Synthesis and antimicrobial studies of novel 1-benzhydryl-piperazine sulfonamide and carboxamide derivatives

A series of novel substituted 1-benzhydryl-piperazine sulfonamide 8(a–f) and benzamides 9(a–h) were synthesized and their antimicrobial activities evaluated in vitro by paper disc diffusion and micro dilution method against standard strains of Gram-positive (Staphylococcus aureus ATCC 25953, Staphylococcus epidermis 25212, Bacillus cereus 11778, Bacillus substilis 6051) and Gram-negative (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 2853, Proteus vulgaris ATCC 2853 and Salmonella typhi ATCC 9484) bacteria. Among the synthesized new compounds 8d, 8e, 9c, 9e, 9f and 9 h showed potent antimicrobial activities compared to the standard drug streptomycin.     

Synthesis and in vitro antimicrobial studies of medicinally important novel N-alkyl and N-sulfonyl derivatives of 1-[bis(4-fluorophenyl)-methyl]piperazine

A series of novel substituted 1-[bis(4-fluorophenyl)-methyl]piperazine derivatives (4a-g) and (5h-m) have been synthesized. The synthesized compounds were characterized by IR and 1H NMR. All the synthesized compounds were evaluated in vitro for their efficacy as antimicrobial agents against representative strains of Gram-positive (Staphylococcus aureus ATCC 25953, Streptococcus pneumoniae ATCC 49619, Bacillus cereus 11778, and Bacillus subtilis 6051) and Gram-negative bacteria (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 2853, Proteus vulgaris ATCC 2853, and Salmonella typhi ATCC 9484) by paper disc diffusion and microdilution methods. Among the newly synthesized compounds 4e, 5l, and 5m showed potent antimicrobial activities, when compared to the standard drug.     

Synthesis of egonol derivatives and their antimicrobial activities

Eighteen derivatives of egonol (A-R) were synthesized and evaluated for their antimicrobial activities against Staphylococcus aureus ATCC 29213, Bacillus subtilis ATCC 6633, Candida albicans ATCC 10231 and Escherichia coli ATCC 8739 microorganisms comparing with egonol. The obtained data reported that compound B exhibited improved activities against all tested bacteria than egonol, others have shown different range of activities.     

Semisynthesis and antimicrobial activity of novel guttiferone-A derivatives

Six derivatives of guttiferone-A (LFQM-79, 80, 81, 82, 113 and 114) were synthesized and evaluated for their antimicrobial activity against the opportunistic or pathogenic fungi Candida albicans (ATCC 09548), Candida glabrata (ATCC 90030), Candida krusei (ATCC 6258), Candida parapsilosis (ATCC 69548), Candida tropicalis (ATCC 750), Cryptococcus neoformans (ATCC 90012), Trichophyton tonsurans, Microsporum gypseum and also against the opportunistic and pathogenic Gram-positive bacteria Staphylococcus aureus (ATCC 6538), Staphylococcus epidermidis (ATCC 12228), Bacillus cereus (ATCC 11778) and Gram-negative Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 9027), Salmonella typhimurium (ATCC 14028), Proteus mirabilis (ATCC 25933). The antimicrobial activities of derivatives were compared with guttiferone-A and they presented to be more potent than the original molecule and sometimes greater than standard drugs established in therapeutics. The current study showed that derivatives of guttiferone-A possess potent antimicrobial activity and are relatively non-cytotoxic, which reveal these new molecules as promising new drug prototype candidates, with innovative structural pattern.     

Synthesis,characterization, antimicrobial activity and structure–activity relationships of new aryldisulfonamides

A series of aromatic disulfonamide (1-8) derivatives and 4-methylbenzenesulfonyl hydrazide (9) were synthesized and characterized. All compounds were evaluated in vitro for their antimicrobial activity against Staphylococcus aureus ATCC 25953, Bacillus cereus ATCC 6633, Bacillus magaterium RSKK 5117, Escherichia coli ATCC 11230, Salmonella enterititis ATCC 13076 by microdilution and disc diffusion methods. Antimicrobial activity of the aromatic disulfonamides decreased as the length of the carbon chain increased. An analysis of the structure- activity relationship (SAR) along with computational studies showed that the most active compound (9) possessed low lipophilicity (AlogP=0.59) and high solubility (logS = -1.33).     

Synthesis of 1-(4-methoxybenzyl)-3-cyclopropyl-1H-pyrazol-5-amine derivatives as antimicrobial agents

A series of novel substituted 1-(4-methoxybenzyl)-3-cyclopropyl-1H-pyrazol-5-amine benzamides 9(a–h) were synthesized to determine their antibacterial and antifungal activities as well as possible structure–activity relationships (SARs) to improve therapeutic efficacy. The pyrazol-5-amine benzamides were screened for their antibacterial activity against standard strains of Gram-positive (Streptococcus pyogenes NCIM 2608, Staphylococcus aureus ATCC 29737, Bacillus subtilis NCIM 2010) and Gram-negative (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 20852, Klebsiella pneumoniae MTCC 618) bacteria by using streptomycin as positive control. They were also tested for their antifungal activities against mycotoxic strains of Fusarium verticillioides, Aspergillus ochraceous, Aspergillus flavus, Alternaria alternata, and Penicillium chrysogenum using nystatin as positive control. Among the synthesized compounds, 9d, 9g, and 9h showed potent antimicrobial activities.     

Antimicrobial activity studies on some piperidine and pyrrolidine substituted halogenobenzene derivatives

The in vitro antibacterial and antifungal activities of the compounds synthesised from some 1,2,3,5-tetrahalogeno benzenes in presence of sodium piperidide and sodium pyrrolidide (2,6-dipiperidino-1,4-dihalogenobenzenes; 2,6-dipyrrolidino-1,4-dibromobenzene; 2,4,6-tripyrrolidino chlorobenzene; and 1,3-dipyrrolidino benzene) were investigated. The in vitro antimicrobial activities were screened against the standard strains: Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6633 as Gram positive, Yersinia enterocolitica ATCC 1501, Escherichia coli ATCC 11230 and Klebsiella pneumoniae as Gram negative, and Candida albicans as yeast-like fungus. Compounds (3, 5, 6, 7) inhibited the growth of all the test strains at MIC values of 32-512 microg/ml. None of the four compounds (1, 2,4,8) studied showed antimicrobial activity against any of the test strains within the MIC range 0.25-512 micro/ml.     

Antimicrobial activity studies on some piperidine and pyrrolidine substituted halogenobenzene derivatives

The in vitro antibacterial and antifungal activities of the compounds synthesised from some 1,2,3,5-tetrahalogeno benzenes in presence of sodium piperidide and sodium pyrrolidide (2,6-dipiperidino-1,4-dihalogenobenzenes; 2,6-dipyrrolidino-1,4-dibromobenzene; 2,4,6-tripyrrolidino chlorobenzene; and 1,3-dipyrrolidino benzene) were investigated. The in vitro antimicrobial activities were screened against the standard strains: Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6633 as Gram positive, Yersinia enterocolitica ATCC 1501, Escherichia coli ATCC 11230 and Klebsiella pneumoniae as Gram negative, and Candida albicans as yeast-like fungus. Compounds (3, 5, 6, 7) inhibited the growth of all the test strains at MIC values of 32–512 μg/ml. None of the four compounds (1, 2, 4, 8) studied showed antimicrobial activity against any of the test strains within the MIC range 0.25–512 μg/ml.     

Synthesis and in vitro antimicrobial activity of new 4-phenyl-5-methyl-4H-1,2,4-triazole-3-thione derivatives

This study presents the synthesis, spectral analysis and antimicrobial evaluation of a new series of substituted 1,2,4-triazole (5a–i) and 1,3,4-thiadiazole derivatives (9a, c, g, h). New compounds were obtained by cyclization reaction of acyl thiosemicarbazide derivatives in the presence of alkaline and acidic media. All synthesized compounds were screened for their in vitro antimicrobial activities. Nine of the compounds had potential activity against Gram-positive bacteria (MIC?=?3.91–500 µg/mL). Some compounds showed good activity especially against: Micrococcus luteus ATCC 10240 (MIC?=?3.91?31.25 µg/mL), Bacillus subtilis ATCC 6633 (MIC?=?15.63? 62.5 µg/mL), and Staphylococcus aureus ATCC 25923 (MIC?=?15.63?125 µg/mL).     

Synthesis, characterization and antimicrobial activity of new aliphatic sulfonamide

A series of novel aliphatic sulfonamide derivatives (1-7) were synthesized and characterized by elemental analyses, FT-IR, (1)H NMR, (13)C NMR and LC-MS techniques. All the synthesized compounds were evaluated in vitro as antimicrobial agents against representative strains of Gram-positive (Staphylococcus aureus ATCC 25953, Bacillus cereus ATCC 6633 and Listeria monocytogenes ATCC Li6 (isolate), Gram-negative bacteria (Escherichia coli ATCC 11230) and antifungal agent against Candida albicans (clinical isolate) by both disc diffusion and minimal inhibition concentration (MIC) methods. All these bacteria and fungus studied were screened against some antibiotics to compare with our chemicals' zone diameters. Our aliphatic sulfonamides have highest powerful antibacterial activity for Gram-negative bacteria than Gram-positive bacteria and antibacterial activity decreases as the length of the carbon chain increases.     

An Escherichia coli cell membrane chromatography-offline LC-TOF-MS method for screening and identifying antimicrobial peptides from Jatropha curcas meal protein isolate hydrolysates

A novel, simple, and rapid method, named cell membrane affinity extraction (CMAE)-offline liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) was developed for screening and identifying antimicrobial peptides from Jatropha curcas meal protein isolate hydrolysates (JCMPIH) obtained by proteolytic enzyme (pepsin, trypsin, protamex, neutrase, flavourzyme, papain, alcalase, and acid protease) hydrolysis. A cationic antimicrobial peptide (CAILTHKR, JCpep8) was successfully isolated and identified by this method. Antimicrobial assay indicated that JCpep8 was active against the tested microorganisms (Escherichia coli ATCC 25922, Shigella dysenteriae ATCC 51302, Pseudomonas aeruginosa ATCC 27553, Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 23631, Streptococcus pneumoniae ATCC 49619) with minimal inhibitory concentration values ranging from 29 to 68 μg/mL. JCpep8 induced significant morphological alterations of the tested microbe surfaces, as shown by transmission electron microscopy, indicating strong membrane disruption. The results showed that CMAE-offline LC-TOF-MS could be a promising method for discovering high-throughput screening antimicrobial peptides from JCMPIH.     

Synthesis, antimicrobial and anticancer activities of a novel series of diphenyl 1-(pyridin-3-yl)ethylphosphonates

A novel series of diphenyl 1-(arylamino)-1-(pyridin-3-yl)ethylphosphonates 1-5 was obtained in high yields from reactions of 3-acetyl pyridine with aromatic amines and triphenylphosphite in the presence of lithium perchlorate as a catalyst. The structures of the synthesized compounds were confirmed by IR, (1)H NMR spectral data and microanalyses. Compounds 1-5 showed high antimicrobial activities against Escherichia coli (NCIM2065) as a Gram-negative bacterium, Bacillus subtilis (PC1219) and Staphylococcus aureus (ATCC25292) as Gram-positive bacteria and Candidaalbicans and Saccharomyces cerevisiae as fungi, at low concentrations (10-100 μg/mL). Also, the synthesized compounds showed significant cytotoxicity anticancer activities against liver carcinoma cell line (HepG2) and human breast adenocarcinoma cell line (MCF7). The lethal dose of the synthesized compounds was also determined and indicated that most compounds are safe to use.     

Determination of usnic acid in some Rhizoplaca species from Middle Anatolia and their antimicrobial activities

Three species of lichens, Rhizoplaca chrysoleuca (Sm.) Zopf, Rhizoplaca melanopthalma (DC.) Leuckert & Poelt and Rhizoplaca peltata Ramonds Leuckert, were collected from middle Anatolia, Erciyes Mountain (Kayseri) in Turkey. Their usnic acid amounts were determined by HPLC in acetone extracts. In addition, antimicrobial activities of these extracts were determined against Escherichia coli (ATCC 35218), Enterococcus faecalis (RSKK 508), Proteus mirabilis (Pasteur Ens. 235), Staphylococcus aureus, Bacillus subtilis, Bacillus megaterium and Pseudomonas aeruginosa. It was shown that, as the usnic acid amount increased, the antimicrobial activities increased too. The usnic acid contents of Rhizoplaca species varied between 0.19-4.0% dry weight.     

Properties of Bac W42, a bacteriocin produced by Bacillus subtilis W42 isolated from Cheonggukjang

Ten Bacillus strains with antimicrobial activities were isolated from Cheonggukjang produced at different parts in Korea. They all inhibited Listeria monocytogenes ATCC 19111 and nine inhibited Bacillus cereus ATCC 14579. Four isolates (W42, H27, SKE 12, and K21) showing strong inhibiting activities were identified as B. subtilis. B. subtilis W42 was the most inhibiting strain. The antimicrobial activity of culture supernatant from B. subtilis W42 was destroyed completely by proteinase K treatment, indicating that a bacteriocin was the responsible agent. The bacteriocin, Bac W42, was most stable at pH 7 and stable between pH 3-6 and 8-9. Bac W42 was stable up to 80°C. BHI (brain heart infusion) and TSB (tryptic soy broth) were the best media for the activity (320 AU/ml) followed by LB (160 AU/ml). Bac W42 was partially purified by column chromatographies. The specific activity was increased from 1,151.2 AU/ml to 9,043.5 AU/ml and the final yield was 26.3%. Bac W42 was 5.4 kDa in size as determined by SDS-PAGE. Bac W42 showed bactericidal activity against L. monocytogenes ATCC 19111.     

Synthesis, structure, and structure-activity relationship analysis of enamines as potential antibacterials

Twenty-four enamines were synthesized and reported for the first time. Their chemical structures were confirmed by means of 1H NMR, ESI mass spectra, and elemental analyses, and four of them were determined by single crystal X-ray diffraction analysis. All of the compounds were assayed for antibacterial (Bacillus subtilis ATCC 6633, Escherichia coli ATCC 35218, Pseudomonas fluorescens ATCC 13525, and Staphylococcus aureus ATCC 6538) and antifungal (Aspergillus niger ATCC 16404, Candida albicans ATCC 10231, and Trichophyton rubrum ATCC 10218) activities by MTT method. Compounds (E)-ethyl 3-(4-hydroxyphenylamino)-2-(4-methoxyphenyl)acrylate (9b), (E)-ethyl 3-(3,5-difluorophenylamino)-2-(4-chlorophenyl)acrylate (11b), (E)-ethyl 3-(3,5-dichlorophenylamino)-2-(4-chlorophenyl)acrylate (12b), and (E)-ethyl 3-(4-methylphenylamino)-2-(4-chlorophenyl)acrylate (15b) showed considerable antibacterial activities against S. aureus ATCC 6538 with MICs of 3.8, 1.9, 1.1, and 0.9 microg/mL, respectively. Structure-activity relationship (SAR) analysis disclosed, generally, an E-isomer exhibited higher antibacterial activity than the corresponding Z-isomer. An electron-withdrawing group on A-ring led to some decrease in activity, while on B-ring, a similar substitution provided higher activity.     

Lactic acid bacteria from healthy oral cavity of Thai volunteers: inhibition of oral pathogens

The aims of the present study were to screen and characterize the antimicrobial lactic acid bacteria which were isolated from healthy oral cavities of Thai volunteers, and to characterize their inhibiting substances. Among 3790 isolates (suspected to be lactic acid bacteria) from 130 volunteers, five showed an appreciable effect against Sarcina lutea ATCC 9341, Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538, Streptococcus mutans DTMU 1, Strep. salivarius DTMU 1, Strep. sanguis DTMU 1, Candida albicans ATCC 13803 and C. albicans DTMU 2, as well as the oral pathogens. These antimicrobial isolates included L17 and N14 which showed the antibacterial activity, D14 which showed the anticandidal activity, and D6 and N8 which showed both the antibacterial and anticandidal activities. The isolates were later found to be facultative anaerobic, Gram-positive, non-spore-forming, non-capsule-forming and catalase-negative bacilli. They could utilize casein but could not hydrolyse starch, and they produced hydrogen peroxide and bacteriocins. Their antimicrobial potentials were found to be affected by pH, catalase, proteolytic enzymes and temperature. The activity was partially inactivated after catalase treatment, significantly declined at pH > or =9.0 or after trypsin and pepsin treatments, and also reduced after heating at > or =100 degrees C. However, the antimicrobial activity of these five isolates was somewhat resistant to heat. When the isolates were tested for their antimicrobial sensitivity, they were shown to be sensitive to a number of antimicrobial agents. The final identification revealed that D6, D14 and N14 were Lactobacillus paracasei subsp. paracasei, and L17 and N8 were Lact. rhamnosus.     

Characterization of a broad range antimicrobial substance from Bacillus cereus

AIMS: The aim of this research was to isolate and characterize an antimicrobial substance from the Bacillus cereus type strain ATCC 14579. METHODS AND RESULTS: A substance with antimicrobial activity was isolated from B. cereus ATCC 14579. The substance was produced during late exponential growth and well into the stationary phase with a maximum 9 h after inoculation. The inhibitory substance was purified by reverse-phase HPLC and shown to be highly active against closely related Bacillus spp. Clinically relevant species such as Staphylococcus aureus and Micrococcus luteus were also inhibited. The substance was characterized as a bacteriocin-like inhibitory substance (BLIS) with a molecular mass of ca 3.4 kDa. The BLIS was very heat stable, and sensitive only to pronase E and proteinase K. Antimicrobial activity was stable and high in the pH range of 2.0-9.0, and relatively unaffected by organic chemicals. CONCLUSIONS: An antimicrobial substance produced by the B. cereus type strain ATCC 14579 was characterized, with a wide spectrum of activity and the potential to be applied as a control agent against pathogenic bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study is the first report of a substance with antimicrobial activity from the B. cereus type strain.     

Novel depsides as potential anti-inflammatory agents with potent inhibitory activity against Escherichia coli-induced interleukin-8 production

Sixteen novel depsides were synthesized for the first time. Their chemical structures were clearly determined by ¹H NMR, ESI mass spectra, and elemental analyses. All the compounds were assayed for antibacterial activities against three Gram-positive bacterial strains (Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538, and Streptococcus faecalis ATCC 9790) and three Gram-negative bacterial strains (Escherichia coli ATCC 35218, Pseudomonas aeruginosa ATCC 13525, and Enterobacter cloacae ATCC 13047) by the MTT method. Compound 2-(2-methoxy-2-oxoethyl)phenyl 5-bromonicotinate (5) exhibited significant antibacterial activities against E. coli ATCC 35218 with an MIC of 0.78 μg/mL, which was superior to the positive control kanamycin B. In addition, compound 5 showed potent inhibitory activity against E. coli-induced interleukin-8 production.     

Synthesis,antitumor and antimicrobial activity of some new 6-methyl-3-phenyl-4(3H)-quinazolinone analogues: in silico studies

Some new derivatives of substituted-4(3H)-quinazolinones were synthesized and evaluated for their in vitro antitumor and antimicrobial activities. The results of this study demonstrated that compound 5 yielded selective activities toward NSC Lung Cancer EKVX cell line, Colon Cancer HCT-15 cell line and Breast Cancer MDA-MB-231/ATCC cell line, while NSC Lung Cancer EKVX cell line and CNS Cancer SF-295 cell line were sensitive to compound 8. Additionally, compounds 12 and 13 showed moderate effectiveness toward numerous cell lines belonging to different tumor subpanels. On the other hand, the results of antimicrobial screening revealed that compounds 1, 9 and 14 are the most active against Staphylococcus aureus ATCC 29213 with minimum inhibitory concentration (MIC) of 16, 32 and 32?μg/mL respectively, while compound 14 possessed antimicrobial activities against all tested strains with the lowest MIC compared with other tested compounds. In silico study, ADME-Tox prediction and molecular docking methodology were used to study the antitumor activity and to identify the structural features required for antitumor activity.     

Antimicrobial and wound healing activities of certain Sudanese medicinal plants

The emergence of drug-resistant organisms have been increasing globally; therefore, it is a burning need to find an alternative drug to get rid of the diseases caused by resistant strains. This study aims to evaluate the antimicrobial and wound healing activities of Loranthus acacia, Cassia obtusifolia and Cymbopogon proximus plants. All the plants were collected and extracted — by maceration method. Antimicrobial activities determined using standard ATCC strain for Gram-positive bacteria (Bacillus subtilis, Bacillus crew, Methicillin-resistant Staphylococcus aureus, Staphylococcus aureus) and Gram-negative bacteria (Shigella sonnnei, Salmonella Typhimurium, Salmonella typhi, Klebsiella pnuemoniae, Escherichia coli and Pseudomonas aeruginosa) following agar well diffusion method. Plants extracts were prepared as gel and investigated for in vivo wound healing activities in rats. Histological studies were performed on animals’ skin. The results showed that all tested plants have various antimicrobial and wound healing activities. Out of these plants, L. acacia exhibited the best result; it revealed a significant result for antimicrobial activities counter to all Gram-positive, Gram-negative bacteria and wound healing activities in comparing with the reference drug. Thus, it is essential to consider L. acacia as a prospective source in progress in the synthesis of a new antimicrobial drug for the treatment of infectious diseases.