• Biomedical Science Letters
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• v.24 no.3
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• pp.263-269
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• 2018

This study aims to investigate the biological activities related to hair loss of short anti-oxidant peptides (DK peptides) $5{\alpha}$-reductase inhibition and anti-oxidation. The series of DK peptides were generated amphipathic helical properties using leucines, lysines and tryptophan residues. Cell viability and free radical scavenging activities were performed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. The DK peptides were investigated for inhibitory activity against $5{\alpha}$-reductase. Antioxidant activities were determined by means of, 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assays. All peptides could inhibit $5{\alpha}$-reductase in lipopolysaccharide-stimulated macrophage. In conclusion, DK peptides was suggested as the most attractive ingredients for improving hair loss, because of the high inhibitory against $5{\alpha}$-reductase inhibition.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.3
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• pp.187-191
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• 2007

The radical scavenging activity of methanol extracts of seaweeds and their active compounds, alginic acid, fucoidan and phloroglucinol, were investigated under in vitro. Among methanol extracts of seaweeds (sea mustard, sea tangle, seaweed papulosa, fusiforme, sea lettuce, purple laver and chlorella), seaweed papulosa and sea tangle showed strong scavenging activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydroxyl radical (${\cdot}OH$). In addition, under in vitro, the scavenging activities on DPPH radical of alginic acid and fucoidan, which are active compounds of brown algae, and phloroglucinol, the active compound from Ecklonia species, were evaluated and compared. Fucoidan and phloroglucinol showed strong DPPH scavenging effect, in particular, phloroglucinol had strongest activity among the active compounds. On the other hand, alginic acid did not exert DPPH scavenging activity. From the present study, we could confirm the antioxidative activity of seaweeds and its active compounds.

• Journal of the Korean Wood Science and Technology
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• v.31 no.6
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• pp.40-44
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• 2003

This study was carried out to investigate the antioxidant activities of domestic trees grown in Korea. Based on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity method, the methanolic extracts of 23 species were screened in order to search for natural antioxidants. Among these species, Acer ginnala, Cotinus coggygria, Acanthopanax koreanum, Thea sinensis and Pinus densiflora showed stronger antioxidative activity comparing with reference compound, ascorbic acid.

• YAKHAK HOEJI
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• v.44 no.4
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• pp.354-357
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• 2000

Two ellagitannins, pedunculagin and 2,3-(S)-Hexahydroxydiphenoyl (HHDP)-D -glucose and three condensed tannins, (+)-catechin, (-)-epicatechin and procyanidin B-4 which were isolated from Rubus coreanum were evaluated for their antioxidative effects with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and lipid peroxidation generation system mediated by addition of $H_2O$$_2$to rat liver homogenate (TBARS). The ellagitannins, 2,3-(S)-HHDP-D-glucose and pedunculagin, showed more potent antioxidative activities by DPPH and TBARS than condensed tannins.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.1060-1063
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• 2007

The antioxidative activity of Alpinia oxyphylla was investigated through measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and inhibitory activity for linoleic acid peroxidation. Two antioxidative diarylheptanoids, yakuchinone A (1) and oxyphyllacinol (2), were isolated from the fruits of A. oxyphylla using thin layer chromatography (TLC) autographic assays. The DPPH scavenging activities of the compounds ($IC_{50}=1$, $57{\pm}2.1\;{\mu}M$; 2, $89{\pm}3.1\;{\mu}M$) were lower than vitamin C ($IC_{50}=51{\pm}1.1\;{\mu}M$), but higher than butylated hydroxytoluene (BHT, $IC_{50}=99{\pm}2.2\;{\mu}M$). Also, inhibitory activities for linoleic acid peroxidation of the compounds ($IC_{50}=1$, $0.19{\pm}0.011\;mM$; 2, $0.31{\pm}0.009\;mM$) were higher than those of vitamin C ($IC_{50}=0.59{\pm}0.017\;mM$) and BHT ($IC_{50}=0.52{\pm}0.014\;mM$). In addition the $^{13}C-NMR$ data of oxyphyllacinol (2) have been first reported in this paper.

• Archives of Pharmacal Research
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• v.20 no.5
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• pp.496-500
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• 1997

A strong antioxidant activity, which was measured by the radical scavenging effect on 1, 1-diphenyl-2-picrylhydrazyl(DPPH) radical, was detected in the methanol extract of Salvia miltiorrhiza Bunge (Labiatae). By activity-directed fractionation, compounds 1 and 2 were isolated as antioxidant principles of S. miltiorrhiza. Compounds 1 and 2 were identified as dimethyl lithospermate and 3-(3, 4-dihydroxyphenyl)lactamide, respectively, on the basis of spectral data. The radical scavenging effect of compounds 1 and 2 on DPPH radical exceeded that of L-ascorbic acid which is a well known antioxidant. These two compounds also showed prominent inhibitory activity against free radical generation in dichlorofluorescein (DCF) method and cytoprotective effect against t-BHP in cultured liver cell.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.402-407
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• 2018

In this study, we investigated the antioxidative effects of AY by measuring 1.1-Diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical ($^{\cdot}OH$), and superoxide radical ($O_2{^-}$) scavenging activities in vitro. AY was extracted with ethanol and then partitioned with n-hexane, methylene chloride ($CH_2Cl_2$), ethylacetate (EtOAc) and n-butanol (n-BuOH). In the DPPH radical scavenging assay, AY at concentrations of 10 to $100{\mu}g/mL$ dose-dependently increased inhibition of DPPH oxidation, with the EtOAc fraction of AY showing the highest DPPH radical scavenging activity fractions. The $^{\cdot}OH$ radical scavenging activities of the extract and four fractions of AY increased by over 80% at a concentration of $50{\mu}g/mL$. In particular, the IC50 value of the EtOAc fraction was $0.03{\mu}g/mL$, which was the lowest value among all fractions. We also found that the EtOAc fraction of AY was better at $O_2{^-}$ radical scavenging than other fractions. Taken together, these results suggest that AY, especially the EtOAc fraction, can be used as a natural antioxidant against free radicals.

• Natural Product Sciences
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• v.17 no.2
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• pp.142-146
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• 2011

In the course of screening for antioxidant compounds by measuring the radical scavenging effect on 1,1-diphenyl- 2-picrylhydrazyl (DPPH), a total extract from the whole plant of Veronica peregrina (Scrophulariaceae) was found to show potent antioxidant activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of six phenolic compounds including chrysoeriol (1), diosmetin (2), 4-hydroxybenzoic acid (3), apigenin (4), caffeic acid methylester (5) and protocatechuic acid (6). Their structures were elucidated by spectroscopic studies. Compounds 1-5 were isolated for the first time from this plant. Compounds 5 and 6 showed significant antioxidative effects in DPPH free radical scavenging and superoxide quenching activity assays.

• Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.13-20
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• 2015

Calculated chemical scores (computed in relation to the FAO/WHO reference protein) for salmon liver protein hydrolysates indicated that all amino acids (other than methionine and threonine) were present in adequate or excess quantities; thus, the raw liver material is a good source of essential amino acids. The hydrophobic amino acids contents in hydrolysates prepared from Oncorhynchus keta and O. gorbuscha were 38.4 and 39.1%, respectively. The proportion of released peptides exceeding 500 kDa was reduced when hydrolysates were treated with the commercial enzyme Alcalase, although proportions in the following MW ranges were elevated: 100-500 kDa and <50 kDa. The optimal conditions for enzymatic hydrolysis were as follows: pH 7.0, $50^{\circ}C$, and a reaction time of 1 h. Of the different proteases tested, Alcalase was the most efficient for production of salmon liver hydrolysate with the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity. The hydrolysates prepared from salmon liver had a balanced amino acid composition. The liver protein hydrolysates contained low molecular weight peptides, some of which may be bio-active; this bio-active potential should be investigated. Inhibition of the DPPH radical increased with increased degree of hydrolysis (DH), regardless of protease type. DPPH radical scavenging abilities, antithrombotic effects and ${\alpha}$-glucosidase enzyme inhibition effects of O. keta liver hydrolysate increased in a dose-dependent manner. Thus, salmon liver hydrolysate may be useful in functional food applications and as a source of novel products.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1299-1304
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• 2008

The potential antioxidant activities of different fractions from a 70% methanolic (MeOH) extract of Sonchus oleraceus were assayed in vitro. All of the fractions exception of n-hexane showed a strong antioxidant activity, especially the ethyl acetate (EtOAc) fraction, which showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity ($IC_{50}=19.25{\mu}g/mL$). The results of hydroxyl radical scavenging activity and a reducing power assay showed concentration dependence, the EtOAc fraction demonstrating a better result than the other fractions at the same concentration in the studies. Additionally, the fractions' total phenolic (TP) contents was measured, phenolic compounds such as tannic acid, p-coumatric acid, quercetin, epicathchin, and kaempferol being detected by high performance liquid chromatography (HPLC). Meanwhile, a regression analysis revealed a moderate-to-high correlation coefficient between the antiradical activity and the TP contents, suggesting that fractions obtained from the 70% MeOH extract of S. oleraceus are of potential use as sources of antioxidant material.