• Journal of Environmental Science International
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• v.24 no.11
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• pp.1541-1546
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• 2015

The objective of this research was to evaluate the toxicity of the industial xenobiotic Aroclor 1248 (A) and natural origin substances~elemental sulfur (S80) and oleic acid (OA) and their binary mixtures to V. fischeri bioluminescence during the prolonged exposure time (up to 60 min). The bioluminescence quenching test was used to determine the toxic effects. Full factorial experiment design and multiple regression analysis and the comparison of binary mixture effect with the sum of effects of individual chemicals were used for the evaluation of combined effects of toxicants. The analysis of general trend of mixture toxicity to bioluminescence showed that mixture toxic effects were reversible up to 60 min. Data analysis revealed different joint effects, which were depended on mixture composition. S80 enhanced toxic effect of A and acted additively with synergistic interaction. Hydrophobic OA in mixture with A acted antagonistically and in mixture with sulfur caused an additive effect with antagonistic component of interaction. It was concluded that low concentrations of natural toxic substances present in environmental samples as mixtures of chemicals can define the toxicodynamic character of industrial xenobiotics.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1113-1126
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• 2000

Humic substances present in landfill leachates were extracted and their characteristics were analyzed with respect to landfilling age as a basic study to evaluate the effect of humic substances on the transport and transformation of other pollutants in pollution plume contaminated by landfill leachate. Element analysis of the extracted humic substances were performed. The information on the functional groups of the humic substances molecules were obtained from the spectroscopic analysis using UV-visible, FT/IR, and fluorescence spectroscopy. The structural characteristics of the humic substances were also analyzed by $^1H$ and $^{13}C$ NMR spectroscopy. From the results of the analyses it was found that the structure of the humic substances present in landfill leachates was more aliphatic than aromatic relative to other common humic substances extracted from natural soils and water. The results indicate that the degree of humification of the humic substances were relatively low. The degree of humification, however, was increased as the landfilling age was increased.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2007.04a
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• pp.101-112
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• 2007

• Journal of Korean Society on Water Environment
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• v.21 no.2
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• pp.125-131
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• 2005

Natural organic matter(NOM) is defined as the complex matrix of organic material and abundant in natural waters. It affects the performance of unit operations for water purification. Several kinds of analytical indicators such as DOC, specific ultraviolet absorbance(SUVA), apparent molecular weight (AMW), fractionation and high performance size exclusive chromatography(HPSEC) have been used to understand characteristics and variations of NOM. This study aims to evaluate the characteristics of NOM in the Geum River system comprising with stream flows and reservoirs. It was identified that SUVA denoting the portion of humic substance in water ranged within 1.60~3.36. Using resin adsorbents, dissolved organic carbon(DOC) was fractionated into three classes: hydrophobic bases(HOB), hydrophobic acids(HOA) and hydrophilic substances(HI). HI dominates in all samples, collectively accounting for more than 62% of the DOC. HOA was the second dominated fraction and it varied considerably but accounted for about 30% of the DOC. The distribution of high molecular weight(HMW) measured by HPSEC being used to determine the molecular weight distribution of aquatic humic substances was 40.1% and 38.7% in reservoir and stream flow, respectively. The distribution of low molecular weight(LMW) in stream flow was 13.2% higher than that in reservoir. And apparent molecular weight less than 1KDa, which include the molecular weight of hydrophilic organic matter, occupied with 69.2% and 68.2% in stream flow and reservoir, respectively. While the molecular weight of 1 to 100 KDa including humic substances ranged with 18.6% and 21.6% in stream flow and reservoir, respectively. Seasonal variation of refractory dissolved organic carbon was similar to that of SUVA.

• Korean Journal of Ecology and Environment
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• v.44 no.4
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• pp.358-363
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• 2011

This study investigated the characteristics of natural organic matter(NOM) with tXAD resin and FT-IR in the Yeongsan river system of Gwangju region. NOM fractionation by XAD 8/4 resins was used to classify hydrophobic and hydrophilic substances. FTIR was applied to classify functional groups in the structure of NOM. In the XAD investigation, most of the four site-samples were mainly hydrophilic substances. In March, hydrophobic substances were dominant in the Gwangju 1 site (GJ-1), while hydrophilic substances were dominant for the other sites. In May, samples of all four sites were hydrophilic with a vigorous activity of microorganism due to increasing temperatures. The October results were very similar with those from March. In the FT-IR investigation, most of the broad and large peaks were assigned to the aliphatic group, particularly the OH group, C-H, $C-H_2$, $C-H_3$, and C-O alcohol group. All were related to hydrophilic substances. Other peaks showed the aromatic group, particularly the C=O (Ketone) Group. As a result, there is an identification of NOM in the Yeongsan river system composing mainly of hydrophilic substances and functional groups (OH, C-H etc.) of the aliphatic compound.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.3
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• pp.255-271
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• 2011

ACE-Asia (Asian Pacific Regional Aerosol Characterization Experiment) in spring 2001 was a turning point to trigger international research interest on Asian dust (AD). This basically arose from the lack of research on AD, the important natural phenomenon to characterize the Northeast Asia. In contrast, health risk related to AD has been the primary concern in Korea. Although due in part to severe AD events of 2001~2002, research and mitigation measures on AD in Korea are typically based on the assumption that AD events are increasing in frequency and severity. However, contrary to the trend in Korea, the number of AD days and emission amounts of AD in China have decreased since 1980s. This paper reviews the impacts of AD on ambient air quality and variations in toxic substances during the AD event, reflecting the concern in Korea. While a great amount of dust particles flow into Korea during the AD event, a considerable amount of dust particles are locally generated as well. Since dust particles are mixed with toxic substances as they pass over polluted areas, the levels of toxic substances become lower in dust particles that do not pass over polluted areas. Broadening the research scope on AD is warranted to understand the AD as an important natural phenomenon, irrespective of its associated health risk.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.62-62
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• 2019

Natural substances have various physiological activities. Substances isolated from natural substances are known to be safer and more potent than pharmaceuticals. Potatoes not only act as energy sources but also contain active ingredients such as vitamins and minerals. In particular, the potato contains a large amount of polar compounds, including the saponin in the polar compounds, and the physiological activity of the saponins, such as immunity enhancement, antioxidant and anti-inflammatory is known. In this study, the antioxidative activity of polar compounds from five potatoes was examined by chemical base anti-oxidation assay and cell based anti-oxidation assay. In the chemical base anti-oxidation assay, DPPH experiment showed activity in the order of Hongyoung, Haryung, Seohong, Sumi, and Jayoung. In the LPA experiment, IC50 was lower in the order of Jayoung, Seohong, Sumi, Hongyoung, and Haryung. In the cell based anti-oxidation assay, the smallest amount of ROS was generated when the compound was derived from Haryung and hongyoung, and strong SOD activity was observed in Sumi and Jayoung. The results of this study reveal the antioxidative effect of polar compounds extracted from various kind of potatoes, which will enable the acquisition of new bioactive candidates and the establishment of new profit generation models for farmers.

• Natural Product Sciences
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• v.12 no.4
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• pp.175-192
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• 2006

Screening for the cytotoxicity from plant origin is the first stage for anti-cancer drug development. A variety of terpenoids with exomethylene, epoxide, allyl, $\alpha,\beta-unsaturated$ carbonyl, acetylenes, and $\alpha-methylene-\gamma-lactone$ induces apoptosis and/or differentiation as well as cytotoxicity through the ROS signal transduction pathways. These are found among monoterpenes, sesquiterpenes, triterpenes, flavonoids, coumarins, diarylheptanoids, and even organosulfuric compounds. The most essential characteristics of natural cytotoxic substances is to possess the strong electrophilicity that is susceptible to nucleophilic biomolecules in the cell. Thiol-reductants and superoxide dismutase can block or delay apoptosis. Thus, ROS and the resulting cellular redox-potential changes can be parts of the signal transduction pathway during apoptosis. Disturbance of the balance of oxireduction by the pigment of natural quinones also caused the induction of the differentiation and apoptosis. Saponins with the cytotoxicity are restricted to their monodesmosides, rather than to bisdesmosides. Those saponins exhibited calcium ion-mediated apoptosis in addition to cytotoxicity whereas they showed also differentiation without extracellular calcium ion. The properties on cytotoxicity, apoptosis, and differentiation were assumed to depend on resultant oxidative stress to the cells. In this review, we describe a spectrum of cytotoxic compounds with various action mechanisms.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.162-162
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• 1998

Various natural compounds act as antioxidants in protection against lipid peroxidation. Lipid peroxidation yields a variety of decomposition products which have been implicated in not only decreasing the nutritional value of food, but also in developing an off-flavor and toxic substances. As a source of safer and more effective natural antioxidants of natural origin have been widely investigated. Some Indonesian plants have evaluated for their antioxidative activity, and suggested the possible existence of various antioxygenic compounds in them. We attempted to study such antioxygenic compounds with simple method evaluation. As we are interested in the natural product compounds, we examined of several sample such as edible sea-weeds, and some edible fruits. Sea-weed, Eisenia bicyclis, one of the edible brown algae, exhibited the activity. As a traditional food additive consumed by Indonesian, Garcinia parvifolia is used as taste supplement in region West Sumatra, have been studied. Our current studies on the semi-polar fractions shows the activity by the thiocyanate method test. Another sample, Garcinia mangostana, a famous fruit with sweet taste, the part kernel have also evaluated. The acidic fraction of the extract showed antioxidative activity. Some other active components were found in the neutral and BuOH fractions.

• Journal of the Korea Concrete Institute
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• v.27 no.1
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• pp.75-83
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• 2015

This study discusses the long-term antifungal effect and antifungal performance of Hwangtoh mortars with various natural antifungal substances on five types of mold: Chaetomium globosum, Aspergillus niger, Aureobasidium pullulans, Gliocladium virens, and Penicillium pinophilum, which can be easily detected in the indoors and outdoors of buildings in damp environments. The antifungal performances of various natural antifungal substances extracted from Marjoram, Phytoncide, Thyme, Ginkgo leaves, and Chitosan (oligosaccharide) were investigated on the five types of mold, as a basic experiment. Using the natural antifungal substances selected for the basic experiment, antifungal mortars were made, and their antifungal performance and long-term antifungal effects were also investigated. The results clearly showed that the marjoram extract and their associated mortars had excellent antifungal performance. Also, their long-term antifungal effects were outstanding and at an equivalent level to those of the mortars with organic chemical antifungal agents. The optimum addition rate of the marjoram extract in the mortar was 5% by mass of binder. It was also shown that the phytoncide extract in the mortar needed an addition rate of more than 10% according to the mass of binder, considering the long-term antifungal effect and the antifungal performance.