• Genomics & Informatics
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• v.6 no.4
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• pp.227-230
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• 2008

Compounds of polyketide origin possess a wealth of pharmacological effects, including antibacterial, antifungal, antiparasitic, anticancer and immunosuppressive activities. Many of these compounds and their semisynthetic derivatives are used today in the clinic. Most of the gene clusters encoding commercially important drugs have also been cloned and sequenced and their biosynthetic mechanisms studied in great detail. The area of biosynthetic engineering of the enzymes involved in polyketide biosynthesis has recently advanced and been transferred into the industrial arena. In this work, we introduce a computational system to provide the user with a wealth of information that can be utilized for biosynthetic engineering of enzymes involved in post-PKS tailoring steps. Post-PKS tailoring steps are necessary to add functional groups essential for the biological activity and are therefore important in polyketide biosynthesis.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.65-70
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• 2011

Coumarins are ubiquitous in plant kingdom and have been used as antitumor, antifungals, anticoagulants, insecticides. Chalcones are also widespread in plant kingdom and have been known to possess diverse biological activities; antibacterial, antifungal, antitumor and anti-inflammatory, etc. As they are considered as important natural products, numerous synthetic approaches have been reported up to the present. We devise a new selective method of preparing dihydrocoumarins and chalcones from aryl cinnamates by the selection of reagents. Dihydrocoumarin derivatives were prepared selectively by using intramolecular cyclization catalyzed by p-toluene sulfonic acid. Also, chalcones were prepared by Fries-rearrangement catalyzed by $TiCl_4$. This method can be used for preparing various coumarin & chalcone compounds.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1511-1518
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• 2011

A series of 1,4-disubstituted octahydroquinoxaline-2,3-dione derivatives was prepared through two steps reaction. The latter involves the formation of N,N-disubstituted cyclohexane-1,2-diamine derivatives (la-j) through reductive alkylation of 1,2-cyclohexanediamine with different aldehydes in presence of sodium cyanoborohydride. Fusion of compounds (1a-j) with diethyl oxalate affording the target compounds (2a-j). Elucidation of structures of compounds (2a-j) was based upon different spectral data as well as the elemental methods of analyses. In addition, mass spectrometry and X-ray diffraction analyses were carried out. Moreover, the lipophilicity of the target compounds as expressed from the Clog P. Most of the test compounds (2a-j) showed weak to moderate antibacterial and antifungal activities against most of the used bacterial and fungal strains in comparison to chloramphenicol and clotrimazole as reference drugs respectively.

• Journal of Integrative Natural Science
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• v.1 no.1
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• pp.47-53
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• 2008

In a previous study, we showed that Cecropin A (1-8)-Magainin 2 (1-12) hybrid peptide (CA-MA)'s analogue, Anal P5, exhibit broad-spectrum antimicrobial activity. Anal P5, designed by flexible region (positions 9, 10)-substitution, Lys- (positions 4, 8, 14, 15) and Leu- (positions 5, 6, 12, 13, 16, 17, 20) substitutions, showed an enhanced antimicrobial and antitumor activity without hemolysis. The primary objective of the present study was to gain insight into the relevant mechanisms of antimicrobial activities of Anal P5 by using flow cytometric analysis. Anal P5 exhibits strong antifungal activity in a salt concentration independent manner. In addition, Anal P5 causes significant morphological alterations of the bacterial surfaces as shown by scanning electron microscopy, supporting its antibacterial activity. Its potent antibiotic activity suggests that Anal P5 is an excellent candidate as a lead compound for the development of novel antibiotic agents.

• Journal of the Korean Chemical Society
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• v.55 no.5
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• pp.794-804
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• 2011

3-Chloro-1-benzothiophene-2-carbonylchloride (1) was allowed to react with glycine to give 3-chloro-1-benzothiophen-2-yl-carbonylaminoacetic acid (2). Various aldehydes were treated with compound (2) in acetic anhydride to get 1,3-oxazol-5-ones (3a-d). These oxazolones were treated with aromatic amines or hydrazides to get various imidazol-4-ones (4a-h or 5al) separately. Oxazolones was also treated with aromatic hydrazine, through which expansion of five membered oxazole ring to six member triazine ring occurs to yield 1,2,4-triazin-6-ones (6a-h). The structures of all the synthesized compounds were confirmed by spectral data and were screened for antibacterial and antifungal activities.

• Journal of Life Science
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• v.25 no.7
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• pp.748-756
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• 2015

The report explores the possibility that the single extract of natural substances and the mixture of single extracts of natural substances create a synergy effect to increase the antimicrobial activity. It also compares the previous researches to find out if the natural medicinal herbs’ extract has antimicrobial activity on dandruff causative organism, Malassezia furfur. For the experiment on the mixture of single extracts of natural substances, the results are like following: 1. Staphylococcus aures’s antibacterial activity is resistant to mixture of three natural substances. 2. Escherichia coil’s antibacterial activity is resistant to mixture with Coptidis rhizoma. 3. Candida albicans’ antifungal activity is resistant to mixture with Chinese galls, which means the different results may be expected when tested with each germ. 4. On the other hand, Malassezia furfur has no antifungal activity on the single extract of natural substances and shows weak antifungal activity, whose diameter is 3.20 mm when tested with the mixture of 50% of Coptidis rhizoma and 50% of Phytoncide. The result is totally different from the one on the same eumycetes, C. albicans. That is because M. furfur has more lipophilic chemicaled cell walls than C. albicans does and it also consists of lamella layer, inner plasma membrane and intermediate multiple layers.

• Archives of Pharmacal Research
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• v.26 no.10
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• pp.773-777
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• 2003

In this study, some new nitroimidazole derivatives were obtained from 2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethylamine dihydrochloride (4) and 1-(2-bromoethyl)-2-methyl-5-nitroimidazole (5), which were prepared using metronidazole. Compound 4 was reacted with arylisothiocyanates (6) to obtain 1-[2-(2-methyl-5-nitroimidazol-1-yl)ethyl]-3-arylthioureas (7) and the latter with $\alpha$-bromoacetophenones (8) to give -3-[2-(2-methyl-5-nitroimidazol-1-yl)ethyl]-2-arylimino-4-aryl-4-thiazolines (9). Also 1-[2-(2-methyl-5-nitroimidazol-1-yl)ethyl]-2-phenyl-4-arylideneimidazolin-5-ones (11) were prepared by reaction of 4 with 2-phenyl-4-arylidene-5-oxazolones (10). The reaction of the other starting material 5 with 5-arylidenethiazolidin-2,4-dione (12) gave 3-[2-(2-methyl-5-nitroimidazol-1-yl)ethyl]-5-arylidenethiazolidin-2,4-dione (13) derivatives. Structural elucidation of the compounds was performed by IR, $^1H-NMR$ and MASS spectroscopic data and elemental analysis results. Antimicrobial activities of the compounds were examined and moderate activity was obtained.

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.189-198
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• 2011

In the present paper two new thiosemicarbazones i.e., 4[N-(4'-ethylbenzalidene)amino]antipyrine thiosemicarbazone (EBAAPTS) and 4[N-(2',4'-dimethylbenzalidene)amino]antipyrine thiosemicarbazone (DMBAAPTS) have been synthesized and characterized. The complexing abilities of these thiosemicarbazones i.e. EBAAPTS and DMBAAPTS towards cobalt(II) and nickel(II) salts have been explored. The reactions of the hot ethanolic solutions of cobalt(II) and nickel(II) salts with EBAAPTS and DMBAAPTS led to the formation of the novel complexes of general composition [$MX_2(L)H_2O$] (M=$Co^{2+}$ or $Ni^{2+}$; X=$Cl^-$, $Br^-$, $NO_3^-$, $NCS^-$ or $CH_3COO^-$; L=EBAAPTS or DMBAAPTS). The newly synthesized complexes have been characterized by elemental analyses, molar mass, molar conductance, magnetic susceptibility, infrared and electronic spectral studies. The molar conductance measurements of the complexes in nitrobenzene correspond to their non-electrolytic nature. All the complexes are of high-spin type. On the basis of spectral studies an octahedral geometry has been assigned for Co(II) and Ni(II) complexes of the type [$MX_2(L)H_2O$]. These complexes were screened for their antibacterial and antifungal activities on different species of pathogens, fungi and bacteria and their biopotency has been discussed.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.271-279
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• 2015

Lactoferrin (LF) is a multifunctional, iron-binding glycoprotein found in physiological secretions of mammals. LF shows antibacterial, antiviral and antifungal activities. In the present study, a gene encoding the N-terminal lobe of human lactoferrin (hLF) was isolated, cloned and expressed in methylotrophic yeast, Pichia pastoris. The recombinant hLF-N (rhLF-N) protein was secreted into the culture medium at the level of $458{\mu}g/ml$ in 3 L fermentor. The size of purified hLF-N was estimated as 35 kDa when analyzed by SDS-PAGE and western blotting. The rhLF-N was further confirmed by immunodiffusion using the anti-hLF polyclonal antibody. The expression profile analysis by qRT-PCR showed that the relative mRNA expression of rhLF-N was maximal after 2-3 days of methanol induction and reduced gradually at 4 days. The purified rhLF-N showed broad antibacterial activities against the pathogens such as Staphylococcus aureus, E. coli, Pseudomonas aeruginosa, Burkholderia cepacia, and Salmonella typhimurium. However, rhLF-N showed relatively lower activity when compared to peptides derived from LF. In spite of this weak activity, the rhLF-N expressed in P. pastoris might be more advantageous for the industrial application, because rhLF-N is secreted into the culture medium and the production can also be increased by optimization of culture conditions.

• Journal of Life Science
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• v.26 no.11
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• pp.1225-1231
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• 2016

In this study, our investigated the antioxidant activities and compared other bioassay including anti-microbial, antifungal activities and total polyphenol contents of functional healthy drinks from some medicinal herbs and coffee mixture. The kind of medicinal herbs, chaga mushroom (Inonatus obliqurs), moringa (Moringa Oleifera), gravila (Anona muricata), mulberry (Morus alba), Dioscoreaceae (Dioscorea quinquelaba), Berberidaceae (Epimedii Herba), Asteraceae (Artemisia capillaries) and siberian ginseng (Acanthopanax senticous,). The functional healthy drinks, named C1, C2, C3, C4, C5, C6 and C7 were summered in Table 1. The in vitro antimicrobial activity was examined against Gram positive bacteria, Gram negative bacteria and a fungus. The functional healthy drinks were broad spectrum of anti-microbial activity without antifungal activity against Candida albicans KCTC7965. In particularly, the C7 showed strong activity against Methicillin Resistant Staphylococcus aureus CCARM3089, CCARM 3115 and CCARM3561. And, the C7 showed 88% of free radical scavenging effect on 0.5 mg/ml using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. Functional healthy drink C7 was mulberry extracts from Morus alba, chaga mushroom from Inonatus obliqurs and moringa from Moringa olifera in additionally coffee extracts. Its results confirm that the potential use of mulberry extracts as a good source of antibacterial compounds or as a health promoting food and health drinks.