Selda Ozgen

Synthesis of some new 2,6-disubstituted-3(2H)-pyridazinone derivatives and investigation of their analgesic, anti-inflammatory and antimicrobial activities

In this study, 12 new 3(2H)-pyridazinone derivatives carrying 4-substituted phenylpiperazinylethyl moiety on lactam nitrogen were synthesized and their chemical structures were confirmed by 1H-NMR, mass, and elemental analysis. Analgesic and anti-inflammatory activities of the synthesized compounds were evaluated in mice. Among the synthesized compounds, compound 9c showed the best analgesic and anti-inflammatory activities without causing any gastric effect in stomachs of tested animals. In addition, the synthesized compounds were screened for their antibacterial and antifungal activities against some pathogenic strains.

Candida albicans and Pseudomonas aeruginosa adhesion on soft contact lenses

BackgroundIn this study it was aimed to determine the adherence of Pseudomonas and Candida to contact lens surfaces, and to determine the difference in adherence between five contact lens types. Biofilm-negative control strains were also used to emphasize the difference between biofilm-positive and biofilm-negative strains in adherence.MethodsFive different soft contact lenses were used to investigate the adherence of Pseudomonas aeruginosa and Candida albicans strains. P. aeruginosa ATCC 27853, P. aeruginosa ATCC 10145, C.albicans ATCC 10231 standard strains and C. albicans clinical isolate were included in the study. Slime formation was investigated by two methods; modified Christensen macrotube method, and a modified microtiter plate test. P. aeruginosa and C. albicans slime formation on soft contact lenses was studied in adherence and separation phases. Pseudomonas and Candida suspensions were serially diluted and inoculated to blood agar and sabouraud dextrose agar surfaces respectively. After overnight incubation, the colonies were counted. Sterile unworn contact lenses were used as negative controls, and bacterial and fungal culture suspensions were used as positive controls. The experiments were conducted in three parallel series.ResultsThe number of adherent Pseudomonas was as follows from high to low in polymacon, etafilcon A, hilafilcon, ocufilcon and lotrafilcon contact lenses respectively. However, the number of adherent yeast were determined higher in lotrafilcon and ocufilcon contact lenses, followed by hilafilcon, etafilcon A and polymacon contact lenses. Biofilm-negative Pseudomonas ATCC standard strain and Candida clinical isolate were used to confirm that the number of adherent cells were lower than the biofilm-positive ones.ConclusionsThis study demonstrates that in addition to the contact lens properties, the microorganisms themselves and their interactions with the lens material also play an important role in adherence.

Novel Benzoxazoles: Synthesis and Antibacterial, Antifungal, and Antitubercular Activity against Antibiotic-Resistant and -Sensitive Microbes

A new series of 5-(p-substituted benzamido/phenylacetamido)-2-(p-tert-butylphenyl)benzoxazole derivatives were synthesized and evaluated for their antibacterial, antifungal, and antimycobacterial activities against antibiotic-resistant and -sensitive Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, and Mycobacterium tuberculosis as well as against Candida albicans and Candida krusei. The compounds possessed broad-spectrum activity against all of the tested Gram-positive and Gram-negative bacteria and yeasts, their minimum inhibitory concentrations (MICs) ranging between 16 - 128 μg/ml. One compound exhibited significant antibacterial activity (16 μg/ml) against an antibioticresistant Enterococcus faecalis isolate, having twice the potency of the compared standard drugs vancomycin and gentamycin sulfate. The compounds also showed moderate antitubercular activity with MIC values between 8 - 128 μg/ml against Mycobacterium tuberculosis and its clinical isolate.

Synthesis and different biological activities of novel benzoxazoles.

A series of 2-[4-(4-substitutedbenzamido/phenylacetamido/butanamido)phenyl]-5-ethylsulphonyl-benzoxazole derivatives were synthesized and biologically evaluated as possible antimicrobial agents and inhibitors of tyrosinase, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE). The results demonstrated that the synthesized compounds exhibited a broad spectrum of activity with minimum inhibitory concentration (MIC) values of 128-16 μg/ml against some Gram-positive, Gram-negative bacteria as well as Candida albicans and C. krusei. The compound 10 displayed higher activity in this series against methicilline resistant Staphylococcus aureus (MRSA) with a MIC value of 16 μg/ml than the compared control drugs ampicillin and ceftriaxone. Compound 14 showed moderate tyrosinase inhibition, however, none of the compounds showed effect as inhibitor of AChE and BChE.

Synthesis and Antimicrobial Evaluation of 2-(p-Substituted Phenyl)-5-[(4-substituted piperazin-1-yl)acetamido]-benzoxazoles

Abstract series of 2-(p-substituted phenyl)-5-(2-{4-[(p-chloro-fluorophenyl)=phenyl] piperazin-1-yl}- acetamido)-benzoxazoles were synthesized and tested for their antimicrobial activities. The structures of the new derivatives were elucidated by spectral techniques. The minimum inhibitory concentrations (MIC) of the new benzoxazoles, along with those of previously synthesized analogues, were determined against standard bacterial and fungal strains and drug-resistant isolates, and compared with those of several reference drugs. The new benzoxazole derivatives were found to possess a broad spectrum of antimicrobial activity with MIC values of 32 - 1024 μg/ml. Although the standard drugs were more active against the tested pathogens, the activities of the new benzoxazoles and the reference drugs were largely similar against the drug-resistant isolates.

Synthesis and Antimicrobial Activity of Novel Benzoxazoles

A series of 2-(p-substituted-benzyl)-5-[[4-(p-chloro/fluoro-phenyl)piperazin-1-yl]ace tamido] -benzoxazoles were synthesized in need of new compounds for the fight against microbial pathogens. Their structures were elucidated by spectral techniques. These new derivatives, along with previously synthesized 2-(p-substituted-benzyl)-5-substituted-benzoxazoles, were evaluated for their antibacterial and antifungal activities against standard strains and drugresistant isolates in comparison with ampicillin, gentamicin sulfate, ofloxacin, vancomycin, fluconazole, and amphotericin B trihydrate. The minimum inhibitory concentration (MIC) of each compound was determined by a two-fold serial dilution technique. The compounds were found to possess a broad spectrum of antimicrobial activities with MIC values of 32 - 256 μg/ml. Although standard drugs were more active against the pathogenes employed in this study, the activities of the new benzoxazoles and reference drugs against drug-resistant isolates of the microorganisms were largely similar