Nam-Jun Cho

Effect of household processing on pesticide residues in field-sprayed tomatoes

Tomatoes sprayed with chlorothalonil, oxadixyl, and thiophanate-methyl in a greenhouse were cooked to juice and puree using washing, blanching, peeling, and boiling. Washing reduced amounts of chlorothalonil, oxadixyl, and thiophanate-methyl pesticide residues by 92, 52, and 84%, respectively. A concentration of 3.66% chlorothalonil remained in peeled tomatoes, 0.32% in juice, with no detection in puree. Oxadixyl remained at a concentration of 40% in peeled tomatoes, 54% in juice, and 77% in puree, and the remaining concentration of thiophanate-methyl was 6.2% in peeled tomatoes, 8.7% in juice, and 16.2% in puree. Non-systemic pesticide residues on tomato surfaces could be largely removed through washing and peeling. Reductions in levels of systemic pesticides in tomato pulp during boiling were dependent on the physico-chemical characteristics of pesticides.

Quantitative Analysis of Cinnamaldehyde, Cinnamylalcohol and Salicylaldehyde in Commercial Biopesticides Containing Cinnamon Extract Using Gas Chromatography - Flame Ionization Detector

BACKGROUND: In an environment-friendly agriculture, plant extracts have been perceived as alternatives of synthetic pesticides. The Environment-friendly Agriculture Promotion Act of Korea has approved cinnamon extract as a matter for the production of commercial biopesticides. Thirteen commercial biopesticides containing cinnamon extract have been marketed locally. However, the analytical method for the quality control of these biopesticides containing cinnamon extract has not been studied. METHODS AND RESULTS: Cartridge clean-up method for the determination of cinnamaldehyde, cinnamylalcohol and salicylaldehyde in biopesticides containing cinnamon extract was developed and validated by gas chromatography (GC). The clean-up method was optimized with HLB SPE cartridges for the bioactive substance in biopesticides containing cinnamon extract, and the eluate was analyzed by GC. The developed method was validated, and the LOQ and recovery rates of cinnamaldehyde, cinnamylalcohol and salicylaldehyde were 0.139, 0.067 and and 84.2, 86.5 and 82.1%, respectively. The contents of cinnamaldehyde, cinnamylalcohol and salicylaldehyde were analyzed using the developed method in the 13 commercial biopesticides. Results showed 0.06-17.37%,

Determination of Dimethyl Disulfide, Diallyl Disulfide, and Diallyl Trisulfide in Biopesticides Containing Allium Sativum Extract by Gas Chromatography

BACKGROUND: Garlic (Allium sativum) extract has been allowed as commercial biopesticide material for pesticidal activity in the Environmentally-friendly Agriculture Promotion Act. Nine commercial biopesticides containing A. sativum extract have been marketed in Korea. However, the analytical method of the active substances in these materials has not been studied. METHODS AND RESULTS: Cartridge clean-up method for the determination of dimethyl disulfide(DMDS), diallyl disulfide(DADS), and diallyl trisulfide(DATS) in biopesticides containing A. sativum extract was developed and validated by gas chromatography(GC). The clean-up method was optimized using hydrophilic lipophilic balance (HLB) solid phase extraction(SPE) cartridges for the bioactive sulfides in biopesticides containing A. sativum extract, and the eluate was analyzed to quantify the DMDS, DADS, and DATS using the GC. The developed method was validated, and the LOQ and recovery rates of DMDS, DADS, and DATS were 0.226, 0.063, and 0.051 mg L -1 and 80.6, 84.8, and 73.1%, respectively. From the nine commercial biopesticide samples, contents of DMDS, DADS, and DATS were analyzed using the developed method and results showed <LOQ, <LOQ-113.4, and <LOQ-2.3 mg L -1 , respectively. CONCLUSION: The developed method could be used in determining the quality of biopesticides for the manufacture of commercial biopesticides containing A. sativum extract.

Monitoring of Cd, Hg, Pb, and As and Risk Assessment for Commercial Medicinal Plants

BACKGROUND: The current study was carried out to investigate Cd, Hg, Pb and As contaminations in 222 commercial medicinal plants and to estimate the potential health risk through dietary intake of commercial medicinal plants in Korea.METHODS AND RESULTS: The Cd, Hg, Pb, and As in medicinal plants were analyzed by ICP/MS and mercury analyzer.The potential health risk was estimated using risk assessment tools. Total amount of Cd in medicinal plants with 29% samples exceeded the standard limit legislated in `Pharmaceutical Affairs Act` while all plant samples were lower than the standard limit value for As, Hg, and Pb. However, when applying the standard limit for root vegetable (fresh weight) in the Food Sanitation Act, four samples exceeded the standard limit of Pb. For health risk assessment, the values of cancer risk probability were 0.3~5.9×10-7which were less than the acceptable cancer risk of 10-6~10-4for regulatory purpose. Also, Hazard quotientvalues were lower than 1.0.CONCLUSION: Therefore, these results demonstrated that human exposure to Cd, Hg, Pb, and As through dietary intake of commercial medicinal plants might notcause adverse health effects although some medicinal plants were higher than the standard limit values for Cd and Pb.

Effect of Ethanol Extract of Herbal Medicine on Crop Growth Inhibitor

BACKGROUND: Herbal extracts have been screened for their inhibitory effect of seed germination and root development on weeds, but there is a scarcity of reports for crop growth regulation. The objective of this research was to develop a growth inhibitor on Brassica campestris, and its effective extraction method from herbal medicine extract. METHODS AND RESULTS: Eighty four herbal medicine extracts were tested for their plant growth inhibition activity on B. campestris. The alcohol extracts of Artemisia annua, Cinnamomum cassia, and Mentha arvensis inhibited over 30% of germination and the extract of A. annua, and C. cassia inhibited over 70% of radicle growth at 0.1 % w/w treatment. The partially purified extracts of A. annua, and C. cassia with dichloromethane and hexane showed stronger radicle growth inhibition than the crude extracts on B. campestris. The diethyl ether extract of A. annua showed a similar 50% radicle growth inhibition (RI50 = 45 mg/L) to its partially purified extract with dichloromethane or hexane, but the diethyl ether extract of C. cassia showed a worse RI50 than the purified extract. CONCLUSION: The alcohol extracts of A. annua, and C. cassia showed potent radicle growth inhibition properties on B. campestris. Diethyl ether proved to be a good solvent for simple extraction from A. annua.

Study of Kidney Toxicity of Azadirachta Indica Extract for Oral Administration in Rats

BACKGROUND: Azadirachta indica has been widely used as environment-friendly organic materials because of its insecticidal properties. This study was carried out to investigate the acute toxicity and the subacute toxicity of Azadirachta indica extract(AIE) in rats. METHODS AND RESULTS: For the oral acute toxicity test, Sprague-Dawley rats were gavaged with 2.0 g/Kg bw of AIE. The value was greater than 2.0 g/Kg bw for both male and female rats. For the subacute toxicity study, rats were treated with AIE at doses of 0.5, 1.0, 2.0 mg/Kg bw once a day for 4 weeks(n=10 animals per each group). There were no significant changes in body weight, food intake and water consumption observed during the experimental duration. In addition, no difference of relative kidney weight was observed among all treated groups. Serum creatinine level in the AIE 2.0 g/Kg group increased significantly compared with that of control group in male rats, but serum blood urea nitrogen was significantly decreased in a dose-dependent manner (p

Heavy Metal(loid) Levels in Paddy Soils and Brown Rice in Korea

There is an increasing concern over heavy metal(loid) contamination of soil in agricultural areas including paddy soils. This study was conducted to monitor the background levels of heavy metal(loid)s, arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn) in major rice growing soils and its accumulation in brown rice in Korea. The samples were collected from 82 sites nationwide in the year 2012. The mean and range values of As, Cd, Cu, Hg, Ni, Pb, and Zn in paddy soils were 4.41 (0.16-18.9), 0.25(0.04-0.82), 13.24 (3.46-27.8), 0.047 (0.01-0.20), 13.60 (3.78-35.0), 21.31 (8.47-36.7), and 54.10 (19.19-103.0) mg kg-1, respectively. This result indicated that the heavy metal(loid) levels in all sampled paddy soils are within the permissible limits of the Korean Soil Environment Conservation Act. The mean and range values of As, Cd, Cu, Hg, Ni, Pb, and Zn in brown rice were 0.146 (0.04-0.38), 0.024 (0.003-0.141), 4.27(1.26-16.98), 0.0024 (0.001-0.008), 0.345 (0.04-2.77), 0.113 (0.04-0.197), and 22.64 (14.1-35.1) mg kg -1 , respectively. The mean and range BCF (bioconcentration factor) values of As, Cd, Cu, Hg, Ni, Pb, and Zn in brown rice were 0.101 (0.01-0.91), 0.121 (0.01-0.70), 0.399 (0.05-2.60), 0.061 (0.016-0.180), 0.033 (0.004-0.44), 0.005 (0.003-0.013), and 0.473 (0.19-1.07), respectively, with Zn showing the highest. The results show that the levels of all metal(loid)s in all sampled brown rice are generally within the acceptable limit for human consumption.

Influence of Various Biochars on the Survival, Growth, and Oxidative DNA Damage in the Earthworm Eisenia Fetida

Received: 21 October 2014 / Revised: 28 November 2014 / Accepted: 23 December 2014 Copyright c 2014 The Korean Society of Environmental Agriculture This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Diminution of mycotoxins from Fusarium sp. in barley and wheat through post-harvest processing methods

The objective of this study was to analyze mycotoxin contents in Korean barley and wheat infected with Fusarium sp. The major contaminant was determine among deoxynivalenol, nivalenol (NIV), and zearalenone, as well as diminution rate of mycotoxin contents by milling, washing, and boiling processes. NIV was found as a major mycotoxin contaminant in Korean barley and wheat, and bran showed higher contamination level than the inner part in whole infected cereal. The results indicate that the milling process of the diseased barley and wheat showed dramatic diminution rate of 84.4%. Furthermore, the washing on barley reduced mycotoxin infection up to 81.0%, and boiling showed 82.7% diminution effect.

Synthesis of Hapten for Indirect Competitive Immunoassay for Measuring 3,5,6-trichloro-2-pyridinol

Received: 10 September 2015 / Revised: 6 October 2015/ Accepted: 24 October 2015 Copyright c 2015 The Korean Society of Environmental Agriculture This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ORCID