• Journal of Microbiology and Biotechnology
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• v.33 no.6
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• pp.797-805
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• 2023

Species belonging to the Vernonia (Asteraceae), the largest genus in the tribe Vernonieae (consisting of about 1,000 species), are widely used in food and medicine. These plants are rich sources of bioactive sesquiterpene lactones and steroid saponins, likely including many as yet undiscovered chemical components. A phytochemical investigation resulted in the separation of three new stigmastane-type steroidal saponins (1 - 3), designated as vernogratiosides A-C, from whole plants of V. gratiosa. Their structures were elucidated based on infrared spectroscopy (IR), one-dimensional (1D) and two-dimensional nuclear magnetic resonance (2D NMR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), and electronic circular dichroism analyses (ECD), as well as chemical reactivity. Molecular docking analysis of representative saponins with α-glucosidase inhibitory activity was performed. Additionally, the intended substances were tested for their ability to inhibit α-glucosidase activity in a laboratory setting. The results suggested that stigmastane-type steroidal saponins from V. gratiosa are promising candidate antidiabetic agents.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.38-49
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• 1985

The water soluble organic fractions (WSOF) from an agricultural soil (W), a soil treated with sludge for 6 years ($WS_6$), a sludge-soil mixture incubated for one week ($WS_1$), and sewage sludge (SS) were extracted, purified, and characterized by elemental analysis, functional group determinations, infrared, UV-visible, and proton nuclear magnetic resonance spectrosocpy. The SS was characterized by higher organic H, N, and P contents, a higher H/C ratio, and a lower C/N ratio than W. Total acidity carboxyl and phenolic hydroxyl group contents were generally highest in SS, intermediate in $WS_6$ and $WS_1$, and lowest in W. Overall aromatic character and aromatic carboxyl group contents were highest in W, and lowest in SS. Aliphatic proton, aliphatic carboxyl, and phenolic hydroxyl group contents were highest in SS, and lowest in W. Protein decomposition products were the pronounced components in SS, and decreased in concentration as the sludge component in the mixtures decreased. The $^1H$-NMR spectra suggested that the SS-protons were bound to a wider range of functional groups than W-protons. Structural complexities around the aromatic protons followed the following order: SS>$WS_1$>$WS_6$>W.

• Journal of Applied Biological Chemistry
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• v.57 no.4
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• pp.321-324
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• 2014

Fresh and chopped aerial parts of Oryza sativa were extracted in 80% aqueous mehthanol, and the concentrated extract was successively partitioned in n-hexane, ethyl acetate (EtOAc), n-butanol (n-BuOH), and $H_2O$ fractions. From the n-BuOH fraction, two compounds were isolated through repeated silica gel and ODS column chromatography (c.c.). Based on nuclear magnetic resonance (NMR), mass spectrometry and infrared spectroscopy spectroscopic data, the compounds were identified to be adenosine (1) and phlomuroside (2). Especially, the configuration of both the anomer hydroxyl groups was determined as ${\beta}$ from the coupling constants of the anomer protons (J =6.0 and 7.6 Hz) in the $^1H-NMR$ spectra. This is the first report for the isolation of these compounds from Oryza sativa L.

• Korean Journal of Food Science and Technology
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• v.40 no.2
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• pp.129-134
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• 2008

Five antioxidative active substances were isolated from the EtOAc layer (20 g/56.2 g) of Korean black raspberry (Rubus coreanus Miquel) wine (11 L, black raspberry 15.7 kg fresh wt. eq.) by various column chromatography and high performance liquid chromatography (HPLC). Proton nuclear magnetic resonance ($^1H$-NMR) spectroscopy and gas chromatography Electro Ionization-Mass Spectrometry (GC-EI-MS) identified these as 4-hydroxybenzoic acid (1, 0.1 mg), 3,4-dihydroxybenzoic acid (2, 0.3 mg), 4-(2-hydroxyethyl)-phenol (3, 0.6 mg; tyrosol), pyrocatechol (4, 0.3 mg), 3,4,5-trihydroxybenzoic acid ethyl ester (5, 0.6 mg; ethyl gallate). The presence of 1 and 2 in Korean black raspberry has previously been reported. However, the presence of 3-5 in Korean black raspberry, and the identification of 1-5 from the Korean black raspberry wine have never before been reported.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.360-368
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• 2017

The objective of this research was to elucidate the physicochemical, structural, pasting and rheological properties of potato starch isolated from a foreign potato cultivar ('Atlantic') and new domestic potato cultivars ('Goun', 'Sebong', and 'Jinsun'). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and one-dimensional nuclear magnetic resonance (1D NMR) showed that the structural properties of potato starch did not vary significantly with cultivars. RVA analysis demonstrated that the 'Atlantic' starch had the highest breakdown viscosity among all potato starches. In steady shear rheological analysis, all potato starch dispersions showed shear-thinning behaviors (n =0.63-0.72) at $25^{\circ}C$. The highest apparent viscosity (${\eta}_{a,5}$), consistency index (K), and yield stress (${\sigma}_{oc}$) were observed in the 'Goun' starch dispersion. In dynamic shear rheological analysis, storage modulus (G') and loss modulus (G") values of new domestic potato starch dispersions were higher than those of the 'Atlantic' starch dispersion.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.312-312
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• 2022

Peanut hull as by-product has been discarded during peanut processing. However, peanut hull contains plenty of polyphenols that shows various physiological activities. The objectives of this study were to investigate anti-inflammatory and enzyme inhibitory activities of polyphenols from 'Sinpalkwang' peanut (Arachis hypogaea L.) hull. Compounds were isolated from methanol extracts of peanut hull by preparative-high performance liquid chromatography after identifying and quantifying polyphenols using Ultra performance liquid chromatography (UPLC) and UPLC-Quadrupole time-of-flight-mass spectrometry profiling. The structures of compounds were elucidated by one-dimensional [¹H, ¹³C] nuclear magnetic resonance (NMR) and two-dimensional NMR (correlated spectroscopy, heteronuclear single quantum coherence and heteronuclear multiple bond correlation). Three compounds were identified as 5,7-dihydroxy-4H-chromen-4-one (peak 2), luteolin (peak 4) and eriodictyol (peak 5). Significant differences in inflammatory mediator such as nitric oxide (NO), interleukin-6 (IL-6) and interleukin-1β (IL-lβ) in lipopolysaccharide stimulated Raw 264.7 macrophages and in enzyme (xanthine oxidase [XO] and α-glucosidase [AG]) inhibitory activities were observed between three compounds (p < 0.05). Peak 5 treated Raw 264.7 macrophages showed lower content of NO (16.4 uM), IL-6 (7.0 ng/mL), and IL-1β (60.6 pg/mL) than peak 2 (NO: 28.3 uM, IL-6: 11.3 ng/mL, IL-1β: 66.9 pg/mL) and peak 4 (NO: 24.7 uM, IL-6: 9.3 ng/mL, IL-1β: 62.6 pg/mL). Peak 5 showed higher XO inhibitory activity (84.7%) and higher AG inhibitory activity (52.4%) than peak 2 (XO inhibitory activity: 45.4%, AG inhibitory activity: 21.6%) and peak 4 (XO inhibitory activity: 37.9%, AG inhibitory activity: 37.5%) at concentration of 0.5mg/mL. This study suggests that peanut hull could be a potential source of anti-inflammatory and physiological materials while creating new use of discarded peanut hull as by-products concomitantly.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.522-528
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• 2023

In this work, adhesive tapes were prepared for the dicing process in semiconductor manufacturing. Compounds with different numbers of photoreactive groups (f = 1 to 3) were synthesized and incorporated into acrylic copolymers to formulate UV-curable acrylic adhesives. Structural confirmation of the synthesized photoreactive compounds (f = 2 or 3) was performed using nuclear magnetic resonance (NMR) spectroscopy. The introduction of the photoreactive compounds into the acrylic adhesive was accomplished by urethane reactions, and the successful synthesis of the UV-curable acrylic adhesive was verified by Fourier transform infrared (FT-IR) measurements. To evaluate the performance of the adhesive, the peel strength was evaluated before and after UV irradiation using a silicon wafer as a substrate. The adhesive exhibited high peel strength (~2000 gf/25 mm) before UV exposure, which was significantly reduced (~5 gf/25 mm) after UV exposure. Interestingly, the adhesive containing multifunctional photoreactive compounds showed the most significant reduction in peel strength. In addition, surface residue measurements by field emission scanning electron microscopy (FE-SEM) showed minimal surface residue (~0.2%) after UV exposure. Overall, these results contribute to the understanding of the behavior of UV-curable acrylic adhesives and pave the way for potential applications in semiconductor manufacturing processes.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.40-44
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• 2003

Soil-borne infectious disease including Pythium aphanidermatum and Rhizoctonia solani causes severe damage to plants, such as cucumber. This soil-borne infectious disease was not controlled effectively by chemical pesticide. Since these diseases spread through the soil, chemical agents are usually ineffective. Instead, biological control, including antagonistic microbe can be used as a preferred control method. An efficient method was developed to select an antagonistic strain to be used as a biological control agent strain. In this new method, surface tension reduction potential of an isolate was included in the ‘decision factor’ in addition to the other factors, such as growth rate, and pathogen inhibition rate. Considering these 3 decision factors by a statistical method, an isolate from soil was selected and was identified as Bacillus sp. GB16. In the pot test, this strain showed the best performance among the isolated strains. The lowest disease incidence rate and fastest seed growth was observed when Bacillus sp. GB16 was used. Therefore this strain was considered as plant growth promoting rhizobacteria (PGPR). The action of surface tension reducing component was deduced as the enhancement of wetting, spreading, and residing of antagonistic strain in the rhizosphere. This result showed that new selection method was significantly effective in selecting the best antagonistic strain for biological control of soil-borne infectious plant pathogen. The antifungal substances against P. aphanidermatum and R. solani were partially purified from the culture filtrates of Bacillus sp. GB16. In this study, lipopeptide possessing antifungal activity was isolated from Bacillus sp. GB16 cultures by various purification procedures and was identified as a surfactin-like lipopeptide based on the Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), high performance liquid chromatography mass spectroscopy (HPLC-MS), and quadrupole time-of-flight (Q-TOF) ESI-MS/MS data. The lipopeptide, named GB16-BS, completely inhibited the growth of Pythium aphanidermatum, Rhizoctonia solani, Penicillium sp., and Botrytis cineria at concentrations of 10 and 50 mg/L, respectively. A novel method to prevent the foaming and to provide oxygen was developed. During the production of surface active agent, such as lipopeptide (surfactin), large amount of foam was produced by aeration. This resulted in the carryover of cells to the outside of the fermentor, which leads to the significant loss of cells. Instead of using cell-toxic antifoaming agents, low amount of hydrogen peroxide was added. Catalase produced by cells converted hydrogen peroxide into oxygen and water. Also addition of corn oil as an oxygen vector as well as antifoaming agent was attempted. In addition, Ca-stearate, a metal soap, was added to enhance the antifoam activity of com oil. These methods could prevent the foaming significantly and maintained high dissolved oxygen in spite of lower aeration and agitation. Using these methods, high cell density, could be achieved with increased lipopeptide productivity. In conclusion to produce an effective biological control agent for soil-borne infectious disease, following strategies were attempted i) effective screening of antagonist by including surface tension as an important decision factor ii) identification of antifungal compound produced from the isolated strain iii) novel oxygenation by $H_2O_2-catalase$ with vegetable oil for antifungal lipopeptide production.

• Journal of Applied Biological Chemistry
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• v.54 no.1
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• pp.63-66
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• 2011

The bark of Machilus thunbergii was extracted with 80% aqueous methanol (MeOH), and the concentrated extract was partitioned using ethyl acetate (EtOAc), butanol (n-BuOH), and $H_2O$, successively. From the EtOAc fraction, five lignans were isolated through the repeated silica gel, octadecyl silica gel (ODS) and, Sephadex LH-20 column chromatography. Based on nuclear magnetic resonance (NMR), mass spectroscopy (MS), and infrared spectroscopy (IR) spectroscopic data, the chemical structures of the compounds were determined to be machilin A (1), machilin F (2), licarin A (3), nectandrin A (4), and nectandrin B, (5). This study presents comparative account of five lignans from M. thunbergii bark contributing inhibition of low density lipoprotein (LDL), ACAT-1, and ACAT-2. Compounds 2-5 showed varied degree of antioxidant activity on LDL with $IC_{50}$ values of 2.1, 11.8, 15.3, and $4.1{\mu}M$. Compounds 1, 2, and 3 showed inhibition activity on ACAT-1 with values $63.4{\pm}6.9%$ ($IC_{50}=66.8{\mu}M$), $53.7{\pm}0.9%$ ($IC_{50}=109.2{\mu}M$), and $78.7{\pm}0.2%$ ($IC_{50}=40.6{\mu}M$), respectively, at a concentration of 50 mg/mL, and on ACAT-2 with values $47.3{\pm}1.5%$ ($IC_{50}=149.7{\mu}M$), $39.2{\pm}0.2%$ ($IC_{50}=165.2{\mu}M$), and $52.1{\pm}1.0%$ ($IC_{50}=131.0{\mu}M$, respectively, at a concentration of 50 mg/mL.

• Korean journal of applied entomology
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• v.53 no.1
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• pp.7-13
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• 2014

This study was performed to investigate the response of the lacewing Chrysopa cognata to both Aphis gossypii-induced plant volatiles and lacewing-derived volatiles. The results of a Y-tube olfactometer bioassay showed that more C. cognata males were attracted to green pepper plants infected with A. gossypii than to uninfected green pepper plants alone or clean air and C. cognata males were attractive to C. cognata females. Gas chromatography-electroantennographic detection (GC-EAD) analysis showed that the antennae of C. cognata females elicited EAD-active responses to the volatiles entrained from A. gossypii-infected green pepper plants. 4-Ethylacetophenone, 3-ethylbenzaldehyde, 3-ethylacetophenone, and 4-ethylbenzaldehyde from A. gossypii-induced green pepper volatiles, and (Z,Z)-4,7-tridecadiene, (Z)-4-tridecene, and (Z)-4-undecene from C. cognata female entrainment were elucidated by further analysis using GC coupled nuclear magnetic resonance spectroscopy. Of the A. gossypii-induced plant volatiles identified in this study, 4-ethylacetophenone and 3-ethylbenzaldehyde significantly increased the attraction of C. cognata males to nepetalactol, but (Z)-4-tridecene and (Z)-4-undecene did not. (Z,Z)-4,7-Tridecadiene significantly reduced the attractiveness of nepetalactol to C. cognata.