Novel Therapeutic and Diagnostic Applications of Hypocrellins and Hypericins

Abstract

Abstract-Hypocrellins and hypericins, structurally related plant pigments isolated from Ilypocrella bambuase and Hypericum respectively, are known photodynamic agents. This review summarizes certain significant advances in the photophysics, photochemistry and photobiology of these pigments in the last 2 years and discusses their prospects as novel therapeutic and diagnostic agents in the future. Recently, certain unique properties of hypocrellins and hypericins have been explored for a variety of therapeutic and diagnostic applications. In particular, substantial progress has been made in both anticancer and antiviral applications (especially anti-human immunodeficiency virus). The promising anticancer and antiviral results obtained both in vitro and in vivo have led to intensive investigation into their photophysical and photochemical processes, especially kinetic studies of their intramolecular proton transfer.

A photodynamic pathway to apoptosis and necrosis induced by dimethyl tetrahydroxyhelianthrone and hypericin in leukaemic cells: possible relevance to photodynamic therapy

“…The photosensitizing properties of two dianthraquinones were examined: the novel DTHe with a perylene quinone chromophore and absorption spectrum which resembles that of the photodynamically potent hypocrellins (Diwu, 1990(Diwu, , 1995Miller, 1997) and HY. The mechanisms by which they inflict damage to leukaemic cells were analysed in vitro.…”

“…DTHe was chosen because of its dibenzperylenequinone chromophore (seven aromatic rings) that has absorption spectral properties virtually identical to hypocrellins, potent anti-tumoral photosensitizers isolated from the parasitic fungus Hypocrella bambuase which grows in China and Tibet (Diwu, 1990;Diwu, 1995;Miller, 1997). DTHe also shares structural similarities with HY and was anticipated to be a potent photosensitizer owing to its considerable light absorbance in the visible range of the spectrum.…”

“…bjoc.1998 Received Efforts to identify novel efficacious agents for photodynamic therapy led us to evaluate the photodynamically induced cytotoxicities of a newly designed photosensitizer 10,13-dimethyl 1,3,4,6-tetrahydroxyhelianthrone (DTHe) (Figure 1), in leukaemic cell lines. DTHe was chosen because of its dibenzperylenequinone chromophore (seven aromatic rings) that has absorption spectral properties virtually identical to hypocrellins, potent anti-tumoral photosensitizers isolated from the parasitic fungus Hypocrella bambuase which grows in China and Tibet (Diwu, 1990;Diwu, 1995; Miller, 1997). DTHe also shares structural similarities with HY and was anticipated to be a potent photosensitizer owing to its considerable light absorbance in the visible range of the spectrum.…”

p27SJ, a novel protein in St John's Wort, that suppresses expression of HIV-1 genome

“…2 In recent years Hypericum perforatum, also known as St John's Wort, has received special attention due to its pharmacological properties, including antiseptic, spasmolytic, tonic, diuretic, and anesthetic remedies. 3,4 Extracts from this plant are utilized in the treatment of mild to moderately severe depression. 5 Further, several studies have pointed to antitumor and antiviral activities of hypericin, a photosensitive and red colored naphthodianthrone which is suspected as the bioactive compound responsible for reversing depression symptoms.…”

Cellular toxicity of elsinochrome phytotoxins produced by the pathogenic fungus, Elsinoë fawcettii causing citrus scab

“…Many of the perylenequinone pigments produced by fungi have been shown to be toxic to mice, bacteria, and many fungi, to be cytotoxic to animal tumors, to be potent antiviral agents, and to inactivate protein kinase C (Tamaoki & Nakano, 1990;Hudson & Towers, 1991;Diwu, 1995;Hudson et al ., 1997). (a) Structure of elsinochromes with various side-groups (R) (redrawn based on the work of Weiss et al, 1987 Except for cercosporin produced by many members of the fungal genus Cercospora (Callahan et al ., 1999;Choquer et al ., 2005Choquer et al ., , 2007Chen et al ., 2007;Dekkers et al ., 2007), none of the perylenequinones of fungal origin have been demonstrated to act as a crucial factor in plant diseases caused by the producing pathogen.…”