Resveratrol enhances UVA-induced DNA damage in HaCaT human keratinocytes.

Resveratrol, a polyphenolic phytoalexin, is a very effective antioxidant that also exhibits strong antiproliferative and anti-inflammatory properties. Recent studies have provided support for the use of resveratrol in human cancer chemoprevention, in combination with either chemotherapeutic drugs or cytotoxic factors for a most efficient treatment of drug refractory tumor cells. Resveratrol is also widely used in topical preparations, as a chemoprotective compound against development of several cutaneous disorders, including skin cancer. Nevertheless, the combined effect of resveratrol and UVA irradiation on cellular toxicity and DNA damage has never been assessed. The aim of this work was to investigate the effect of resveratrol on cell fate in immortalized human keratinocytes HaCaT cells. The results indicated that resveratrol potentiates the production of significant amounts of 8-oxo-7,8-dihydro-2'-deoxyguanosine in UVA-irradiated genomic DNA. Moreover, the combination of resveratrol with UVA significantly enhances the induction of DNA strand breaks and cell death in HaCaT keratinocytes. The conclusion is a potential hazardous effect of topical application of resveratrol, particularly on regions exposed to sunlight.

[New substituted 4-thioxothiazolidin-2-one derivatives: synthesis and structural study]. / Synthèse et étude structurale de nouvelles 4-thioxothiazolidin-2-ones substituées.

Synthesis and physico-chemical properties of some 3-benzyl- and 3-phenacyl-4-thioxo-5-benzylidenethiazolidin-2-one derivatives are described. Fifteen new compounds were synthesized from thiazolidin-2-one by thionation of the 4-carbonyle, alkylation of the 3-N and aldolisation-crotonisation of 5-CH(2) with aromatic aldehydes. Soon, these new compounds will be tested for their bacteriostatic activity.

[Synthesis and structural study of substituted arylideneimidazolidines and arylidenebenzothiazines]. / Synthesis and structural study of substituted arylideneimidazolidines and arylidenebenzothiazines.

Synthesis and physico-chemical properties of six 5-arylidène-3-benzyl-1-methyl-2-thioxoimidazolidin-4-ones and three 2-arylidene-6-nitro-2H-1,4-benzothiazin-3(4H)-ones have been described. These new compounds were synthetised by Knoevenagel condensation reaction from aromatic aldehydes. The N-alkylation reaction of arylidenebenzothiazines by methyl iodide give the N-methylarylidenebenzothiazines.

Synthesis and antimicrobial activity of substituted imidazolidinediones and thioxoimidazolidinones.

Synthesis and physico-chemical properties of new 3-benzyl-4-thioxo-5-arylideneimidazolidine-2-ones and 3-benzyl-5-arylideneimidazolidine-2,4-dione are described. These compounds were synthesized by condensation reaction from aromatic aldehydes and 3-substituted imidazolidine-2,4-diones or 4-thioxoimidazolidine-2-ones. The N-alkylation of 5-benzylideneimidazolidine-2,4-dione led simultaneously to mono- and dialkylated derivatives. The nucleophilic addition of 1-methyl-3-benzylimidazolidine-2,4-dione with 2-cyano-3-(3,4-dichlorophenyl) acrylate also yielded the 3-substituted 5-arylideneimidazolidine-2,4-dione derivative. Antimicrobial in vitro activity was determined on some compounds.

[Substituted thio-arylidene thiazolidinones: synthesis and structural study]. / Thio-arylidène thiazolidinones substituées: synthèse et étude structurale.

The synthesis and physico-chemical properties of fourteen 4-thio-5-arylidene-thiazolidine-2-ones and eight 3-(4-bromophenacyl)-4-thio-5-arylidene-thiazolidine-2-ones are described. These products were synthetized by the aldolisation-crotonisation reaction between aromatic aldehydes and 4-thio-thiazolidine-2-one followed by N-alkylation of this substituted compounds.

[Synthesis and structure of substituted arylazo-imidazolidines and arylidenethiazolidines]. / Synthèse et structure des arylazo-imidazolidines et arylidènethiazolidines substituées.

Synthesis and physico-chemical properties of four 3-benzyl or 3-(4-chlorobenzyl)-4-thioxo-5-arylazo-imidazolidin-2-ones, five 3-(4-nitrobenzyl)-5-arylidenethiazolidine-2,4-diones and three 3-(4-phenyl-phenacyl)-4-thioxo-5-arylidenethiazolidin-2-ones have been described. These new products were synthesized by an aldolisation-crotonisation reaction from aromatic aldehydes and 3-substituted thioxothiazolidin-2-ones or thiazolidine-2,4-diones. The arylazo-imidazolidine compounds were synthesized by copulation of diazonium ions with imidazolidines. Antimicrobial activity was determined for some compounds.

Substituted thiazolidinediones and thio-imidazolidinones: synthesis, structural study and pharmacological activity.

Synthesis and physico-chemical properties of six 3-(4-bromophenacyl)-5-arylidene-thiazolidine-2,4-diones and eight 3-(4-chlorobenzyl)-5-arylidene-4-thio-imidazolidine-2-ones are described. These products were synthesized by an aldolisation-crotonisation reaction from aromatic aldehydes and 3-substituted thiazolidine-2,4-diones or 4-thio-imidazolidine-2-ones. Hypoglycemic and peripheral antinociceptive activities were investigated for these compounds.

[Synthesis and structural study of 5-arylidene thiazolidine-2,4-diones and 3-substituted-4-thio-imidazolidine-2-ones]. / Synthèse et étude structurale des 5-arylidène thiazolidine-2, 4-diones et 4-thio-imidazolidine-2-ones-3-substituées.

The synthesis and the physico-chemical properties of four 3-(4-bromophenacyl)-5-arylidene-thiazolidine-2,4-diones, two 3-(4-bromobenzyl)-5-arylidene-thiazolidine-2,4-diones and seven 3-(4-chlorobenzyl)-5-arylidene-4-thio-imidazolidine-2-ones were described. These products were synthetized by the aldolisation-crotonisation reaction between aromatic aldehydes and substituted thiazolidinediones or thio-imidazolidinones.

[Substituted imidazolidinediones and thiazolidinediones: synthesis, structure and cytotoxic activity]. / Imidazolidinediones et thiazolidinediones substituées: synthèse, étude structurale et activité cytotoxique.

Synthesis and physico-chemical properties of nine 3-(4-fluoro or chlorobenzyl)-5-arylidène-imidazolidine-2,4-diones, four 3-(4-fluoro or bromobenzyl)-5-arylidène-thiazolidine-2,4-diones and three 3-)4-bromophénacyl)-5-arylidène-thiazolidine-2,4- diones has been described. These compounds were synthesized by aldolisation-crotonisation reaction from aromatic aldehydes and 3-substituted imidazolidine-2,4-diones or thiazolidine-2,4-diones. In vitro cytotoxic activity was determined for compounds 8, 17, 18, 21 and 22.

Synthesis and pharmacological evaluation of some 3-phenacyl-5-benzylidene-thiazolidine-2,4-diones.

The synthesis of 54 3-phenacyl-5-benzylidene-thiazolidine-2,4-diones is reported. Eight of them were tested for anti-oedema, analgesic and anticonvulsant activity. Only one compound showed significant anti-oedematous and analgesic activity. Three compounds protected against tonic seizures and death.

Failure of N-(2,4-dinitrophenyl)-5-methoxytryptamine (a putative melatonin antagonist) and of N-(3,5-dinitrophenyl)-5-methoxytryptamine to prevent the effects of injections of melatonin in the late afternoon on testicular activity of the golden hamster.

Daily injections of 10 micrograms melatonin in the late afternoon into male golden hamsters kept under a long photoperiod (14 h light: 10 h darkness) and at low ambient temperature 6 +/- 1 degrees C) induced a complete gonadal atrophy after 4 weeks. When administered under the same conditions at doses of 25 micrograms, neither N-(3,5-dinitrophenyl)-5-methoxytryptamine or N-(2,4-dinitrophenyl)-5-methoxytryptamine, a putative melatonin antagonist termed ML-23 in the literature, showed any effect on testicular activity. Moreover, these two drugs were also unable to prevent melatonin-induced gonadal atrophy when injected 30 min before melatonin. The results demonstrate that in the golden hamster and in the present experimental conditions, these drugs do not have the melatonin-antagonistic properties as described in the rat.