• Korean Journal of Food Science and Technology
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• v.33 no.4
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• pp.497-500
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• 2001

The purpose of this study was to investigate the extraction method and antioxidative activities of phenolic compounds from Korean red tail ginseng. Antioxidative activities of red tail ginseng were evaluated with its ability to donate hydrogen to DPPH, and to inhibit the oxidation of linoleic acid and LDL induced by $H_2O_2$ and $FeCl_2$, respectivly by measuring the MDA formation. Total phenolic compounds expressed as % caffeic acid were 0.80%, 0.12%, 0.06%, 0.03%, 0.01% when red tail ginseng was consecutively extracted with 60% ethanol for 5 times, most of the phenolic compounds was recovered in the extract obtained after 3 times of extraction. The extraction efficacy of 60% ethanol was superior to that of water in extraction phenolic compounds, and the efficacy did not change after evaporating the extract followed by dissolving with water. 60% ethanol extract of red tail ginseng had weak ability to donate hydrogen to DPPH. MDA determination showed the antioxidative effect with inhibition ratio of 72.23% on linoleic acid oxidation by addition of red tail ginseng extract at the concentration of 1,500 ppm. 22.52% of LDL oxidation was inhibited by addition of 250 ppm.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.801-807
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• 1988

Antithiamine activity of raw and processed brackens (Pteridium aquilinum) was evaluated by means of the thiochrome fluorescence and Lactobacillus viridescens bioassay methods and inter-related with the phenolic content and degree of browning. As blanching time of bracken elapsed, its antithiamine activity was enhanced whereas the phenolic content and brewing declined. Increased salt concnetrations in boiling water also raised the antithiamine activity, phenolic content and browning of raw bracken. When dried bracken was treated with sodium bicarbonate solution or soaked in running water, its antithiamine activity greatly decreased along with the increased phenolic content and browning. Heat cooking of bracken brought about a slight decrease in the antithiamine activity, phenolic content and browning. It was concluded that antithiamine activity existing in raw bracken Is reduced by various treatments, particularly by soaking in running water and that phenolics in bracken may play an important role in thiamine decomposition.

• Applied Biological Chemistry
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• v.38 no.4
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• pp.293-296
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• 1995

Fig leaves were extracted with methanol and then fractionated with ethyl acetate and various buffers to get active fractions and determined the antimicrobial activities. The acidic and phenolic fractions fractionated from the methanol extract of fig leaves showed the strong antimicrobial activities, but the basic and neutral fractions did not show any activities. The degree of antimicrobial activities of phenolic fraction against tested bacteria was higher than those of acidic fraction, but these against yeasts and mold were almost equivalent to those of acidic fraction. Especially, phenolic fraction was mostly affected on Staphylococcus aureus and Pseudomonas aeruginosa. Four antimicrobial substances purified from the phenolic fraction which showed the strongest antimicrobial activities among the fractions from fig leaves, were identified as psoralen($C_{11}H_{6}O_{3}$, MW. 186), bergapten($C_{12}H_{8}O_{4}$, MW. 216), ${\beta}$-sitosterol($C_{29}H_{50}O$, MW. 414) and umbelliferone ($C_{9}H_{6}O_{3}$, MW. 162).

• Journal of the Korean Wood Science and Technology
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• v.14 no.2
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• pp.29-35
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• 1986

This study was carried out to examine the effect of aluminium sulfate addition to the alkali-acid catalyst phenolic resin for the manufacture of the kapur (Dryobalanops spp.) plywood on the reduction of phenolic resin spreading. On the manufacture of plywood, Adhesive Contents such as 50g/$m^2$, 75g/$m^2$ and 150g/$m^2$ were treated. The spreading adhesive content of 50g/$m^2$ and 75g/$m^2$ had been controlled to about 150g/$m^2$ added with the water in order to get sufficient spreading and controlled to pH 4.5 with aluminium sulfate [$Al_2(SO_4)_3$]. The results are summarized as follows: 1. Specific gravities of air dried plywood manufactured from each adhesive ranged from 0.77 to 0.86 and their moisture contents met the KS requirements. 2. In dry and wet shear strengths, 150 $P_{Al{\cdot}Ac}$ adhesive showed the highest and 75 $P_{Al{\cdot}Ac{\cdot}Am}$ adhesive indicated higher value than 150 $P_{Al{\cdot}Ac}$ adhesive. 3. In case of glue shear strength after boiling test, 150 $P_{Al{\cdot}Ac}$ adhesive was the best and adding of aluminium sulfate was not effective on reinforcement of boiling water resistance of phenolic resin, but met KS requirements. 4. 75 $P_{Al{\cdot}Ac{\cdot}Am}$ adhesive showed the good shear strength and met KS requirements. Therefore, adding of aluminium sulfate was very efficient for economical plywood manufacture.

• Composites Research
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• v.26 no.5
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• pp.309-314
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• 2013

Highly ablation resistant carbon nanotube (CNT)-phenolic composites were fabricated by the addition of low concentrations of CNT nanofiller. Tensile and compressive properties as well as ablative resistance were significantly improved by the addition of only 0.1 and 0.3 wt% of uniformly dispersed CNTs. An oxygen-kerosene-flame torch and a field emission scanning electron microscope (FE-SEM) were used to evaluate the ablative properties and microstructures of these CNT-phenolic composites. Thermal gravimetric analysis (TGA) revealed that the ablation rate was lower for the 0.3 wt% CNT-phenolic composites than for neat phenolic or the composite with 0.1 wt% CNT. Ablative mechanisms for all three materials were investigated using this TGA in conjunction with microstructural studies using a FE-SEM. The microstructural studies revealed that CNT acted as an ablation resistant phase at high temperatures, and that the uniformity of dispersion of the CNT played an important role in this resistance to ablation.

• The Korean Journal of Food And Nutrition
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• v.32 no.6
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• pp.717-729
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• 2019

The chemical informs about 70 individual phenolic compounds were constructed from various lettuce samples based on literature sources and analytical data. A total of 30 phenolic compounds including quercetin 3-O-glucuronide, quercetin 3-O-(6''-O- malonyl) glucoside, cyanidin 3-O-(6''-O-malonyl)glucoside, chlorogenic acid and chicoric acid as major components were identified in 6 lettuce samples from Korea using UPLC-DAD-QToF/MS on the basis of constructed library. Among these, quercetin 3,7-di-O-glucoside(m/z 627 [M+H]⁺), quercetin 3-O-(2''-O-malonyl)glucoside(morkotin C, m/z 551 [M+H]⁺), quercetin 3-O-(6''- O-malonyl)glucoside methyl ester(m/z 565 [M+H]⁺), 5-O-cis-p-coumaroylquinic acid(m/z 339 [M+H]⁺) and 5-O-caffeoylquinic acid methyl ester(m/z 369 [M+H]⁺) were newly confirmed from the lettuce samples. In total content of phenolic compounds, 4 red lettuce samples(2,947.7~7,535.6 mg/100 g, dry weight) showed higher than green lettuce(2,687.3 mg) and head lettuce(320.1 mg).

• Preventive Nutrition and Food Science
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• v.22 no.2
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• pp.107-117
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• 2017

The purpose of this study was to evaluate the antioxidant and anticholinesterase activities of yellow and white bitter yams from South Western Nigeria using methanolic extraction and simulated gastrointestinal digestion models. The phenolic compounds in the bitter yam varieties were evaluated by high performance liquid chromatography with a diode array detector (HPLC-DAD). The total phenolic content of the bitter yams was measured by the Folin-Ciocalteu method, reductive potential by assessing the ability of the bitter yam to reduce $FeCl_3$ solution, and the antioxidant activities were determined by the 2,2-diphenyl-1-picrylhydrazyl radical ($DPPH^{\cdot}$) scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation ($ABTS^{{\cdot}+}$) scavenging activity, nitric oxide radical ($NO^{\cdot}$) scavenging ability, hydroxyl radical scavenging ability, and ability to inhibit $Fe^{2+}$-induced lipid oxidation. The HPLC-DAD analysis revealed the presence of some phenolic compounds in the studied bitter yam varieties, with varying degree of quantitative changes after cooking. The antioxidant indices (total phenolic content, total flavonoid content, reducing power, $DPPH^{\cdot}$ scavenging activity, $ABTS^{{\cdot}+}$ scavenging activity, and $NO^{\cdot}$ scavenging activity) were higher in the simulated gastrointestinal digestion model compared to the methanolic extract, with the in vitro digested cooked white bitter yam ranking higher. Similarly, the in vitro digested yams had a higher inhibitory action against lipid oxidation compared to the methanolic extracts, with the cooked white bitter yam ranking high. The methanolic extracts and in vitro enzyme digests showed no acetylcholinesterase inhibitory abilities, while methanolic extracts and the in vitro enzyme digest displayed some level of butyrylcholinesterase inhibitory activities. Therefore the studied bitter yams could be considered as possible health supplements.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.2
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• pp.363-367
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• 2003

Oriental pear was used as treatment of asthma, control of blood pressure tonic medicine vasoaction, diabetes in oriental medicine. In this study, it was investigated that pear phenolic compound effects on cardiovascular system as blood pressure and renin and atrial natriuretic peptide(ANP) in plasma, Cardiac hypertrophy. The experiments were performed on Sprague Dawley rats, 2K1C hypertension model was prepared by constricting the left renal artery with a sliver clip. Animals were then divided into four groups, 5mg/Kg(PPC-A) 10mg/Kg(PPC-B) 15mg/Kg(PPC-c) and control group. Pear phenolic compound solution were supplied with them for 3weeks, a day's interval. The results are that The blood pressure was significantly decreased at 15days in PPC-A group than control group. The plasma ANP was increased in PPC-A and PPC-C group, and cardiac hypertrophy was significantly decrease in PPC-C group compared with control group.

• Natural Product Sciences
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• v.21 no.3
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• pp.162-169
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• 2015

Hamamelis japonica (Hamamelidaceae), widely known as Japanese witch hazel, is a deciduous flowering shrub that produces compact clumps of yellow or orange-red flowers with long and thin petals. As a part of our ongoing search for phenolic constituents from this plant, eleven phenolic constituents including six flavonol glycosides, a chalcone glycoside, two coumaroyl flavonol glycosides and two galloylated compounds were isolated from the flowers. Their structures were elucidated as methyl gallate (1), myricitrin (2), hyperoside (3), isoquercitrin (4), quercitrin (5), spiraeoside (6), kaempferol 4'-O-β-glucopyranoside (7), chalcononaringenin 2'-O-β-glucopyranoside (8), trans-tiliroside (9), cis-tiliroside (10), and pentagalloyl-O-β-D-glucose (11), respectively. These structures of the compounds were identified on the basis of spectroscopic studies including the on-line LCNMR-MS and conventional NMR techniques. Particularly, directly coupled LC-NMR-MS afforded sufficient structural information rapidly to identify three flavonol glycosides (2 - 4) with the same molecular weight in an extract of Hamamelis japonica flowers without laborious fractionation and purification step. Cytotoxic effects of all the isolated phenolic compounds were evaluated on HCT116 human colon cancer cells, and pentagalloyl-O-β-D-glucose (11) was found to be significantly potent in inhibiting cancer cell growth.

• Journal of the Korean Society of Food Culture
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• v.33 no.1
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• pp.78-85
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• 2018

This study examined the changes in antioxidant activity and contents of phenolic compounds inblanched, steamed, and autoclaved burdock root (BR). The total polyphenolic and flavonoids contents of raw and cooked BR were determined spectrophotometrically. The antioxidant activity of BR was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and oxygen radical absorbance capacity (ORAC) assays. The main phenolic compounds in BR were quantified by HPLC (high performance liquid chromatography). Both blanching and steaming treatments significantly increased the antioxidant activities of BR in all groups (5 min, 15 min, and 30 min), whereas in autoclaving treatment, the 30 min treatment only showed an increase in the antioxidant activities of BR. The 30 min blanched BR exhibited the strongest DPPH and ABTS radical scavenging activities and possessed the highest total polyphenol and flavonoid phenolic contents. The 15 min-steamed BR showed the highest ORAC value. The main phenolic compound of the 15 min-steamed BR was CGA (chlorogenic acid). These results suggest that heat cooking methods, such as blanching and steaming, improve the antioxidant activity of BR by increasing the concentration of phenolic compounds.