EPR studies of singlet oxygen (1O2) and free radicals (O2.-, .OH, HB.-) generated during photosensitization of hypocrellin B.
AuthorsZhiyi Z, Nenghui W, Qian W, Meifan L
JournalFree Radic Biol Med
PubMed ID8384147
Hypocrellin B(HB), a peryloquinone derivative, is one of the main photosensitive agents, hypocrellin. This pigment, in combination with phototherapy, has been used in human medicine to cure various skin diseases. The photochemistry (Type I and II) of HB has been studied using spin-trapping and spin-counteraction techniques. The results show that ... More
Electric magnetic resonance and spectrophotometry evidence on the photodynamic activity of a new perylenequinonoid pigment.
AuthorsHe YY, An JY, Jiang LJ
JournalJ Photochem Photobiol B
PubMed ID10577050
'Di-cysteine substituted hypocrellin B (DCHB) is a new water-soluble photosensitizer with significantly enhanced red absorption at wavelengths longer than 600 nm over the parent compound hypocrellin B (HB). The photosensitizing properties (Type I and/or Type II mechanisms) of DCHB have been investigated in dimethylsulfoxide (DMSO) and aqueous solution (pH 7.4) ... More
Spectroscopic studies and photodynamic actions of hypocrellin B in liposomes.
AuthorsYu C, Chen S, Zhang M, Shen T
JournalPhotochem Photobiol
PubMed ID11367568
'Hypocrellin B (HB), a lipid-soluble natural pigment of perylenequinone derivative, is considered as potential photosensitizer for photodynamic therapy. Liposomes loaded with HB can constitute a simple model system, appropriate for better understanding the photodynamic action of HB in vivo. The steady-state absorption and emission spectra, quantum yield and lifetime of ... More
Fluorescence characterization of type I collagen from normal and silicotic rats and its quenching dynamics induced by hypocrellin B.
AuthorsLi YH, Yue JC, Cai GP
JournalBiopolymers
PubMed ID9235000
'In this paper, we studied the quenching mechanism of intrinsic fluorescence of type I collagen by a new type photosensitizer and fluorescence quencher, hypocrellin B (HB). It was indicated that type I collagen can emit Tyr-intrinsic fluorescence with the excitation wavelength of Tyr (lambda(ex) = 269 nm). Its fluorescence decay ... More
Phototherapeutic potential of alternative photosensitizers to porphyrins.
AuthorsDiwu Z, Lown JW
JournalPharmacol Ther
PubMed ID7972342
'Because of promising clinical results obtained with photodynamic therapy, more and more photosensitizers continue to be isolated (from natural sources), synthesized and evaluated, the development of which is considered to be a key factor for the successful clinical application of photodynamic therapy. Porphyrins and their analogs (as classical types of ... More
Novel therapeutic and diagnostic applications of hypocrellins and hypericins.
AuthorsDiwu Z
JournalPhotochem Photobiol
PubMed ID7568399
'Hypocrellins and hypericins, structurally related plant pigments isolated from Hypocrella 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 ... More
Raman spectroscopic study of microcosmic and photosensitive damage on the liposomes of the mixed phospholipids sensitized by hypocrellin and its derivatives.
AuthorsXu Y, Zhao H, Zhang Z
JournalJ Photochem Photobiol B
PubMed ID9639913
'Using Raman spectroscopy, we studied and compared the characteristics of microcosmic and photosensitive damage of the liposomes of mixed DPPE and DPPC sensitized by hypocrellin and its derivatives at the molecular level. After photosensitive damage, the structure of the liposomes of mixed phospholipids changed considerably. The trans conformation decreased and ... More
Photosensitized damage to calf thymus DNA by a hypocrellin derivative: mechanisms under aerobic and anaerobic conditions.
AuthorsHe YY, Jiang LJ
JournalBiochim Biophys Acta
PubMed ID11099855
'The di-cysteine substituted hypocrellin B (DCHB) derivative has been found to be a potential phototherapeutic agent and exhibit photosensitized damage to DNA. Electronic paramagnetic resonance (EPR) and spectrophotometry demonstrate that one-electron transfer from calf thymus DNA to triplet DCHB induces the generation of the reduced form of DCHB (DCHB*- radical), ... More
Glycoconjugated hypocrellin: photosensitized generation of free radicals (O2*-, *OH, and GHB*-) and singlet oxygen (1O2).
AuthorsYuying H, Jingyi A, Lijin J
JournalFree Radic Biol Med
PubMed ID10443937
'To improve water solubility and specific affinity for malignant tumors, glycoconjugated hypocrellin B (GHB) has been synthesized. Illumination of deoxygenated DMSO solution containing GHB generates a strong electron paramagnetic resonance (EPR) signal. The EPR signal is assigned to the semiquinone anion radical of GHB (GHB*-) based on a series of ... More
New potential photodynamic therapeutic anti-cancer agents: synthesis and characterization of demethoxy amino-substituted hypocrellins.
AuthorsWu T, Xu S, Shen J, Song A, Chen S, Zhang M, Shen T
JournalAnticancer Drug Des
PubMed ID11200504
'A novel method was used to obtain demethoxy amino-substituted hypocrellin derivatives. The reaction condition was mild and amino substitution occurred at position 2 or 11 of hypocrellins with high yield. The photophysical and photochemical properties of the amino-substituted hypocrellins derivatives were investigated, and their significantly enhanced red absorptivities and strong ... More
Synthesis and EPR investigations of new aminated hypocrellin derivatives.
AuthorsHe YY, Jiang LJ
JournalFree Radic Biol Med
PubMed ID10938461
'Hypocrellins are novel photodynamic agents. A recent advance in the synthesis of hypocrellin congeners results in the production of two amino-substituted hypocrellin B derivatives in high yield via photochemical reaction. Both compounds exhibit similar photodynamic activity as hypocrellin B in terms of type I and type II mechanisms. In anaerobic ... More
ESR evidence of the photogeneration of free radicals (GDHB*-, O2*-) and singlet oxygen ((1)O2) by 15-deacetyl-13-glycine-substituted hypocrellin B.
AuthorsSong YZ, An J, Jiang L
JournalBiochim Biophys Acta
PubMed ID10572952
'15-Deacetyl-13-glycine-substituted hypocrellin B (GDHB) is a new type of hypocrellin derivative with an enhanced red absorption longer than 600 nm and water solubility. Visible light (> 470 nm) irradiation of an anaerobic aqueous solution of GDHB, the formation of GDHB*- was detected by an ESR method in the absence or ... More
Glycoconjugated hypocrellin: synthesis of [(beta-D-glucosyl)ethylthiyl]hypocrellins and photosensitized generation of singlet oxygen.
AuthorsHe YY, An JY, Jiang LJ
JournalBiochim Biophys Acta
PubMed ID10572945
'In order to improve the water solubility and specific affinity for malignant tumors of hypocrellin, glycoconjugated hypocrellins have been synthesized using an improved Königs-Knörr reaction from mercaptoethanol substituted hypocrellin B and 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide precursors. Deprotection of glucose moieties allows the production of derivatives which had improved solubility in neutral aqueous ... More
Photosensitization by anticancer agents 21: new perylene- and aminonaphthoquinones.
AuthorsDiwu ZJ, Haugland RP, Liu J, Lown JW, Miller GG, Moore RB, Brown K, Tulip J, McPhee MS
JournalFree Radic Biol Med
PubMed ID8904300
Hypocrellins are under intensive investigation as photosensitizing agents for photodynamic therapy (PDT). A recent advance in the synthesis of hypocrellin congeners resulted in the production of an amino-substituted hypocrellin-B, and its "half chromophore." Both compounds exhibit stronger red light absorption than previously reported hypocrellins, and, therefore, merit investigation as photosensitizers. ... More
New long-wavelength perylenequinones: synthesis and phototoxicity of hypocrellin B derivatives.
AuthorsLi L, Chen Y, Shen J, Zhang M, Shen T
JournalBiochim Biophys Acta
PubMed ID11099852
Five new derivatives of hypocrellin B were obtained from the reactions of hypocrellin B with ammonia and ethanolamine. Their photophysical and photochemical properties were investigated. The phototoxicity of one compound on AH cells irradiated with red light (lambda = 600-700 nm) was also studied. Their significantly enhanced red absorptivities at ... More
Multidimensional reaction coordinate for the excited-state H-atom transfer in perylene quinones: importance of the 7-membered ring in hypocrellins A and B.
AuthorsDatta A, Smirnov AV, Wen J, Chumanov G, Petrich JW
JournalPhotochem Photobiol
PubMed ID10687390
The excited-state intramolecular H-atom transfer reactions of hypocrellins B and A are compared by using time-resolved absorption and fluorescence upconversion techniques. The hypocrellin B photophysics are well described by a simple model involving one ground-state species and excited-state forward and reverse H-atom transfer with a nonfluorescent excited state. We suggest ... More
Photosensitization with anticancer agents. 18. Perylenequinonoid pigments as potential photodynamic therapeutic agents: preparation and photodynamic properties of amino-substituted hypocrellin derivatives.
AuthorsDiwu Z, Zhang C, Lown JW
JournalAnticancer Drug Des
PubMed ID8494603
Perylenequinonoid pigments have demonstrated several photodynamic therapeutic advantages over the commonly used hematoporphyrin derivatives. Certain new amino-substituted hypocrellin B derivatives have been prepared, and both direct and reductive aminations of hypocrellin B are described. The photophysical and photochemical properties of the amino-substituted hypocrellin B derivatives were investigated, and their significantly ... More
Fluorescence study on ligand induced conformational changes of human erythrocyte glucose transporter.
AuthorsXie WS, Yuc JC, Tu YP
JournalBiochem Mol Biol Int
PubMed ID8799454
The nanosecond time-resolved fluorescence and fluorescence lifetime quenching have been used to detect the conformational changes of human erythrocyte glucose transporter induced by its ligands. Results show that D-glucose can decrease the fluorescence lifetimes, while L-glucose exhibits no effect. The fluorescence lifetime quenching results also show that in the presence ... More
Hypocrellins and their use in photosensitization.
AuthorsZhenjun D, Lown JW
JournalPhotochem Photobiol
PubMed ID2284353
Hypocrellins A and B are pigments which are isolated from parasitic fungi Hypocrella bambuase (B. et Br) sacc. and Shiraia bambusicola P. Heen found in the People's Republic of China (P.R.C.) and Sri Lanka respectively. These agents, which belong to the general class of perylene quinonoid pigments, have a long ... More
Antiviral activities of photoactive perylenequinones.
AuthorsHudson JB, Imperial V, Haugland RP, Diwu Z
JournalPhotochem Photobiol
PubMed ID9066311
Nine perylenequinones (PQ), including some familiar naturally occurring pigments, were compared for their light-mediated antiviral efficacies. Calphostin C was the most active compound against the two target viruses, herpes simplex virus type 1 and Sindbis virus. Hypocrellins A and B were also very active. However, three cercosporin-like PQ were substantially ... More
Uptake kinetics and intracellular localization of hypocrellin photosensitizers for photodynamic therapy: a confocal microscopy study.
AuthorsMiller GG, Brown K, Moore RB, Diwu ZJ, Liu J, Huang L, Lown JW, Begg DA, Chlumecky V, Tulip J
JournalPhotochem Photobiol
PubMed ID7568409
Hypocrellins are naturally occurring compounds with photosensitizing properties in biological systems. We have prepared synthetic derivatives of hypocrellin B, which have promise as photosensitizers in the clinical application of photodynamic therapy. The intracellular localization and uptake kinetics of hypocrellin B and several selected hypocrellin congeners were determined semiquantitatively by fluorescence ... More
Photodynamic action of amino substituted hypocrellins: EPR studies on the photogenerations of active oxygen and free radical species.
AuthorsWu T, Shen J, Song A, Chen S, Zhang M, Shen T
JournalJ Photochem Photobiol B
PubMed ID11100833
A novel method has been employed to prepare 2-butylamino-2-demethoxy hypocrellin A (BADMHA) and 2-butylamino-2-demethoxy hypocrellin B (BADMHB). Both compounds exhibit stronger absorption at the phototherapeutic window (600-900 nm). The spin trapping and spin counteraction studies have shown that they are both efficient generators of the active oxygen (1O2, O2*-) in ... More
Fluorescence study on transmembrane Ca2+ gradient-mediated conformation changes of sarcoplasmic reticulum Ca(2+)-ATPase.
AuthorsTu YP, Yang FY
JournalBiosci Rep
PubMed ID7620082
The conformational states of Ca(2+)-ATPase in sarcoplasmic reticulum (SR) vesicles with or without a thousand-fold transmembrane Ca2+ gradient have been studied by fluorescence spectroscopy and fluorescence quenching. In consequence of the establishment of the transmembrane Ca2+ gradient, the steady-state fluorescence results revealed a reproducible 8% decrease in the intrinsic fluorescence ... More
Zn(2+)-mediated domain-domain communication in human erythrocyte band 3.
AuthorsTu YP, Yang FY
JournalJ Biochem (Tokyo)
PubMed ID8537306
Zn2+ could inhibit the anion transport activity of spectrin-stripped inside-out human erythrocyte membrane vesicles (IOVs). Removal of the cytoplasmic domain from Band 3 by trypsin could eliminate Zn2+ inhibition. The location of a Zn(2+)-binding site was confirmed by atomic absorbance spectrometry. The results of time-resolved fluorescence and intrinsic fluorescence quenching ... More
Se-mediated domain-domain communication in band 3 of human erythrocytes.
AuthorsYang FY, Fen C, Tu YP
JournalBiol Trace Elem Res
PubMed ID9096855
Na2SeO3 could affect the anion flux of Band 3 of inside-out erythrocyte membrane vesicles (IOVs). Such effect was believed to be based on the interaction of SH groups of Band 3 with Na2SeO3. This effect could be eliminated when the cytoplasmic domain of Band 3 was proteolytically removed by trypsin. ... More
Hypocrellins as photosensitizers for photodynamic therapy: a screening evaluation and pharmacokinetic study.
AuthorsEstey EP, Brown K, Diwu Z, Liu J, Lown JW, Miller GG, Moore RB, Tulip J, McPhee MS
JournalCancer Chemother Pharmacol
PubMed ID8548880
Hypocrellin compounds were selected as potential photosensitizers for photodynamic therapy (PDT) owing to their high quantum yields of singlet oxygen (1O2), and facility for site-directed chemical modification to enhance phototoxicity, pharmacokinetics, solubility, and light absorption in the red spectral region, among other properties. Parent hypocrellins A and B share an ... More
Photosensitization with anticancer agents. 15. Perylenequinonoid pigments as potential photodynamic therapeutic agents: formation of semiquinone radicals and reactive oxygen species on illumination.
AuthorsDiwu Z, Lown JW
JournalJ Photochem Photobiol B
PubMed ID8394416
Visible light illumination of solutions of perylenequinonoid pigments generates the corresponding semiquinone radicals, singlet oxygen, superoxide anion radical, hydroxyl radical and hydrogen peroxide. In anaerobic solution, the semiquinone radicals are predominantly photoproduced via the self-electron transfer between the excited and ground state species. In aerobic solution, singlet oxygen is the ... More
Preclinical assessment of hypocrellin B and hypocrellin B derivatives as sensitizers for photodynamic therapy of cancer: progress update.
AuthorsMiller GG, Brown K, Ballangrud AM, Barajas O, Xiao Z, Tulip J, Lown JW, Leithoff JM, Allalunis-Turner MJ, Mehta RD, Moore RB
JournalPhotochem Photobiol
PubMed ID9114749
Hypocrellins are perylenequinone pigments with substantial absorption in the red spectral region and high singlet oxygen yield. They are available in pure monomeric form and may be derivatized to optimize properties of red light absorption, tissue biodistribution and toxicity. In vitro screening of synthetic derivatives of the naturally occurring compound, ... More
EPR and spectrophotometric studies on free radicals (O2.-, Cysa-HB.-) and singlet oxygen (1O2) generated by irradiation of cysteamine substituted hypocrellin B.
AuthorsHe YY, An JY, Jiang LJ
JournalInt J Radiat Biol
PubMed ID9848284
PURPOSE: The aim of this work was to investigate the photodynamic action of cysteamine substituted hypocrellin B (Cysa-HB) photochemically and survey the effect of oxygen on its reaction mechanism. MATERIALS AND METHODS: The EPR method is used to detect the generation of the semiquinone anion radical of Cysa-HB (Cysa-HB.-), and ... More
Hypocrellin and hypericin-induced phototoxicity of HL-60 cells: apoptosis or necrosis?
AuthorsMirossay A, Mojzis J, Tóthová J, Hájiková M, Lacková A, Mirossay L
JournalPhytomedicine
PubMed ID11194175
Hypericin and hypocrellin are potential antiviral and antineoplastic agents with multiple modes of light-induced biological activity connected with a production of singlet oxygen and/or excited-state proton transfer and consequent pH drop formation in the drugs environment. In present work light-induced cytotoxicity of hypericin and hypocrellin and mechansim of cell death ... More
Design, synthesis and investigation of mechanisms of action of novel protein kinase C inhibitors: perylenequinonoid pigments.
AuthorsDiwu Z, Zimmermann J, Meyer T, Lown JW
JournalBiochem Pharmacol
PubMed ID7508231
A series of perylenequinonoid pigments (PQPs) and related compounds were synthesized and screened for the inhibition of protein kinase C (PKC), a key enzyme involved in cellular differentiation and proliferation, and a potential target for anticancer and antiviral chemotherapeutic drugs. This study has established PQPs as efficient PKC inhibitors, and ... More
Effect of structural modifications on photosensitizing activities of hypocrellin dyes: EPR and spectrophotometric studies.
AuthorsYuying H, Jingyi A, Lijin J
JournalFree Radic Biol Med
PubMed ID10381185
Mono-substituted hypocrellin B (MHB) and di-substituted hypocrellin B (DHB) by mercaptoacetic acid are new photosensitizers synthesized to improve the red absorption and water solubility of the parent hypocrellin B (HB). The photochemistries (Type I and/or Type II) of MHB and DHB have been studied in homogeneous solutions using electron paramagnetic ... More