• Journal of Applied Biological Chemistry
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• v.52 no.3
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• pp.147-150
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• 2009

The fruit body of Phellinus linteus was extracted with 80% aqueous MeOH, and the concentrated extract was successively partitioned using EtOAc, n-BuOH and $H_2O$. From the EtOAc and n-BuOH fractions, three phenolic compounds were isolated through repeated silica gel and ODS column chromatography. The chemical structures of these compounds were determined as 2-(3',4'-dihydroxyphenyl)-1,3-benzodioxole-5-aldehyde (1), 4-(3,4-dihydroxyphenyl)-3-buten-2-one (2), and protocatechuic acid methyl ester (3) by spectroscopic data including NMR, MS and IR. Compounds $1{\sim}3$ exhibited low density lipoprotein (LDL) antioxidant activity with $IC_{50}$ values of 1.7, 0.7, and $2.4{\mu}M$, respectively.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.270-270
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• 2017

Brown rice flour (BRF) was treated with different carbohydrases (Viscozyme, Termamyl, Celluclast, AMG, Ultraflo, and Pentopan), and then aqueous alcoholic extracts (70% ethanol) from the treated RBF were examined for their phenolic compositions and antioxidant activities (ABTS and DPPH radical scavenging activity). All the carbohydrases tested induced significant increases in ABTS radical scavenging activity (2.1-3.0 times). Moreover, These enzymes increased the amount of extractable free phenolic acids by 10-15 times, especially for ferulic and p-coumaric acid. Among the enzymes tested, Pentopan which was active in arabinoxylan hydrolysis appeared to be most effective in increasing the free phenolic acid content and ABTS radical scavenging activity than other enzymes. Enzymatic hydrolysis of cell wall polysaccharides in BRF could be used as an effective procedure for raising the amount of extractable phenolic acids and thus increasing the antioxidant activity of BRF extract.

• Korean Journal of Medicinal Crop Science
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• v.16 no.6
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• pp.397-401
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• 2008

Changes in the contents of total phenolic compounds in as Agrimonia pilosa well as their antioxidant capacity according to the havest time and positions were examined. The contents of the total phenolic compounds were determined by extraction with MeOH. Among havest times harvestry in July showed highest contents of the total phenolic compounds and harvestry in May showed lowest contents of the phenolic compounds. Among the 4 positions (root, branch, leaf, flower) of Agrimonia pilosa the root contained highest contents of the phenolic compounds. The antioxidant capacities of Agrimonia pilosa were increased roughly with increasing level of contents of phenolic compounds according to positions.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.114-122
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• 1995

Complexation experiment between humic acid and heavy metal cations was conducted to clear information on heavy metal adsorption by soil organic constituent. The absorbance of UV-visible light of humic acid-metal complexes increased with increasing wavelength, and the order of their absorbance was in the order of Zn->Cd->Cu- saturated humic acid. Carboxyl and phenolic OH groups participated in the complex formation between heavy metal cations and functional groups of humic acid, and the amounts complex was in the order of $Cu^{+{+}}$ > $Zn^{+{+}}$ $\geq$ $Cd^{+{+}}$. The stability constants of humic acid-metal complexes increased with increasing pH, and the order of first stability constants was $Zn^{+{+}}$ > $Cd^{+{+}}$ > $Cu^{+{+}}$, and those of second and overall stability constants were $Cu^{+{+}}$ > $Zn^{+{+}}$ > $Cd^{+{+}}$. With increasing pH, the average binding numbers betwen heavy metal cations and functional groups of humic acid increased the order of $Cu^{+{+}}$ > $Zn^{+{+}}$ > $Cd^{+{+}}$. It was postulated that two types of complexations between heavy metal cations and functional groups of humic acid. One was the reactions in which only carboxyl groups participated to form complexes, and the other was those in which both carboxyl and phenolic OH groups simultaneously participated.

• Natural Product Sciences
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• v.21 no.2
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• pp.87-92
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• 2015

The stem barks, heartwoods, and leaves of Acer tegmentosum (Aceraceae) are widely used in Korea to treat hepatic or cerebral disorders mainly due to alcohol poisoning. This study was aimed to analyze phenolic substances in A. tegmentosum. Quantitative analysis of the three phenolic substances (salidroside, (+)-catechin and scopoletin) was performed by HPLC and the identification of volatile phenolic substances were done by GC-MS. The contents of the three compounds in the three MeOH extracts were higher in the stem bark (salidroside: 80.22 mg/g, (+)-catechin: 23.31 mg/g, and scopoletin: 9.45 mg/g) compared to the heartwoods and leaves. And GC-MS analysis of the stem bark extract demonstrated that p-tyrosol is a main substance of twenty-one compounds identified.

• Carbon letters
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• v.4 no.2
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• pp.86-92
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• 2003

A series of micro- and mesoporous activated carbons were prepared from two kinds of phenolic resin using a metal treated chemical activation methodology. $N_2$-adsorption data were used to characterize the surface properties of the produced activated carbons. Results of the surface properties and pore distribution analysis showed that phenolic resin can be successfully converted to micro- and mesoporous activated carbons with specific surface areas higher than 973 $m^2/g$. Activated carbons with porous structure were produced by controlling the amount of metal chlorides ($CuCl_2$). Pore evolvement depends on the amount of additional metal chloride and precursors used. From the SEM and EDX data, copper contents were shown to be most effected by the incremental addition of metal chloride.

• Current Research on Agriculture and Life Sciences
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• v.10
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• pp.11-17
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• 1992

In this study, antioxidative effectiveness of BHA, BHT at 0.02%(w/w) was compared with those of separated free phenolic acid, ester form and insoluble bound phenolic acid which were extracted from 50 g of Terminalia chebula Retz by MeOH/aceton solvents. Antioxidative effectiveness was measured by peroxide values and TBA values for 7 days, storaging respective substrates and contrast tube at $45{\pm}1^{\circ}C$ for 35days. Laboratory tubes was added by BHA, BHT, separated free, soluble and insoluble phenolic acid extracts and peroxide value of contrast tube after 21 day storage were 60, 30, 14, 11, 100. On the other hand, at the same conditions, TBA values of each antioxidants were 0.150, 0.108, 0.105, 0.073, 0.078, 0.185. This results remarkably appeared antioxidative effectiveness in meal soybean oil substrates. Phenolic acid separated and identificated were p-coumaric acid, Ferulic acid, Phloroglucinol, Pyrogallol, Vanillic acid and Caffeic acid.

• Journal of Applied Biological Chemistry
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• v.50 no.3
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• pp.115-119
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• 2007

To discover the sources with antioxidant and tyrosinase inhibitory activities in Korean traditional medicines, 10 extract of medicinal plants were screened for their potential to scavenge stable 1,1-diphenyl-2-picryhydrazyl (DPPH) free radical, inhibit hydroxyl radical (${\cdot}OH$), total phenolic content, and inhibition of tyrosinase. The potency of DPPH radical scavenging activity was shown in the extract of Ulmus davidiana var. japonica Nakai that has a greater effect with $IC_{50}$ values of $6.49{\pm}5.43{\mu}g/mL$, than BHA ($IC_{50}=20.99{\pm}0.74{\mu}g/mL$), L-ascorbic acid $(IC_{50}=20.59{\pm}1.06{\mu}g/mL),\;and\;{\alpha}-tocopherol\;(IC_{50}=25.55{\pm}0.26{\mu}g/mL)$ as a positive control. The ${\cdot}OH$ scavenging activities were observed in the plants tested. Acanthopanax senticosus, Cirsium setiders, U. davidiana exhibited scavenging activity of more than 60% at $500{\mu}g/mL$. The scavenging activity(%) of BHA and a-tocopherol were 64.32 and 55.87% at $500{\mu}g/mL$, respectively. The total phenolic content was determined, in order to assess its effect on the extract's antioxidant activity. The total phenoic content of $33.37{\pm}0.52mg/g$ was conformed by methanolic extract of U. davidiana. The U. davidiana and Morus bombycis exhibited tyrosinase inhibitory activity with a $34.28{\pm}1.32\;and\;75.57{\pm}1.10%$, respectively. In particular, M. bombycis has stronger tyrosinase inhibitory activity than albutin with $36.48{\pm}3.56%$ as a positive control. This work showed that the inhibitory abilities of Korean medicinal plants, such as U. davidiana and M. bombycis, on DPPH free radical, inhibit hydroxyl radical (${\cdot}OH$), and inhibition of tyrosinase and total phenolic content, can be useful in the prevention and treatment of free radical-relate disease. Investigations into further isolation of inhibitory principles of U. davidiana and M. bombycis are now in progress.

• Journal of Applied Biological Chemistry
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• v.53 no.1
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• pp.8-12
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• 2010

The antioxidant activity of hawthorn fruit (Crataegus pinnatifida Bunge var. typica Schneider) extracts was investigated by several in vitro antioxidants properties, including DPPH free radical scavenging activity, total phenolic and flavonoid contents, hydroxyl radical scavenging activity, reducing power activity, iron-chelating capacity and nitrite scavenging activity. Among the extracts in this study, the 70% EtOH extract showed higher antioxidant activity than the others. The $IC_{50}$ value of DPPH free radical scavenging activity was $99.26\;{\mu}g/mL$. Furthermore, the 70% EtOH extract also showed significantly high total phenolic and flavonoids contents and reducing power activity. However, the MeOH extract exhibited stronger effects on hydroxyl radical scavenging activity, iron-chelating capacity and nitrite scavenging activity. All the results implicated that, the hawthorn fruit may has the available potential to be utilize as a potential source of natural antioxidant.

• Korean Chemical Engineering Research
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• v.61 no.1
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• pp.109-115
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• 2023

The extraction and adsorption characteristics for three phenolic ketones with high physicochemical similarity among phenolic compounds, which are alcohol fermentation inhibitors in lignocellulosic biomass hydrolysates, were investigated. The most suitable basic extractant for selectively separating acetosyringone from three phenol ketones by reactive extraction was found to be trioctylphosphine oxide. In addition, it was found that adsorption using XAD16, a polymer neutral resin adsorbent, or physical extraction using hexane, was a suitable separation method for separation of 4'-hydroxyacetophenone (HAP) and acetovanillone (AVO). A five-step fractionation process including extraction and adsorption mentioned above has been first proposed to separate and concentrate the three phenol ketones present at equal mass percentages. When physical extraction with n-hexane and re-extraction with an aqueous NaOH solution were used as the steps 4 and 5 in the fractionation process respectively, it was possible to obtain almost 70% or more of the purity of three phenolic ketones.