Interaction of new tri-, tetra-, and pentacyclic azaphenothiazine derivatives with calf thymus DNA: Spectroscopic and molecular docking studies.

Azaphenothiazines (AZA), modified phenothiazine derivatives, have been reported to exhibit a wide spectrum of biological activities, including anticancer activities, but the mechanisms of their interactions with biomolecules are not fully recognized. In this work, the mode of interaction of selected AZA with calf thymus DNA was investigated using UV-Vis absorption, fluorescence spectroscopy (competition experiment with ethidium bromide, quenching of fluorescence) and molecular docking. The investigated AZA represent dipyrido[3,4-b;3'4'-e][1,4]thiazine, quino[3,2-b]benzo[1,4]thiazine and diquino[3,2-b;2',3'-e][1,4]thiazine possessing tricyclic, tetracyclic and pentacyclic ring system with the additional N,N-dimethylaminopropyl group at the nitrogen atom in the 1,4 thiazine ring.

Application of phenol red as a marker ligand for bilirubin binding site at subdomain IIA on human serum albumin.

The drug-bilirubin interaction for all drugs administered especially to infants with hyperbilirubinemia should be evaluated for their ability to displace bilirubin and vice versa. In order to examine whether phenol red (PhRed) can be used as a marker for bilirubin binding site located in subdomain IIA the interaction between PhRed and human serum albumin (HSA) in buffer solution or in normal and pathological sera solutions with different HSA:bilirubin molar ratio was investigated using absorption/absorption difference spectroscopy and molecular docking method. Six sulfonamides representing the binding site in the subdomain IIA and known to influence the binding of bilirubin were used for the PhRed displacement studies.

The investigation of the binding of 6-mercaptopurine to site I on human serum albumin.

6-Mercaptopurine (6-MP) is one of a large series of purine analogues which has been found active against human leukemias. The equilibrium dialysis, circular dichroism (CD) and molecular docking were employed to study the binding of 6-MP to human serum albumin (HSA). The binding of 6-MP to HSA in the equilibrium dialysis experiment was detected by measuring the displacement of 6-MP by specific markers for site I on HSA, warfarin (RWF), phenylbutazone (PhB) and n-butyl p-aminobenzoate (ABE).

[Effect of accumulating fluorine and sulphur compounds on the content of chlorophyll in pine needles (Pinus sylvestris L.) from some areas of southern Poland in 2001-2003].

Concentrations of F(-), S and chlorophyll in needles of pines growing near metallurgical works and power plants were determined. A statistically significant positive correlation between F(-) (in the range of 4.32 to 21.

Toxicity and biodegradability of sulfonamides and products of their photocatalytic degradation in aqueous solutions.

The photocatalytic degradation of sulfacetamide, sulfathiazole, sulfamethoxazole and sulfadiazine in water solutions during their illumination of UV radiation (lambda(max) 366 nm) with TiO2 catalyst was examined. The growth-inhibition effect of sulfonamides and intermediate products theirs photodegradation was investigated in aqueous solution with the green alga Chlorella vulgaris. The biodegradability of the investigated compounds was determined in the illuminated solutions and is expressed as Biochemical Oxygen Demand.

Synthesis, physicochemical properties and biological activity of 2,6-disubstituted 7-methylpurines and the 7,9-dialkyl analogues.

The preparation of several derivatives of 2,6-disubstituted-7-methylpurines and the 7,9-dialkyl analogues possessing a potential cytotoxic or cytostatic activity has been described. These compounds were tested for biological activity using a method for the determination of the toxic effects of chemical compounds on the growth of green alga Chlorella vulgaris, Beijerinck 1890. The effective concentration (EC50) was calculated.