title: UV protection and singlet oxygen quenching activity of aloesaponarin I.
abstract: The UV protection and singlet oxygen quenching of aloesaponarin I have been studied by means of laser spectroscopy. The excited-state intramolecular proton transfer that provides the UV protection takes place along only one of the molecule's two intramolecular hydrogen bonds, and this can be understood by considering the nodal pattern of the wave function. The functional groups participating in the excited-state intramolecular proton transfer also play important roles in the singlet oxygen quenching. Aloesaponarin I has a quenching rate constant larger than that of vitamin E and has a long duration of action due to its resistance to UV degradation and chemical attacks by singlet oxygen and free radicals.
authors.affiliation: Department of Chemistry, Faculty of Science, Ehime University, Matsuyama 790-8577, Japan. nagaoka@ehimegw.dpc.ehime-u.ac.jp
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Nagaoka
authors.forename: Akiko
authors.initials: A
authors.lastname: Fujii
authors.forename: Megumi
authors.initials: M
authors.lastname: Hino
authors.forename: Mai
authors.initials: M
authors.lastname: Takemoto
authors.forename: Misaki
authors.initials: M
authors.lastname: Yasuda
authors.forename: Mariko
authors.initials: M
authors.lastname: Mishima
authors.forename: Keishi
authors.initials: K
authors.lastname: Ohara
authors.forename: Akane
authors.initials: A
authors.lastname: Masumoto
authors.forename: Hidemitsu
authors.initials: H
authors.lastname: Uno
authors.forename: Umpei
authors.initials: U
authors.lastname: Nagashima
mesh_terms: D000504:Aloe / Q000737:chemistry*; D000880:Anthraquinones / Q000737:chemistry*; D010777:Photochemistry; D011522:Protons; D026082:Singlet Oxygen / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D000880:Anthraquinones; D011522:Protons; D026082:Singlet Oxygen