Penetration of the pulp chamber by bleaching agents in teeth restored with various restorative materials.

It is thought that externally applied bleaching agents may penetrate into the pulp chamber. This study was conducted to evaluate the diffusion of peroxide bleaching agents into the pulp chamber of teeth restored with various restorative materials. Sixty-five human extracted anterior maxillary teeth were separated into the 13 groups containing 5 teeth. Five teeth (control group) were not subjected to any cavity preparation and restoration. Standardized class V cavities were prepared in the other 60 teeth and restored using composite resin (Charisma), polyacid modified composite resin (Dyract), or resin-modified glass ionomer cement (Vitremer). All teeth were sectioned 3 mm apical to the cementoenamel junction to remove the intracoronal pulp tissue, and the pulp chamber was filled with acetate buffer to absorb and stabilize any peroxide that might penetrate. Vestibular crown surfaces of teeth in the experimental groups were subjected to four different bleaching agents for 30 min at 37 degrees C, whereas the teeth in the control groups were exposed only to distilled water. Then the acetate buffer solution in the pulp chamber of each tooth was removed, and the pulp chamber of each tooth was rinsed with 100 ml of distilled water twice. Leukocrystal violet and enzyme horseradish peroxidase were added to the mixture of the acetate buffer and rinse water. The optical density of the resulting blue solution was determined spectrophotometrically and converted into microgram equivalents of hydrogen peroxide. Higher hydrogen peroxide concentrations resulted in a higher pulpal peroxide penetration. The highest pulpal peroxide penetration was found in resin-modified glass ionomer cement groups, whereas composite resin groups showed the lowest pulpal peroxide penetration.

Synthesis and antimicrobial activity of some new piperidinyl benzimidazoles.

A series of 2-(4-methylpiperidin-1-yl)-1,5(6)-disubstituted-1H-benzimidazoles (1-18) were prepared through the reaction of 2-chloro (or 2-chloromethyl)-1H-benzimidazole derivatives with 4-methylpiperidine. For the preparation of the individual isomers, compounds 7, 9 and 18 were synthesized by a multistep procedure. The prepared compounds were screened for their in vitro antibacterial and antifungal activities. Compound 3 and 4 exhibited the best antifungal activity.

Synthesis and X-ray crystal structure of the calcium channel antagonist: dimethyl 1,4-dihydro-2,6-dimethyl-4-[4'-(4H-4-oxo-1-benzopyran-2-yl)phenyl]- 3,5-pyridine dicarboxylate.

The synthesis of the title compound via the Hantzsch method from 4'-flavone carboxaldehyde is described, and its molecular structure was determined by X-ray crystallography. The 1,4-dihydropyridine (1,4-DHP) ring adopts a boat conformation. The phenyl ring of the flavone is not exactly perpendicular to the DHP ring. Calcium antagonistic activity of this compound was evaluated in vitro by using BaCl2-stimulated rat ileum.

Synthesis of some 4-[3' or 4'-(4H- 4-oxo-1-benzopyran-2-yl)phenyl]-1,4-dihydropyridine derivatives as potential calcium channel antagonists.

In this study, the synthesis of new flavonoid derivatives, which possess a 1,4-dihydropyridine (1,4-DHP) moiety on the phenyl ring of flavone were realized. 3' or 4'-Formyl-flavones were synthesized, then the aldehyde groups of these compounds were converted to the 1,4-DHP moiety by the Hantzsch method. A series of 23 new derivatives having different substituents at C-3 and C-5 of the 1,4-DHP ring were prepared. Two compounds (8a, 8b) were tested for their calcium channel blocker activity and 8b exhibited the best result.

Synthesis and antioxidant properties of some new flavone derivatives on lipid peroxidation in the rat liver.

A series of 2'-, 3'-, 4'- and 6-substituted flavone derivatives was synthesized and their in vitro effects on rat liver microsomal NADPH-dependent lipid peroxidation (LP) levels were determined. Retinoic acid, at 10(-4) M concentration, decreased the LP level by about 34%. A significant decrease in male liver microsomal LP level was noted for the compounds 3d, 1a, 3b and 4b at a concentration of 10(-4) M (100%, 95%, 75% and 62%, respectively).

Penetration of the pulp chamber by carbamide peroxide bleaching agents on teeth restored with a composite resin.

This in vitro study was performed to evaluate the effect of various concentrations of carbamide peroxide bleaching agents on the pulp chambers of teeth restored by a composite resin. Forty-nine human extracted anterior teeth were used. All the teeth were sectioned 3 mm apical of the cemento-enamel junction and the intracoronal tissue removed. The teeth were separated into the seven groups each containing seven teeth. Twenty-eight teeth were used as controls (groups I-IV), standardized cavities were prepared with the remaining 21 teeth (groups V, VI, VII), and restored with a hybrid composite resin (XR Herculite). Acetate buffer was placed in the pulp chamber to absorb and stabilize any peroxide that might penetrate. Group I was exposed only to distilled water. Groups II and V were applied with 10% CP (Contrast PM), groups III and VI were applied with 15% CP (Contrast PM), groups IV and VII were applied with 35% CP (Quik Start) and left for 30 min at 37 degrees C. Then, the acetate buffer solution in the pulp chamber of each tooth was removed and the chamber was then rinsed twice with 100 ml of distilled water. The contents then had leucocryctal violet and enzyme horseradish peroxidase added. The optical density of the resulting blue solution was determined spectrophotometrically, and was converted into microgram equivalents of hydrogen peroxide. A higher level of bleaching agent penetrated into the pulp chamber in the restored teeth than in the sound teeth.

Synthesis and hypoglycemic activity of some new flavone derivatives. 3rd communication: 3'-flavonyl-2,4-thiazolidinediones.

A new series of 3'-flavonyl-2,4-thiazolidinedione, 2,4-imidazolidinedione and 2-thiohydantoin derivatives (1-10) were synthesized and their chemical structures have been elucidated by various spectral data. The prepared compounds were tested for their insulinotropic effects in INS-1 cells. Inhibitory effects were observed for compounds 1 and 2. In contrast compounds 4, 7 and 8 were able to increase insulin release compared with glibenclamide.

Synthesis and hypoglycemic activity of some new flavone derivatives. 2nd communication: 4'-flavonyl-2,4-thiazolidinediones.

A new series of 4'-flavonyl-2,4-thiazolidinedione, 2,4-imidazolidinedione and 2-thiohydantoin derivatives (1-10) were synthesized. Their chemical structures have been elucidated by IR, 1H-NMR, mass spectra and elementary analysis. The synthesized compounds were tested for their insulinotropic effects in INS-1 cells. Inhibitory effects were observed for compounds 1, 2, 6 and 7.

Synthesis and antifungal activity of some new benzimidazole derivatives.

Synthesis and antifungal evaluation of 5-ethoxycarbonyl-2-(substituted-benzyl or phenoxymethyl)benzimidazoles are reported. Structures of the compounds were elucidated with IR-, 1H-NMR-, 13C-NMR-, mass-spectra and elemental analysis. Preliminary results show that none of the synthesized benzimidazole derivatives has antifungal activity at the concentration of 100 micrograms/ml against Candida parapsilosis, Candida stellatoidea, and Candida pseudotropicalis.

Synthesis and antifungal activities of some new triazolylacetophenone derivatives.

In this study some alpha-(1,2,4-triazolyl)acetophenone derivatives were synthesized by the condensation of various triazole and alpha-bromoacetophenone rings. The structures of the compounds have been elucidated by UV, IR, 1H-NMR, mass spectra and elementary analysis. The in vitro antifungal activity of the compounds were investigated against some yeast-like fungi (Candida albicans, C. parapsilosis, C. stellatoidea and C. pseudotropicalis) and moulds such as Trichophyton rubrum and T. mentagrophytes by the tube dilution method and MIC (minimal inhibitory concentration), MFC (minimal fungicidal concentration) values were determined. Compound A16 was significantly more effective than the other compounds. The results obtained for antifungal activity against moulds were not significant.

Synthesis and antipseudomonal activities of some ofloxacin esters as prodrugs.

Three new ofloxacin esters have been synthesized as prodrug by the reaction of ofloxacin (CAS 82419-36-1) with chloromethylacetate, 1-chloroethylacetate and 1-chloroethylethylcarbonate in acetonitrile. The structures of the compounds have been elucidated by UV, IR, 1H-NMR, Mass spectra and elementary analysis. In vitro activities of these compounds against clinical isolates of various Pseudomonas aeruginosa species have been determined by microtiter tube dilution method, and octanol/water partition coefficients and pH dependent hydrolysis rates have been investigated in comparison with ofloxacin.

Synthesis of new annellated flavonoid derivatives possessing spasmolytic activity--VII.

7,8-Dihydroxyflavone reacts with ethyl 2,3-dibromopropanoate to form the new, annellated, 1,4-benzodioxanes 1 containing a flavone structural unit. The regioisomers 1a and 1b thus obtained were separated and 1a was converted to the amides 2a-2f. The constitutions of 1 and 2 were elucidated by 500 MHz 1H-NMR spectroscopy. In the spasmolysis test, 2e showed significant antagonistic effect towards the agonists acetylcholine, barium chloride, and histamine.

Synthesis and hypoglycaemic activity of some new flavone derivatives. Part 1: Flavonylsulphonylurea derivatives.

A new series of flavonyl-3'-sulphonylurea derivatives (1-7) was prepared by reaction of several isocyanates with flavone-3'-sulphonamide (III). The prepared compounds were tested for their insulinotropic activities in INS-1 cells. Compounds 1 and 4 were able to increase insulin release in the presence of 8.3 mM glucose at least at the higher concentrations used.

Synthesis and inhibitory activities on platelet aggregation of some flavonoid analogues.

A series of 26 benzodioxan and benzodioxol derivatives of flavone have been prepared. The activity of the compounds on washed human platelet aggregation induced by adenosine diphosphate (ADP, 5 mumol/l), collagen (10 micrograms/ml) and calcimycin (20 mumol/l) was evaluated. The alkoxycarbonyl side chain derivatives inhibited all three types of aggregation inducers. Among the tested compounds Ia is the most potent inhibitor of collagen-induced aggregation but possesses a weak activity against the other two used inducers. The esters IIIb and in particular, IIIc are active against all the three used inducers. These results suggest that ethoxycarbonyl group is a potent substituent to provide the antiplatelet action in this series of flavonoids.

Synthesis and antimicrobial activity of some new anilino benzimidazoles.

A series of 2-(anilino or 2,6-dichloroanilino)-1,5(6)-disubstituted-1H-benzimidazoles (1-13) were prepared by reaction of several 2-chloro- or 2-chloromethyl-1H-benzimidazoles with aniline derivatives. The prepared compounds were screened for their in vitro antibacterial and antifungal activities. Compounds 2, 8, and 9 exhibited the best activity.

Synthesis and evaluation of anti-inflammatory activity of some thiazolo[3,2-b]-1,2,4-triazole-5(6H)-ones and their Michael addition products.

Thiazolo[3,2-b]-1,2,4-triazole-5(6H)-ones (4-10) were obtained in a one step synthesis by heating 3-aryl-5-mercapto-1,2,4-triazoles (3a-d) with chloroacetic acid and appropriate aromatic aldehyde in acetic acid and acetic anhydride in the presence of anhydrous NaOAc. Michael type addition of cyclic secondary amines (N-methylpiperazine, piperidine) to 4-10 gave 2-phenyl-6-(alpha-aminoarylmethyl)thiazolo[3,2-b]-1,2,4-triazole-5 -ols (4a-10b). The structures of the compounds were confirmed by spectral and elementary analysis. The compounds synthesized in previous and present studies were investigated for their anti-inflammatory activities.

Synthesis and antimicrobial activity of some new flavonyl oxime ether derivatives.

The synthesis of a series of 6 compounds related to 2-(4'-formyl-phenyl)-4]H-1-benzopyran-4-one O-substituted oxime and the results of a study of their biological activity are reported. The structural assignments of the compounds is based upon various spectral data. The prepared compounds were screened for their in vitro antibacterial and antifungal activities. Compound F3 exhibited the best antifungal activity compared with ketoconazole and fluconazole.

Synthesis and hypoglycemic activity of some new flavone derivatives. 4th communication: 6-flavonyl-2,4-thiazolidinediones.

A new series of flavonyl compounds (1-10) was prepared and tested for their insulinotropic activities in INS-1 cells. Compounds 2, 5 and 6 (at higher concentrations) and compounds 3 and 7-10 were able to increase insulin release in the presence of 5.6 mmol/l glucose at both concentrations used (1 and 10 micrograms/ml).

Antioxidant activity of 4-flavonil-1,4-dihydropyridine derivatives.

The effect of 4-flavonil-1,4-dihydropyridine derivatives on a chemical system involving a superoxide radical anion was tested using the chemiluminescence and spectrophotometry methods. All tested compounds enhanced the light emission from the system. The obtained results indicated that the tested derivatives may catalyze the conversion of superoxide radicals, thus showing superoxide dismutase activity.