• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.364-368
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• 2014

This study investigated the antioxidant activity of onion peels extracted from onion byproducts by hot water treatment. Hot water extraction of freeze dried onion peel powder was analyzed for total polyphenol content, 2,2'-diphenyl-1-picryllhydrazyl (DPPH), and 2,2'-azino-bis(3-ehtylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities, reducing power, oxygen radical absorbance capacity (ORAC). Total polyphenol content was the highest (233.90 mg/g) in onion peel extract mix with ethanol (OPME-1). The DPPH radical scavenging activity ($IC_{50}$), reducing power, and ORAC obtainbed from onion peel extract mix with ethanol precipitation (OPMPE-1) were the highest at 1.15 mg/mL, 1.69 $A_{700}$, and $318,509{\mu}M\;TE/mL$, respectively. The ABTS radical scavenging activity was the highest at 432.78 mg amino acids (AA) eq/g in the OPM. The results of this study suggest that onion peel extracts have marked antioxidant activity, which can have significant health benefits.

• Journal of Microbiology and Biotechnology
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• v.19 no.7
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• pp.675-680
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• 2009

There is considerable interest in the isolation of potent radical scavenging compounds from natural resources to treat diseases involving oxidative stress. In this report, four new fungal metabolites including one new bisdihydroanthracenone derivative (1, eurorubrin), two new seco-anthraquinone derivatives [3, 2-O-methyl-9-dehydroxyeurotinone and 4, 2-O-methyl-4-O-(${\alpha}$-D-ribofuranosyl)-9-dehydroxyeurotinone], and one new anthraquinone glycoside [6,3-O-(${\alpha}$-D-ribofuranosyl)-questin], were isolated and identified from Eurotium rubrum, an endophytic fungal strain that was isolated from the inner tissue of the stem of the marine mangrove plant Hibiscus tiliaceus. In addition, three known compounds including asperflavin (2), 2-0-methyleurotinone (5), and questin (7) were also isolated and identified. Their structures were elucidated on the basis of spectroscopic analysis. All of the isolated compounds were evaluated for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity.

• Korean Journal of Pharmacognosy
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• v.40 no.2
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• pp.143-149
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• 2009

Among aging diseases, the most basic problem is a decrease in bone mineral density. Patients with osteoporosis are steadily increasing in the world. This study was investigated to show the relationship between osteoporotic effects and oxidative damage. Water extracts of 15 medicinal plants and ethanol extracts of 14 medicinal plants with known anti-osteoporotic effects, were tested for their radical scavenging activity using DPPH, ABTS, SRSA and FRAP assay. Water extract of Cornus officinalis, Rubus coreanus and ethanol extract of Rubus coreanus, Viscium album var. coloratum, Cimicifuga heracleifolia showed about 15-20 mg/g of total phenolic contents. Water extract of Cornus officinalis, Rubus coreanus and Epimedium koreanum showed high radical scavenging activity. Ethanol extract of Drynaria fortunei, Cornus officinalis, Rubus coreanus, Gentiana scabra and Astragalus membranaceus showed high radical scavenging activity. Water extract of Drynaria fortunei, Cornus officinalis, Nelumbo nucifera, Epimedium koreanum, and Gentiana scabra showed very strong protective effect against oxidative damage to DNA. These results suggest the correlation between anti-osteoporotic effects and antioxidative effects.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.31-31
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• 2022

Plant-derived antioxidants are used as a healthy diet and are known to inhibit various human diseases. In this study, we investigated free radical scavenging and antioxidant activity of extracts from three plants (Ammannia multiflora, Ammannia coccinea and Salix gracilistyla) with the most DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity from 196 plant extracts inhabiting along Nakdong River in Republic of Korea. The three extracts also have strong total antioxidant activity. Moreover, the extracts inhibited hydrogen peroxide (H₂O₂)-induced reactive oxygen species production and depolarized mitochondrial membrane potential in RAW264.7 macrophages. In zebrafish larvae, 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescent intensity, induced by H₂O₂, was markedly reduced by the extracts of A. multiflora, A. coccinea and S. gracilistyla. Meanwhile, the extracts were upregulated Nrf2 and HO-1 expression, and an HO-1 inhibitor reversed the extract-induced oxidative responses both in vivo and in vitro. The data suggest that the extracts of A. multiflora, A. coccinea, and S. gracilistyla exert potential free radical scavenging and antioxidant capacities both in vivo and in vitro by activating the Nrf2/HO-1 signaling pathway.

• Natural Product Sciences
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• v.12 no.2
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• pp.94-100
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• 2006

The essential oil (EC-oil) obtained from the buds of Eugenia caryophyllata (Myrtaceae) was examined for its free radical-scavenging activity, cytotoxicity, and in vivo toxicity. To find the xenobiotic properties of EC-oil, serum thiobarbituric acid reactive substances (TBARS) level and hepatic drug-metabolizing enzyme activities were measured. It was found that EC-oil displayed xenobiotic properties like bromobenzene. The cytotoxicities of eugenol and of the EC-oil were greatly attenuated by the sulfhydryl-containing N-acetyl-L-cysteine (NAC), suggesting that eugenol was susceptible to nucleophilic sulfhydryl. In addition, eugenol also showed potent free radical-scavenging activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Moreover, methyleugenol considerably exhibited less cytotoxicity and less potent free radical-scavenging activity than eugenol, and the cell viability of the methyleugenol was more increased with NAC treatment than the eugenol. These results indicate that the phenolic OH in eugenol may play a crucial role in both cytotoxicity and free radical-scavenging activity. The fashion on oxidative stress and hepatic drug-metabolizing enzyme activities of eugenol resembled those of bromobenznene.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.713-719
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• 2011

The antioxidant activities of the ethanol extract of Arctium lappa were assessed by measuring the 1,1-diphenyl-2-picrylhydrazyl( DPPH) radical scavenging effect, inhibition of $Fe^{2+}$-induced lipid peroxidation, inhibition of malondialdehyde(MDA)-bovine serum albumin(BSA) conjugation reaction and antimutagenic capacities using the Ames test. The DPPH radical scavenging activity and inhibition of $Fe^{2+}$-induced lipid peroxidation of the $Arctium$ $lappa$ ethanol extract significantly increased in a dose-dependent manner. In the radical scavenging assay using DPPH, the $IC_{50}$ of the Arctium lappa extract was 296 ${\mu}g$/assay(1.29 mg of dry sample). In addition, the $IC_{50}$ in the inhibition of $Fe^{2+}$-induced lipid peroxidation was 1,759 ${\mu}g$/assay(7.65 mg of dry sample). This extract also significantly inhibited the MDA-BSA conjugation reaction with an $IC_{50}$ of 57.58 mg/assay(250 mg of dry sample). However, no inhibitory effects against the direct and indirect mutagenicities in $Salmonella$ Typhimurium TA98 and TA100 were observed. Based on these results, the ethanol extract of $Arctium$ $lappa$ was shown to display considerable antioxidative activities.

• Journal of Life Science
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• v.26 no.9
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• pp.1022-1026
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• 2016

In this study the hot water extract was prepared from Hydrocotyle sibthorpioides (Araliaceae) leaves and stems to study antioxidant activities and lipoxygenase inhibition. The extract showed the protective hydroxyl radical (-OH) which can damage virtually all types of macromolecules: carbohydrates, nucleic acids (mutations), lipids (lipid peroxidation), and amino acids. Hydroxyl radical scavenging activity of H. sibthorpioides was 78.6%. The extract showed strong activity against 1, 1- diphenyl 2-picrylhyorazyl (DPPH) which is a well-known radical and a trap (scavenger) for other radicals. DPPH scavenging activity of leaves of H. sibthorpioides was evaluated at 8.0 mg/ml was 86.0%. Lipoxygenases (LOXs) constitute a heterogeneous family of lipid peroxidizing enzymes capable of oxygenating polyunsaturated fatty acids to their corresponding hydroperoxy derivatives. The inhibitory effect of 15-LOX by H. sibthorpioides was assayed using a Morgan microplate assay. The extract of H. sibthorpioides was 55.5% inhibitory effects on the inhibition of LOX at 8.0 mg/ml. The IC₅₀ values for OH activity, DPPH activity, and LOX inhibition from leaves 5.23 mg/ml, 6.44 mg/ml, and 3.71 mg/ml, respectively. Antioxidative activity assay showed that the water extracts from leaf and stem had a strong reducing power. These results show that H. sibthorpioides has some phytochemical constituents which may be active against the free radicals (OH and DPPH) and lipoxygenase enzyme.

• Preventive Nutrition and Food Science
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• v.12 no.3
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• pp.177-180
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• 2007

Tocotrienols (T3) are minor plant constituents found abundantly in rice bran, which provide a significant source of vitamin E in animal feeds. T3 was reported to have an intrinsic hypocholesterolemic effect by inhibiting HMG-Co A reductase. It has similar antioxidative properties as tocopherols in food and biological system due to their similar chemical structures. However, the antioxidant activity and mechanism of T3 to scavenge free radicals and to inhibit the peroxidation of linoleic acid are less understood. The purpose of this study was to investigate the scavenging effect of T3 on free radicals and its inhibition of peroxide formation. Free radical scavenging activity was monitored by the DPPH (1,1-diphenyl-2-picrylhydrazyl) method whereas inhibition of linoleic acid peroxidation was evaluated using the thiocyanate method. Thiobarbituric acid (TBA) test was used to determine malonaldehyde formation from linoleic acid peroxidation. Free radical scavenging activity increased with increasing concentration levels of T3. T3 exhibited 38.2, 78.6, 92.7 and 96.2% radical scavenging activity at concentrations of 2, 8, 32 and 128 ppm, respectively. At 128 ppm, it was highly effective in inhibiting linoleic acid peroxidation. The activity of T3 evaluated by the thiocyanate method showed low absorbance values indicating a high level of antioxidant activity. All treatments showed similar trends in antioxidant activity when evaluated by both the thiocyanate method and TBA test.

• Korean Journal of Organic Agriculture
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• v.23 no.4
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• pp.987-997
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• 2015

Schisandra chinensis (Sc), a species of the family Schisandraceae used fruits as medicinal herbs. In the study, we performed to determine a comparison of antioxidant activity from Sc water extracts depending on stir-frying and stir-frying with liquids by 30% ethanol pretreatments. The contents of polyphenol and flavonoid, DPPH radical scavenging, ABTS radical scavenging and reducing power activity were measured to evaluate the antioxidant activity. Total polyphenol and flavonoid contents of Sc extracts were increased in stir-frying and 30% ethanol stir-frying pretreatments compared to a control. In particular, contents of stir-frying pretreatments Sc were highest increased at $220^{\circ}C$ treatments. The DPPH radical scavenging activity were highest increased in stir-frying pretreatments at $220^{\circ}C$. And result that measurement of the ABTS radical scavenging, it showed higher activity in 30% ethanol stir-frying pretreatments at $180^{\circ}C$ and $220^{\circ}C$. But Sc in the $140^{\circ}C$ showed higher activity in stir-frying pretreatments. In the reducing power activity, stir-frying pretreatments increased higher than 30% ethanol stir-frying pretreatments at $220^{\circ}C$. As in results, antioxidant activity of Sc water extracts in stir-frying and stir-frying with liquids process increased higher than a control, and it was most effectively in stir-frying pretreatments at $220^{\circ}C$.

• 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.