Antifungal derivatives from Piper mollicomum and P. lhotzkyanum (Piperaceae)

Bioguided fractionation of the extracts from leaves of Piper mollicomum and Piper lhotzkyanum against the fungi Cladosporium cladosporioides and C. sphaerospermum afforded seven bioactive compounds, four being chromenes: methyl 2,2-dimethyl-2H-chromene-6-carboxylate, methyl 8-hydroxy-2,2-dimethyl-2H-chromene-6-carboxylate, 2-methyl-2-[4'-methyl-3'-pentenyl]-2H-1-benzopyran-6-carboxylic acid, 2,2-dimethyl-2H-chromene-6-carboxylic acid, one a dihydrochalcone: 2',6'-dihydroxy-4'-methoxydihydrochalcone, and two flavanones: 7-methoxy-5,4'-dihydroxy-flavanone and 7,4'-dimethoxy-5-hydroxy-flavanone. The structures of the bioactive isolated derivatives were elucidated by interpretation of their NMR data [¹H and 13C (BBD, DEPT 135º)], and mass spectral data as well as by comparison with data described in the literature.

An easy and direct method for the synthesis of 1,2,4-triazole derivatives through carboxylic acids and hydrazinophthalazine

We have developed an easy method for the synthesis of thirteen compounds derived from 1,2,4-triazoles through a carboxylic acid and hydrazinophthalazine reaction, with a 75-85% yield mediated by the use of agents such as 1-ethyl-3-(3'-dimethylaminopropyl)-carbodiimide hydrochloride and 1-hydroxybenzotriazole. The operational simplicity of this method and the good yield of products make it valuable for the synthesis of new compounds with pharmacological activity.

Synthesis and antitubercular activity of isoniazid condensed with carbohydrate derivatives

A series of 13 compounds analogous of isoniazid condensed with carbohydrate was synthesized and evaluated for their in vitro antibacterial activity against Mycobacterium tuberculosis H37Rv using Alamar Blue susceptibility test and the activity expressed as the minimum inhibitory concentration (MIC90) in μg/mL. Several compounds exhibited antitubercular activity (0.31-3.12 μg/mL) when compared with first line drugs such as isoniazid (INH) and rifampicin (RIP) and could be a good starting point to develop new compounds against tuberculosis.

Synthesis and biological activity of n-{5-(4-methylphenyl) diazenyl-4-phenyl-1, 3-thiazol-2-yl}benzamide derivatives

In the present study, various amides of 2-amino-5-(4-methylphenyl)-diazenyl-4-phenyl-1, 3-thiazole was synthesized and their biological activities were evaluated. All the synthesized compounds were characterized by the combination of elemental analysis and standard spectroscopic methods. They are screened for anti-bacterial activity against Escherichia coli and Staphylococcus aureus as well as screened for antifungal activity against Aspergillus niger and Apergillus oryzae by cup plate method at 1 µg/ mL concentration in DMF.

Efficient synthesis of sulfonamide derivatives on solid supports catalyzed using solvent-free and microwave-assisted methods

In this work we report the synthesis of sulfonamide derivatives using a conventional procedure and with solid supports, such as silica gel, florisil, alumina, 4Å molecular sieves, montmorillonite KSF, and montmorillonite K10 using solvent-free and microwave-assisted methods. Our results show that solid supports have a catalytic activity in the formation of sulfonamide derivatives. We found that florisil, montmorillonite KSF, and K10 could be used as inexpensive alternative catalysts that are easily separated from the reaction media. Additionally, solvent-free and microwave-assisted methods were more efficient in reducing reaction time and in increasing yield.

Synthesis of quinoxaline 1,4-di-N-oxide derivatives on solid support using room temperature and microwave-assisted solvent-free procedures

We describe the synthesis of 12 new ethyl and methyl quinoxaline-7-carboxylate 1,4-di-N-oxide derivatives on solid supports with room temperature and microwave-assisted solvent-free procedures. Results show that solid supports have good catalytic activity in the formation of quinoxaline 1,4-di-N-oxide derivatives. We found that florisil and montmorillonite KSF and K10 could be used as new, easily available, inexpensive alternatives of catalysts. Additionally, room temperature and microwave-irradiation solvent-free synthesis was more efficient than a conventional procedure (Beirut reaction), reducing reaction time and increasing yield.

Poly(ethylene-co-methyl acrylate)/poly(caprolactone) triol blends for drug delivery systems: characterization and drug release

Poly(ethylene-co-methyl acrylate) (EMA) and poly (caprolactone) triol (PCL-T) blends, a biodegradable aliphatic polyester with low molecular weight and moderate water solubility containing diltiazem hydrochloride (DZ) were studied in terms of the thermal and morphological properties, and drug release mechanism. An increase in the PCL-T content in the EMA/PCL-T/DZ films decreased the degree of DZ crystallinity. Drug release from these films is temperature-dependent, and it is possible to modify the drug release rate by adjusting the EMA/PCL-T composition of the blends. The mechanism of drug release is governed by PCL-T melting and PCL-T leaching from EMA matrix.

Synthesis, antimicrobial and cytotoxic activities of 5-benzylidene-2-[(pyridine-4-ylmethylene)hydrazono]-thiazolidin-4-one and 2-[(pyridine-4-ylmethylene) hydrazono]-thiazolidin-4-one derivatives

A new series of 5-benzylidene-2-[(pyridine-4-ylmethylene)hydrazono]-thiazolidin-4-ones 4a-l have been synthesized. These compounds were designed by a molecular hybridization approach. 2-[(Pyridine-4-ylmethylene)hydrazono]-thiazolidin-4-ones 3a-d were also obtained and used as intermediates to give the target compounds. The in vitro antimicrobial and cytotoxic activities were evaluated for both series. The intermediate 3b showed considerable antibiotic activity against B. subtilis and C. albicans. In the cytotoxic activity compounds 3b (IC50= 4.25 ± 0.36 µg/mL) and 4l (IC50= 1.38 ± 0.04 µg/mL) were effective for inhibition of human erythromyeloblastoid leukemia (K-562) and human lung carcinoma (NCI-H292) cell lines, respectively.

Characterization and in vitro release of cyclosporine-A from poly(D,L-lactide-co-glycolide implants obtained by solvent/extraction evaporation

Cyclosporine-A-loaded PLGA implants were developed intended for ocular route. Implants were prepared using solvent extraction/evaporation technique followed by casting of the cake into rods in a heated surface. XRD patterns showed that cyclosporine-A was completely incorporated into PLGA. FTIR and DSC results indicated alterations on drug molecular conformation aiming to reach the most stable thermodynamic conformation at polymer/drug interface. Implants provided controlled/sustained in vitro release of the drug. During the first 7 weeks, the drug release was controlled by the diffusion of the cyclosporine-A; and between 7-23 week period, the drug diffusion and degradation of PLGA controlled the drug release.

Nitro derivatives and other constituents of Aristolochia melastoma

A phytochemical study of Aristolochia melastoma Manso has led to the isolation and identification of 20 known compounds, including aristolochic acids, sodium aristolochates, lignan, flavonoids, and nitro phenylethyl derivatives. Their structures were established by spectroscopic analysis. The presence of thalictricoside and secoisolariciresinol dimethyl ether diacetate is reported for the first time in the Aristolochiaceae family. In addition, the presence of nitro compounds in this species is significant.

Synthesis of 2-azetidinone derivatives of 6-nitro-1H-indazole and their biological importance

A new series of 3-chloro-1-{[2-(6-nitro-1H-indazol-1-yl)ethyl]amino}-4-(substituted phenyl)-2-azetidinones (4a-j) was synthesized in four steps from 6-nitro-1H-indazole and characterized by IR, ¹H NMR, 13C NMR, FAB-mass spectrometry and chemical methods. Compounds 4(a-j) were screened in vitro for their antibacterial, antifungal and antitubercular activities against some selected microorganism and for their antiinflammatory activity (in vivo) against albino rats (either sex). All above activities of compounds 4(a-j) showed acceptable results.

Phenolic derivatives and other chemical compounds from Cochlospermum regium

This study describes the chemical investigation of the ethyl acetate fraction obtained from the hydroethanolic extract of the xylopodium of Cochlospermum regium (Mart. & Schr.) Pilger, which has been associated with antimicrobial activity. Phytochemical investigation produced seven phenol derivatives: ellagic acid, gallic acid, dihydrokaempferol, dihydrokaempferol-3-O-β-glucopyranoside, dihydrokaempferol-3-O-β-(6"-galloyl)-glucopyranoside, pinoresinol, and excelsin. It also contained two triacylbenzenes, known as cochlospermines A and B. The hydroethanolic extract and its fractions exhibited antimicrobial activity (0.1 mg/mL) against Staphylococcus aureus and Pseudomonas aeruginosa. Gallic acid showed activity against S. aureus. Dihydrokaempferol-3-O-β-(6"-galloyl)-glucopyranoside is reported here for the first time in the literature.

Synthesis, characterization and application of ion imprinted poly(vinylimidazole) for zinc ion extraction/preconcentration with faas determination

In this paper, we describe the synthesis of an ion imprinted polymer (IIP) by homogeneous polymerization and its use in solid-phase to extract and preconcentrate zinc ions. Under optimal conditions (pH 5.0, preconcentration flow rate of 12.0 mL min-1, and eluted with 1.0 mol L-1 HNO3) this procedure allows the determination of zinc with an enrichment factor of 10.2, and with limits of detection and quantification of 1.5 and 5.0 µg L-1, respectively. The accuracy of our results was confirmed by analysis of tap water and certified reference materials: NIST 1570a (Spinach leaves) and NIST 1515 (Apple leaves).

DFT study on low molecular weight α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene and α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene S-oxide bridged derivatives

The equilibrium geometries of α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene (DBDT) and α,α-ditert-butyl-4H-cyclopenta[2,1-b,3;4-b']dithiophene S-oxide (DBDTO) were studied at the DFT level of theory with a standard 6-311G* basis set. The molecular structures of the DBDT series were more planar than the corresponding DBDTO series, as revealed by dihedral angles. The UV-visible absorption calculated at TD-DFT/6-311G* showed two absorption peaks for all the molecules except C=S and C=O bridged molecules. In DBDTOs, C=S and C=O bridged molecules showed three and four absorption peaks, respectively. The DBDTOs had lower band gaps and longer wavelengths compared to the corresponding DBDTs.

Synthesis, characterization, and biological activity of a new class of dialkylphosphorylhydrazone derivatives of isatin

Sixteen dialkylphosphorylhydrazones were synthesized by condensation of phosphorylhydrazines with substituted isatins. Products were characterized by FTIR, ¹H-NMR, 13C-NMR, and 31P-NMR. Fungicidal activities of these compounds against Rhizoctonia solani and Fusarium oxysporum were also evaluated. Some compounds inhibited the growth of Rhizoctonia solani and Fusarium oxysporum by 43% and 51%, respectively. These compounds exhibited no effects on germination of lettuce seeds (Lactuca sativa L).