• Weed & Turfgrass Science
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• v.4 no.4
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• pp.321-329
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• 2015

The present study aimed to evaluate the phytotoxic potential of essential oils. For this purpose, 18 essential oil samples extracted from Korean plants and 64 commercial essential oils were screened for their phytotoxic potential against the seedling growth of Brassica napus L. (rapeseed). Among the 82 samples, 11 commercial oils (cinnamon, citronella, clove, cumin seed, geranium, jasmine, lemongrass, palmarosa, pimento, rose otto and spearmint) strongly inhibited the seedling growth with $GR_{50}$ value < $150{\mu}g\;mL^{-1}$. Major components from these effective essential oils were identified by solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS). GC-MS analyses revealed that the effective samples mainly consist of benzyl benzoate, carvone, citral, citronellol, eugenol, geraniol, D-limonene and terpinene. Subsequently, bioactivity of these individual components was evaluated against the seedling growth of B. napus, Echinochloa crus-galli and Aeschynomene indica. The components from different chemical groups exhibited different potency in inhibiting the seedling growth with varied $GR_{50}$ values ranged from $29{\mu}g\;mL^{-1}$ to > $1000{\mu}g\;mL^{-1}$. In the greenhouse experiment, citral and geraniol completely suppressed the growth of all the tested 10 plants at $100kg\;ha^{-1}$. In conclusion, the individual essential oil components geraniol and citral could be used as natural herbicides for weed management.

• Elastomers and Composites
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• v.47 no.3
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• pp.210-215
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• 2012

Whitening phenomena of the EPDM composites with different inorganic filler compositions which were aged at $90^{\circ}C$ for 7 days in air and tap water atmospheres, respectively, were investigated. The aged samples in tap water containing stearic acid exhibited severe whitening phenomena, while all the samples aged in air did not show any whitening. Depending on the filler compositions, there was no big difference in the whitening phenomena. The whitening materials were analyzed using gas chromatography/mass spectrometry (GC/MS), image analysis, energy-dispersive X-ray spectroscopy (EDX), and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The whitening materials were identified to be salts of stearic acid. The salts of stearic acid were formed by reaction of metal cation in tap water and stearic acid in the sample.

• Korean Journal of Plant Resources
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• v.30 no.1
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• pp.17-21
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• 2017

Since the acetylcholinesterase (AChE) inhibitor is used to treat Alzheimer's disease, the present study aimed to analyze the component with anti-AChE activity from the essential oil of Artemisia iwayomogi (Compositae). The four major components of the essential oil were identified to be camphor (29.8%), borneol (28.0%), eucalyptol (5.81%) and coumarin (5.49%) from a gas chromatography-mass spectrometry (GC-MS). The essential oil and its three components, camphor, borneol, and coumarin, were subjected to anti-AChE assay. The $IC_{50}$ values of the essential oil and coumarin were shown to be $0.298mg/m{\ell}$ and $0.236mg/m{\ell}$, though those of other two components, camphor and borneol, were more than $0.250mg/m{\ell}$. These results suggest that coumarin is an active substance of this essential oil with anti-AChE activity.

• Journal of the Korean Wood Science and Technology
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• v.48 no.5
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• pp.591-607
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• 2020

This study was aimed to investigate the changes of chemical composition of the volatile organic compounds (VOCs) emitted from red pine needles in the process of needle abscission or senescence. The VOCs in intact, senescent, and litter red pine needle samples were analyzed by headspace-solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC/MS). And then, multivariate statistical interpretation of the processed data sets was conducted to investigate similarities and dissimilarities of the needle samples. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to investigate the dataset structure and discrimination between samples, respectively. From the data preview, the levels of major components of VOCs from needles were not significantly different between needle samples. By PCA investigation, the data reduction according to classification based on the chlorophyll a / chlorophyll b (Ca/Cb) ratio were found to be ideal for differentiating intact, senescent, and litter needles. The following OPLS-DA taking Ca/Cb ratio as y-variables showed that needle samples were well grouped on score plot and had the significant discriminant compounds, respectively. Several compounds had significantly correlated with Ca/Cb ratio in a bivariate correlation analysis. Notably, the litter needles had a higher content of oxidized compounds than the intact needles. In summary, we found that chemical compositions of VOCs between intact, senescent, and litter needles are different each other and several compounds reflect characteristic of needle.

• Journal of Chitin and Chitosan
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• v.22 no.3
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• pp.185-193
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• 2017

Red tide Heterosigma akashiwo (H. akashiwo), a microscopic alga of the class Raphidophyceae, causes extensive damage to all marine ecosystems. It is essential to reduce the damage to marine ecosystems for them to be used as a resource. In this study, we used organic solvent fractionation to obtain an ethyl acetate-methanol extract from H. akashiwo (HAEM80) and then evaluated its anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and a zebrafish model. HAME80 markedly inhibited the production of nitric oxide (NO) and prostaglandin $E_2$ ($PGE_2$). It also down-regulated the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and decreased the secretion of interleukin-$1{\beta}$ ($IL-1{\beta}$) in LPS-stimulated RAW 264.7 cells. HAME80 reduced yolk edema and improved the survival rate of LPS-stimulated zebrafish embryos; in addition, the extract significantly reduced the production of ROS and NO and attenuated cell death in this model. Gas chromatography-mass spectrometry (GC-MS) of the extract was used to confirm the identity of peaks 1-20. Taken together, our data suggest that H. akashiwo is a beneficial anti-inflammatory agent.

• Journal of Microbiology and Biotechnology
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• v.29 no.1
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• pp.66-78
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• 2019

In this study, strain KNU17Pc1 was tested for its antifungal activity against Rhizoctonia solani AG-1(IA), which causes banded leaf and sheath blight (BLSB) of maize. KNU17Pc1 was tested further for its broad-spectrum antifungal activity and in vitro plant growth promoting (PGP) traits. In addition, the in vivo effects of KNU17Pc1 on reduction of BLSB severity and seedling growth promotion of two maize cultivars under greenhouse conditions were investigated. On the basis of multilocus sequence analysis (MLSA), KNU17Pc1 was confirmed as P. chlororaphis subsp. aurantiaca. The study revealed that KNU17Pc1 had strong in vitro antifungal activity and was effective toward all in vitro PGP traits except phosphate solubilization. In this study, for the first time, a strain of P. chlororaphis against Colletotrichum dematium, Colletotrichum gloeosporioides, Fusarium oxysporum f.sp. melonis, Fusarium subglutinans and Stemphylium lycopersici has been reported. Further biochemical studies showed that KNU17Pc1 was able to produce both types of phenazine derivatives, PCA and 2-OH-PCA. In addition, solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analysis identified 13 volatile organic compounds (VOCs) in the TSB culture of KNU17Pc1, 1-undecene being the most abundant volatile. Moreover, for the first time, Octamethylcyclotetrasiloxan (D4), dimethyl disulfide, 2-methyl-1,3-butadiene and 1-undecene were detected in P. chlororaphis. Furthermore, this study reported for the first time the effectiveness of P. chlororaphis to control BLSB of maize. Hence, further studies are necessary to test the effectiveness of KNU17Pc1 under different environmental conditions so that it can be exploited further for biocontrol and plant growth promotion.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.2
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• pp.153-162
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• 2022

Objectives: Fused deposition modeling (FDM) 3D printer which is one of the material extrusion (MEX) technologies is an additive manufacturing (AM) process. 3D printers have been distributed widely in Korea, particularly in school and office, even at home. Several studies have shown that nanoparticles and volatile organic compounds (VOCs) were emitted from an FDM 3D printing process. The objective of this study was to identify types of chemicals possibly emitted from FDM 3D printing materials such as PLA (polylactic acid), ABS (acrylonitrile butadiene styrene), nylon, PETG (polyethylene terephthalate glycol), PVA (polyvinyl alcohol), PC (polycarbonate) filaments. Methods: 19 FDM 3D printing filaments which have been distributed in Korea were selected and analyzed VOCs emitted of 3D printing materials by headspace gas chromatography mass spectrometry (headspace GC-MS). Subsamples were put into a vial and heated up to 200℃ (500 rpm) during 20 minutes before analyzing FDM 3D printing filaments. Results: In the case of PLA filament, lactide and methyl methacrylate, the monomer components of one, were detected, and the volume ratio ranged 27~93%, 0.5~37% respectively. In the case of ABS filaments, styrene (50.5~59.1%), the monomer components of one, was detected. Several VOCs among acetaldehyde, toluene, ethylbenzene, xylene, etc were detected from each FDM 3D printing filaments. Conclusions: Several VOCs, semi-VOCs were emitted from FDM 3D printing filaments in this study and previous studies. Users were possibly exposed to ones so that we strongly believe that we recommend to install the ventilation system such as a local exhaust ventilation (LEV) when they operate the FDM 3D printers in a workplace.

• Applied Biological Chemistry
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• v.45 no.2
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• pp.101-107
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• 2002

The essential oils isolated from leaves, flowers, stems, and fruits of Vitex rotundifolia by steam distillation and extraction (SDE) method were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). A total of 76 components detected by GC, 42 components were identified positively by GC-MS and GC co-injection with authentic standards, and 34 components were identified tentatively by mass spectral data only. They included 16 monoterpene hydrocarbons, 30 oxygenated hydrocarbons, 10 sesquiterpene hydrocarbons, 8 oxygenated sesquiterpenes, 3 diterpenes, and 9 miscellaneous components. The major components in the oil from the leaves were ${\alpha}-pinene$ (30.25%), 1,8-cineole (19.89%), sabinene (9.56%), ${\alpha}-terpineol$ (7.94%), ${\beta}-pinene$ (5.69%), and terpinen-4-ol (2.37%), and those in the flower oil were ${\alpha}-pinene$ (25.47%), 1,8-cineole (7.69%), manoyl oxide (6.21%), ${\beta}-pinene$ (4.20%), ${\alpha}-te.pineol$ (3.76%), and sabinene (2.78%). The major components in the oil from the stems were ${\alpha}-pinene$ (13.24%), ${\alpha}-terpineol$ (10.64%), 1,8-cineole (4.40%), manoyl oxide (4.02%), ${\beta}-pinene$ (2.39%), and terpinen-4-ol (2.21%) while those in the oil from the fruits were ${\alpha}-pinene$ (20.24%), 1,8-cineole (11.47%), ${\beta}P-pinene$ (9.79%), ${\alpha}-terpineol$ (7.08%), sabinene (3.68%), and limonene (2.77%). The percentage composition of monoterpenes in the oils from the leaves and the fruits were higher than in those from the flowers and the stems, whereas the oil from the flowers and the stems were characterized by a large content of sesquiterpenes, diterpenes and other unknown high molecular weight components.

• Journal of Microbiology and Biotechnology
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• v.18 no.3
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• pp.497-502
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• 2008

The essential oil from the cones of Pinus koraiensis was prepared after removing the seeds, and its chemical composition analyzed using gas chromatography-mass spectrometry (GC-MS). Hydrodistillation of the P. koraiensis cones yielded 1.07% (v/w) of essential oil, which was almost three times the amount of essential oil extracted from the needles of the same plant. Moreover, the antimicrobial activities of the oil against the growth of Gram-positive bacteria, Gram-negative bacteria, and fungi were evaluated using the agar disc diffusion method and broth microdilution method. Eighty-seven components, comprising about 96.8% of the total oil, were identified. The most abundant oil components were limonene (27.90%), ${\alpha}$-pinene (23.89%), ${\beta}$-pinene (12.02%), 3-carene(4.95%), ${\beta}$-myrcene (4.53%), isolongifolene (3.35%), (-)-bornyl acetate (2.02%), caryophyllene (1.71%), and camphene (1.54%). The essential oil was confirmed to have significant antimicrobial activities, especially against pathogenic fungal strains such as Candida glabrata YFCC 062 and Cryptococcus neoformans B 42419. Therefore, the present results indicate that the essential oil from the cones of Pinus koraiensis can be used in various ways as a nontoxic and environmentally friendly disinfectant.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1086-1091
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• 2008

The antioxidant activities of the extracts of dangyuja (Citrus grandis Osbeck) leaves were evaluated. The highest phenolic content was obtained from the ethyl acetate fraction (EF) (202.1$\pm$0.8 mg GAE/g dried extract) and it exhibited the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. The cytoprotective effects of EF on oxidative damage induced by tert-butyl hydroperoxide (t-BHP) in a human hepatoma cell line, HepG2 cells, were investigated to understand the intracellular antioxidant mechanisms. Treatment of HepG2 cells with EF prior to oxidative stress was found to inhibit reactive oxygen species (ROS) generation, lipid peroxidation, and DNA damage in a dose-dependent manner. Gas chromatography-mass spectrometry (GC-MS) studies on EF resulted in tentative identification of 19 compounds representing 94.3% of the total content. Taken together, these results demonstrated that EF has excellent antioxidant activities and thus dangyuja leaves have great potential as a source for natural antioxidant which can be applied in food products.