Anion of hypericin is crucial to understanding the photosensitive features of the pigment.
Photosensitive behaviors of hypericin (HYP) have attracted much attention, because of HYP's great potential in photodynamic therapy. It has been found that HYP differs from homologous pigments, such as hypocrellin A (HA), in photosensitive features. For instance, despite the comparable triplet state quantum yields, HYP holds a much lower singlet oxygen yield than HA. To understand the unique photosensitive behaviors of HYP, time-dependent density functional theory is employed to calculate a series of excited-state properties of HYP and its anion (dominant in polar solvents), which are then compared with excited-state properties of HA. It is revealed that the stronger electron-donating power of HYP anion than that of HA is responsible for the HYP's photosensitive features.
Shen
Liang
L
Shandong Provincial Research Center for Bioinformatic Engineering and Technique, Center for Advanced Study, Shandong University of Technology, Zibo 255049, PR China.
Ji
Hong-Fang
HF
Zhang
Hong-Yu
HY
D000838:Anions / Q000737:chemistry / Q000494:pharmacology; D000873:Anthracenes; D004583:Electrons; D015394:Molecular Structure; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D019800:Phenol; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000494:pharmacology*; D010860:Pigments, Biological / Q000737:chemistry* / Q000494:pharmacology*; D011809:Quinones / Q000737:chemistry; D026082:Singlet Oxygen
D000838:Anions; D000873:Anthracenes; D017319:Photosensitizing Agents; D010860:Pigments, Biological; D011809:Quinones; D026082:Singlet Oxygen; D019800:Phenol; D010569:Perylene; C004965:hypericin; C048388:hypocrellin A