by both optical RNO (para-nitrosodimethylaniline) bleaching and electron paramagnetic resonance spectroscopy (EPR)-2,2,6,6-tetramethyl piperidinol (TEMPL) methods. In comparison with rose bengal (RB), singlet oxygen generating efficiencies of ERG, TEL, HYQ and MEQ are determined to be 0.10, 0.14, 0.02 and 0.13, respectively. The formation of O2− was monitored by optical spectroscopy using SOD inhibitable cytochrome c reduction assay. Photolysis of ERG and MEQ in DMSO, in the presence of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) generated a multiline EPR spectrum characteristic of mixture of O2−, OH and OCH3 adducts. Both electron transfer (Type I) and energy transfer (Type II) paths are involved in the photosensitisation of ERG, TEL, HYQ and MEQ. Quantum efficiencies of the quinones exhibit correlation with their half-wave potentials. The photoinduced DNA cleavage by quinones was examined with covalently closed circular plasmid DNA, in vitro. Observed DNA photo strand scission correlates with the reactive oxygen species (ROS) generating efficiencies of the quinones.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Photochemistry and Photobiology A: Chemistry
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
