• Natural Product Sciences
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• v.9 no.4
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• pp.213-219
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• 2003

Five aromatic compounds, of which two are new glucosides, and six flavonols were isolated and identified for the first time from the flower heads and aerial shoots of Helichrysum conglobatum (Asteraceae). Their structures were established on the basis of chemical and spectroscopic methods including UV, MS, 1D- and 2D-NMR. Some fractions and isolates were screened for anti-microbial activities. This is the first report of the isolation of the chemical constituents of this species.

• Natural Product Sciences
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• v.4 no.4
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• pp.185-202
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• 1998

A large number of chemical constituents have been reported from the Himalayan yew [Taxus baccata (Linn) or T. wallichiana (Zucc)]. These constituents are mainly taxoids and phenolics. Taxol, a lead anticancer agent, is the most important constituent. Other compounds have also been found to possess interesting biological properties. The literature concerning the chemistry and bioactivity of the constituents of the Himalayan yew has been briefly reviewed.

• Journal of the Korean Society of Tobacco Science
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• v.25 no.2
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• pp.95-102
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• 2003

To get the informations of quality uniformity of threshed burley tobacco produced from 1997 to 2001 and processed at various leaf processing factories, chemical constituents contents and coefficient of variation(C.V.) were analysed. The average chemical constituents contents of 12 grades during 5 years ranged as follows; nicotine 1.76～2.66%, total nitrogen 4.15～4.80%, crude ash 21.6～22.4% and chlorine 1.08～1.20%. The variations of chemical constituents contents among crop years was higher in nicotine while lower in crude ash. The nicotine content of upper leaves were influenced negatively by rainfalls, while total nitrogen content were influenced positively by air temperature and sunshine hours during July. The C.V. of chemical content in same grade was higher in chlorine and nicotine while lower in crude ash. The ratio of C.V. among leaf tobacco processing factories/C.V. of total sample in same grade was high in nicotine. To reduce the C.V. of chemical constituents, it is recommendable to thresh the leaf tobacco at one processing factory. When the leaves being processed at one factory, the decreasing effect of deviation was higher in nicotine, particularly.

• Natural Product Sciences
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• v.11 no.1
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• pp.1-9
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• 2005

The chemical constituents from Hedyotis diffusa Willd and their pharmacological activities were summarized. It has been known data that this herb contains anthraquinones, terpenoids, steroids, flavonoids, organic acid, and polysaccharides. The studies of pharmacology have shown that Hedyotis diffusa Willd possess various levels of activities such as anticancer, anti-inflammatory, immunostimulatory, antioxidative, neuroprotective, and hepatoprotective activities.

• Natural Product Sciences
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• v.1 no.1
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• pp.70-85
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• 1995

The chemical constituents of the soft corals of Lobophytum are reviewed.

• The Korea Journal of Herbology
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• v.36 no.6
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• pp.47-61
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• 2021

Objectives : 'Steaming and drying' is a traditional processing method that has been used to produce Suk-ji-hwang (熟地黃; Rehmanniae Radix Preparata) from Ji-hwang (地黃, the fresh root of Rehmannia glutinosa Liboschitz ex Steudel; Rehmanniae Radix). The steaming and drying process, which is proceeded in heating and moisturizing conditions, plays a crucial role in the change of therapeutic effect of Ji-hwang, presumably due to the modification of its chemical constituents. In this article, the chemical influence of the 'Steaming and drying' process was investigated for understanding the underlying mechanism of chemical modification of Ji-hwang. Methods : The articles regarding the modifications of chemical constituents of Ji-hwang during the 'Steaming and drying' process were collected and analyzed to investigate the influence of the processing to Ji-hwang. Results : The results indicated that iridoid glycosides were degraded to their aglycones and sugars, and such degradations occurred faster at a high pressure than at an atmospheric pressure during the process. The contents of catalpol, ajugol, and acteoside were decreased, while those of rehmannioside A and D were slightly increased during the repeated processing. The contents of oligosaccharides, namely sucrose, maltose, raffinose, and stachyose (except for manninotriose), were decreased, while those of monosaccharides, glucose and fructose, were increased by the repeated processing. Conclusions : These results demonstrate that the 'Steaming and drying' process influenced the chemical constituents of Ji-hwang and provide probable basis for the therapeutic modification of Suk-ji-hwang after the processing of Ji-hwang.

• Safety and Health at Work
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• v.11 no.4
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• pp.500-508
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• 2020

Background: Research on the status of many chemicals used in the semiconductor industry is needed. The purpose of this study was to describe the overall status of chemical use in the semiconductor industry in Korea and to examine it from a health perspective. Methods: Data on the status of chemical use and safety data sheets at 11 of 12 major semiconductor workplaces in Korea were collected. The number of chemical products and chemical constituents, quantities of chemicals, and trade secret ingredients used, as well as the health hazards were examined. Results: On average, 210 chemical products and 135 chemical constituents were used at the surveyed workplaces. Among all chemical products, 33% (range: 16-56%) contained at least one trade secret ingredient. Most of the trade secret ingredients were used in the photolithography process. Several carcinogens, including sulfuric acid, chromic acid, ethylene oxide, crystalline silica, potassium dichromate, and formaldehyde were also used. Only 29% (39 of 135) of the chemical constituents had occupational exposure limits, and more than 60% had no National Fire Protection Association health, safety, and reactivity ratings. Based on the aforementioned results, this study revealed the following. First, many chemical products and constituents are being used in the semiconductor industry and many products contained trade secret ingredients. Second, many products contained significant amounts of carcinogenic, mutagenic, and reproductive toxicant materials. Conclusion: We conclude that protecting workers in the semiconductor industry against harm from chemical substances will be difficult, due to widespread use of trade secret ingredients and a lack of hazard information. The findings of the status of chemical use and the health and safety risks in semiconductor industry will contribute to epidemiological studies, safe workplace, and worker health protection.

• Korean Journal of Pharmacognosy
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• v.25 no.4 s.99
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• pp.342-347
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• 1994

Soybean and beanpaste have been used as ore of the important food in Korea. Beanpaste is made from soybean(seed of Glycine max $M_{ERRIL}$, Leguminosae) by traditional fermentation. It was expected that the secondary metabolites might be formed by the action of some microorganisms or enzymes on the constituents primarily contained in soybean during manufacturing or storage of beanpaste. A systematic investigation on the chemical constituents was carried out. As a result, sterol glycoside named daucosterin, lipo-daucosterin have been isolated from the lipid fraction soybean and their structures elucidated basis of chemical and physicochemical evidences. A ratio of composition of the lipid constituents in soybean and beanpaste were estimated.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.2
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• pp.131-136
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• 2008

With the development of diverse agricultures worldwide, biofortified rice noted for its preferable marketability and palatability plays an important role in the world's agricultural economics and rice breeding programs. In this report, several $M_5$ of T-DNA inserted lines derived from the donor cultivars, 'Hwayong' and 'Dongjin', were selected for high or low protein, high lipid and low amylose content, respectively. The coefficients and ranges of variation for the chemical constituents between $M_4$ and $M_5$ T-DNA inserted lines were evaluated in comparison with those of the donor varieties. Results indicated that T-DNA insertion might be an effective way to generate useful variations for chemical composition of rice grains which could be used for the development of biofortified rice cultivars.

• Journal of the Korean Society of Tobacco Science
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• v.26 no.1
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• pp.17-26
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• 2004

This study was conducted to get the informations for reducing the variation of chemical contents of leaf tobacco. The contents and variations of some chemical constituents of leaf(Leaf, Grade 2) produced in various growing areas from 1999 to 2003 and the effects of meteorological factors on the chemical constituents of leaf were analysed. The contents of analysed constituents of leaf showed high significant differences among crop years in flue-cured and burley, particularly the variation among crop years were higher in chlorine and nicotine contents while lower in total nitrogen content. There were significant differences among growing areas in nicotine and total sugar contents of flue-cured leaf and chlorine content of burley leaf. The total sugar content were negatively correlated to the nicotine and total nitrogen contents in flue-cured leaf. The average air temperature in June and July were positively correlated to the nicotine content of leaf while negatively to total sugar, and the precipitation in May were negatively correlated to the nicotine while positively to total sugar.