Seçkin Özden

Synthesis and microbiological activity of 5-methyl-2-[p-substituted phenyl]benzoxazoles

The synthesis and microbiological activity of a series of 5-methyl-2-(p-substituted phenyl)benzoxazoles 7a–7g are described. The in vitro microbiological activity of these compounds was determined against some Gram-positive and Gram-negative bacteria and C albicans. The observed minimum inhibitory concentration (MIC) values of the derivatives were compared to some other 2,5-disubstituted benzoxazoles and clinically used drugs. The in vitro microbiological data showed that the derivatives 7a–7g exhibited a broad spectrum of antibacterial activity and 7a–c and 7g were significantly active against E coli and/or K pneumoniae at an MIC of 6.2 μg/ml.

Acylated kaempferol glycosides from the flowers of delphinium formosum

Abstract One new flavonol glycoside, kaempferol 3-(4″,6″-diacetylglucoside)-7-rhamnoside and three other known kaempferol glycosides: kaempferol 3-glucoside-7-rhamnoside, kaempferol 3-(6″-acetylglucoside)-7-rhamnoside, and kaempferol 7-rhamnoside, were isolated and characterised from flowers of Delphinium formosum. The structures were elucidated by spectral and chemical methods.

A QSAR study of the biological activities of some benzimidazoles and imidazopyridines against Bacillus subtilis

Summary A set of benzimidazole (1) and imidazopyridine (II) derivatives that have previously been tested for their antibacterial activities against Bacillus subtilis were analyzed using the quantitative structure-activity relationship (QSAR) method. The activity contributions for structural and substituent effects were determined from the correlation equations, which were derived using all possible combination and stepwise regression techniques. The best equation was chosen among the other equations by considering the various statistical criteria. The resulting QSAR revealed that the activity contributions of benzimidazoles and imidazopyridines against B subtilis depend almost entirely on their relative lipophilic character as defined by their octanol/water partition coefficients, log P . The ideal lipophilic character for the investigated imidazole nuclei has been found to be about 4.9.

Acylated delphinidin glycosides in the blue-violet flowers of Consolida armeniaca.

Four new acylated delphinidin 3,7-glycosides were isolated from the blue-violet flowers of Consolida armeniaca as major anthocyanin pigments. The first pigment was based on delphinidin 3,7-diglucoside and was identified as delphinidin 3-O-[6-O-(malonyl)-beta-D-glucopyranoside]-7-O- [6-O-(4-O-(6-O-(p-hydroxybenzoyl)-beta-D-glucopyranosyl)-p-hydroxybenzoy l)- beta-D-glucopyranoside] by spectral methods. The other three acylated anthocyanins were based on delphinidin 3-glucoside-7-sophoroside. The second pigment was determined to be delphinidin 3-O-[6-O-(malonyl)-beta-D-glucopyranoside]-7-O-[2-O-(beta-D- glucopyranosyl)-6-O-(4-O-(6-O-(p-hydroxybenzoyl)-beta-D-glucopyranosyl)- p- hydroxybenzoyl)-beta-D-glucopyranoside]. The third pigment was elucidated to be delphinidin 3-O-[6-O-(malonyl)-beta-D-glucopyranoside]-7-O-[2-O-(6-O-(p- hydroxybenzoyl)-beta-D-glucopyranosyl)-6-O-(4-O-(6-O-(p-hydroxybenzoyl)- beta-D- glucopyranosyl)-p-hydroxybenzoyl)-beta-D-glucopyranoside], and the fourth as delphinidin 3-O-[6-O-(malonyl)-beta-D-glucopyranoside]-7- O-glucopyranosyl[(2-O-(6-O-(p-hydroxybenzoyl)-beta-D-glucopyranosyl)-6-O - (4-O-(6-O-(p-hydroxybenzoyl)-beta-D-glucopyranosyl)-p-hydroxybenzoyl)-be ta-D- glucopyranoside].

Synthesis and antimicrobial activity of some new 4-hydroxy-2H-1,4-benzoxazin-3(4H)-ones

Some 4-hydroxy-2H-1,4-benzoxazin-3(4H)-ones were synthesized and evaluated for their antimicrobial activities against Staphylococcus aureus, Escherichia coli and Candida albicans. Compounds 9, and 10 exhibited the best activity against Candida albicans.

Norditerpenoid alkaloids from Delphinium formosum

Abstract From the aerial parts of Delphinium formosum , a new norditerpenoid alkaloid, N -acetyldelectine (14-demethylajacine), was isolated, in addition to six known compounds, lycoctonine, delsemine A, delsemine B, delectine, delcosine and anthranoyllycoctonine. The structures of the compounds were determined by spectroscopic methods.

QSAR study on antibacterial and antifungal activities of some 3,4-disubstituted-1,2,4-oxa(thia)-diazole-5(4 H)-ones(thiones) using physicochemical, quantumchemical and structural parameters

Abstract This work demonstrated the quantitative structure-activity relationships of 3,4-disubstituted-1,2,4-oxa(thia)-diazole-5(4 H)-ones (thiones) using quantum chemical parameter R( I ), hydrophobicity descriptor and structural parameters. Semiempirical molecular orbital calculations were used to determine the quantum chemical parameter R( I ), which is the electron density of HOMO at the sulfur and oxygen in position 1 of the compounds investigated, divided by the orbital energy of HOMO. It was shown that the electron density of HOMO at the sulfur and oxygen of the molecules was strongly related to the biological activities of these molecules. The results obtained from the QSAR application indicated that there was a parabolic dependence between the biological activities and the R( I ) index. The structural factor I Y which shows the presence of a sulfur atom in position 1 was the dominant predictor for the antibacterial and antifungal activities. On the other hand, the other structural variable I X which shows the presence of a sulfur atom double bonded to the C atom in position 5 caused a decrease, but the hydrophobicity of the whole molecule (Σ) caused an increase in activity.

The Quantitative Determination of some Phenolic Acids In Delphinium Formosum by HPLC

ABSTRACT Some phenolic acids from the flowers of Delphinium formosum have been determined quantitatively by reversed-phase high-performance liquid chromatography with diode-array detection. A comparative study was performed by extracting the following phenolic acids: p-hydroxy benzoic, p-coumaric, caffeic, protocatechuic and vanillic acids with four different methods. The results were supported with recovery studies.

Quantitative Proton Magnetic Resonance Analysis of Primidone in Solid Dosage Forms

Abstract A rapid and specific proton magnetic resonance (PMR) spectroscopic method was developed for determining primidone in tablets. Maleic acid was used as the internal standart and DMSO-d6 served as the PMR solvent.

Antimicrobial evaluation of indole-containing hydrazone derivatives.

There has been an increasing importance of drug-resistant pathogens in clinical microbiological and antibacterial research. Indoles and hydrazone-type compounds constitute important classes of compounds in the search for effective agents against multidrug-resistant microbial infections. In this study a series of 1-methylindole-3-carboxaldehyde hydrazone derivatives were evaluated for their in vitro antimicrobial activities using the two-fold serial dilution technique against Staphylococcus aureus, methicillin-resistant S. aureus, methicillinresistant S. aureus isolate, Escherichia coli, Bacillus subtilis, and Candida albicans. The minimum inhibitory concentration (MIC) of the test compounds and the reference standards sultamicillin, ampicillin, fluconazole, and ciprofloxacin was determined. All compounds possessed a broad spectrum of activity having MIC values of 6.25 - 100 μg/ml against the tested microorganisms. Aromaticity and disubstitution of the phenyl ring with especially fluorine and chlorine atoms were found to be significant for the antimicrobial activity