• Journal of Microbiology and Biotechnology
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• v.22 no.6
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• pp.814-817
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• 2012

In the continued search for melanogenesis inhibitors from microbial metabolites, we found that the culture broth of Clitocybe sp. MKACC 53267 inhibited melanogenesis in B16F10 melanoma cells. The active component was purified by solvent extraction, silica gel chromatography, Sephadex LH-20 column chromatography, and finally by preparative HPLC. Its structure was determined as 5-pentyl-2-furaldehyde on the basis of the UV, NMR, and MS spectroscopic analysis. The 5-pentyl-2-furaldehyde potently inhibited melanogenesis in B16F10 cells with an $IC_{50}$ value of 8.4 ${\mu}g/ml$, without cytotoxicity.

• Journal of the Korean Applied Science and Technology
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• v.6 no.1
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• pp.59-66
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• 1989

Inclusion complex formation of octyldimethyl p-aminobenzoate with ${\beta}-cyclodextrin$in aqueous solution and in the solid state was studied by the solubility method, spectroscopic (UV, FT-IR) and X-ray diffractornetry. The solid complex of octyldimethyl p-aminobenzoate with ${\beta}-cyclodextrin$ was obtained in molar ratio of 1:2 (guest/host). A spatial relationship between host and guest molecule was clearly reflected in the magnitude of the apparent stability constant (K') and in the stoichiometry of the inclusion complex. Furthermore, a typical type Bs phase-solubility diagram was obtained for octyldimethyl p-aminobenzoate and ${\beta}-cyclodextrin$ in water at $25^{\circ}C$. The results indicated that the solubility of the guest molecule was higher by the formation of ${\beta}-cyclodextrin$ inclusion complex.

• YAKHAK HOEJI
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• v.28 no.2
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• pp.101-127
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• 1984

The study of interaction between riboflavin derivatives and biologically active substances was reviewed. With combination of spectroscopic methods such as NMR, UV, Fluorescence and IR, informations about interaction mechanism including hydrogen bond formation, conformation of association complex, and association constant were obtained. 1. Riboflavin associated with adenine but not with other bases found in the nucleic acids. -CONHCO- group was included in the formation of hydrogen bond with adenine. 2. Riboflavin interacted with alcohol to make a 1 : 1 association complex through the 3N-imino and 2C-carbonyl group of the isoalloxazine ring and the hydroxyl group of the alcohols. 3. Riboflavin associated with salicylates to produce the cyclic hydrogen-bonded dimer. The strongest complex was formed with salicylic acid, a weaker one with aspirin, and an even weaker one with salicylamide. 4. Other bio-active substances, orotic acid and inhibitors such as phenol, trichloroacetic acid and indol also formed hydrogen bond with riboflavin. 5. Reduced riboflavin showed strong self-association to produce the cyclic hydrogen-bonded complex and it associated with adenine and with cytosine to form 1 : 3 complex.

• YAKHAK HOEJI
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• v.37 no.2
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• pp.193-197
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• 1993

For the investigation of medicinal resources in Crataegus species, a study was carried out to clarify the constituents in the leaves of Crataegus Pinnatifida var. pubescens (Rosaceae), of which fruits have been used to stomachic, digestive, astringent, analgesic, and cardiotonic, etc. as a folk medicine in Korea. From the n-BuOH fraction of MeOH extract two flavone glycosides, vitexin(apigenin-8-C-$\beta$-D-glucopyranoside) and 2"-O-rhamnosyl vitexin(apigenin-8-C-$\alpha$-L-rhamnosyl-(1$\rightarrow$2)-$\beta$-D-glucopyrano side) were isolated and identified on the basis of their physico-chemical properties and spectroscopic evidences(UV, IR, NMR, FAB-Mass etc.) in comparision with authentic samples.amples.

• Archives of Pharmacal Research
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• v.18 no.6
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• pp.458-461
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• 1995

+To prove uniqueness of allylic alcohol formation from ${\alpha},{\beta}-unsaturated$ ketones by mammal enzymes, a metabolic pattern of dehydroparadols, non-pungent synthetic analogs of shogaol by Aspergillus niger was examined. Two biotransformation products of a dehydroparadol, 1-(4hydroxy-3-methoxyphenyl)-non-1-en-3-one were accumulated in the culture broth of A. niger. They were characterized as 1-(4-hydroxy-3-methoxyphenyl)-non-1-en-9-01-3-one and 1-(4-hydroxy-3-methoxyphenyl)-nonan-9-o1-3-one by UV, NMR and mass spectroscopic analyses. Accumulation of allylic alcohol metabolites was not observed.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3788-3792
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• 2012

Spherical-shape melanin nanoparticles with good water-dispersibility were successfully synthesized by a simple oxidation polymerization of 3,4-dihydroxy-phenylalanin (DOPA) with $KMnO_4$. Similar features to those known from natural and synthetic melanin polymers were observed from prepared melanin nanoparticles by FT-IR, UV-Vis., and ESR spectroscopic methods. Their binding ability with several heavy metal ions from aqueous solution was quantitatively investigated, and the maximum binding capacities with melanin nanoparticles to lead, copper, and cadmium ions were obtained as 2.45, 2.17 and 1.88 mmol/g, respectively, which are much larger values than those reported from natural and synthetic melanin polymers. The large binding capacity and fast binding rate of melanin nanoparticles to metal ions can make them an excellent candidate for the remediation of contaminated water.

• Bulletin of the Korean Chemical Society
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• v.30 no.8
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• pp.1715-1718
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• 2009

A series of sitting-atop (SAT) complexes, [(ZrO)$H_2t(X)pp(NO_3)_2$], have been prepared via the reactions of free base meso-tetraarylporphyrins, $H_2$t(X)pp, with zirconyl nitrate hydrate, ZrO(N$O_3)_2{\cdot}xH_2$O. The products have been characterized by a variety of methods including $^1H\;NMR,\;^{13}C$ NMR, IR and UV-Vis spectroscopies, elemental analysis and conductance measurements. The data indicate that the meso-tetraarylporphyrins coordinate with two pyrrolenine nitrogen atoms to the zirconyl cation located above the distorted porphyrin plane and two protons remain on the pyrrole nitrogens. Such half sandwich-type sitting-atop complexes may be considered as models for the initial steps of the metallation of the macrocycles.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1485-1488
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• 2010

Novel photoluminescent graphene, graphene/europium/picolinate, was made from the reaction of the graphene carboxylate, europium(III) and $\alpha$-pyridoin anion in methanol solution. There was evidence on IR spectroscopic data that europium metal was coordinated by graphene carboxylate. The graphene/europium/picolinate materials emitted the red luminescence with main peaks at 609 and 695 nm, when solid sample was excited by an UV light at the wavelength of 254 nm. The surface morphology and physical properties of the graphene/europium/picolinate product have been investigated by IR, PL, SEM, TEM and TGA measurements.

• Journal of the Korean Ceramic Society
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• v.54 no.5
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• pp.388-394
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• 2017

Here, utilizing rhodamine B (RhB) as standard color dye, we examined the photo degradation proficiency of $Ag_2Se-Graphene-TiO_2$ nanocomposites under visible light irradiation; samples were prepared by ultrasonication techniques and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopic investigation and UV-Vis absorbance spectra examination. Our outcomes demonstrate that the $Ag_2Se-G-TiO_2$ nanocomposite showed significant photodegradation efficiency as compared with those of $TiO_2-G$ and $Ag_2Se-G$, with around 85.2% of Rhodamine B (RhB) degraded after 180 min. It is concluded that the $Ag_2Se-G-TiO_2$ nanocomposite is a competent candidate for dye pollutants.

• Archives of Pharmacal Research
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• v.27 no.10
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• pp.1023-1028
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• 2004

A new 12a-dehydrorotenoid 1, 11-dihydroxy-9, 10-methylenedioxy-12a-dehydrorotenoid (1), together with a new isoflavonoid glycoside tectorigenin-7-O-${\beta}$-glucosyl-4'-O-${\beta}$-glucoside (3), were isolated and identified from the rhizomes of I. spuria (Zeal). In addition, 4 known compounds, tectorigenin (2) tectorigenin-7-O-${\beta}$-glucosyl $(1{\leftrightarrow}6)$ glucoside (4), tectoridin (a tectorigenin- 7-O-${\beta}$-glucoside) (5) and tectorigenin-4'-O-${\beta}$-glucoside (6) were isolated and identified for the first time from this plant. The structures of the isolated compounds were determined by spectroscopic methods (UV, IR, $^1H,\;^{13}C$NMR, DEPT, HMQC, NOESY, and HMBC experiments and MS spectrometry) and by comparison with literature data of known compounds. Compounds 2, 4, 5, and 6 are reported for the first time from this plant through the present study.