• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.211-215
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• 2004

Near infrared reflectance spectroscopy (NIRS) is a rapid and accurate analytical method for determining the composition of agricultural products and feeds. This study was conducted to determine tocopherol and tocotrienol contents in rice bran by using NIRS system. Total 80 rice bran samples previously analyzed by HPLC were scanned by NIRS and over 60 samples were selected for calibration and validation equation. A calibration equation calculated by MPLS(modified partial least squares) regression technique was developed and coefficient of determination for tocopheyol and tocotyienol content were 0.975 and 0.984, respectively, in calibration sets. Each calibration equation was fitted to validation set that was performed with the remaining samples not included is the calibration set, which showed high positive correlation both in tocopherol and tocotrienol content file. This results demonstrate that the developed NIRS equation can be practically used as a rapid screening method for quantification of tocopherol and tocotrienol contents in rice bran.

• Natural Product Sciences
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• v.18 no.1
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• pp.39-46
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• 2012

In Korea, the leaves of Sonchus brachyotus (Compositae), an edible mountainous vegetable, are traditionally used to treat hepatitis and hemorrhage and are known to have diuretic action. The aqueous ethanolic extract of this plant was selected in our screening experiment using the peroxynitrite ($ONO_2^-$)-scavenging assay, and the present study was performed to qualitatively and quantitatively identify the active compounds from S. brachyotus and validate the present high-permormance liquid chromatography (HPLC) coupled with ultraviolet absorption detection method based on accuracy, precision and repeatability. Five phenolic substances including the main compound, luteolin $7-O-{\beta}-D$-glucuronopyranoside, as well as chlorogenic acid, luteolin 7-O-rutinoside, luteolin $7-O-{\beta}-D$-glucopyranoside, and luteolin, were found in the aqueous ethanolic extract of S. brachyotus. In the HPLC validation experiment, the linearity of the four compounds was established by $R^2$ values of more than 0.999 within the test ranges, and the recovery rate ranged from 98.2 - 105.3%. Luteolin 7-O-glucuronide was a predominant compound (143 mg/g of extract and 18.3 mg/g of the dry weight of plant material) with a potent peroxynitrite-scavenging effect ($IC_{50}$, $1.02{\pm}0.08{\mu}M$). Luteolin and its three glycosides together with chlorogenic acid were qualitatively and quantitatively determined using an HPLC method validated in the present study.

• Food Science of Animal Resources
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• v.37 no.3
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• pp.402-409
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• 2017

A novel peptide having free radical scavenging activity was separated, using an on-line high-performance liquid chromatography (HPLC) - ABTS screening method, from bovine skim milk fermented by Lactococcus lactis SL6 (KCTC 11865BP). It was further purified using reverse phase-HPLC (RP-HPLC) and sequenced by RP-HPLC-tandem mass spectrometry. The amino acid sequence of the identified peptide was determined to be Phe-Ser-Asp-Ile-Pro-Asn-Pro-Ile-Gly-Ser-Glu-Asn-Ser-Glu-Lys-Thr-Thr-Met-Pro-Leu-Trp (2,362 Da), which is corresponding to the C-terminal fragment of bovine ${\alpha}_{s1}$-casein (f179-199). The hydroxyl radicals scavenging activity ($IC_{50}$ $28.25{\pm}0.96{\mu}M$) of the peptide chemically synthesized based on the MS/MS data showed a slightly lower than that of the natural antioxidant Trolox ($IC_{50}$ $15.37{\pm}0.52{\mu}M$). Furthermore, derivatives of the antioxidant peptide were synthesized. The antioxidative activity of the derivatives whose all three proline residues replaced by alanine significantly decreased, whereas replacement of two proline residues in N-terminal region did not affect its antioxidative activity, indicating that $3^{rd}$ proline in C-terminal region is critical for the antioxidative activity of the peptide identified in this study. In addition, N-terminal region of the antioxidant peptide did not show its activity, whereas C-terminal region maintained antioxidative activity, suggesting that C-terminal region of the peptide is important for antioxidative activity.

• Korean Journal of Veterinary Service
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• v.27 no.1
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• pp.17-29
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• 2004

A multiresidual analysis was performed to determine 12 sulfonamides(sulfacetamide, sulfadiazine, sulfisomidine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethazine, sulfamonomethoxine, sulfisoxazole, sulfamethoxazole, sulfaquinoxaline, and sulfadimethoxine) in beef and pork simultaneously. The multiresidual analysis for the sulfonamides currently used was able to analyze 5 kinds of sulfonamides at the same time. The method of this 12 sulfonamides multiresidual analysis in this study was matrix solid-phase dispersion(MSPD) by high performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC/MS). The recovery rate of the materials was measured by MSPD method with 3 different extraction solvents; Dichloromethane, DCM: Ethylacetate(3:1), DCM:EA(9:1). Also, samples (84 beef and 205 pork samples) which were positive by EEC-4 plate test from 2001 to 2003 were tested to investigate the kinds of sulfonamides using HPLC. The results from the study were as follows; 1. The recovery rate of the materials was measured by MSPD method with 3 different extraction solvents; Dichloromethane, DCM:Ethylacetate(3:1), DCM:EA(9:1). The method of extraction solvent with DCM:ethyl acetate(9:1) was the most excellent(87.7∼99.3%) in separation and reappearance. 2. In the LC/MS analysis. of sulfonamides, signal to noise ratio was showed relatively high in the positive mode and special ion in the quality analysis was determined via [M+H]$\^$+/ and m/z 156. A spectrum of sulfonamides was showed from all 12 sulfonamides. 3. The samples positive by the EEC-4 plate, a screening test method, were categorized by sulfonamides through Charm II and confirmed the kinds of sulfonamides through HPLC. 1) Among 84 beef samples positive by EEC-4 plate, 20 samples were positive by Charm II and identified as 7 sulfamethazine, 9 sulfadimethoxine, 1 sulfamonomethoxine and 3 unknown status. 2) Among 205 pork samples positive by EEC-4 plate, 42 samples were positive by Charm II and identified as 19 sulfamethazine, 1 sulfadimethoxine, 4 sulfamonomethoxine and 5 unknown status.

• Journal of Microbiology and Biotechnology
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• v.17 no.10
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• pp.1629-1637
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• 2007

An immunochromatography (ICG) strip test using a nanocolloidal gold-antibody probe was developed and optimized for the rapid detection of aflatoxin B1 (AFB1). A monoclonal antibody specific to AFB1 was produced from the cloned hybridoma cell (AF78), coupled with nanocolloidal gold, and distributed on the conjugate pad of the ICG strip test. The visual detection limit of the ICG strip test was 0.5 ng/ml, and this method showed a cross-reaction to aflatoxin B2, G1, and G2. In total, 172 grain and feed samples were collected and analyzed by both the ICG strip test and HPLC. The results of the ICG strip test showed a good agreement with those obtained by HPLC. These results indicated that the ICG strip test has a potential use as a rapid and cost-effective screening tool for the determination of AFB1 in real samples and could be applied to the preliminary screening of mycotoxin in food and agricultural products, generating results within 15 min without complicated steps.

• Korean Journal of Weed Science
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• v.18 no.4
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• pp.348-355
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• 1998

This study was conducted to identify allelopathic compounds in rye and oat straw extracts by HPLC analysis. These extracts were analyzed with 12 standard chemicals including salicylic acid. 11 chemicals in rye extract except for naringin and in oat extract except for catechin were identified. Salicylic acid(8.34mg/g) in rye straw extracts and naringin(7.50mg/g) in oat straw extracts among these standard chemicals were identified as the largest amount substance. The germination of Chenopodium ablum seeds was significantly inhibited by these chemicals at $10^{-3}$ and $10^{-4}M$ concentrations as compared to control. Salicylic acid in rye and naringin in oat were considered as the major allelopathic substances although allelopathy may be caused by an interaction of many substances. Yet many unidentified chemical compounds are present in both extracts.

• Applied Biological Chemistry
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• v.47 no.2
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• pp.164-169
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• 2004

In the course of our screening for biocontrol agent (BCA) against Streptomyces scabiei and S. turgidiscabies causing potato scab using 5,000 actinomtcete isolates, 9 antagonistic strains were selected as BCA candidates through in vitro and in vivo assay. An antagonistic strain, A020645 was highly resistant to some pesticides and antibiotics such as dazomet and mancozeb and showed high control value in vivo. Two bioactive compounds (compound A, B) were purified by anion exchange chromatography, solid phase (ODS) extraction, TLC and reverse phase HPLC. Their chemical structures are now thought to be nucleoside derivative as determined by $^1H-NMR$ data analysis. Their full chemical structures would be elucidated through $^{13}C-NMR$, HMQC and HMBC analyses. Further studies will be focused on fitness in soil and formulation of the BCA candidates.

• Journal of Food Hygiene and Safety
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• v.5 no.3
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• pp.131-138
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• 1990

Aflatoxins is a chemically diverse group of toxic secondary metabolites that are produced by fungi and often occur in agricultural commodities. Because of their wide range of toxic effects, Aflatoxins cause severe economic losses to farmers and livestock producers and pose a health to human consuming contaminated foods. Long term prospects for biotechnological control of Aflatoxins require elucidation of the specific steps and regulation of their biosynthetic pathways . Aflatoxin determinations can be approached many ways. It is essential to safely handle all experimental materials associated with aflatoxin analysis or aflatoxigenic fungi Visual screening of suspect samples, base on the presence of conidial head of the aspergillus flavus group, and screening samples for the presence of bright greenish yellow flourescence are not chemical tests and such screening techniques may allow aflactoxin contaminated lots into commerce. Microcolumn screening procedures should always be used in conjunction with a quantitative method. Several thin layer chromatography(TLC) and high performance liquid chromatography(HPLC) methods are suitable for quantitation and are in general use. Immunochemical Methods such as the ELISA or affinity column chromatography methods are being rapidly developed. The chemical and immunochemical methods can be reliable if care is taken, using suitable controls and personnel that are well trained . All analytical laboratories should stress safety and include suitable analytical validation procedure. Especially a worldwide enquiry was undertaken in recent to obtain up-to-date information about aflatoxin legislation in as many countries of the world as possible. The information concerns aflatoxin in foodstuffs. aflatoxin MI in dairy products, aflatoxins in animal feedstuffs. Limits and regulations for aflatoxin have been expended in recent with more countries having legislation on subject, more products, and more aflatoxins covered by this legislation.

• The Journal of Korean Medicine
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• v.18 no.1
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• pp.187-197
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• 1997

Major separation for the active ingredients and characterization of chemical properties in conjunction with screening test on animal were performed in order to analyze and standardize Ligustici Rhizoma or Angelicae Tenuissimae Radix as an important oriental herbal medicine for antiphlogistic or an important oriental herbal medicine for antiphlogistic or an anodyne. Furthermore the structure, composition and contents of ingredients for essential oil in Angelicae Tenuissimae Radix(Suckpo, Korea) were determined by means of Ge/MS followed by screening test on Z-ligustilide(82%) known as major ingredient as well as butylidenephthalide collected by HPLC with normal phase semiprep-column. The total active ingredient in Ligustici Rhizoma from China or Angelicae Tenuissimae harvested at Choonyang(Kyungnam, Korea), Jungsun(Kangwon, Korea), Suckpo(Kyungnam Korea), Youngchun(Kyungnam, Korea) have been determined showing higher abundant for three times on the product in Korea compared to that in China. In addition, the major component in Ahgelicae Tebyussunae Radux extract was found to be Z-ligustilide(70-80%) which is very different from that in Ligustici Rhizoma senkyunolide(39%) as major species. For screening test of Ligustici Rhizoma or Angelicae Tenuissimae Radix extracts toward the target animal, the efficiency has been shown the similarity on both extracts. Taking into account the level of ingredient, the total efficiency may be three times higher on Angelicae Tenuissimae Radix in Korea compared to Ligustici Rhizoma in China. As a result of present study, it is preferable to distinguish between Ligustici Rhizoma and Angelicae Tenuissimae Radix for better usage of oriental herbal medicine because of very different composition and abundant in spite of their similar screening effect.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.2
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• pp.67-73
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• 2018

$[^{11}C]PIB$ synthesis has been performed by a loop-methylation and HPLC purification in our lab. However, this method is time-consuming and requires complicated systems. Thus, we developed an on-cartridge method which simplified the synthetic procedure and reduced time greatly by removing HPLC purification step. We compared 6 different cartridges and evaluated the $[^{11}C]PIB$ production yields and specific activities. $[^{11}C]MeOTf$ was synthesized by using TRACERlab FXC Pro and was transferred into the cartridge by blowing with helium gas for 3 min. To remove byproducts and impurities, cartridges were washed out by 20 mL of 30% EtOH in 0.5 M $NaH_2PO_4$ solution (pH 5.1) and 10 mL of distilled water. And then, $[^{11}C]PIB$ was eluted by 5 mL of 30% EtOH in 0.5 M $NaH_2PO_4$ into the collecting vial containing 10 mL saline. Among the 6 cartridges, only tC18 environmental cartridge could remove impurities and byproducts from $[^{11}C]PIB$ completely and showed higher specific activity than traditional HPLC purification method. This method took only 8 ~ 9 min from methylation to formulation. For the tC18 environmental cartridge and conventional HPLC loop methods, the radiochemical yields were $12.3{\pm}2.2%$ and $13.9{\pm}4.4%$, respectively, and the molar activities were $420.6{\pm}20.4GBq/{\mu}mol$ (n=3) and $78.7{\pm}39.7GBq/{\mu}mol$ (n=41), respectively. We successfully developed a facile on-cartridge methylation method for $[^{11}C]PIB$ synthesis which enabled the procedure more simple and rapid, and showed higher molar radio-activity than HPLC purification method.