• Journal of the Korean Chemical Society
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• v.47 no.5
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• pp.530-532
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• 2003

• YAKHAK HOEJI
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• v.43 no.4
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• pp.442-446
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• 1999

The synthesis and antimicrobial activity of N-substituted glycyl derivatives of Norfloxacin were described. Norfloxacin was treated with chloroacetyl chloride to yield chloroacetyl norfloxacin (1). This compounds was treated with alkylamines to obtain quinolone carboxylic acids (2-6), which were reacted with pivaloyloxymethyl chloride to get pivaloyloxymethyl quinolone carboxylates (7-11). Free carboxylic quinolones (2-6) showed little stronger activities to their pivaloyloxymethyl esters (7-11). In quinolone analogues, longer alkyl chain compounds showed stronger activities than shorter one.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1992.05a
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• pp.17-17
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• 1992

항균성 물질을 이용한 화학 요법의 역사는 1930 년대 초 술폰아미드의 발견으로부터 비롯되었고, 페니실린의 발견 이래 $\beta$-lactam 계 항생제가 주종을 이루고 있다. 1963년 Lesher 와 Gruett 에 의해 합성된 nalidixic acid 가 요도염 치료제로 임상에 사용된 이후 이와 유사한 구조를 갖는 항균제 개발에 많은 연구가 진행되어 제 1세대, 제 2세대의 quinolone 개발에 이어 1950년대에 들어 제 3세대 quinolone의 개발이 활발히 진행되어 왔다. 제 3세대 항생제는 C-6 위치에 F기를 도입한 것으로 연구의 진행 방향은 항균력의 향상과 체내에서의 지속 시간의 연장, 경구 투여시 흡수로의 증가와 독성의 약화를 위한 것이다. 본 연구는 quinolone의 기본 골격을 유지하면서 C-7 위치에 새로운 group을 도입하여 그에 대한 항균력을 측정하여 새로운 quinolone계 항생제의 개발을 시도하였다.

• Journal of Life Science
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• v.13 no.6
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• pp.943-949
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• 2003

New quinolone derivatives of 7-(cis- or trans-3-amino-4-mehtylthiomethylpyrrolidinyl) quinolone-3-carboxylic acids were synthesized by condensation of 7-halo substituted quinolone-3-carboxylic acids with cis- or trans-3-amino-4-mehtylthiomethylpyrrolidine. Some of these compounds showed broad spectra of antibacterial activities against Gram-positive and Gram-negative organisms except Pseudomonas aeruginosa, and exhibited much stronger activity against MRSA.

• Biomolecules & Therapeutics
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• v.15 no.2
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• pp.102-107
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• 2007

Cimetidine, a substrate for P-glycoprotein (P-gp), is a well known drug interacting with a variety of drugs and results in alteration of pharmacokinetic parameters by concomitant administration. The aim of present study was to investigate whether cimetidine affects the transport of various quinolone antibiotics in human colorectal cancer cell line (Caco-2) system which has been typically used to investigate drug transport via P-gp. The apparent permeability coefficients (P$_{app}$) value of 9 quinolone antibiotics in the co-treatment with cimetidine was examined. Apical to basolateral (AP-to-BL) transport of fleroxacin in the co-treatment with cimetidine was increased to 1.5-fold (p<0.01) compared with that of fleroxacin alone, whereas basolateral to apical (BL-to-AP) transport of fleroxacin was decreased to 0.83-fold significantly (p<0.05). Ofloxacin was decreased to 0.8-fold (p<0.01) and 0.72-fold (p<0.01) significantly in AP-to-BL and BL-to-AP direction, respectively by cimetidine cotreatment. The P$_{app}$ values of gatifloxacin, moxifloxacin, ciprofloxacin and rufloxacin also were changed by cimetidine. These results have a potential that cimetidine influences on the pharmacokinetics of quinolone antibiotics. It suggests that careful drug monitoring and dosage adjustment may be necessary during the co-administration of quinolone antibiotics with cimetidine.

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1605-1612
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• 2016

Quinolone-resistant Salmonella strains were isolated from patient samples, and several quinolone-sensitive strains were used to analyze mutations in the quinolone resistance-determining region (QRDR) of gyrA, gyrB, parC, and parE and to screen for plasmid-mediated quinolone resistance. Among the 21 strains that showed resistance to nalidixic acid and ciprofloxacin (MIC 0.125-2.0 μg/ml), 17 strains had a mutation in QRDR codon 87 of gyrA, and 3 strains had a single mutation (Ser83 → Phe). Another cause of resistance, efflux pump regulation, was studied by examining the expression of acrB, ramA, marA, and soxS. Five strains, including Sal-KH1 and Sal-KH2, showed no increase in relative expression in an analysis using the qRT-PCR method (p < 0.05). In order to determine the genes involved in the resistance, the Sal-9 isolate that showed decreased susceptibility and did not contain a mutation in the gyrA QRDR was used to make the STM (MIC 8 μg/ml) and STH (MIC 16 μg/ml) ciprofloxacin-resistant mutants. The gyrA QRDR Asp87 → Gly mutation was identified in both the STM and STH mutants by mutation analysis. qRT-PCR analysis of the efflux transporter acrB of the AcrAB-TolC efflux system showed increased expression levels in both the STM (1.79-fold) and STH (2.0-fold) mutants. In addition, the expression of the transcriptional regulator marA was increased in both the STM (6.35-fold) and STH (21.73-fold) mutants. Moreover, the expression of soxS was increased in the STM (3.41-fold) and STH (10.05-fold) mutants (p < 0.05). Therefore, these results indicate that AcrAB-TolC efflux pump activity and the target site mutation in gyrA are involved in quinolone resistance.

• Bulletin of the Korean Chemical Society
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• v.28 no.7
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• pp.1203-1205
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• 2007

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.673-675
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• 1990

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.65-70
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• 2010

We describe the immune stimulatory effects of compounds determined by means of activity-monitored extraction and isolation techniques. As a result, 4-carboethoxy-6-methoxy-2-quinolone (1) and 4-carboethoxy-6-hydroxy-2-quinolone (2) were isolated from the ethyl acetate-soluble fraction of the Oryza sativa cv. Heugnambyeo bran, and were determined to exert significant inhibitory effects in macrophage cell line (murine RAW 264.7) and murine splenocytes. The structures were elucidated on the basis of spectroscopic evidence, particularly the results obtained via hetero nuclear multiple-bond connectivity and high-resolution MS spectroscopy. Up to date, compound (1) was isolated as natural sources for the first time.

• Journal of Life Science
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• v.15 no.3 s.70
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• pp.423-426
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• 2005

Two isoquinolines and one quinolone were isolated from the stem bark of Pellodendron amurense Rupr. (Rutaceae). Two isoquinolines were elucidated as thalifoline (2) and pharmacological active berberine (3) has been blocking the release of $Ca^{2+}$ from internal stores. One quinolone was identified as N-methylatanine (1). This is the first report on the isolation of N-methylatanine (1) and thalifoline (2) from this plant.