title: Photodynamic properties of hypocrellin A, complexes with rare Earth trivalent ions: role of the excited state energies of the metal ions.
abstract: Fifteen complexes of hypocrellin A (HA) with rare earth trivalent ions (except Pm3+) along with the complex of HA with Sc3+ were prepared, and their photodynamic activities, including absorption in the phototherapeutic window (600-900 nm); water-solubility; triplet lifetime; generation of reactive oxygen species (ROS), such as singlet oxygen (1O2), superoxide anion radical (O2-*), and hydroxyl radical (OH*); generation of semiquinone anion radical; and affinity to DNA, as well as photosensitized damage on calf thymus DNA (CT DNA), were compared in detail using the UV-visible spectrum, fluorescence spectrum, spin-trapping EPR technique, and laser photolysis technique. All complexes exhibit a red-shifted absorption spectrum, an increased absorbance above 600 nm, improved water solubility, and an enhanced affinity to CT DNA over the parent HA. For ions that possess low-energy excited states, including Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, and Yb3+, the corresponding complexes show undetectable or nearly undetectable fluorescence, a triplet excited-state lifetime, generation of ROS, and photodamage in CT DNA. In contrast, for ions that do not possess low-energy excited states, including Sc3+, Y3+, La3+, Gd3+, and Lu3+, the corresponding complexes exhibit higher photodamage abilities with CT DNA with respect to HA, benefitting from both their comparable or even higher 1O2 quantum yields and an electrostatic affinity that is higher for DNA than HA.
authors.affiliation: Lab of Organic Optoelectronic Functional Materials and Molecular Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China.
authors.forename: Zhanghua
authors.initials: Z
authors.lastname: Zeng
authors.forename: Jiahong
authors.initials: J
authors.lastname: Zhou
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Rui
authors.initials: R
authors.lastname: Qiao
authors.forename: Shengqin
authors.initials: S
authors.lastname: Xia
authors.forename: Jinrong
authors.initials: J
authors.lastname: Chen
authors.forename: Xuesong
authors.initials: X
authors.lastname: Wang
authors.forename: Baowen
authors.initials: B
authors.lastname: Zhang
mesh_terms: D016227:Benzoquinones / Q000737:chemistry; D002412:Cations / Q000737:chemistry*; D004247:DNA / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry; D008674:Metals, Rare Earth / Q000737:chemistry*; D009691:Nucleic Acid Denaturation; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry; D019800:Phenol; D010777:Photochemistry; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000737:chemistry*; D011809:Quinones / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000737:chemistry*; D013057:Spectrum Analysis; D055672:Static Electricity; D013481:Superoxides / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D016227:Benzoquinones; D002412:Cations; D008674:Metals, Rare Earth; D017319:Photosensitizing Agents; D011809:Quinones; D017382:Reactive Oxygen Species; D014867:Water; D013481:Superoxides; C025232:semiquinone radicals; D017665:Hydroxyl Radical; D019800:Phenol; D010569:Perylene; D004247:DNA; C048388:hypocrellin A