Synthesis and antimicrobial activity of some novel 2-(p-substituted-phenyl)-5-substituted-carbonylaminobenzoxazoles

A series of 2-(p-substituted-phenyl)-5-substituted-carbonylamino benzoxazole derivatives (5-22) was synthesized and their antimicrobial activities determined in comparison to several control drugs. The synthesized compounds were tested in vitro against Staphylococcus aureus, Streptococcus faecalis and Bacillus subtilis as Gram-positive, Pseudomonas aeruginosa and Escherichia coli as Gram-negative bacteria and the yeast Candida albicans. Microbiological results showed that the compounds possessed a diffuse spectrum of antibacterial activity against these microorganisms. Compound 9 which bears a phenylacetamido moiety at position 5 and a 4-fluorophenyl group at the 2-position of benzoxazole ring was the most active derivative against S. aureus, S. faecalis and P. aeruginosa with a MIC value of 12.5 microg/ml. Compound 11 provided higher potency than the other tested compounds against B. subtilis at a MIC value of 12.5 microg/ml. Compounds 5-22 showed antifungal activity against C. albicans with MIC values between 50 and 12.5 microg/ml.     

Synthesis and biological evaluation of novel benzimidazol/benzoxazolylethoxypiperidone oximes

Some novel benzimidazol/benzoxazolylethoxypiperidone oximes were synthesized and their antibacterial activity against Staphylococcus aureus (NCIM-2492), Bacillus subtilis (NCIM-2439), Escherichia coli (NCIM-2345) and Pseudomonas aeruginosa (NCIM-2035) and antifungal activity against Candida albicans (NCIM-C27), Candida-6 (NCIM-C27), Candida-51 (NCIM-C27), Aspergillus niger (NCIM-590) and Aspergillus flavus (NCIM-539) have been evaluated. Compounds 26 and 27 exerted potent in vitro antibacterial activity against Bacillus subtilis, Escherichia coli and Staphylococcus aureus while compounds 26, 29 and 30 exhibited potent in vitro antifungal activity against Candida albicans, Candida-51, and Aspergillus niger.     

Evaluation of Composition and Antimicrobial Activity of Supercritical Fluid Extract of Leaves of Vitex negundo

Supercritical fluid extract of leaves of Vitex negundo was tested for its antimicrobial potential and was compared with that of ethanol extract, ether extract and hydrodistilled oil of leaves. The chemical constituents of extracts were studied by chromatographic techniques. Extracts were evaluated for antimicrobial potential against bacterial strains like Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and yeast Candida albicans. Extracts showed prominent antibacterial activity against Bacillus subtilis and Staphylococcus aureus. Supercritical fluid extract exhibited good antibacterial potential.     

Antimicrobial Activity of Acanthus ilicifolius (L.)

The antimicrobial activity of alcoholic, butanolic and chloroform extracts of leaves and roots of the plant Acanthus ilicifolius ware studied. Ampicillin and clotrimazole were used as standard antibacterial and antifungal agents respectively. The result of the study revealed that the alcoholic extract and chloroform extract of leaves exhibited strong inhibitory action against Bacillus subtilis, Staphylococcus aureus, Candida albicans, Aspergillus fumigatus and Aspergillus niger and moderate inhibitory action against Pseudomonas aeruginosa and Proteus vulgaris. The rest of the extracts showed moderate activity.     

Antibacterial diterpenes from the roots of Salvia viridis

Three new diterpenes, salviviridinol, viridinol, viridone, five known diterpenes, sugiol, 1-oxoferruginol, ferruginol, aethiopinone and microstegiol, abietane and rearranged abietane diterpenes were isolated from the roots of Salvia viridis. These compounds were assayed against S. aureus ATCC 6538 P, E. coli ATCC 8739, P. mirabilis ATCC 14153, K. pneumonia ATCC 4352, P. aeruginosa ATCC 27853, S. epidermidis ATCC 12228, E. faecalis ATCC 29212 and a yeast C. albicans ATCC 10231. 1-Oxoferruginol showed activity against B. subtilis, S. aureus, S. epidermidis and a modest activity against P. mirabilis, migrostegiol had a little activity against B. subtilis. The structures of the compounds were established by 1D and 2D NMR spectroscopic techniques.     

Evaluation of the antimicrobial potency of tannins and related compounds using the microdilution broth method.

The antimicrobial activity of a total of 27 tannins and related compounds was evaluated against 8 microorganisms, including 2 Gram-positive (Bacillus subtilis, Staphylococcus aureus), 4 Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis), and 2 yeasts (Candida albicans, Cryptococcus neoformans). The compounds tested were generally found to possess only weak to moderate antibacterial, but fairly high anticryptococcal activities. Attention is given to structure-activity relationships with emphasis on simple galloyl esters, hydrolyzable tannins and proanthcyanidins among this class of secondary products.     

PRELIMINARY INVESTIGATION OF THE ANTIMICROBIAL AND BRINE SHRIMP LETHALITY PROPERTIES OF SOME NIGERIAN MEDICINAL PLANTS

Abstract

Thirty ethanol extracts or latex from twenty-nine plants employed in Nigerian ethnomedicine were screened for antimicrobial activity and brine shrimp lethality. At a concentration of 25 mg/ml, most of these extracts exhibited activity against the fungi Curvularia clavata and Candida albicans and against the Gram positive bacterium Bacillus subtilis; but they were all inactive against the Gram negative bacterium Pseudomonas aeruginosa Ten extracts had LC₅₀ values between 40 and 100 ppm against the brine shrimp.     

Screening of plants used by North American indians for antifungal,bactericidal, larvicidal and molluscicidal activities

Nineteen plant species from fourteen families used in the traditional medicine of North American Indians have been tested for their fungicidal (Cladosporium cucumerinum, Candida albicans), bactericidal (Bacillus subtilis, Escherichia coli), larvicidal (Aedes aegypti) and molluscicidal (Biomphalaria glabrata) activities. Of the species investigated, 9 were active against Cladosporium cucumerinum, 9 against Candida albicans, 12 against Bacillus subtilis, 18 against Escherichia coli, 3 against Aedes aegypti, and 11 against Biomphalaria glabrata.     

Antibacterial,antifungal, antiherbicidal,and antifungicidal activity of 4,6-dimethoxyhomophthalic acid and related compounds

4,6-Dimethoxyhomophthalic acid (5) has been synthesized efficiently in four steps from 3,5-dimethoxycinnamic acid (1) and characterized and screened for their in vitro antibacterial activity against four Gram negative (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhii, and Shigella flexneri) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains, and for in vitro antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani, and Candida glaberata. The compounds were screened for their in vitro antiherbicidal and antifungicidal activities.     

Antimicrobial activities of some amino derivatives of 5,7-dibromo-2-methyl-8-hydroxyquinoline

The bromine atoms of the title compound, 5,7-dibromo-2-methyl-8-hydroxyquinoline were replaced by the requisite amino compound to afford 6 amino derivatives viz: bis(diethylamino)-, bis(dibutylamino)-, bis(dicyclohexylamino)-, dipyrolidino-, dipiperidino- and dipiperazino derivatives. The antimicrobial activity of these compounds were investigated against selected gram positive (Staphylococcus aureus and Bacillus subtilis), gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and yeast (Candida albicans). All the compounds showed significant activity against the test microorganisms, from 5-30 times compared to the title compound. It was observed that all derivatives were more effective against gram positive bacteria. No correlation has been established between the minimum inhibitory (MIC) concentrations of the derivatives and the structural modifications.     

Flavonoid analysis and antimicrobial activity of commercially available propolis products

Propolis ethanolic solutions are the most used propolis products on the market for the treatment of minor ulcers in the mouth, angina, thrush or skin infections. Since it is still an unofficial drug in pharmacy, we analyzed the contents of flavonoids in ten commercially available ethanolic solutions of propolis from the Croatian market using two complementary colorimetric methods. Antimicrobial activities, determined with the diffusion method, against six bacterial species (Bacillus subtilis NCTC 8236, Staphylococcus aureus ATCC 25923, Streptococcus pyogenes ATCC 12204, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 10536, Pseudomonas aeruginosa ATCC 27853, and one yeast-like fungus Candida albicans ATCC 10231 were compared. Results of flavonoids analysis suggested that the contents of flavones and flavonols in the products were uniform and ranged from 0.14 to 0.41%, but the content of flavanones varied greatly from 0.43 to 18.78%. Total flavonoid content, as the sum of two colorimetric methods, in propolis products was between 0.78 and 18.92%, and most products had the flavonoids content below 9%. All products with the total flavonoids content above 1% showed antimicrobial activity against the four Gram-positive bacterial species tested, and against P. aeruginosa and the yeast-like fungus C. albicans. Total flavonoids contents, expressed as the sum of two colorimetric methods, could be useful methods for estimating the flavonoid contents of propolis products. Our results indicate that the quality of commercially available propolis products requires verification.     

3-(Arylacetylamino)-N-methylbenzamides: a novel class of selective anti-Helicobacter pylori agents.

After chemical modification preceded by the random screening of our chemical library, a novel class of selective anti-Helicobacter pylori agents was generated. Consequently, the 3-(arylacetylamino)-N-methylbenzamides, which were quite easy to prepare, showed potent inhibitory activity against Helicobacter pylori but exhibited no inhibitory activity against other sorts of bacteria and fungi, e.g., Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Bacteroides fragilis, and Candida albicans. These compounds showed potent anti-H. pylori activity under acidic conditions, whereas amoxicillin and clarithromycin decreased activity. The 3-(3-arylpropionylamino)-N-methylbenzamides, 3-(aryloxyacetylamino)-N-methylbenzamides, and (3-methylcarbamoylphenyl)carbamic acid 1-arylmethyl esters also exhibited potent anti-H. pylori activity. Finally, we selected 7n (BAS-118) as a candidate compound for further evaluation.     

Chemical composition and antimicrobial activity of the essential oil of Rosemary

The composition of the essential oil of Rosemary was analyzed by gas chromatography-mass spectrometry (GC-MS). 22 components, which constitute 97.41% of the oil, were identified. The major constituents were 1,8-Cineole (26.54%) and α-Pinene (20.14%). Minimum inhibitory concentrations (MICs), minimal bactericidal concentration (MBC) and time-kill dynamic processes against three Gram-positive bacteria (Staphylococcus epidermidis, Staphylococcus aureus and Bacillus subtilis), three Gram-negative bacteria (Proteus vulgaris, Pseudomonas aeruginosa and Escherichia coli) and two fungi (Candida albicans and Aspergillus niger) were determined for the oil, 1,8-Cineole and α-Pinene. The oil showed pronounced antibacterial and antifungal activity than 1,8-Cineole and α-Pinene against all of the tested microbes. Furthermore, the survival rates and morphological changes of S. aureus after treatment with different concentrations of the essential oil were assessed by flow cytometry (FCM) and atomic force microscopy (AFM).     

New 6-Bromo-2-Methyl-3-(Substituted Phenyl)-(3H)-Quinazolin-4-Ones with Antimicrobial and Antiinflammatory Activities

New quinazolin-4-one derivatives, 6-bromo-2-methyl-3-(substituted phenyl)-(3H)-quinazolin-4-one, were synthesized and evaluated for antimicrobial and antiinflammatory activities. The structures attributed to synthesized compounds 1-8 were supported by the results of elemental analysis as well as by the UV, IR and (1)H NMR spectral data. Investigation of antimicrobial activity was performed using cup-plate agar diffusion method against Bacillus subtilis, Staphylococcus aureus and Pseudomonas aeruginosa and Candida albicans, Aspergillus niger and Curvularia lunata. Antiinflammatory activity was evaluated using the carrageenan-induced paw oedema test in rats. The results showed that compounds 2b, 2c, 2d, 2g and 2h exhibited significant antibacterial and antifungal activity comparable to standard drugs and compounds 2b and 2c showed good antiinflammatory activity comparable to ibuprofen.     

Synthesis and antimicrobial activity of some new 2-indolinone derived oximes and spiro-isoxazolines

The synthesis and spectral analysis of some new 1,3-dihydro-3-hydroxy-3-[2-hydroxyimino-2-(substituted phenyl)ethyl]-2H-indol-2-ones (21-32) and spiro[3H-indol-3,5'-(4'H)-isoxazol]-2(1H)-ones (33-44) are described. Sixteen of the synthesized compounds were screened in vitro for their growth inhibitory activity against thirteen species of microorganisms, viz, S. aureus, S. epidermidis, S. faecalis, B. subtilis, B. cereus, E. aerogens, E. coli, P. aeruginosa, P. vulgaris, A. baumonia, A. faecalis, C. albicans and S. cervicae. Most of the compounds exhibited significant antimicrobial activity especially the oximes 28 and 29.     

Antiviral and antimicrobial activities of new nitrobutane derivatives

It is known that some addition products of beta-nitrostyrenes exhibit potent antimicrobial activity. In order to investigate the effects of structural modifications on the biological properties, some new Michael type addition products of beta-ethyl-beta-nitrostyrenes were synthesized. In this study, eight new 1-[(2-aminophenyl)thio]-1-phenyl-2-nitrobutane (2) derivatives were synthesized by addition of 2-aminothiophenol to the double bond of beta-ethyl-beta-nitrostyrenes (1). The chemical structures were proved by IR and 1H-NMR data and by elemental analysis. Antimicrobial activities of the synthesized compound were investigated against Escherichia coil, Pseudomonas aeruginosa, Proteus mirabilis, Enterococcus faecalis, Bacillus subtilis, Staphylococcus aureus, Candida albicans by the microdilution method. In addition, the newly synthesized compounds were studied for antiviral activities. All of them were found to be almost 100 fold more active than the standard compound aciclovir (CAS 59277-89-3).     

Synthesis and antimicrobial activity of silver(I) and copper(II) complexes with 2-(4,6-di-tert-butyl-2,3-dihydroxyphenylsulfanyl) acetic acid

Ag(I) and Cu(II) complexes with 2-(4,6-di-tert-butyl-2,3-dihydroxyphenylsulfanyl)acetic acid ligands (L) have been synthesized and characterized using a combination of methods, including x-ray powder diffraction, elemental analysis, TG/DTA, FT-IR, and EPR. The antimicrobial properties of 2-(4,6-di-tert-butyl-2,3-dihydroxyphenylsulfanyl]acetic acid and its complexes with Ag(I) and Cu(II) were tested against standard E. coli, Ps. aeruginosa, C. albicans, B. subtilis, St. aureus, and Pr. vulgaris strains. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 8, pp. 7–9, August, 2006.     

抗菌敷料抗菌功效体外评价研究

目的：评价抗菌敷料的体外抗菌功效。方法：本研究基于模拟临床创面微生物的实际生长状态,构建体外创面模型并建立抗菌敷料抗菌功效评价方法,用以评价抗菌敷料对金黄色葡萄球菌、铜绿假单胞菌、大肠杆菌和白色念珠菌的体外抗菌功效。结果：试验样品在12 h内抑制了金黄色葡萄球菌的增殖,在72 h内杀灭对数值未超过1.00;在24 h对铜绿假单胞菌的杀灭对数值达到4.24,随后大幅下降, 在72 h的杀灭对数值降为0.37;在12 h对大肠杆菌的杀灭对数值达到4.10,在其后至72 h内杀灭对数值均大于3.00;在12 h对白色念珠菌的杀灭对数值达到1.11,在72 h的杀灭对数值仅为0.04。结论：该抗菌敷料对金黄色葡萄球菌、铜绿假单胞菌、大肠杆菌和白色念珠菌均显示了抗菌效果,其中对铜绿假单胞菌、大肠杆菌的抗菌功效要好于金黄色葡萄球菌和白色念珠菌。     

The synthesis and antimicrobial activities of some 1,4-naphthoquinones (II)

In order to evaluate the antimicrobial effect of 2,3-disubstituted-1,4-naphthoquinone derivatives we newly synthesized several 2-chloro and 2-bromo-3-(substituted)-1,4-naphthoquninones. Amination reaction of 2,3-dihalo-1,4-naphthoquinones with aryl and aliphatic amines in ethanol gave 2-halo-3-(N-alkyl or N-aryl)-1,4-naphthoquinone derivatives (1a,b–10a,b) in 60%–90% yield. These derivatives subjected to antibacterial and antifungal activities,in vitro, againstBacillus subtilis ATCC 6633, Candida albicans 10231 and local, Pseudomonas aeruginosa NCTC10490, Staphylococcus aureus ATCC 6538p, Escherichia coli NIHJ, Aspergillus niger KCTC 1231. Tricophyton mentagrophytes KCTC 6085. Among these derivatives,1b, 6b and7a showed the potent antibacterial activities.1b, 8b and9b have the antifungal activities.1b is most effective in preventing the growth ofBacillus subtilis and Pseudomonas aeruginosa, Candida albicans, Aspergillus niger. Tricophyton mentagrophytes. The several of these compounds demonstrated a broad spectrum of activitiesin vitro.     

Synthesis and biological activity of new heterocyclic structures: [1,3]thiazino[2,3-i]purine, thiazolo[3,2-c] [1,2,3]triazolo[4,5-e]pyrimidine and [1,2,3]triazolo [4', 5': 4,5] pyrimido[6,1-b][1,3]thiazine.

Some derivatives of thiazolo[3,2-c]pyrimidine, pyrimido[6,1-b][1,3]thiazine, thiazolo[2,3-i]purine, [1,3]thiazino[2,3-i]purine, thiazolo[3,2-c][1,2,3]triazolo[4,5-e]pyrimidine and [1,2,3]triazolo[4',5':4,5]pyrimido[6,1-b][1,3]thiazine were prepared. The compounds were tested for antimicrobial and antimycotic activity on a number of strains, namely, Escherichia coli, Proteus vulgaris, P. mirabilis, Pseudomonas aeruginosa, Salmonella sp., Staphylococcus aureus, Streptococcus faecalis, Bacillus subtilis, Sarcina lutea, Candida albicans, Aspergillus sp., and for antiviral activity on Herpes simplex virus, Type 1 (HSV-1), Vesicular stomatitis virus (VSV) and Coxsackievirus B5 (CoxB5). The compounds proved to be devoid of activity against viruses, mycetes and gram-negative bacteria, while some of them exhibited a modest activity against gram-positive bacterial strains.