• Journal of Applied Biological Chemistry
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• v.63 no.3
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• pp.267-274
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• 2020

The dissipation characteristics and kinetics of fungicide mandipropamid and insecticide thiamethoxam in lettuce under greenhouse conditions were investigated at three different lettuce-growing fields for estimating the pre-harvest residue limits (PHRLs). The analytical methods were fully validated for the quantitation of pesticide residues using High-Performance Liquid Chromatography-Photo Diode Array detector or Ultraviolet-Visible Detector and applied to real samples. The lettuces suitable for shipment were harvested during 10 days including pre-harvest interval after treatment at the recommended dose by safe-use guidelines. The initial mean residues in different fields were 6.68-17.87 and 4.96-8.31 mg/kg for mandipropamid and thiamethoxam, respectively, which decreased to 16-54 and 14-44% in 10 days. The clothianidin, a metabolite of thiamethoxam, was detected in <0.02 to 0.37 mg/kg. The dissipation of both pesticides followed first-order kinetics over a period of 10 days after application. Based on the residue data, the mean dissipation rate constant (λ) and biological half-lives (T_1/2) were estimated to be -0.1060 and 6.5 days of mandipropamid and -0.1236 and 5.6 days of thiamethoxam. The PHRLs for lettuce on the 10th and 5th day before harvesting were calculated to be 63.24 and 43.56 mg/kg for mandipropamid, and 44.66 and 25.88 mg/kg for thiamethoxam, with -0.0746 and -0.1091 of the upper 95% confidence intervals of dissipation rate constant, respectively. This work would be useful as guidance for adjusting the shipment date and contribute to stabilizing the income of farmers in Korea.

• Environmental Engineering Research
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• v.18 no.4
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• pp.253-257
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• 2013

Exposure assessment for three major active ingredients used for humidifier disinfectants, polyhexamethylene guanidine (PHMG), oligo(2-(2-ethoxy)ethoxyethyl guanidinium chloride (PGH), and 5-chloro-2-methylisothiazol-3(2H)-one/2-methylisothiazol-3(2H)-one (CMIT/MIT) mixture, was conducted in a bedroom using an air sampler for a refined risk assessment. The experimental site was selected to reflect consumer exposure conditions. Aerosols formed by a humidifier were sampled during 8 hr at 7.5 L/min. Absorbed PHMG and PGH by the sampler were quantified using a spectrophotometric method, and high performance liquid chromatography-ultraviolet detection was used for CMIT/MIT. Three exposure scenarios were assumed for adding humidifier disinfectants to the humidifier water at 1, 2, and 10 times the volume recommended by the product suppliers, and the humidifier was on at its maximum rate of producing aerosols in order to consider reasonable worst-cases. The sampled mass of PHMG and PGH ranged 200 to $2,800{\mu}g$ and 140 to $1,900{\mu}g$, respectively, under different exposure conditions, whereas the absorbed mass of CMIT/MIT was barely detected at the detection limit of 0.11/0.29 mg/L, only at 10 times the recommended level. The resulting risk quotients for PHMG and PGH ranged 1,400 to 20,000 and 1,000 to 13,000, indicating that health risks could be significant. For CMIT/MIT mixture, risk quotients were much smaller than estimated by assuming that they are conservative in the indoor environment, probably due to oxidative reactions. The refined exposure assessment presented here may provide a useful tool for assessing risks posed by active ingredients in spray-type biocidal products.

• Journal of the Korean Applied Science and Technology
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• v.2 no.2
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• pp.39-46
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• 1985

The study was carried out to investigate interrelationships among the acid, peroxide, iodine, thiobarbituric acid values, and changes of fatty acid compositions of some vegetable oils added to soybean milk. A storage temperature of $100^{\circ}C$ was used for the oxidation of the oils, and to determine of variation of the chemical properties and changes of the fatty acid composition, all the samples were carried out in every 8 hours for 40 hours. The changes in fatty acid compositions of the vegetable oils were measured by high performance liquid chromatography. The results obtained were as follow; 1. The acid values of the fresh soybean, corn, and palm oils added to the soybean milk were 0.05, 0.12, and 0.06, whereas those of the oils stored for 40 hours were 0.08, 0.18, and 0.09, respectively. 2. The peroxide values of the fresh soybean, corn, and palm oils added to the soybean milk were 0.3, 1.0, and 0.3, whereas those of the oils stored for 40 hours were 1.1, 1.1, and 0.9, respectively. 3. The iodine values of the fresh soybean, corn, and palm oils added to the soybean milk were 132.7, 124.1, and 57.0, whereas those of the oils stored for 40 hours were 127.3 108.3, and 52.0, respectively. 4. The thiobarbituric acid values of fresh soybean, corn, and palm oils added to the soybean milk were 0.18, 0.05, and 0.02, whereas those of the oils stored for 40 hours were 0.25, 0.19, and 0.07, respectively. 5. The percent content of the major fatty acids of the soybean, corn, and palm oils freshly added to the soybean milk were 2.3%,2.5%,and 25.2%for palmitic acid, 3.2%,3.2%,and 4.8%for stearic acid, 39.7%, 40.7%, and 59.3% for oleic acid, 49.9%, 53.0%, and 10.5% for linoleic acid, and 4.7%, 0.4%, and 0.7% for linolenic acid, respectively. Those of the oils stored for 40 hours were 2.9%, 4,5%, and 36.7% for palmitic acid, 8.5%, 6.8%, and 7.0% for stearic acid, 37.8%, 38.8%, and 49.2% for oleic acid, 46.2%, 49.5%, and 5.8% for linoleic acid, and 4.2%, 0.1%, and 0.1% for linolenic acid, respectively. The fatty acid compositions changed significantly: the amounts of the unsaturated fatty acid decreased considerably. The rsults of the present study demonstrated greater stability of the palm oil as compared with the stability of soybean oil and corn oil added to the soybean milk.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.368-372
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• 1984

This paper deals with a rapid method for determination of ATP and its related compounds in fish and shellfish products using high performance liquid chromatography(HPLC). The HPLC used is a HPLC/ALC-224 equiped with UV-spectrophotometer (254 nm) as detector and integrator (Yanagimoto system-1000). The column used is a stainless steel tubing ($30.0\;cm{\times}3.9\;mm\;i.d.$) packed with ${\mu}-Bon-dapak\;C_{18}$. A mixture of $1\%$ triethylamine-phosphoric acid(pH6.5) was used as an eluent and the flow rate of the eluent was controlled at 2 ml/min. For the separation of ATP and its related compounds, a standard mixture of ATP, ADP, AMP, IMP, inosine and hypoxanthine was subjected to HPLC under the above mentioned conditions. Six peaks were obtained with retention times within 20 min, and elution order were hypoxanthine, IMP, inosine, AMP, ADP and ATP. But 5'-IMP and 5'-GMP fractions were not separated by this method. In generally, IMP content in boiled-dried fish and shellfish products purchased from the market was comparatively higher than that of other nucleotides. Especially, boiled-dried big eye herring marked higher value in IMP content than other boiled-dried ones. Hypoxanthine and inosine were major components of ATP-related compounds in dried products and seasoned-dried ones. And IMP content in seasoned-dried products was higher than that of dried ones. This fact is suggested that a part of IMP in seasoned-dried ones was derived from flavoring matter (MSG, 5'-IMP and 5'-GMP) which is added during the seasoning treatment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.1
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• pp.124-128
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• 2008

This study was aimed to analyze the composition and to quantify the contents of stilbenoids in the leaves and fruits of Morus alba L. using high performance liquid chromatography with phodtodiode array detector and UV detector. Optimal wavelength for the detection of various stilbenoids such as resveratrol, piceatannol, rhapontigenin, astringin, pterostilbene, piceid, rhaponticin and vitisin A was screened by DAD detector and set to 308 nm. Seven kinds of stilbenoids except vitisin A were identified in fruits, while 5 kinds of stilbenoids in leaves. Total stilbenoids contents were $609.15{\pm}7.24$ mg/100 g d.w. in fruits and $188.57{\pm}1.70$ mg/100 g d.w in leaves. Stilbenoids contents in fruits were 3 times higher than those in leaves. Rhaponticin was the most profound stilbene, analyzed to $389.26{\pm}5.22$ mg/100 g d.w. (63.8% of total stilbenoids) in fruits and $99.17{\pm}2.79$ mg/100 g d.w. (52.5% of total stilbenoids) in leaves. Astringin and piceatannol were only detected in fruits and vitisin A was not detected. Contents of piceid and rhaponticin were higher than those of aglycone forms, rhapontigenin and resveratrol.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.2
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• pp.163-168
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• 1984

The composition of amino acids and the related compounds of nucleotides in the dorsal muscle of sweet fish Hemibarbus labeo, Mandarin fish Siniperca scherzeri and read fish Gobius similis was analyzed by amino acid autoanalyzer and high performance liquid chromatography. The result showed that IMP was dominant in the nucleotides of all the dorsal muscle of the fishes and a less amount of UMP, hypoxanthine and AMP was detected. In the free amino acid composition, the important amino acids were taurine and histidine in sweet fish, taurine, glycine and histidine in cornet fish, taurine, histidine and alanine in mandarin fish, taurine, proline and threonine in read fish, respectively, and in all the dorsal muscle of fishes, taurine was the dominant amino acid. In the amino acid compositions of the muscle protein, glutamic acid, glycine, aspartic acid and lysine were reached to 44.0% of total amino acids in sweet fish, glutamic acid, aspartic acid, lysine and glycine were 43.5% in cornet fish, glutamic acid, aspartic acid, lysine and leucine were 43.3%, 43.5% of total amino acids in mandarin fish and read fish, respectively. Glutamic acid was the dominant amino acid in all the fresh fishes.

• Journal of Ginseng Research
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• v.42 no.4
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• pp.447-454
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• 2018

Background: Korean ginseng has been widely evaluated to treat human diseases; however, most studies on Korean ginseng have focused on its root. In this study, polysaccharides [acidic-polysaccharide-linked glycopeptide (APGP) extracted with 90% ethanol and hot water] were prepared from Korean ginseng berries, and their effect on immunosenescence was explored. Methods: The effect of APGP on thymic involution was evaluated by measuring the size of thymi dissected from aged mice. The effect of APGP on populations of immune cells, including natural killer (NK) cells, dendritic cells, age-correlated CD11c-positive B cells, and several subtypes of T cells [CD4-positive, CD8-positive, and regulatory (Treg) T cells] in the thymi and spleens of aged mice was analyzed by fluorescence-activated cell sorting analysis. Serum levels of interleukin (IL)-2 and IL-6 were evaluated by enzyme-linked immunosorbent assay analysis. Profiles of APGP components were evaluated by high-performance liquid chromatography (HPLC) analysis. Results: APGP suppressed thymic involution by increasing the weight and areas of thymi in aged mice. APGP increased the population of NK cells, but showed no effect on the population of dendritic cells in the thymi and spleens of aged mice. APGP decreased the population of age-correlated CD11c-positive B cells in the spleens of aged mice. APGP showed no effect on the populations of CD4- and CD8-positive T cells in the thymi of aged mice, whereas it increased the population of Treg cells in the spleens of aged mice. APGP further decreased the reduced serum levels of IL-2 in aged mice, but serum levels of IL-6 were not statistically changed by APGP in aged mice. Finally, HPLC analysis showed that APGP had one major peak at 15 min (a main type of polysaccharide) and a long tail up to 35 min (a mixture of a variety of types of polysaccharides). Conclusion: These results suggested that APGP exerted an anti-immunosenescent effect by suppressing thymic involution and modulating several types of immune cells.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.77-77
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• 2018

미역의 뿌리부분인 미역귀에는 알긴산과 후코이단 성분이 풍부하고 고혈압과 당뇨등과 같은 성인병을 예방하는데 도움이 된다. 후코이단은 미역과 다시마 같은 갈조류에서 추출된 천연물질로 특히 면역력을 활성화하고 항암작용으로 잘 알려져 있다. 알긴산 등 유용성분이 함유된 것으로 알려진 미역귀의 유용성분을 분석하여, 향후 미역귀를 활용한 제품개발의 기초자료를 제공하고자 본 연구를 수행하였다. 본 연구에 사용된 미역귀는 2015년 12월 완도 금일수산에서 제공받아 연구재료로 활용하였다. AOAC방법에 따라 분석한 미역귀의 일반성분은 수분이 대부분을 차지하였으며, 조섬유와 가용성 무질소물 함량이 높게 나타났다. 이는 시료로 사용한 미역귀가 수확 후 바로 냉동보관 되어서 수분함량이 높은 것으로 보여진다. 유리당은 미역귀 1g에 증류수를 가하여 $60^{\circ}C$에서 4시간 추출 한 후, 원심분리(3,000 rpm, 30 min)하여 $0.45{\mu}m$ membrane filter (Millipore Co., USA)로 여과한 여액을 HPLC (High Performance Liquid Chromatography)를 이용하여 분석한 결과, 미역귀의 유리당은 Galactose 1종만이 검출되었다. 미역귀의 구성아미노산과 유리아미노산은 $0.45{\mu}m$ membrane filter로 여과하여 얻은 여액을 일정량 취하여 AccQ-Tag 시약을 사용하여 유도체화 시킨 후 HPLC로 분석하였다. 미역귀의 구성아미노산은 glutamic acid, aspartic acid, alanine, lysine, threonine, valine, arginine 순으로 높은 함량을 나타내었으며, 유리아미노산은 glutamic acid, alanine, threonine, arginine, lysine 순으로 높은 함량을 나타내었다. 미역귀의 유리아미노산함량은 표고에 비하여 현저히 낮은 함량이 나타났으며, 주요아미노산은 해조류의 풍미를 대표하는 아미노산인 glutamic acid와 alanine으로 나타났다.

• The Korean Journal of Ecology
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• v.22 no.1
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• pp.51-58
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• 1999

Korean native plants and naturalized plants were analyzed for allelochemicals, and their antimicrobial effects were studied. The difference in soluble solid contents between Korean native plants and naturalized species was not significant, and the Korean native plant, Solanum nigrum showed the highest soluble solid content of 90 mg/ml. The ethanol extract of the Korean native plant, Solanum nigrum showed antifungal activity to Aspergillus phoenicis KCTC 1228, with a clear zone of 18 mm, and spore formation was not observed from the treatment. The naturalized plants Ambrosia artemisiifolia var. elatior and Erigeron canadensis showed inhibition of spore formation and the clear zones were at 24 mm and 22 mm, respectively. The clear zones of Aspergillus phoenicis KCTC 1228 treated with ethanol extrats of Phytolacca americana and Rudbeckia bicolor were 22 mm and 19 mm, respectively, and spore formation was observed from the treatment. The Korean native plant, Solanum nigrum and naturalized plants, Phytolacca americana and Ambrosia artemisiifolia var. elatior showed antimicrobial activity against Bacillus sphiaericus 2362, and Bacillus sphiaericus 2297, Bacillus thuringiensis var. subtilis and Baicillus thuringiensis var. cereus. The antimicrobial activity of Ambrosia artemisiifolia var. elatior showed the largest clear zone of 32 mm against Bacillus thuringiensis var. subtilis. In general, the more soluble the solid contents of the extracts, the greater were the antifungal and antimicrobial activities. The phenolic compounds from the Korean native plant, Solanum nigrum and the naturalized species, Phytolacca americana and Ambrosia artemisiifolia var. elatior were analyzed by high performance liquid chromatography. Three phenolic compounds including hydroquinone were identified in Solanum nigrum. In contrast, five and seven phenolic compounds were identified in Phytolacca americana and Ambrosia artemisiifolia var. elatior, respectively. The antifungal activity against Aspergillus phoenicis KCTC 1228 was found to be due to the coumaric and benzoic compounds.

• Journal of Korean Medicine Rehabilitation
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• v.27 no.2
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• pp.29-38
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• 2017

Objectives The present study aimed to investigate the change in marker compounds, anti-oxidative and anti-inflammatory effects of salt-water processed Cortex Eucommiae. Methods To evaluate the influence of processing on anti-oxidant effect of Cortex Eucommiae, changes in total phenol, total flavonoid, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) free radical scavenging, and ferric reducing antioxidant power (FRAP) between processed and raw Cortex Eucommiae were assessed. In addition, nitrite assay was conducted to determine the influence of processing on anti-inflammatory effect of Cortex Eucommiae. Cell viability was also examined as to elucidate whether processing affects cytotoxicity of Cortex Eucommiae. Finally, high-performance liquid chromatography (HPLC) analysis was conducted to monitor changes in pinoresinol diglucoside amount of processed and raw Cortex Eucommiae. Results Salt-water processed Cortex Eucommiae showed higher total phenol and flavonoid amount, compared to raw Cortex Eucommiae. Furthermore, anti-oxidative activity of processed Cortex Eucommiae was improved as discovered in DPPH, ABTS, and FRAP assays. Anti-inflammatory effect of Cortex Eucommiae was also enhanced following salt-water processing, as evidenced in nitrite assay. HPLC analysis found that the amount of pinoresinol diglucoside, widely known as the marker compound of Cortex Eucommiae, increases through salt-water processing. All experiments were performed with non-toxic concentration of Cortex Eucommiae; processing did not affect the cytotoxicity of Cortex Eucommiae up to the currently adopted concentration. Conclusions The present results support that salt-water processing of Cortex Eucommiae is beneficial in terms of marker compound amount, anti-oxidative, and anti-inflammatory activities. Additional investigations are needed to standardize the processing method of Cortex Eucommiae.