• Proceedings of the PSK Conference
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• 2002.10a
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• pp.314.1-314.1
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• 2002

Bacterial ${\beta}$-lactamases provide resistance to ${\beta}$-lactams by hydrolyzing the ${\beta}$-lactam bond, On the basis of their catalytic mechanisms. ${\beta}$-lactamases are divided into two major groups. Class A. C and D which belong to the first group require serine in the active site and class B which is the second group require Zn(II) for their activity. Among class B enzymes, Bacteroides fragilis ${\beta}$-lactamase (CcrA enzyme) require two Zn(II) ions per monomer for maximal enzymatic activities. (omitted)

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.171-175
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• 1982

An oxytetracycline as being a tetracycline-antibiotic substance displayed a general synergism in the antimicrobial activity by the interaction of ginseng saponin and antibiotics, but did not to Sarcina maginata. Penicillin G.Na as being a $\beta$-lactam-antibiotic substance displayed a synergism in the antimicrobial activities by the addition of ginseng saponin to microorganisms used, but changed the effects in the antimicrobial activity of penicillin G.Na against the genus Serratia. An antimicrobial activity by the addition of ginseng saponin to antibiotics showed a non-specificity, and it varied synergism or antagonism to Gram-positive or Gram-negative bacterium. It was assumed that a drug-resistance could be eliminated by the dual administration of ginseng saponin and antibiotics.

• Biomedical Science Letters
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• v.11 no.3
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• pp.389-396
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• 2005

Resent studies have reported increased isolation of extended-spectrum $\beta-lactamase$ (ESBL) producing strains at several hospital in Korea. We studied to investigate the isolation rates of ESBL strains from clinical isolates of Klebsiella pneumoniae and to characterize differences in types using analyses of genotyping and antibiotic susceptibility test. Antibiotic susceptibility test with confirmation of ESBL by double disk synergy test was performed on the 54 ESBL strains of Klebsiella pneumoniae from a hospital in Busan. Transfer of resistant gene in ESBL strains resistant to 3rd generated antibiotics was confirmed by transconjugation test using E. coli $RG176^{nal(r)}$. blaTEM, blaSHV, blaCTX-M genes were detected by PCR. ESBL producing strains had 100% of resistant rate to ampicillin, azteronam, cefazolin, cefepime and ceftriaxone ($\beta-lactam$ antibiotics). Forty strains of bla TEM$(74\%)$, 41 strains of bla SHV $(76\%)$, 23 strains of bla CTX-M $(43\%)$ were found, respectively. The strains had one or more genes. They had high resistant rates to $\beta-lactam$ antibiotics including cephalosporin. The resistant rates of strains with multiple resistant genes were higher than those of strains with single resistant gene.

• YAKHAK HOEJI
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• v.46 no.6
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• pp.387-391
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• 2002

In vitro $\beta$-lactamase inhibitory activity of 6-exomethylene sulbactam compounds (CH-120, 130, 140, 145, 150, 155) was compared with clavulanic acid, sulbactam and tazobactam. The inhibitory activity of CH-140 was stronger than sulbactam and clavulanic acid against Type II, III, IV, TEM enzymes and stronger than tazobactam against Type IV enzyme. The inhibitory activity of CH-145 was stronger than sulbactam and clavulanic acid against Type I, II, III, IV, TEM enzymes and stronger than tazobactam against Type III, IV enzymes. The in vitro antimicrobial activity of CH-140 and CH-145 combined with piperacillin and ceftriaxone was compared with the sulbactam and tazobactam against $\beta$-lactamase producing 31 strains. But, synergistic activity of CH-140 and CH-145 was inferior to tazobactam.

• YAKHAK HOEJI
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• v.47 no.6
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• pp.456-460
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• 2003

In vitro $\beta$-lactamase inhibitory activity of 6-exomethylenepenam compounds ( 1, 2, 3, 4 and 5) was compared with clavulanic acid, sulbactam and tazobactam. The inhibitory activity of compound 3 was stronger than those of sulbactam and clavulanic acid against Type I and II enzymes and stronger than tazobactam against Type III, IV, TEM enzymes. The inhibitory activity of 5 was stronger than sulbactam and clavulanic acid against Type I and II enzymes and stronger than tazobactam against Type III, and IV enzymes. The in vitro antimicrobial activity of 3, 4 and 5 combined with ampicillin and cefoperazone was compared with the sulbactam against $\beta$-lactamase producing 27 strains. But, synergistic activity of 3 and 5 was inferior to tazobactam.

• Korean Journal of Pharmacognosy
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• v.24 no.1
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• pp.32-37
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• 1993

Phytochemical studies of the root of Aristolochia contorta afforded an unidentified N-glycoside rarely found in natural products. It's structure was elucidated as 8-desmethoxy-aristolactam $N-{\beta}-D-glucopyranoside$ by spectral data and chemical analysis. 6-Hydroxy-8-desmethoxy-aristolactam $N-{\beta}-D-glucopyranoside$, aristolactam I and aristolactam AII were also isolated from the same source. $^{13}C-NMR$ spectra were first assigned and the result confirmed N-C-O-glycosidic linkages in the glycosides.

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.2990-2994
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• 2014

The studies on design and synthesis of new monocyclic ${\beta}$-lactam esters 4(R/S)-(1'-methoxycarbonylpropyl- 2'(R/S)-thio)-3(R)-phenylacetamidoazetidin-2-one (3a) and 4(R/S)-(1'-methoxycarbonyl-2'-methylpropyl-2'- thio)-3(R)-phenylacetamidoazetidin-2-one (3b) were described. Compounds 3a and 3b were specifically designed to retain all penicillin substructures except the bicyclic system, which would be conceived by cleaving the C(3)-N(4) bond of penicillin G. Compounds 3a and 3b are of particular interest in the context of the structural elucidation of monocyclic ${\beta}$-lactams originated from penicillin. Key intermediates, ${\beta}$-mercapto esters 6a and 6b, were synthesized from conjugate acids 4a and 4b using three-step synthetic sequences, respectively, and 4(S)-acetoxy-3(S)-phenylacetamidoazetidin-2-one (7) was obtained from the degradation of penicillin G. Reactions of 6a and 6b with 7, thus obtained, provided the target compounds 3a and 3b, respectively.

• YAKHAK HOEJI
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• v.52 no.4
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• pp.306-310
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• 2008

In vitro ${\beta}-lactamase$ inhibitory activity of 6-benzothiazole penicillins (1, 2, 3 and 4) was compared with clavulanic acid, sulbactam and tazobactam. The inhibitory activity of exomethylene compounds (3 and 4) was stronger than those of non-exomethylene compounds (1 and 2). The sulfide 3 showed stronger inhibitory activity than sulbactam, clavulanic acid andsimilar to tazobactam against ${\beta}-lactamase$ Type I enzymes. The inhibitory activity of 4 was stronger than those of sulbactam, clavulanic acid and tazobactam against Type III and IV enzymes. The in vitro antimicrobial activity of ampicillin or cefoperazone combined with 3 or 4 was stronger than those of ampicillin or cefoperazone alone against many ${\beta}-lactamase$ producing strains to show that compounds 3 and 4 have some synergistic effect. The synergistic activity of 3 and 4 was comparable to sulbactam in some ${\beta}-lactamase$ producing strains, but it was inferior to tazobactam.

• Biomolecules & Therapeutics
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• v.7 no.1
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• pp.44-53
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• 1999

The resistant strains due to the extended-spectrum $\beta$-lactamase (ESBL) were susceptible to cefatrizine combined with clavulanic acid. The purpose of this study was to evaluate the in vitro and in vivo antibacterial activities of cefatrizine/clavulanic acid (CTRZ/CV) combination at a ratio of 2 : 1 in comparison with cefaclor (CCLO), cefuroxime (CRXM), cefuroxime axetil (CRXMA) and amoxicillin/clavulanic acid (AMXCCV). CTRZ/CV showed good activity against laboratory strains of gram-positive and gram-negative bacteria and exhibited excellent antibacterial activity against $\beta$-lactamase-producing strains. The bactericidal activity of CTRZ/CV was superior to that of CCLO and CRXM, and almost equal to that of AMXCCV against the $\beta$-lactamase-producing strains. The in vitro results were substantiated. by in vivo mouse experimental infection studies with $\beta$-lactamase-producing and non-producing strains. In mixed experimental infection due to $\beta$-lactamase-producing and non-producing strains, the therapeutic efficacy of CTRZ/CV was superior to that of CTRZ, CCLO, CRXMA and AMXCCV. In respiratory tract infection in mice due to Klebsiella pneumoniae EB4O, CTRZ/CV was more erective than CCLO, CRXMA and AMXCCV and also more efficacious than CCLO, CRXMA and AMXCCV in urinary tract infection in mice due to Escherichia coli EB13. These results indicate that CTRZ/CV is a useful drug for the treatment of infection caused by $\beta$-1actamase-producing strains including ESBL-producing strains.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3644-3652
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• 2010

The metallo-$\beta$-lactamases ($M{\beta}Ls$) are clinically significant enzymes which readily hydrolyze most $\beta$-lactam antibiotics. Discovering potential inhibitors for the $M{\beta}Ls$ is an expensive, time consuming endeavor. Virtual screening can sieve out inhibitor candidates with incompatible features prior to synthesis, decreasing these costs. Using Autodock 4.0, the binding locations and energies of four previously-studied potential inhibitors and four additional compounds obtained from the National Cancer Institute (NCI) database were computationally calculated. Based on the docking models of these eight compounds, we then designed several hypothetical inhibitor structures, compounds A through F, and performed their respective docking experiments. The docking results for compound F showed that it binds to the zinc containing active sites with a lowest predicted binding energy of -6.70 kcal/mol, suggesting F is the most likely potential $M{\beta}L$ inhibitor.