• Journal of Embryo Transfer
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• v.23 no.4
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• pp.229-237
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• 2008

Recently, parabens have been believed to act as xenoestrogens, an identified class of endocrine disruptors (EDs). These environmental compounds are the most well-known as preservatives in many commercial products, including food, cosmetics and pharmaceutical industries. It has been demonstrated that the human health risks of parabens result from a long-term exposure to skin in which this chemical group is rapidly absorbed through the skin. On the other hand, parabens are also completely absorbed from gastrointestinal tract. It has reported that these substances possess several biological effects in which inhibitory property involved in membrane transports and mitochondrial functions is considered to be important for their action. Testing of parabens has revealed that estrogen-like activities of these chemicals are much less potent than natural estrogen, $17{\beta}$ estradiol (E2). Additionally, the estrogenicity of individual paraben- compounds is distinct depending upon their biochemical structure. Recent findings of paraben-estrogenic activities have shown that these compounds may affect breast cancer incidence in women, suggesting adverse ecological outcomes of this environmental group on human and animal health. Although the biological and toxicological effects of parabens have been demonstrated in many previous studies, possible mechanism(s) of their action are required to be explored in order to bring the better understanding in the detrimental impacts of parabens in human and wildlife. There have several different types of parabens which are the most widely used as preservatives. These include methyl-paraben, ethylparaben, propylparaben, butylparaben and p-hydroxybenzoic acid, a major metabolite of parabens. In this review, we summarize current database based on in vitro and in vivo assays for estrogenic activities and health risk assessment of paraben- EDs which have been published previously.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1131-1136
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• 2013

Parabens, the esters of p-hydroxybenzoic acid, have been widely used as antimicrobial preservatives in cosmetic products, drugs, and processed foods and beverages. However, some parabens have been shown to have weak estrogenic effects through in vivo and in vitro studies. Because such widespread use has raised concerns about the potential human health risks associated with exposure to parabens, we developed a simultaneous analytical method to quantify 4 parabens (methyl, ethyl, propyl, and butyl) in human urine, by using solid-phase extraction and high-performance liquid chromatography coupled with triple quadrupole mass spectrometry. This method showed good specificity, linearity ($R^2$ > 0.999), accuracy (92.2-112.4%), precision (0.9-9.6%, CV), and recovery (95.7-102.0%). The LOQs for the 4 parabens were 1.0, 0.5, 0.2, and 0.5 ng/mL, respectively. This method could be used for quick and accurate analysis of a large number of human samples in epidemiological studies to assess the prevalence of human exposure to parabens.

• Environmental Engineering Research
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• v.18 no.1
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• pp.29-35
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• 2013

This study noted that the actual mechanism of N-nitrosodimethylamine (NDMA) photodecomposition in the presence of $H_2O_2$ is missing from the previous works. This study investigated a key unknown reactive species (URS) enhanced by the addition of $H_2O_2$ during the photolysis of NDMA with $H_2O_2$, not hydroxyl radicals. In order to provide experimental evidences in support of URS formation, we have mainly used p-nitrosodimethylaniline, methanol, and benzoic acid as well-known probes of ${\cdot}OH$ in this study. Both loss of PNDA and formation of hydroxybenzoic acids were dependent on NDMA concentrations during the photolysis in a constant concentration of $H_2O_2$. In particular, competition kinetics showed that the relative reactivity of an URS was at least identical with ${\cdot}OH$-like reactivity. In addition, the decay of NDMA was estimated to be about 65% by the direct UV light and about 35% by the reactive species or URS generated through the photolysis of NDMA and $H_2O_2$. Therefore, our data suggest that a highly oxidizing URS is formed in the photolysis of NDMA with $H_2O_2$, which could be peroxynitrite ($ONOO^-$) as a potent oxidant by itself as well as a source of ${\cdot}OH$.

• The Korean Journal of Food And Nutrition
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• v.29 no.5
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• pp.767-776
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• 2016

The aim of this study was to evaluate key properties of the prickly pear cactus (Opuntia ficus-indica var. saboten (OFI) ie, levels of key chemicals (carotenoids, flavonoids and polyphenolic compounds as well as phenolic acid) and its antioxidative potential, depending on where the plant had been cultivated in Korea. The levels of flavonoids and polyphenolic compounds in OFI were 55.45~65.32 mg (+)-catechin/g and 149.00~181.15 mg gallic acid/g, respectively. Protocatechuic acid was the most abundant phenolic acid in the ON1 and ON2 (161.90 and $196.25{\mu}g/g$ DW (dry weight)). Nineteen flavonoids were identified and analyzed by LC-ESI-MS in cladodes from OFI. Narcissin was the most abundant flavonoid in all of the samples ($1,241.89{\sim}1,775.10{\mu}g/g$ DW). Capxanthin and zeaxanthin were the most abundant carotenoids in OFI (64.88~128.08 and $48.10{\sim}93.82{\mu}g/g$ DW). The level of DPPH radical and ABTS radical scavenging activities in OFI were 10.78~25.35 and 16.85~34.16 mg AA eq/100 g, respectively. OFI by cultivar has different kind of phenolic acid, flavonoids, and carotenoids. Therefore, dietary intake of cladodes from OFI may be helpful for improving human health.

• Korean Journal of Weed Science
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• v.30 no.4
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• pp.371-379
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• 2010

Crimson clover (Trifolium incarnatum), hairy vetch (Vicia villosa) and rye (Secale cereale) are common leguminous cover crops. Because they contain water-soluble allelopathic substances that show a variable level in tissue depending on growth stage of the plants, the weed inhibition effects are dependent on the growth stage of cover crops. This study investigated the allelopathic effects of crimson clover, hairy vetch and rye on soybean, radish, oilseed rape and lettuce seeds germination and seedling growth. We used extract that were prepared from the shoots of crimson clover, hairy vetch and rye at different growth stages, vegetative growth stage, flowering stage, and fruiting stage. Applications of aqueous extracts from three growth stage of cover crops strongly affected to oilseed rape and lettuce seeds germination but the treatment resulted in a slight inhibition of the germination in soybean and radish. Radical length was more sensitive to aqueous extracts than seed germination rate. Especially, three cover crops extracts at vegetative growth stage highly inhibited seedling root growth of oilseed rape and lettuce by over 80% and 90% respectively. Furthermore, the $GR_{50}$ values were lowest in the treatment of extracts from vegetative growth stage and the level of phenolics was decreased by the order of vegetative growth stage, flowering stage and fruiting stage.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.205-214
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• 1989

The present experiment was conducted to investigate effects of soil conditioner applied on continuous cropping fields of red pepper from 1985 to 1986 in Imsil, Chunbuk province. 1. The ratios of bacteria/fungi (B/F) and actinomycetes/fungi (A/F) in the soils of continuous cultivation were increased with application of phytotoxin decomposers such as deep tillage (De), compost (Co), magnesium lime (Mg), gypsum silicate, and De + Co + Mg. 2. Degradation of phytotoxin (p-hydrohylenyons aeid) in the continuous soils was promoted with application of De, Co, Mg, gypsum, silicate and De + Co + Mg resulting in yield increase. 3. The infection rate plant by phytophthora were decreased with deep tillage and application of compost and magnesium lime and caused the increase of yield (22%) due to the increase of fruit per hill.

• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1158-1163
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• 2006

Bisphenol A (BPA), 2,2-bis(4-hydroxyphenyl) propane, has been widely used as a monomer for production of epoxy resins and polycarbonate plastics, and final products of BPA include adhesives, protective coatings, paints, optical lens, building materials, compact disks and other electrical parts. Since BPA is a toxic chemical to elicit acute cell cytotoxicity and chronic endocrine disrupting activity, the degradation of BPA has been focused during last decades. To overcome the problem of photo-, and chemical-degradation of BPA, in this study, a bacterium that is able to biodegrade BPA, was isolated. The bacterium, isolated froln the soil of plastic factory, was identified as Acinetobacter calcoaceticus (strain BP-2) based on physiological and 16S rDNA sequencing analysis. A. calcoaceticus BP-2 was able to grow in the presence of $1140{\mu}g\;ml^{-1}$ BPA. Biodegradation experiments showed that BP-2 mineralized BPA via 4-hydroxybenzoic acid and 4-hydroxyacetophenone, and average degradation rate was $53.3{\mu}g\;ml^{-1}\;day^{-1}$ under optimal conditions (pH 7 and $30^{\circ}C$). In high density resting cell $(3.5g-dcw.1^{-1})$ experiments, the maximal degradation rate was increased to $89.7{\mu}g\;ml^{-1}\;h^{-1}$. Our results suggest that BP-2 has high potential as a catalyst for practical BPA bioremediation.