• YAKHAK HOEJI
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• v.36 no.3
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• pp.259-268
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• 1992

A procedure for the determination of KR-30075 and its metabolites in plasma and urine by high performance liquid chromatography is described. For the study of pharmacokinetic properties of KR-30075, a new PDE III inhibitor, the plasma concentration and urinary excretion after an oral administration of KR-30075 (4 mg/kg) in the male rat (Sprague Dawley) were determined by high performance liquid chromatography. The best extraction efficiency of KR-30075 and KR-30072 is obtained with ethyl ether adjusted to pH 4.0. Retention times of both KR-30072 and KR-30075 were within 5 min and resolution was complete at the flow rate of 1.0 ml/min. The sensitivity and specificity of this HPLC assay appears to be satisfactory for the pharmacokinetic study of KR-30075 and its metabolites. One-compartment open model with first-order absorption was applied to evaluate the pharmacokinetic parameters of KR-30075 according to Minimum AIC Estimation. $T_{max}$ was 1 hr, $C_{max}$ was $0.789{\pm}0.31\;{\mu}g/ml$ and elimination half $T_{1/2}$ was 6.31 min after oral administration of 4 mg/kg KR-30075 to male rats.

• Natural Product Sciences
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• v.19 no.3
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• pp.236-241
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• 2013

A high-performance liquid chromatography-diode array detector (HPLC-DAD) method was established for quantitative evaluation of nine constituents of Fraxinus rhynchophylla such as four coumarins, esculin (1), fraxin (2), esculetin (3), fraxetin (4), three lignans, syringaresinol 4,4'-O-${\beta}$-diglucoside (5), pinoresinol 4-O-${\beta}$-glucoside (6), pinoresinol (9), one secoiridoid, oleuropein (7), and one coumarinolignan, cleomiscosin C (8). The preferred chromatographic condition was obtained on Phenomenex Gemini-NX (3 ${\mu}m$, C18 110A, $150{\times}4.60$ mm) and the mobile phase was composed of water and acetonitrile using a gradient elution. The wavelength was set at 220 nm. Extraction condition of these constituents in F. rhynchophylla was also optimized through extraction time, extraction solvent and extraction method using established method. From this study, extraction at $70^{\circ}C$ with the mixture of ethanol and water for more than 12 h was suggested to be good extraction condition for these constituents. Quantitation of nine constituents in different F. rhynchophylla samples was also successfully accomplished with the newly established method.

• Journal of the Korean Society of Food Culture
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• v.35 no.3
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• pp.278-284
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• 2020

In this study, biotin (vitamin B7) contents of frequently consumed foods in Korea were determined by using immunoaffinity column in conjunction with high-performance liquid chromatography (HPLC). The biotin contents of 24 foods of plant origin and 27 foods of animal origin were selected. The highest biotin contents in frequently consumed foods of plant origin were found in red beans (Huinguseul; 11.475 ㎍/100 g). On the other hand, biotin was not detected in any varieties of sorghum. For frequently consumed foods of animal origin, salted pollack roe (7.486 ㎍/100 g) showed the highest biotin content. However, beef and fish contained less biotin. All biotin analyses were conducted under analytical quality control. The limits of detection and limits of quantification of biotin were 0.007 and 0.023 ㎍/100 g, respectively, and the accuracy/recovery percentage was 95.35-105.02%. The precision values were 4.041% (repeatability) and 3.835% (reproducibility). Taken together, our data provide reliable data on the biotin contents of frequently consumed foods in Korea.

• Journal of Food Hygiene and Safety
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• v.13 no.1
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• pp.41-46
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• 1998

A postcolumn derivatization method was tried for the simultaneous determination of four major aflatoxins ($B_1,\;B_2,\;G_1,\;and\;G_2$) by high-performance liquid chromatography with fluorescence detection. As compared with a previous precolumn derivatization method, it was found that the postcolumn derivatization combined with an electrochemical cell (Kobra cell) was less time-consuming, safer, improved the sensitivity and selectivity, and provided good recoveries for aflatoxin $B_1$ (88.9%) and $G_1$ (100.5%). This method showed linearity from 10~100 ppb for aflatoxin $B_1\;and\;G_1$, and from 3~30 ppb for aflatoxin $B_2\;and\;G_2$. However, aflatoxin Bz and Gz were not detected satisfactorily although they showed good resolution.

• The Korean Journal of Mycology
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• v.40 no.4
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• pp.299-302
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• 2012

Yeast cell wall extract (YCWE) was treated on leaves and roots of pepper seedlings at the dosage of 4 mg/mL and salicylic acid (SA) production in pepper was detected by ultra high performance liquid chromatography (UHPLC). The SA production in pepper stem was induced by YCWE. SA was produced at the highest level of 20.29 ${\mu}g/g$ after 48 hrs of foliar spray with YCWE, which is 3.7 times higher than that of root perfusion with YCWM. SA production was gradually reduced after 72 hrs of YCWE treatment.

• YAKHAK HOEJI
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• v.43 no.3
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• pp.300-305
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• 1999

A sensitive and efficient assay method was applied to determine the level of glutamic acid (GA) and ${\gamma}-aminobutyric$ acid (GABA) in frontal cortex and hippocampus of rat administrated with ethanol and drugs. The compounds were derivatized with ο-phthalaldehyde (OPA) and 2-mercaptoethanof for precolunm analysis. The condition for the simultaneous determination of GA, GABA and $\beta-aminobutyric$ acid (BABA) by high performance liquid chromatography with electrochemical detection was reverse phase $C_{18}$ column as stationary phase, 0.1 M phosphate buffer containing 0.1 mM $Na_4EDTA$ : methanol = 55:45 (v+v) pH 3.8 as mobile phase and 0.7V electrode voltage. The stability of reaction product of GA, GABA and BABA with OPA could be increased by adding the same volume of polyethylene glycol 400 to reaction mixture. The GABA level in frotal cortex of rat was significantly decreased by the administration of picrotoxin and diazepam, but it was significantly increased by the administration of red ginseng total saponin, N-methyl-D-glucamine and (-)-deprenyl.

• Mycobiology
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• v.42 no.4
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• pp.339-345
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• 2014

During 2011~2013, a total of 729 samples for 19 types of medicinal plant were collected from Seoulyekryungsi in Seoul, Korea, and investigated for the presence of aflatoxins. The samples were analyzed using immunoaffinity column cleanup and high-performance liquid chromatography coupled to a fluorescence detector after post-column derivatization. Aflatoxins were found in 124 out of the 729 analyzed samples: 65 containing aflatoxin B1 (AFB1), 24 with aflatoxin B2 (AFB2), 15 with aflatoxin G1 (AFG1), and 20 samples with aflatoxin G2 (AFG2). The ranges for positive samples were $0.1{\sim}404.7{\mu}g/kg$ for AFB1, $0.1{\sim}10.0{\mu}g/kg$ for AFB2, $0.1{\sim}635.3{\mu}g/kg$ for AFG1, $0.1{\sim}182.5{\mu}g/kg$ for AFG2, and $0.1{\sim}1,043.9{\mu}g/kg$ for total aflatoxins. Most of the medicinal plant samples (721, 98.9%) were below legal limits, but 8 samples exceeded the legal limits of 10 and $15{\mu}g/kg$ established by the Korean standard for AFB1 and total aflatoxins (the sum of AFB1, AFB2, AFG1 and AFG2), respectively.

• Journal of Applied Biological Chemistry
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• v.56 no.1
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• pp.43-48
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• 2013

In this study, methanol extracts from 25 indigenous Korean corals were prepared and their carotenoid constituents were analyzed by high-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (HPLC-APCI-MS). Among them, extracts from nine species showed detectable peaks in the HPLC chromatogram at 450 nm and the ultraviolet/visible spectra exhibiting carotenoid-specific characteristics were chosen. The mass data of carotenoid peaks revealed that only peridinin could be identified based on literature comparison and suggested the potential presence of novel carotenoid structures. This is the first reported investigation of indigenous Korean coral carotenoids and further work is needed to explore the carotenoids and their potential roles in the ecosystem of indigenous Korean corals.

• Journal of Applied Biological Chemistry
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• v.61 no.3
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• pp.227-232
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• 2018

Simultaneous determination of three methoxyflavones, namely, cirsimarin (1), hispidulin (2), and cirsimaritin (3) in selected Korean thistles was performed via reversed-phase high performance liquid chromatography system. Compound 1 was present in all the thistle species examined, whereas 2 and 3 were only detected in Cirsium japonicum and C. japonicum var. maackii (CJM). The concentration of compounds 1-3 in CJM varied according to the time of harvest. Plants collected in the spring (CJMS) and fall (CJMF) had the highest contents of 3 and 1, respectively. A lower content of 2 was observed in CJMF than in CJMS. This indicates that seasonal variation affects the flavonoid content of CJM. The results of this study show that CJM is an excellent source of compounds 1-3 and it can potentially be cultivated for industrial and pharmaceutical applications involving these compounds.

• Journal of Microbiology and Biotechnology
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• v.27 no.7
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• pp.1257-1265
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• 2017

The present study was carried out to investigate the antioxidative and neuroprotective effects of sea buckthorn (Hippophae rhamnoides L.) leaves (SBL) harvested at different times. Reversed-phase high-performance liquid chromatography analysis revealed five major phenolic compounds: ellagic acid, gallic acid, isorhamnetin, kaempferol, and quercetin. SBL harvested in August had the highest total phenolic and flavonoid contents and antioxidant capacity. Treatment of neuronal PC-12 cells with the ethyl acetate fraction of SBL harvested in August increased their viability and membrane integrity and reduced intracellular oxidative stress in a dose-dependent manner. The relative populations of both early and late apoptotic PC-12 cells were decreased by treatment with the SBL ethyl acetate fraction, based on flow cytometry analysis using annexin V-FITC/PI staining. These findings suggest that SBL can serve as a good source of antioxidants and medicinal agents that attenuate oxidative stress.