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14 recordsLinked to original sources
PubMed2026

UVB photoprotection by thiourea and (thio)semicarbazone derivatives: cellular and molecular evidence.

BACKGROUND: Ultraviolet B (UVB) radiation is a major environmental stressor that contributes to oxidative stress, inflammation, DNA damage, and ultimately an increased risk of skin carcinogenesis. The development of safer, multifaceted UV filters with improved photostability and bioprotective properties remains an important research priority. Here, alkyl chain-conjugated thiourea (I-XIX) and aryl-linked (thio)semicarbazone (XX-XXV) derivatives have been systematically assessed for their photoprotective potential against UVB-induced cellular damage. METHODS: The UV absorption properties, molar absorptivity, and photostability of the test compounds were assessed through spectroscopic studies. Cytotoxicity, effective concentrations, and bioprotective effects of the compounds were evaluated using in vitro cellular methods. RESULTS: Several compounds exhibited robust UVB absorption with high molar absorptivity, particularly semicarbazone derivatives, while displaying minimal cytotoxicity to normal human dermal fibroblasts. Among the evaluated compounds, ten compounds were found to be more photostable than benzophenone (reference compound). Selected compounds significantly reduced UVB-induced intracellular reactive oxygen species and nitric oxide production, signifying effective attenuation of oxidative and nitrosative stress. In addition, compounds IV, XXI, and XXIII alleviated UVB-induced inflammatory cascades by diminishing Interleukin-1 beta (IL-1β) and Tumor Necrosis Factor alpha (TNF-α) levels. Therefore, these compounds also protected fibroblast morphology. Moreover, the same compounds protected from DNA damage by preventing UVB-induced genomic DNA fragmentation and formation of cyclobutane pyrimidine dimers. In particular, compound XXIII displayed selective UVB absorption, better photostability, low cytotoxicity, and moderate biological photoprotection (SPF 16). CONCLUSION: Together, the results suggest that thiourea and (thio)semicarbazone derivatives, notably compound XXIII, represent promising photoprotective scaffolds requiring further formulation, in vivo, permeability, phototoxicity, and safety studies to validate their potential as UV-filtering agents.

Humans↗
PubMed1975

[Antiviral thiosemicarbazone and related compounds. III. Quantitative relationships between structure and antiviral activity of isantin-beta-isothio-semicarbazone against mengo virus].

The virostatic activity of isatin-beta-isothiosemicarbazones can be described quantitatively by hydrophobic, electronic, and steric substituent constants using multivariate regression analysis. A preceding Free-Wilson analysis allows data smoothening, and thus improved adaptation. Predictions made on the basis of the quantitative structure-action relationships obtained could be confirmed experimentally by synthesizing and testing the corresponding compounds.

Antiviral Agents↗
PubMed1978

The inhibitory effect of cysteine on the mutagenic activities of several carcinogens.

The Salmonella/microsome mutagenesis assay was used to determine the effect of cysteine (alpha-amino-beta-mercaptopropionic acid) on the mutagenic actions of several carcinogens: N-methyl-N'-nitro-N-nitrosoguanidine. N-acetoxy-2-acetylaminofluorene, N-hydroxy-2-acetylaminofluorene, 4-nitroquinoline-1-oxide, methyl methanesulfonate, 5-nitro-2-furaldehyde semicarbazone, 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide, aflatoxin B1 and the nitrosation products of methylurea and methylguanidine. Cysteine, at non-toxic concentrations, significantly decreased the frequency of reversion to histidine prototrophy when it was added to treatment mixtures. The extent of the inhibition of mutagenic action by cysteine depended on the carcinogen studied as well as the doses of cysteine and carcinogen employed. Cysteine (2.5--10 mM) completely inhibited the mutagenic actions of N-methyl-N'-nitro-N-nitrosoguanidine and methylguanidine nitrosation products while only partially preventing the mutagenic effects of the other carcinogens assayed. Inhibition of 5-nitro-2-furaldehyde semicarbazone-induced mutagenesis occurred only with higher cysteine concentrations (20--200 mM).

2-Acetylaminofluorene↗
PubMed1979

An improved method for the determination of acetaldehyde in human blood with minimal ethanol interference.

A sensitive method for the determination of acetaldehyde in human blood is described which involves the derivatization of acetaldehyde with semicarbazide followed by head-space gas chromatographic analysis of acetaldehyde in plasma samples after acid hydrolysis of the semicarbazone derivative. Quantitative recovery of acetaldehyde from human blood was achieved and interference from ethanol, a major problem associated with earlier methods, was negligible.

Acetaldehyde↗
PubMed1978

Molecular interaction between E-prostaglandins and selected polymers and its potential utilization in oral dosage form design.

Coacervate formation was observed between some E-prostaglandins and povidone in acetonitrile. This molecular interaction was studied using differential scanning calorimetry, IR spectrophotometry, and light microscopy. The structural requirements for coacervate formation between E-prostaglandins and povidone were investigated. Possible utilization of this molecular interaction in the development of E-prostaglandin formulations was explored. The dissolution rate of some insoluble E-prostaglandin esters increased when they were coprecipitated with povidone and polyethylene glycol. For example, the p-hydroxybenzaldehyde semicarbazone ester of 16,16-dimethyldinoprostone dissolved about 200 times faster as a povidone coprecipitate than did the control mixture. Enhancement of the dissolution rate was observed for the povidone coprecipitates of dinoprostone and its p-acetylphenyl and beta-naphthyl exters but not for the p-phenylphenyl ester. Fast dissolving dispersions of the E-prostaglandin esters also could be prepared with the water-insoluble cross-linked polyvinylpyrrolidone. This type of dispersion was nonglassy and easily dispersible in water. Thus, it might have certain advantages over the classical soluble povidone coprecipitates in terms of ease of handling. The degree of enhancement in dissolution of dispersions of cross-linked polyvinylpyrrolidone and E-prostaglandin esters is apparently dependent on the structure of the esters. The potential dissolution enhancement may be related to the strength of the interaction between the macromolecule and the esters, as indicated by the qualitative relationship between the extent of adsorption of the prostaglandins to cross-linked polyvinylpyrrolidone and the dissolution rate enhancement.

Administration, Oral↗
PubMed1979

Guanabenz degradation products and stability assay.

Guanabenz, [(2,6-dichlorobenzylidene)amino]guanidine, acetate was shown to be the E-isomer. It decomposed to form the Z-isomer, 2,6-dichlorobenzaldehyde, aminoguanidine, and 2,6-dichlorobenzaldehyde semicarbazone. A stability-indicating assay for the intact drug in the presence of all of its decomposition products by the use of UV spectroscopy is presented.

Chemical Phenomena↗
PubMed1979

Reactivity of the imino acids formed in the amino acid oxidase reaction.

The reactivity of the imino acids formed in the D- or L-amino acid oxidase reaction was studied. It was found that: (1) When imino acids reacted with the alpha-amino group of glycine or other amino acids, transimination yielded derivatives less stable to hydrolysis than the parent imino acids. In contrast, when imino acids reacted with the epsilon-amino group of lysine or other primary amines, transimination yielded derivatives more stable to hydrolysis than the parent imino acids. (2) Imino acids react rapidly with hydrazine and semicarbazide, forming stable hydrazones and semicarbazones. At pH 7.7, the rate of reaction of the imino acid analogue of leucine with semicarbazide was 10(4) times greater than that of the corresponding keto acid. The reaction of imino acids with these reagents is rapid enough to permit one to follow spectrophotometrically the amino acid oxidase reaction. Imino acids also reacted with cyanide to yield stable adducts. (3) The rate of hydrolysis of the imino acid analogue of leucine was independent of pH above pH 8.5. At lower pH values, the rate of hydrolysis increased with decreasing pH. At 25 degrees C and in the absence of added amino compounds, this imino acid had a half-life of 22 s at pH 8.5. Its half-life was 9.9 s at pH 7.9.

D-Amino-Acid Oxidase↗
PubMed1975

Synthesis and antibacterial properties of methylsulfinyl and methylsulfonyl analongs of some nitrofurans.

The sulfoxides 5-methylsulfinyl-2-furaldehyde semicarbazone (2) and 1-[(5-methylsulfinyl-2-fufurylidene)amino]hydantoin (3) as well as the sulfones 1-[(5-methylsulfonyl-2-furfurylidene)animo]hydantoin (1) and 1-(5-methylsulfonly-2-furyl)-2-(6-amino-3-p-ridazyl)ethylene hydrochloride (4) have been prepared and tested for antibacterial activity against a number of gram-negative and gram-positive organisms. The compounds are much less active than the corresponding 5-nitrofuran derivatives, possibly because their reduction potentials are too negative for them to interfere with reductive enzyme systems within the bacteria.

Anti-Bacterial Agents↗
PubMed1979

Specific methods for the determination of radioactivity in D-(-)-3-hydroxybutyrate in blood plasma.

Two simple, high-yield rapid methods with good reproducibility are described, which permit the determination of radioactivity in plasma D-(-)-3-hydroxybutyrate. The compound is converted to acetoacetate, using a modified enzymatic method. In procedure 1, acetoacetate is reacted with 2,4-dinitrophenylhydrazine; the resulting hydrazone is oxidised by means of a sample oxidiser, and the product 14CO2 is collected in scintillation liquid and counted. In procedure 2, a Conway microdiffusion unit is applied. The acetoacetate is decarboxylated to acetone in the presence of o-phenylenediamine, and the acetone is then diffused into semicarbazide solution. This solution, containing the semicarbazone derivative of labelled acetone, is transferred to liquid scintillation and counted. In both procedures the radioactivity is measured simultaneously in a separate sample which was not subjected to the enzymatic conversion of D-(-)-3-hydroxybutyrate. The difference in radioactivity between the two samples is attributed to labelled (D-(-)-3-hydroxybutyrate.

Carbon Radioisotopes↗
PubMed1979

[Quantitative determination of drugs by in situ spectrophotometry of chromatograms for pharmacokinetic studies. I. Sulpiride and other benzamides, vincamine, naftazone (author's transl)].

Assays are proposed for sulpiride and other benzamides, vincamine and naftazone in plasma (or blood) and urine with direct UV reflectance spectrophotometry on this are applied directly on TLC along with a calibration curve on each plate. Plasma (or total blood) samples are extracted, and an internal standard is added before aplication; slopes of the obtained calibration curves do not change significantly from plate to plate, thus allowing several determinations on the same plate. The sensitivity is 2 microgram in a 1-ml sample (amount applied 30 ng) for sulpiride and related compounds and about the same for vincamine. Naftazone is determined in plasma with simultaneous reflectance and transmittance spectrophotometric measurements at 520 nm on chromatoplates sprayed with lead acetate, the sensitivity reached is 10 ng in a 1-ml sample (amount applied 0.5 ng). For all drugs studied, the proposed techniques are specific, reliable and sensitive enough and can be used to perform pharmacokinetic studies in human or in animal after administration of doses in the therapeutic range.

Animals↗
PubMed1977

A comparison between placebo, pizotifen and 1-isopropyl-3-hydroxy-5-semicarbazono-6-oxo-2.3.5.6-tetrahydroindol (Divascan) in migraine prophylaxis.

The effects and side-effects in migraine prophylaxis of placebo, Divascan (1-isopropylnoradrenochrome--5--monosemicarbazone) and pizotifen were compared in a double-blind cross-over study. The dosage was for Divascan 15 mg a day and for pizotifen 3 mg a day. Data from the last 6 weeks of each test period of 8 weeks were used to assess the effect of the treatment. Thirty patients entered the trial. Data from 28 patients treated with placebo and Divascan and 27 patients treated with pizotifen were used for final evaluation. Pizotifen significantly reduced the number of migraine attacks, headache index and the consumption of ergotamine. Divascan also seemed to have effect. The consumption of ergotamine was reduced compared with placebo and there was a reduction, although not significant, of headache frequency and headache index. Pizotifen gave significantly larger reduction in headache frequency and headache index than Divascan and signficantly more patients stated a preference for pizotifen compared with Divascan. A good or very good effect was reported by 11 per cent of the patients on placebo, 39 per cent on Divascan and 70 per cent on pizotifen. Pizotifen had frequent side-effects, mainly drowsiness and weight gain, whereas Divascan in this respect did not differ from placebo. Physical examinations and laboratory investigations did not show any significant changes, apart from weight gain.

Adrenochrome↗
PubMed1975

[Healing of the donor area after transplantation of splitted grafts].

The healing of wounds in the donor area of splitted grafts was observed. The transplants served to graft an already existing wound which had not healed spontaneously. 120 wounds sustained by 95 patients were examined either histologically or by Rebuck's method of skin fenestration. 30 wounds were dressed with ointment and tulle, in 55 cases the wound was covered with perforated cellophane and an Allen-Koch compression bandage. These patients also received 1500 mg Complain in 500 ml physiological saline solution daily, by continuous drip infusion, for three days postoperatively. In 35 patients the wounds were only covered with perforated cellophane, but without additional medication. The application of Complamin shortened the healing process to seven to ten days in contrast to the control group where the wounds took 15 to 17 days to heal.

Aged↗