• Korean Journal of Pharmacognosy
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• v.52 no.4
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• pp.203-207
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• 2021

LC/MS approach targeting secondary metabolites of bacterial strain resulted in the discovery of boholamide A (1), from the culture of marine actinomycete strain which was isolated from a tidal mudflat in Muan, Republic of Korea. Boholamide A (1), a cyclodepsipeptide with HDMN, APD, glycine, and valine was structurally determined by using 1D/2D NMR spectroscopy, mass spectrometry and UV spectroscopy. Boholamide A (1) showed the inhibitory activity against Bacillus subtilis, with IC₅₀ value of 0.08 mM.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.350-356
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• 2011

Environment-friendly agro-materials tend to be preferred to chemical insecticides recently. For this reason, many studies were conducted to develop environment-friendly insecticides containing natural materials. The purpose of this study was to assess ecotoxicity for 5 plant essential oils (Thyme white, Clove bud, Cassia, Lavender, Lemon eucalyptus) expected to prevent from pests and be used for agro-materials. Target species used to assess acute toxicity were aquatic invertebrate (Daphina magna), fish (Oryzias latipes), honeybee (Apis mellifera L.) and earthworm (Eisenia fetida). The EC50 value, toxicological responses of thyme white, clove bud, and cassia to Daphina magna were 2.5, 2.8, and $6.9mg\;L^{-1}$ respectively and these values were moderately toxic according to standard of USEPA. $EC_{50}$ of Lavender and lemon eucalyptus were >$10mg\;L^{-1}$ then they were considered as slightly toxicity. In case of acute toxicity test to fish, $LC_{50}$ of thyme white and cassia were 6.7 and $7.5mg\;L^{-1}$ each other. The other plant essential oils indicated $LC_{50}$ >$10mg\;L^{-1}$. Acute contact and oral toxicity test to Honeybee were conducted. As a result, $LD_{50}$ of all essential oils were >$100{\mu}g$ a.i. $bee^{-1}$ in both of tests. In case of acute toxicity test to earthworm, $LC_{50}$ of thyme white, clove bud, cassia, lavender, and lemon eucalyptus were 149, 230, 743, 234, and $635mg\;kg^{-1}$, respectively. In conclusion, if the safety for earthworm is confirmed, 5 plant essential oils are expected to be use for environment-friendly insecticide materials with low risk against ecosystem and contribute to developing environment-friendly agro-materials.

• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.570-577
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• 2011

We developed insect-resistant GM rice(Bt transgenic rice) by inserting the mCry1Ac1 a modified gene from the soil bacterium, Bacillus thuringiensis. The Bt transgenic rice expressing the Bttoxin mCry1Ac1 was tested for the effects on survival of Misgurnus anguillicaudatus and Cyprinus carpio, commonly used as a model organism in ecotoxicological studies. M. anguillicaudatus and C. carpio fed 100% ground rice in suspension, using either Bt rice or non-GM counterpart rice(Nakdong). The Bt rice used for the test were confirmed to have the mCry1Ac1 gene expression by the immuno-strip and ELISA analysis. Feeding test showed that no significant differences in cumulative immobility and abnormal response of M. anguillicaudatus and C. carpio fed on between Bt rice and non-GM counterpart rice. The 96hr-LC₅₀ values showed no difference between Bt rice(>1,000mg/L) and non-GM rice(>1,000mg/L). We concluded that there was no significant difference in toxicity for non-target organisms(M. anguillicaudatus and C. carpio) between Bt rice and non-GM counterparts.

• Journal of Food Hygiene and Safety
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• v.36 no.3
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• pp.220-227
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• 2021

Fluoroimide is a fungicide and is also used as a pesticide for persimmons and potatoes. The established fluoroimide pesticide analysis method takes a long time to perform and uses benzene, a carcinogen. In addition, a lower limit of quantification is required due to enforcement of the Positive List System. Therefore, this study aimed to improve the analysis method for residual fluoroimide to resolve the problems associated with the current method. The analytical method was improved with reference to the increased stability of fluoroimide under acidic conditions. Fluoroimide was extracted under acidic conditions by hydrogen chloride (4 N) and acetic acid. MgSO₄ and NaCl were used with acetonitrile. C₁₈ (octadecylsilane) 500 mg and graphitized carbon black 40 mg were used in the purification process. The experiment was conducted with agricultural products (hulled rice, potato, soybean, mandarin, green pepper), and liquid chromatograph-tandem mass spectrometry was used for the instrumental analysis. Recovery of fluoroimide was 85.7-106.9% with relative standard deviations (RSDs) of less than 15.6%. This study reports an improved method for the analysis of fluoroimide that might contribute to safety by substituting the use of benzene, a harmful solvent. Furthermore, the use of QuEChERS increased the efficiency of the improved method. Finally, this research confirmed the precise limit of quantification and these results could be used to improve the analysis of other residual pesticides in agricultural products.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.539-545
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• 2014

Styrene-acrylamide co-polymer was immobilized on porous partially sub-$2{\mu}m$ silica monolith particles and inner surface of fused silica capillary ($50{\mu}m$ ID and 28 cm length) to result in ${\mu}LC$ and CEC stationary phases, respectively, for separation of anomeric D-glucose derivatives. Reversed addition-fragmentation transfer (RAFT) polymerization was incorporated to induce surface polymerization. Acrylamide was employed to incorporate amide-functionality in the stationary phase. The resultant ${\mu}LC$ and CEC stationary phases were able to separate isomers of D-glucose derivatives with high selectivity and efficiency. The mobile phase of 75/25 (v/v) acetonitrile (ACN)/water with 0.1% TFA, was used for HPLC with a packed column (1 mm ID, 300 mm length). The effects of pH and ACN composition on anomeric separation of D-glucose in CEC have been examined. A mobile phase of 85/15 (v/v) ACN/30 mM sodium acetate pH 6.7 was found the optimized mobile phase for CEC. The CEC stationary phase also gave good separation of other saccharides such as maltotriose and Dextran 1500 (MW~1500) with good separation efficiency (number of theoretical plates ~300,000/m).

• Korean Journal of Medicinal Crop Science
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• v.28 no.4
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• pp.245-253
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• 2020

Background: Research on hot water extracts of medicinal plants that are easily applicable in the clinical setting is essential. To confirm the anti-inflammatory-related active compounds present in the hot water extract of Eriobotrya japonica leaves, ability to inhibit nitric oxide (NO) production was measured and active compounds isolated from the extract were analyzed. Methods and Results: Sovent fractionation by solvent was performed to identify the active compounds present in the hot water extract, and the ability of the extract and the fractions obtained to inhibit NO production was measured. Subsequently, based on the results of liquid chromatography (LC) profile analysis of the n-butanol fraction that had a relatively high inhibitory ability of NO production, six subfractions were separated around the main peak. Among the separated subfractions spectra from mass spectroscopy (MS) were analyzed and standard comparisons were performed on the compounds of the three main peaks on the chromatogram. NO production inhibitory activity of subfraction 2 identified as neochlorogenic acid was the highest with an IC₅₀ of 18.49 ㎍/㎖ followed by that of subfraction 5 identified as cryptochlorogenic acid with IC₅₀ of 25.82 ㎍/㎖. Conclusions: Our result, it was confirmed that several caffeoylquinic acids, including neochlorogenic acid and cryptochlorogenic acid present in the hot water extract of E. japonica leaves have an important role as compounds exhibiting anti-inflammatory activity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.1
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• pp.21-27
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• 2023

Lotus Nelumbo nucifera seed protein (LSP) was isolated by alkaline solubilization after removing fat and phenolics by hexane and ethanol treatment. Antioxidant peptides from LSP were produced with Alcalase^® and pepsin and hydroxyl radical scavenging activities were determined. LSP-Alcalase^® hydrolysates showed higher hydroxyl radical scavenging activity than LSP-pepsin hydrolysates. To purify antioxidant peptides, LSP-Alcalase^® hydrolysates were subjected to high performance liquid chromatography (HPLC) separation on the C18 column and the active fraction was further purified using a Superdex^TM peptide 10/300 GL column. Finally, the active fraction (F8-2) was evaluated for antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical scavenging, and oxygen radical absorbance capacity (ORAC) assays. The EC₅₀ values of the F8-2 were 105.81±0.02 ㎍/mL for DPPH and 32.26±0.02 ㎍/mL for hydroxyl radical and the F8-2 exhibited 7.22 μM trolox equivalent (TE)/100 ㎍ F8-2. Glutathione (GSH), which is a positive control, showed EC₅₀ values of 19.87±0.01 ㎍/mL for DPPH and 15.95±0.03 ㎍/mL for hydroxyl radical and an ORAC value of 14.17±0.03 μM TE/100 ㎍ GSH. Finally, sixteen peptides were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Among them, Ile-Tyr and Leu-Tyr showed higher antioxidant scores.

• Journal of Korean Neurosurgical Society
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• v.63 no.5
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• pp.566-578
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• 2020

Objective : Radiation is known to induce autophagy in malignant glioma cells whether it is cytocidal or cytoprotective. Dexamethasone is frequently used to reduce tumor-associated brain edema, especially during radiation therapy. The purpose of the study was to determine whether and how dexamethasone affects autophagy in irradiated malignant glioma cells and to identify possible intervening molecular pathways. Methods : We prepared p53 mutant U373 and LN229 glioma cell lines, which varied by phosphatase and tensin homolog (PTEN) mutational status and were used to make U373 stable transfected cells expressing GFP-LC3 protein. After performing cell survival assay after irradiation, the IC₅₀ radiation dose was determined. Dexamethasone dose (10 μM) was determined from the literature and added to the glioma cells 24 hours before the irradiation. The effect of adding dexamethasone was evaluated by cell survival assay or clonogenic assay and cell cycle analysis. Measurement of autophagy was visualized by western blot of LC3-I/LC3-II and quantified by the GFP-LC3 punctuated pattern under fluorescence microscopy and acridine orange staining for acidic vesicle organelles by flow cytometry. Results : Dexamethasone increased cell survival in both U373 and LN229 cells after irradiation. It interfered with autophagy after irradiation differently depending on the PTEN mutational status : the autophagy decreased in U373 (PTEN-mutated) cells but increased in LN229 (PTEN wild-type) cells. Inhibition of protein kinase B (AKT) phosphorylation after irradiation by LY294002 reversed the dexamethasone-induced decrease of autophagy and cell death in U373 cells but provoked no effect on both autophagy and cell survival in LN229 cells. After ATG5 knockdown, radiation-induced autophagy decreased and the effect of dexamethasone also diminished in both cell lines. The diminished autophagy resulted in a partial reversal of dexamethasone protection from cell death after irradiation in U373 cells; however, no significant change was observed in surviving fraction LN229 cells. Conclusion : Dexamethasone increased cell survival in p53 mutated malignant glioma cells and increased autophagy in PTEN-mutant malignant glioma cell but not in PTEN-wildtype cell. The difference of autophagy response could be mediated though the phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin signaling pathway.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.749-758
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• 2019

The aim of this study is to provide a scientific basis for decision making regarding environmental damage in case of future chemical accidents by evaluating the ecotoxicity of 4 substances requiring preparation for accidents. For this purpose, acute and chronic toxicities of nitric acid, sulfuric acid, hydrogen peroxide, and ammonia solution, which can change the physical and chemical properties of soil to Paronychiurus kimi(Collembola) were investigated. The pH of artificial soil spiked with a series of test chemical concentrations was also measured. The pH of soil spiked with 10,000 mg kg^-1 of soil nitric acid, sulfuric acid, hydrogen peroxide, and ammonia solution were 2.86, 2.72, 7.18 and 9.69, respectively. The 28-d LC₅₀ of nitric acid, sulfuric acid, hydrogen peroxide and ammonia solution were 2,703, 5,414, 3,158 and 859 mg kg^-1 soil dry wt., respectively and 28-d EC₅₀ were 587, 2,148, 1,300 and 216 mg kg^-1 soil dry wt., respectively. These results indicated that the mortality and juvenile production of P. kimi were influenced by not only the soil pH but also by the reduced organic content and products produced by the reaction of soil with the tested chemicals. Given the fact that most substances requiring preparation for accidents can change soil characteristics, assessment and restoration methods that take into account changes in soil properties are needed for accurate decision making after chemical accidents.

• The Korea Journal of Herbology
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• v.34 no.6
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• pp.57-62
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• 2019

Objective : Gastritis is a major complication of gastrointestinal disease. Lonicera japonica is used in folk medicine to treat different diseases such as exopathogenic wind-heat, epidemic febrile diseases, sores, carbuncles and some infectious diseases. Therefore, this study examined the effects of Lonicera japonica water extract (LJE) on HCl/ethano-linduced acute gastric ulceration and anti-oxidants properties. Methods : LC-ESI-IT-TOF MS was employed for rapid identification of major compound from LJE. The antioxidant activities were evaluated through total polyphenol and flavonoid contents and radical scavenging assays and superoxide dismutase (SOD)-like activity. SD rats were randomly divided into five different groups including the normal group, ulcer group, positive group (20 kg/mg of omeprazole, ip), and experimental groups (100 kg/mg and 500 kg/mg of LJE, ip). Results : 4,5-Dicaffeoyl quinic acid, loganic acid, secologanic acid, sweroside, loganin, vogeloside were identified based on the detection of the molecular ion with those of literature data. The LJE was possessed free radical scavenging activities such as DPPH (IC₅₀=189.7 ㎍/㎖), ABTS (IC₅₀=164.5 ㎍/㎖), and SOD-like activity (IC₅₀=405.02 ㎍/㎖). Macroscopic and histological analyses showed LJE treated group were significantly reduced to an extent that it allowed leukocytes penetration of the gastric walls compared with the ulcer group. In addition, an ulcer inhibition rate and prostaglandin E₂ levels were increased in rats treated with LJE. Conclusion : The present study has demonstrated the antioxidantive and gastroprotective effect of LJE, these findings suggested that LJE has the potential for use in treatment of gastric disorders.