Results 161 to 170 of about 1,024 (191)

Photochemistry of hypocrellin A (IV)--Hypocrellin A-sensitized photooxidation of diphenylamine.

Scientia Sinica. Series B, Chemical, biological, agricultural, medical & earth sciences, 1988
The photooxidation of diphenylamine is acetonitrile and methanol using Hypocrellin A as sensitizer will be reported in this paper. The products in the two solvents were isolated and identified. The reaction mechanisms were investigated. In acetonitrile, diphenylamine was oxidized by singlet oxygen to form N-phenyl-p-benzoquinonimine.
J N, Ma, M H, Zhang, J Y, An, L J, Jiang
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Effect of Structural Modification on Photodynamic Activity of Hypocrellins

Photochemistry and Photobiology, 2001
Aluminum ion complexed 5,8-di-Br-hypocrellin B is a new water-soluble perylenequinonoid derivative with enhanced absorption over hypocrellin B (HB) in the phototherapeutic window (600-900 nm). Electron paramagnetic resonance and 9,10-diphenyl-anthracene bleaching methods were used to investigate the photosensitizing activity of [AL2(5,8-di-Br-HB)Cl4]n ...
J, Ma, J, Zhao, L, Jiang
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Spectroscopic studies on the interaction of Ga3+-hypocrellin A with myoglobin

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2014
In this article, the interaction mechanism of Ga(3+)-hypocrellin A (Ga(3+)-HA) with myoglobin (Mb) is studied in detail through various spectroscopic technologies. UV-vis absorption and fluorescence spectra demonstrate the interaction process. The Stern-Volmer plot and the time-resolved fluorescence study suggest the fluorescence quenching mechanism of
Wenli, Xie, Shaohua, Wei, Jihua, Liu, Xuefeng, Ge, Lin, Zhou, Jiahong, Zhou, Jian, Shen   +6 more
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Antibacterial activity of hypocrellin A against Staphylococcus aureus

World Journal of Microbiology and Biotechnology, 2012
The antibacterial activity and acting mechanism of hypocrellin A (HA) were conducted regarding in vitro activity of HA on Staphylococcus aureus GZ86 by analyzing the growth, permeability, and morphology of the bacterial cells following treatment with HA. The experimental results indicated 1.5 mg/l HA could completely inhibit the growth of 10⁷ CFU/ml S.
Wen, Du, Chunlong, Sun, Zongqi, Liang, Yanfeng, Han, Jianping, Yu   +4 more
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Photoreactions of hypocrellin B with thiol compounds

Journal of Photochemistry and Photobiology B: Biology, 1998
Abstract The photoreactions of hypocrellin B (HB) with thiol compounds (RSH) in ethanol buffer solutions have been investigated by electron spin resonance (ESR), α-phenyl-N-tert-butyl nitrone (PBN) spin trapping and quenching experiments. The mechanism of photothiylation of HB is proposed to involve a nucleophilic anion (RS−) addition of Michael type
Yu-Ying He, Jing-Yi An, Li-Jin Jiang
exaly   +2 more sources

Prediction on amphiphilicity of hypocrellin derivatives

Science in China Series B, 2002
Hypocrellins are most suitable for photodynamic therapy (PDT) of the diseases occurring in the superficial layer, such as microvascular diseases, because of their special absorption spectral properties. However, hypocrellins and most of their derivatives are basically lipophilic, while the hydrophilic derivatives lose the PDT activity in vivo ...
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The Role of Oxygen in the Antiviral Activity of Hypericin and Hypocrellin

Photochemistry and Photobiology, 1998
AbstractThe light‐induced antiviral activity of hypericin and hypocrellin in the presence and absence of oxygen was examined under experimental conditions where the effect of oxygen depletion could be quantified. There was a significant reduction of light‐induced antiviral activity of hypericin and hypocrellin under hypoxic conditions.
J, Park, D S, English, Y, Wannemuehler, S, Carpenter, J W, Petrich   +4 more
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Photo-induced interactions of hypocrellin A with phycobiliproteins

Research on Chemical Intermediates, 2004
Photo-induced interaction of hypocrellin A (HA) with a water-soluble protein (C-phycocyanin, C-PC) was studied by monitoring the changes of the photo-physical properties of C-PC, as well as those of HA. It was found that the solubility of HA in phosphate-buffered saline solution was greatly promoted in the presence of C-PC. Furthermore, energy transfer
Baozhong Zhao, Jie Xie, Jingquan Zhao
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Photochemical properties of hypocrellin A, B and their oxides

Chinese Journal of Chemistry, 1990
AbstractHypocrellin A and B in methanol were autosensitized and photooxygenated to 1, 4, 6, 7 and 2, 5, 8, 9 respectively. 1 in methanol was photooxygenated to 6 and 7 under the sensitization by HB. 1 in methanol was photooxygenated to 7 under the sensitization by Rose bengal.
Kai‐Hong Zhao, Li‐Jin Jiang
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A theoretical study on photobleaching mechanisms of hypocrellins

Dyes and Pigments, 2005
Abstract In this paper, quantum chemical method RHF/6-31G(d,p)//AM1 was employed to investigate the photobleaching behaviors of hypocrellins. It is found that frontier charge rather than Mulliken charge is an applicable parameter to predict the 1 O 2 - and O 2 − -addition positions of the pigments; accordingly some experimental observations on the
L WANG, X WANG, H ZHANG
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