Results 111 to 120 of about 2,331 (162)

Aromaticity and Electron Density of Hypericin

Journal of Natural Products, 2019
The influence of the substituents on the geometry of the central ring system of hypericin has been analyzed. Substitution that causes flattening of the hypericin central rings is connected with introducing the aromatic character of the empty rings. All the hypericin rings have an aromatic character illustrated by the Harmonic Oscillator Measure of ...
Sebastian Szymanski, Irena Majerz
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Properties and Permeability of Hypericin and Brominated Hypericin in Lipid Membranes

Journal of Chemical Theory and Computation, 2009
The promising photosensitizing properties of hypericin, a substituted phenanthroperylene quinone naturally found in Saint John's wort, has led to the proposal that it can be utilized in photodynamic therapy. Structurally modified derivatives are at the present time being investigated to generate a more effective hypericin photosensitizer.
Eriksson, Emma S. E., dos Santos, Daniel J. V. A., Guedes, Rita C., Eriksson, Leif A.   +3 more
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Interaction between hypericin and hemoglobin

Journal of Photochemistry and Photobiology B: Biology, 2010
In the present work the hypericin interaction with hemoglobin was studied by absorption and fluorescence spectroscopy both under incubation in dark and visible light exposure. An absorption reduction in Soret band of hemoglobin (407 nm) was revealed under the photodynamic influence and incubation in dark with hypericin that had hypericin concentration ...
H R, Vardapetyan, A S, Martirosyan, S G, Tiratsuyan, A A, Hovhannisyan   +3 more
exaly   +3 more sources

Antifungal properties of hypericin, hypericin tetrasulphonic acid and fagopyrin on pathogenic fungi and spoilage yeasts [PDF]

Pharmaceutical Biology, 2016
Context: The role of hypericin-mediated photodynamic antimicrobial properties on pathogenic fungi and photodynamic therapy for human cancer cells is known. Antifungal properties of Hypericum perforatum L.
Oksana Sytar, Algimantas Paškevičius, Kristina Ložienė   +2 more
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The Structure of Hypericin in Solution. Searching for Hypericin's 1,6 Tautomer¶

Photochemistry and Photobiology, 2001
Hypericin in organic solvents displays two types of electronic spectra: one type which shows a distinct solvatochromic effect, the stable form, and the other, the unstable form, which lacks this property. The latter type is formed in dry nonprotic solvents (e.g.
D, Freeman, L, Konstantinovskii, Y, Mazur   +2 more
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Antiviral activities of hypericin

Antiviral Research, 1991
Hypericin, a photodynamic plant quinone, readily inactivated murine cytomegalovirus (MCMV), Sindbis virus, and human immunodeficiency virus type 1 (HIV-1), especially on exposure to fluorescent light. Sindbis virus was significantly more sensitive than MCMV.
J B, Hudson, I, Lopez-Bazzocchi, G H, Towers   +2 more
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Concerning the Association of Hypericin Tautomers and their Hypericinate Ions

Monatshefte für Chemie/Chemical Monthly, 2000
The association of the like and unlike configured propeller and butterfly conformers of unionized and bay-ionized 7,14-, 1,6-, and 1,7-tautomers of hypericin was investigated by means of semiempirical calculations of the MM3 type. From the various possible stack dimers it was found that the homodimer with like configurations of the propeller ...
Christoph Etzlstorfer, Heinz Falk
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LASER PHOTOSENSITIZATION OF CELLS BY HYPERICIN

Photochemistry and Photobiology, 1994
Abstract— Administering a light dose of 90 J/cm2 at 599 nm during incubation with hypericin to a highly differentiated normal epithelial cell line(FRTL–5), derived from Fisher rat thyroid, and to a neoplastic cell line(MPTK–6), derived from the lung metastases of a thyroid carcinoma induced in Fisher rats, produces cell kill at drug doses 1000 times ...
A. ANDREONI, A. COLASANTI, P. COLASANTI, M. MASTROCINQUE, RICCIO, PATRIZIA, ROBERTI, GIUSEPPE   +5 more
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Zur Kenntnis des Hypericins und Pseudo‐Hypericins

Chemische Berichte, 1957
AbstractBei einer Untersuchung über die Verbreitung von Hypericin bei Hypericum‐Arten wurde ein neuer, dem Hypericin sehr ähnlicher Farbstoff, das Pseudo‐hype‐ricin aufgefunden. Es kann im Ring‐Papierchromatogramm von Hypericin getrennt werden. Einige der untersuchten Hypericum‐Arten bilden Pseudo‐hypericin neben Hypericin, andere nur Pseudo‐hypericin ...
Hans Brockmann, Walter Sanne
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On the Tautomers of Hypericin

Monatshefte für Chemie / Chemical Monthly, 1998
Hypericin has 16 theoretically conceivable tautomers (10 with and 6 without Kekule structural formulas). AM1 calculations show that two factors determine the relative stability of the tautomers. The dominant factor is the mode of conjugation of the π-electrons.
I. Gutman, Z. Marković, S. Solujić, S. Sukdolak   +3 more
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