• Food Science and Biotechnology
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• v.17 no.3
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• pp.489-494
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• 2008

In order to develop a potent antidementia $\beta$-secretase inhibitor from phytochemicals, $\beta$-secretase inhibitory activities of extracts from many medicinal plants and herbs were determined. Water extracts from Rubus coreanus showed the highest $\beta$-secretase inhibitory activity of 84.5%. After purification of the $\beta$-secretase inhibitor from R. coreanus using systematic solvent extraction, ultrafiltration, Sephadex G-10 column chromatography, and reverse-phase high performance liquid chromatography (HPLC), a purified $\beta$-secretase inhibitor with $IC_{50}$ inhibitory activity of $6.3{\times}10^3\;ng/mL$ ($1.56{\times}10^{-6}\;M)$ was obtained with a 0.08% solid yield. The molecular mass of the purified $\beta$-secretase inhibitor was estimated to be 576 Da by liquid chromatography-mass spectrometry (LC-MS) and $\beta$-secretase inhibitor also is a new tetrapeptide with the sequence Gly-Trp-Trp-Glu. The purified $\beta$-secretase inhibitory peptide inhibited $\beta$-secretase non-competitively and also show less inhibition on trypsin, however no inhibition on other proteases such as $\alpha$-secretase, chymotrypsin, and elastase.

• Journal of Microbiology and Biotechnology
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• v.19 no.4
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• pp.387-390
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• 2009

Microbial UDP-glycosyltransferases can convert many small lipophilic compounds into glycons using uridine-diphosphate-activated sugars. The glycosylation of flavonoids affects solubility, stability, and bioavailability. The gene encoding the UDP-glycosyltransferase from Bacillus cereus, BcGT-3, was cloned by PCR and sequenced. BcGT-3 was expressed in Escherichia coli BL21(DE3) with a glutathione S-transferase tag and purified using a glutathione S-transferase affinity column. BcGT-3 was tested for activity on several substrates including genistein, kaempferol, luteolin, naringenin, and quercetin. Flavonols were the best substrates for BcGT-3. The enzyme dominantly glycosylated the 3-hydroxyl group, but the 7-hydroxyl group was glycosylated when the 3-hydroxyl group was not available. The kaempferol reaction products were identified as kaempferol-3-O-glucoside and kaempferol-3,7-O-diglucoside. Kaempferol was the most effective substrate tested. Based on HPLC, LC/MS, and NMR analyses of the reaction products, we conclude that BcGT-3 can be used for the synthesis of kaempferol 3,7-O-diglucose.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1149-1154
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• 2010

Liquid chromatography/mass spectrometry using isotope dilution method has been established as a primary method for the measurement of cortisol in human serum. Verification of this method was accomplished by the participation in Consultative Committee for Amount of Substance-Metrology in Chemistry (CCQM) pilot study. Two levels of cortisol certified reference materials were prepared and certified by the established method. They were used as sample materials for the proficiency testing. The expanded uncertainty in the measurement of cortisol in human serum was approximately 1.2% at 95% confidence level. The results of the proficiency testing showed a good precision among the participants, but some bias to the certified values. This means that commercial field laboratories should keep traceability chain to SI unit through available reference measurement procedures and/or available reference materials.

• Nutrition Research and Practice
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• v.2 no.1
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• pp.46-49
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• 2008

Anthocyanin pigments from varieties of black, red and wild rice were identified and quantified to evaluate their potential as nutritional function, natural colorants or functional food ingredients. Anthocyanin extraction was conducted with acidified methanol with 0.1M HCl (85:15, v/v) and identification of anthocyanin, aglycone and sugar moieties was conducted by comparison with purified standards by HPLC, Ultraviolet-Visible absorption spectrophotometer and paper chromatography. Black and wild rice showed three different types of pigments by HPLC whereas red rice variety did not show any anthocyanins. Out of three pigments detected, one (peak 2) was characterized as cyanidin-3-glucoside (C3G) by comparison of spectroscopic and chromatographic properties with an authentic standard, and another (peak 3) was tentatively identified as cyanidin-fructoside on the basis of spectroscopic properties with ${\lambda}_{max}$ of aglycone in 1% HCl methanol at 537 nm, electrospray ionization mass spectra with major ions at 449 and 287 m/z and chromatographic properties. But another pigment (peak 1) has not been characterized. The most abundant anthocyanin in black and wild rice was C3G.

• Journal of Ginseng Research
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• v.37 no.3
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• pp.371-378
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• 2013

Serum and liver metabolites in rats fed red ginseng (RG) were analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. The mass data were analyzed by partial least squares-discriminant analysis (PLS-DA) to discriminate between control and RG groups and identify metabolites contributing to this discrimination. The RG group was clearly separated from the control group on PLS-DA scores plot for serum samples, but not liver samples. The major metabolites contributing to the discrimination included lipid metabolites (lysophosphatidylcholine, acyl-carnitine, and sphingosine), isoleucine, nicotinamide, and corticosterone in the serum; the blood levels of all but isoleucine were reduced by RG administration. Not all metabolites were positively correlated with the health benefits of RG. However, the blood levels of lysophosphatidylcholine, which stimulate various diseases, and long-chain acylcarnitines and corticosterone, which activate the stress response, were reduced by RG, suggesting long-term RG might relieve stress and prevent physiological and biological problems.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3298-3302
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• 2012

Although offline enrichment of phosphorylated peptides is widely used, enrichment for phosphopeptides using $TiO_2$ is often performed manually, which is labor-intensive and can lead to irreproducible results. To address the problems associated with offline enrichment and to improve the effectiveness of phosphopeptide detection, we developed an automated online enrichment system for phosphopeptide analysis. A standard protein mixture comprising BSA, fetuin, crystalline, ${\alpha}$-casein and ${\beta}$-casein, and ovalbumin was assessed using our new system. Our multidimensional system has four main parts: a sample pump, a 20-mm $TiO_2$-based column, a weak anion-exchange, and a strong cation-exchange (2:1 WAX:SCX) separation column with LC/MS. Phosphorylated peptides were successfully detected using the $TiO_2$-based online system with little interference from nonphosphorylated peptides. Our results confirmed that our online enrichment system is a simple and efficient method for detecting phosphorylated peptides.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.181-184
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• 2000

A new photo-alignment material, copoly (PM4Ch-ChMA), copoly (poly (4-methacryloyloxy) chalcone-chalconemethacryl) was synthesized and the electro-optical (EO) characteristics for the photo-aligned vertically aligned (VA)-LC display (LCD) were investigated. The monodomain alignment of the NLC for the photo-aligned VA-LCD by linearly polarized UV exposure on the photo-dimerized copoly (PM4Ch-ChMA) surfaces was observed. Excellent voltage-transmittance characteristics for the photo-aligned VA-LCD by UV exposure for 1 min. on the copoly (PM4Ch-ChMA) surfaces were achieved. The response time of the photo-aligned VA-LCD by UV exposure on for 1 min. the copoly (PM4Ch-ChMA) surfaces was about 39.3 ms. The response time for the photo-aligned VA-LCD decreased with increasing UV exposure time.

• KSBB Journal
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• v.15 no.4
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• pp.398-401
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• 2000

Taxiods inclusive paclitaxel were produced isolated and purified from plant cell cultures of Taxus chinensis in large-scale process. their structures were elucidated by spectroscopic analyses. These compounds were exactly identical as those in previous studies from the other biomasses of Taxus chinensis and also other species. Also the concentrations of these compounds were compared with the concentration of the paclitaxel in various batches of plant cell cultures. As paclitaxel concentration increased at the end of cell cultures. the concentrations of the other paclitaxel derivatives decreased. The profile of these taxoids production can provide information for better understanding of structure-activity relationships and biosynthesis Importantly it can be utilized as an useful parameter for the quality control of paclitaxel production.

• Mass Spectrometry Letters
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• v.3 no.2
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• pp.50-53
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• 2012

After success of sildenafil for the treatment of erectile dysfunction, a large number of its analogues have been approved from FDA. Recently, the illegal dietary supplements which include sildenafil, vardenafil, tadalafil, or analogues of these drugs as ingredient have been widely distributed. Therefore, the determination of the residue of synthetic phosphodiesterase- 5 (PDE-5) inhibitors in dietary supplements is highly required due to indiscriminate and unintentional overdose caused nausea, chest pains, fainting and irregular heartbeat. In this paper, we report a rapid and sensitive analytical method for the simultaneous determination of nine phosphodiesterase-5 inhibitors by liquid chromatography-high resolution mass spectrometry. The present method was found to be accurate and reproducible with 40 ${\mu}g$/g of the limit of quantification for the nine PDE-5 inhibitors. The developed method can be successfully applied to the analysis of the seven illegal dietary supplements.

• Natural Product Sciences
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• v.21 no.1
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• pp.42-48
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• 2015

Lactuca raddeana (Compositae) is used to treat obesity and complications due to diabetes. The five phenolic compounds including chlorogenic acid, chicoric acid, luteolin 7-O-glucoside, luteolin 7-O-glucuronide, luteolin were qualitatively identified by LC-ESI-MS analysis. The contents were quantitatively determined by HPLC, under the condition of a Capcell Pak C18 column ($5{\mu}m$, $250mm{\times}4.6mm\;i.d.$) and a gradient elution of 0.05% trifluoroacetic acid (TFA) and 0.05% TFA in $MeOH-H_2O$ (60 : 40). The contents of chicoric acid (100.99 mg/g extract) and luteolin 7-O-glucoside (101. 69 mg/g extract) were high, while those of other three phenolic substances were very low. The 3T3-L1 adipocyte cells treated with chicoric acid and luteolin 7-O-glucuronide significantly suppressed the accumulation of fat, suggesting they are effective against obesity. Since high level of peroxynitrite (ONOO) causes cardiovascular disease in obese patients, its scavenging activity was also studied.