• Archives of Pharmacal Research
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• v.23 no.3
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• pp.237-239
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• 2000

The antioxidant activity of Artemisia montana was determined by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and inhibitory activity against free radical generation of hepatocytes ($AC_2$F). The methanol extract of A. montana showed strong radical scavenging activity at a concentration of $10.1{\mu}g/m{\ell}$, and thus fractionated by solvent extraction. Esculetin and luteolin 7-O-rutinoside (scolymoside) were isolated as the active principles from the EtOAc and interphase fractions, respectively. The antioxidant activity of these compounds were comparable to that of L-ascorbic acid.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.312-316
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• 2006

Crude extract of young dangyuja (Citrus grandis Osbeck) fruit was investigated for its antioxidant activity as measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. Among the samples, including 4 Citrus species and various solvent-extracted-fractions of young dangyuja fruit, the water-extracted fraction (WF) and butanol-extracted fraction (BF) showed the greatest DPPH free radical scavenging activity. WF and BF were further examined for their antioxidant activities by three different in vitro assays. The cell viability tests using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay showed that both fractions significantly reduced $H_2O_2$-induced cytotoxicity in HepG2 cells dose-dependently. Generation of the reactive oxygen species (ROS) was also reduced in cells pretreated with both fractions. In addition, BF showed a higher level of lipid peroxidation inhibitory capacity than WF in $H_2O_2$-treated HepG2 cells. Taken together, these results indicate that young dangyuja fruit can be used as an easily accessible source of natural antioxidants.

• Preventive Nutrition and Food Science
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• v.17 no.2
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• pp.116-121
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• 2012

Water extract from Pinus densiflora (WPD) was investigated for its antioxidant activity and its ability to provide protection from DNA damage. A series of antioxidant assays, including a 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging assay, a reducing power assay, a metal-chelating assay, a superoxide radical scavenging assay, and a nitrite scavenging ability, as well as a DNA damage protection assay were performed. Total phenolic content was found to be 211.32 mg Tan/g WPD. The extract scavenged 50% DPPH free radical at a concentration of 21.35 ${\mu}g/mL$. At that same concentration, the reducing power ability of WPD was higher than that of ${\alpha}$-tocopherol. The extract chelated 68.9% ferrous ion at the concentration of 4 mg/mL. WPD showed better nitrite scavenging effect at the lower pH. Meanwhile, WPD exhibited a strong capability for DNA damage protection at 1 mg/mL concentration. Taken together, these data suggest water extract from Pinus densiflora could be used as a suitable natural antioxidant.

• Journal of the Korean Wood Science and Technology
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• v.28 no.3
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• pp.78-84
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• 2000

Two flavanones and one flavone were isolated from the diethylether soluble fraction of ethanol extract of Larix leptolepis heartwood. These compounds were identified 3,3',4',5,7-pentahydroxyflavanone(taxifolin), 3,4',5,7-tetrahydroxyflavanone(aromadendrin) and 3,3',4',5,7-pentahydroxyflavone(quercetin) by instrumental analyses using UV, IR, MS and NMR spectrometries. Antioxidative activies of these compounds were investigated by 1,1-diphenyl-2-picrylhydrazyl(DPPH) free radical scavenging activity. Quercetin and taxifolin indicated high free radical scavenging activities compared to ${\alpha}$-tocopherol and BHT(butylated hydroxytoluene).

• The Korean Journal of Food And Nutrition
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• v.26 no.4
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• pp.857-864
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• 2013

This study was investigated the effects of heat treatment on polyphenolic compounds and antioxidant activities of yacon. Raw yacon was heated at $100^{\circ}C$ and $121^{\circ}C$ for 15, 30, or 60 min by using an autoclave. The browning intensity, levels of free and bound phenolic and flavonoid compounds, and 1,1-diphenyl-2-picrylhydrazyl(DPPH) and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) radical-scavenging activity of yacon extracts following heat treatment were measured. The browning index, free polyphenolic content, and antioxidant activities in the extracts were significantly increased (p<0.05) with both increased heating temperature and time, while bound polyphenolic levels were decreased. The levels of free phenolic and flavonoid compounds in the yacon extract heated to $121^{\circ}C$ for 60 min were increased by 1.2 and 1.1 folds compared to raw yacon respectively. Moreover, DPPH and ABTS radical-scavenging activities of the yacon heated to $121^{\circ}C$ for 60 min were 1.7 fold and 2.0 fold higher, respectively, than those of raw yacon. A significant (p<0.01) correlation was observed among browning intensity, free and bound phenolic and flavonoid levels, and DPPH and ABTS radical-scavenging activities in heated yacon extract. Thus, heat treatment can be used as a method to enhance the antioxidant compound content in and the antioxidant activity of yacon.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.30-35
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• 2010

The potential biological activities of methanol extract and 5 fractions (hexane, $CH_2Cl_2$, EtOAc, BuOH and water) from roots of Astragalus membranaceus were examined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, hydroxyl radical (${\cdot}OH$) scavenging activity, reducing power assays, lipid peroxidation inhibitory activity, $\alpha$-amylase and $\alpha$-glucosidase inhibition assays. The EtOAc fraction showed high DPPH free radical scavenging activity ($EC_{50}=170.34\;{\mu}g/mL$), hydroxyl radical scavenging activity ($EC_{50}=32.14\;{\mu}g/mL$), lipid peroxidation inhibitory activity ($EC_{50}=52.46\;{\mu}g/mL$) and a concentration dependence, with OD value ranging from 0.234 to 0.345 (0.1 to 0.5 mg/mL), for reducing power. The EtOAc fraction has the highest total phenolic content ($142.13\;Gal\;{\mu}g/mg$) and the $CH_2Cl_2$ fraction has the highest flavonoid content ($71.63\;Que\;{\mu}g/mg$). Meanwhile, hexane and EtOAc showed certain $\alpha$-amylase and $\alpha$-glucosidase inhibition activities. These results suggest that the methanol extract and fractions from Astragalus membranaceus root have significant antioxidant and anti-diabetes activities, which could be used as a potential source of pharmaceutical materials.

• The Korean Journal of Food And Nutrition
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• v.34 no.5
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• pp.553-559
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• 2021

The aim of study to investigate the phytochemicals and biological activities the bark of Betula schmidtii. The studies consisted of the solvent extraction, followed by the isolation of phenolic components 1~3 from ethyl acetate-soluble fraction of Betula schmidtii Bark. Their chemical structures were identified as arbutin (1), ρ-coumaric acid (2) and ferulic acid (3) using Ultraviolet-Visible (UV-Vis) Spectrophotometer, Electrospray Ionization Mass Spectrometry (ESI-MS) (negative ion mode), ¹H-Nuclear Magnetic Resonance (NMR), ¹³C-NMR, ¹H-¹H Correlation Spectroscopy (COSY) and ¹H-¹³C Hetero Nuclear Multiple Quantum Correlation (HMQC) spectral data. Compounds 1~3 shows the anti-oxidant effect with IC₅₀ values of 29.74±1.52, 21.32±1.07 and 34.41±1.24 in 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, respectively. Also, compounds 1~3 exhibited mushroom tyrosinase inhibitory activity with IC₅₀ values of 31.14±1.07, 42.54±1.46 and 69.22±1.43 µM, respectively.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1025-1035
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• 2017

In this study, the hot water extract from Mulberry (Morus alba) Leaves fermented with Hericium erinaceum mycelium (MA-HE) was assessed for antioxidant activity. Radical scavenging activity of MA-HE evaluated using 2,2-diphenyl-1-picrylhydrazyl(DPPH) radical and 2,2'-azino-bis(3-ethyl-benzothiazoline-6-sulfonic acid)(ABTS) radical. MA-HE showed 63% DPPH radical scavenging activity at $500{\mu}g/mL$ and 98.27% ABTS radical scavenging activity at $250{\mu}g/mL$. MA-HE was shown to significantly inhibited DNA strand breakage induced by free radical. MA-HE also inhibited free radical-mediated human serum albumin modification. MA-HE effectively inhibited $H_2O_2$ induced cell death and significantly increased of the 8% cell survival at $100{\mu}g/mL$. MA-HE decreased intracellular reactive oxygen species (ROS) levels in $H_2O_2$-treated cells. The results suggested that MA-HE can contribute to antioxidant and protected cells from oxidative stress-induced cell injury.

• Korean Journal of Medicinal Crop Science
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• v.13 no.2
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• pp.85-90
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• 2005

Phytochemical study on the EtOAc fraction from a MeOH extract of the leaves of Alnus hirsuta Rupr. led to the isolation of nine compounds betulin (1), betulinic acid (2), hirsutanonol (3), hirsutenone (4), quercetin (5), avicularin (6), gallic acid (7), hyperin (8), and daucosterol (9). Among them, six compounds 1, 2, 57, and 9 are report from this plant for the first time. All isolated compounds were evaluated for their antioxidant activity using DPPH radical scavenging capacity and inhibition effect on mitochondrial lipid peroxidation. Six phenolic compounds 3-8 were found to have potent antioxidant activity. Of which, compounds 3, 4 and 5 showed significant free radical scavenging activity with the $IC_{50}$ values of $18.3\;{\pm}\;2.5,\;15.7\;{\pm}\;3.8\;and\;23.5\;{\pm}\;3.1\;{\mu}m$, respectively. In addition, the compounds 3-8 exhibited inhibition effect on the mitochondrial lipid peroxidation with the $IC_{50}$ values of $88.0\;{\pm}\;6.5,\;12.6\;{\pm}\;1.2,\;8.0 \;{\pm}\;1.1,\;58.5\;{\pm}\;4.3,\;173.6\;{\pm}\;15.2,\;and\;75.0\; {\pm}\; 6.7\;{\mu}m$, respectively.

• Applied Chemistry for Engineering
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• v.26 no.4
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• pp.470-476
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• 2015

In this study, three dicaffeoylquinic acids (DCQAs) isolated from Gnaphalium affine D. DON. extracts were structurally identified and evaluated for their antioxidant activities, cellular protective effects, and tyrosinase inhibitory activities. The ethyl acetate fraction of G. affine was chromatographed, which yielded 3 DCQA derivatives of 1-3 : 3,5-dicaffoylquinic acid (3,5-DCQA, 1), 4,5-dicaffeoylquinic acid (4,5-DCQA, 2), 1,5-dicaffoylquinic acid (1,5-DCQA, 3). The structure of each compounds was determined using $^1H$ NMR and MS analyses. Compounds of 1-3 showed strong free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activities ($FSC_{50}=3.70$, 5.80, and $5.50{\mu}M$, respectively) compared to those of a commonly used lipophilic antioxidant, (+)-${\alpha}$-tocopherol ($21.90{\mu}M$). Cellular protective effects of 1-3 compounds on the $^1O_2$ sensitized photohemolysis of human erythrocytes were similar to (+)-${\alpha}$-tocopherol. 1-3 compounds also exhibited higher tyrosinase inhibitory effects ($IC_{50}=0.15$, 0.16, and 0.13 mM) compared to arbutin (0.33 mM), known as a skin-whitening agent. These results indicate that three DCQA derivatives may be applied as an antioxidant and a skin whitening agent in food or cosmetic industries.