title: Total inhibition of (1)O2-induced oxidative damage to guanine bases of DNA/RNA by turmeric extracts.
abstract: The guanine base of nucleic acids is known to be very reactive towards degradation by (1)O2-induced oxidative stress. Oxidative reactions of DNA are linked to many human diseases including cancer. Among the various forms of reactive O2 species (OH, (1)O2 or O2(-)), the oxidative stress caused by (1)O2 is of particular physiologic importance because of its selectively long life in aqueous medium and its ability to diffuse through a cell membrane. In this study we investigated the degradation of a model compound guanosine (Guo) by (1)O2, which was generated by riboflavin-induced photosensitization and by molybdate ion catalyzed disproportionation of H2O2. We observed the remarkable ability of an aqueous and alcoholic extracts of Turmeric (Curcuma longa) as an extraordinary scavenger of (1)O2 to completely inhibit the degradation of Guo. The alcoholic extracts were more effective in their antioxidant activity than the corresponding water extract. This naturally occurring antioxidant offers a most economical supplement to protect biologically significant molecules from the oxidative stress induced by (1)O2.
authors.affiliation: Department of Chemistry and Biochemistry, ISES Labs, Russell Sage College, Troy, NY 12180, USA; Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180, USA. Electronic address: joship2@rpi.edu.
authors.forename: Prakash C
authors.initials: PC
authors.lastname: Joshi
authors.affiliation: Department of Chemistry and Biochemistry, ISES Labs, Russell Sage College, Troy, NY 12180, USA.
authors.forename: Hsin H
authors.initials: HH
authors.lastname: Li
authors.affiliation: Department of Chemistry and Biochemistry, ISES Labs, Russell Sage College, Troy, NY 12180, USA.
authors.forename: Monique
authors.initials: M
authors.lastname: Merchant
authors.affiliation: Department of Chemistry and Biochemistry, ISES Labs, Russell Sage College, Troy, NY 12180, USA. Electronic address: keanet@sage.edu.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Keane
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D030024:Curcuma / Q000737:chemistry*; D004249:DNA Damage; D000431:Ethanol; D006147:Guanine / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D008027:Light; D000432:Methanol; D008956:Models, Chemical; D008982:Molybdenum / Q000737:chemistry; D017319:Photosensitizing Agents / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D012256:Riboflavin / Q000737:chemistry; D026082:Singlet Oxygen / Q000737:chemistry*; D012996:Solutions; D012997:Solvents; D014867:Water
chemical_list: D000975:Antioxidants; D017319:Photosensitizing Agents; D010936:Plant Extracts; D012996:Solutions; D012997:Solvents; D014867:Water; C044659:molybdate; D026082:Singlet Oxygen; D000431:Ethanol; D006147:Guanine; D008982:Molybdenum; C012596:turmeric extract; D006861:Hydrogen Peroxide; D012256:Riboflavin; D000432:Methanol
keywords: DNA damage; Guanine base; Natural antioxidants; Singlet oxygen