Studies of the sulfonation of hypocrellin A and the photodynamic actions of the product

Hu, Yi-Zhen; J, An; Jiang, Lijin

doi:10.1016/1011-1344(93)80013-y

Cited by 66 publications

(18 citation statements)

References 9 publications

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“…Natural hypocrellins are generally lipophilic compounds, although a few hydrophilic hypocrellin derivatives have been synthesized 17–18 . Unfortunately there have been few studies on the properties of these water‐soluble hypocrellin derivatives.…”

Section: Synthetic Chemistry and Novel Analogsmentioning

confidence: 99%

Novel Therapeutic and Diagnostic Applications of Hypocrellins and Hypericins

Diwu¹

1995

Photochem & Photobiology

339

111

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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.

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Section: Synthetic Chemistry and Novel Analogsmentioning

confidence: 99%

Novel Therapeutic and Diagnostic Applications of Hypocrellins and Hypericins

Diwu¹

1995

Photochem & Photobiology

339

111

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“…In our in vitro con· 6 Photodynamic action of hypocrellin derivatives ( i ) Generation of semiquinone anion radical of hy· pocrellin derivatives. Irradiation of oxygen·free DMSO solution of hypocrellin derivatives can generate semi· quinone anion radicals of these derivatives, which could be detected by EPR [55,57,[66][67][68][69][70][71][72][73][74][75]. The EPR signal is consid· ered to result from the electron transfer between excited sensitizer and ground state sensitizer.…”

Section: Reviewmentioning

confidence: 99%

Photophysics, photochemistry and photobiology of hypocrellin photosensitizers

Jiang

2001

Chin.Sci.Bull.

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Hypocrellins are novel photosensitizers from China, which are demonstrated to have significant antitumor and anti-virus activity and to be potential photodynamic therapy (PDT) agents. As compared with hematoporphyrin, the only approved photosensitizer, hypocrellins have several advantages, such as easy preparation and easy purification, high triplet quantum yield, high singlet-oxygen quantum yield, high phototoxicity but low dark toxicity, and rapid clearance from normal issues. This article reviews briefly the photophysics, photochemistry and photobiology of hypocrellins on the basis of the domestic and international research results.Hypocrellins are natural photosensitizers isolated from Hypocrella bambusae (B. et Br.) sacc., a parasitic fungus of Sinarundinaria sp. that grows abundantly in China. Natural hypocrellins mainly include two components, hypocrellin A (HA) and hypocrellin B (HB) ( fig. 1), and 95% of hypocrellins are HA. However, HA can be converted into HB by dehydration in alkaline conditions [l]. Our group started the research on hypocrellins, the novel type of photosensitizers, in the early 1980s and investigated systematically on the characterization of the chemical structures of HA and HB, photophysics, photochemistry and the molecular mechanisms of photodynamic action[2,3]. "C) , OH""'O H}'pocrellill B Fig. IHypocrellins attract more and more international interest, which results in the increasing research on the photophysics, photochemistry and photobiology of hypocrellins. Prof. Lown [4] from Alberta University in Canada focuses his research on the manual synthesis of hypocrellins and isotope-marked hypocrellins, synthesis of aminated hypocrellin, and photobiology of hypocrellins. 6 Prof. Petrich [5][6][7][8][9][10][11][12] from Iowa University in USA investigated the antiviral activity and cytotoxicity of hypocrellins and the toxicity mechanisms and compared hypocrellin with hypericin. Other scientists and groups also made great contributions to the clarification of the properties of the excited state, the structural modifications, the mechanisms of photosensitization, quantum-chemical calculation, and the photodynamic damage to macrobiomolecules such as lipids and DNA [13][14][15][16][17][18][19][20][21][22][23][24][25].With the development and application of laser technology and optic fiber technology, the light source and delivery of irradiation in photodynamic therapy (PDT) have been settled increasingly, and the photosensitizers are the key issue in PDT application. Currently, the only approved Photofrin II ® has several disadvantages, such as complex composition, weak red absorption, slow clearance from normal tissues and high side effects. Presently, the ideal photosensitizers with high PDT efficacy, low dark toxicity and better distribution selectivity are the aims for PDT scientists. Hypocrellins are a novel type of photosensitizers, and have the following advantages as compared with haematoporphyrin derivatives (HPD): easy preparation and purification, high quantum yields of trip...

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“…While their low absorption in the photodynamic window (600-900 nm) limit their applications in photodynamic therapy (PDT) because the longer wavelength light can penetrate in tissues effectively. The hypocrellin derivatives have been prepared recently [6][7][8][9][10], but with few promising results.…”

Section: Introductionmentioning

confidence: 99%