Sulhiye Yıldız

Synthesis of some new 2-substituted-phenyl-1H-benzimidazole-5-carbonitriles and their potent activity against Candida species.

New 2-substituted-phenyl-1H-benzimidazole-5-carboxylic acids (35, 38), ethyl-5-carboxylate (36), -5-carboxamides (37, 39),-5-carboxaldehyde (42), -5-chloro (40), -5-trifluoromethyl (41), and -5-carbonitriles (44-53, 55-67), -6-carbonitrile (54) were prepared and evaluated in vitro against Candida species. The cyano substituted compounds 53, 57, 58 and 61 exhibited the greatest activity with MIC values of 3.12 microg/mL, values similar to that of fluconazole.

Antimicrobial activity of propolis samples from two different regions of Anatolia

Antimicrobial activity of two propolis samples from Kazan and Marmaris regions in Turkey were investigated by the disc diffusion method. Antimicrobial activity was tested with four different ethanolic extracts (30, 50, 70, and 96% ethanol) of each sample against seven Gram positive, four Gram negative bacteria and one fungus culture. The activity was found to be mainly due to caffeic acid and its esters. An isomeric mixture containing 3,3-dimethylallyl caffeate, and isopent-3-enyl caffeate was isolated from Kazan propolis samples.

Antimicrobial activities of some tetrahydronaphthalene-benzimidazole derivatives.

Novel retinoid derivatives containing a benzimidazole moiety were synthesized and tested for their antimicrobial activity. Their antimicrobial activities against methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Candida krusei and Candida albicans were evaluated. While some of the compounds exhibited moderate activity against MRSA, S. aureus, E. faecalis, C. krusei and C. albicans, none of the compounds showed activity against E. coli and P. aeruginosa.

Synthesis and Potent Antimicrobial Activity of Some Novel N-(Alkyl)-2-Phenyl-1H-Benzimidazole-5-Carboxamidines

A series of 22 novel 1,2-disubstituted-1H-benzimidazole-N-alkylated-5-carboxamidine derivatives were synthesized and evaluated for in vitro antibacterial activity against S. aureus and methicillin resistant S. aureus (MRSA), E. coli, E. faecalis and for antifungal activity against C. albicans. Compound 59 [1-(2,4-dichlorobenzyl)-N-(2-diethylaminoethyl)-1H-benzimidazole-5-carboxamidine], with a 3,4-dichlorophenyl group at the C-2 position, displayed the greatest activity (MIC = 3.12 μg/mL against both some bacteria and the fungus C. albicans).

Biological activities of Pseudevernia furfuracea (L.) Zopf extracts and isolation of the active compounds

ETHNOPHARMACOLOGICAL RELEVANCE Pseudevernia furfuracea (L.) Zopf (Parmeliaceae) is a common epiphytic lichen in the conifer-hardwood forest of Anatolia. This species is used in traditional medicine in Turkey as a treatment for wounds, eczema and hemorrhoids. AIM OF THE STUDY The present study was designed to investigate the active compounds from Pseudevernia. furfuracea, and the isolation studies yielded atraric acid (Aslan et al., 2006) as the major compound and a mixture of methyl hematommate (Baumann, 1960) and methyl chlorohematommate (Bayır et al., 2006). Furthermore, methanolic extract from thalli of Pseudevernia. furfuracea and its fractions and isolates (Aslan et al., 2006; Baumann, 1960; Bayır et al., 2006) were investigated for in vitro antimicrobial and antioxidant activities, and in vivo antinociceptive, anti-inflammatory and wound healing activities. MATERIAL AND METHODS Antimicrobial activities of the samples were determined by using the disc diffusion technique. 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used as a rapid TLC screening method to evaluate the antioxidant activity of Pseudevernia. furfuracea. The thiobarbituric acid (TBA) test was used to assess the efficacy of the extracts in protecting liposomes from lipid peroxidation. In vivo inhibitory effect of the extracts on the carrageenan-induced hind paw edema model in mice was studied for the assessment of anti-inflammatory activity. p-Benzoquinone-induced abdominal constriction test was used to explore the antinociceptive effects of the extracts. Moreover, the wound healing potential of the plant extracts that were evaluated by using in vivo incision and excision wound models on rats and mice, were comparatively assessed with a reference ointment Madecassol(®). RESULTS Significant antimicrobial activities were observed against Gram (+) microorganisms and Candida krusei and Candida. dubliniensis in dichloromethane (DCM) and ethyl acetate (EtOAc) extracts and isolates. The methanol (MeOH), DCM and EtOAc extracts of the lichen were found to possess moderate inhibitory activity on lipid peroxidation. Methanolic extract of the lichen was found to possess significant inhibitory activity on the carrageenan-induced hind paw edema model in mice whereas the other fractions did not show any activity. While DCM and EtOAc extracts and fractions showed notable anti-inflammatory activity on carrageenan-induced hind paw edema model without inducing any apparent acute toxicity or gastric damage. Moreover, topical application of the ointment prepared with MeOH extract and EtOAc fraction onto the incised wounds exerted remarkable wound healing activity. CONCLUSION The results of these experimental studies exhibited that nonpolar fractions of Pseudevernia. furfuracea have significant antimicrobial activity against especially Candida species and polar fractions (especially MeOH) display antioxidant, anti-inflammatory, antinociceptive and wound healing activities.

Preparation and Characterization of Chitosan-Based Spray-Dried Microparticles for the Delivery of Clindamycin Phosphate to Periodontal Pockets

Biodegradable spray-dried chitosan microparticles loaded with clindamycin phosphate (CDP) were formulated to deliver drugs locally into the periodontal pocket. The effects of spray dryer conditions, drug/polymer ratio, and added amounts of glutaraldehyde (GA) solution on the characterization of microparticles were investigated by determining process yield, encapsulation efficiency, particle size and size distribution, surface morphology, drug release, release kinetics, thermal analysis, and antimicrobial efficacy of formulations. Burst release was obtained for all formulations due to the water solubility of the drug, but the increased amount of chitosan decreased the drug release rates. Microparticles with a more wrinkled surface were obtained by increasing the amount of the drug. Incorporation efficiencies higher than 80% were obtained for all preparation conditions. The addition of GA caused higher viscosity of the chitosan solution, leading to larger particles with more spherical and smooth surface characteristics. However, the increased GA amount did not significantly influence the drug release. The data obtained from in vitro release experiments were best fitted to the Weibull and Higuchi models. The amorphous nature of the drug-loaded microparticles was detected by differential scanning calorimetric (DSC) thermographs. A delayed drug release of more than one week could be obtained by loading the drug into the chitosan microparticles. Antimicrobial efficacy studies reflected a positive drug release profile. These results indicate that spray-dried clindamycin-loaded microparticles with sustained antimicrobial efficacy appear to be a promising periodontal therapy for drug delivery into the periodontal pocket.

Synthesis and potent in vitro activity of novel 1H-benzimidazoles as anti-MRSA agents.

A new class of 1H‐benzimidazolecarboxamidines was synthesized and evaluated for in vitro antibacterial and antifungal activities, including drug‐resistant bacterial strains. The most potent compound (32) has the same ratio of anti‐MRSA activity as Vancomycin (minimal inhibitory concentrations value 0.78 μg/mL). The mechanism of action for 1H‐benzimidazolecarboxamidine appears to be different from existing antibacterial agents. These compounds have potential for development as a new class of potent anti‐MRSA agent.

Antimicrobiological Studies on Turkish Cistus. Species

ABSTRACT The genus Cistus. L., mainly growing in the Mediterranean region, is represented by five species in Turkey: C. creticus. L., C. laurifolius. L., C. monspeliensis. L., C. parviflorus. Lam., and C. salviifolius. L. In this study, in vitro. antimicrobial activity of water, methanol, chloroform, ethyl acetate, and buthanol extracts, prepared from dried and powdered leaves and the fruits of the five Cistus. species, were investigated by the disk diffusion method against the following microorganisms: Staphylococcus aureus. (ATCC 29213 and ATCC 25923), Streptococcus faecalis. (ATCC 29212), Bacillus subtilis. (ATCC 6633), Bacillus cereus. (RSKK 1122), Pseudomonas aeruginosa. (ATCC 27853), Escherichia coli. (ATCC 25922), and Candida albicans. (ATCC 10231). Chloroform, ethyl acetate, butanol, and the remaining aqueous extracts, obtained from the fractionation of methanol extract, were also tested. All of the extracts showed some activity against B. subtilis. and B. cereus.. Lyophylized extracts showed the highest activity against Staphylococcus aureus. 25923 and 29213. Buthanol extracts of the leaves and fruits of C. creticus. showed the highest activity. Extracts of all Cistus. species did not show any activity against Pseudomonas aeruginosa. and Candida albicans..

Synthesis and antistaphylococcal activity of N-substituted-1H-benzimidazole-sulphonamides.

A series of N‐substituted‐1H‐benzimidazole‐5(6)‐sulfonamides and 3‐(5,6‐dichloro‐1H‐benzimidazol‐2‐yl)‐N‐substituted benzensulfonamides were synthesized and evaluated for antibacterial activity against Staphylococcus aureus and methicillin‐resistant S. aureus (MRSA). Certain compounds inhibit bacterial growth with low MIC (μg/mL) values. The most active compounds 30, 31, and 32 have the lowest MIC values with 0.39 to 0.19 μg/mL. Among the compounds having sulfonamido moities, 16, 23, and 24 exhibited the strongest antibacterial activity with 1.56 μg/mL MIC values.

Synthesis and In Vitro Activity of Polyhalogenated 2-phenylbenzimidazoles as a New Class of anti-MRSA and Anti-VRE Agents.

A series of novel polyhalogenated 2‐phenylbenzimidazoles have been synthesized and evaluated for in vitro antistaphylococcal activity against drug‐resistant bacterial strains (methicillin‐resistant Staphylococcus aureus, and vancomycin‐resistant Enterococcus faecium. Certain compounds inhibit bacterial growth perfectly. 11 was active than vancomycin (0.78 μg/mL) with the lowest MIC values with 0.19 μg/mL against methicillin‐resistant Staphylococcus aureus, 8 and 35 exhibited best inhibitory activity against vancomycin‐resistant Enterococcus faecium (1.56 μg/mL). The mechanism of action for this class of compounds appears to be different than clinically used antibiotics. These polyhalogenated benzimidazoles have potential for further investigation as a new class of potent anti‐methicillin‐resistant Staphylococcus aureus and anti‐vancomycin‐resistant Enterococcus faecium agents.