• Korean Journal of Food Science and Technology
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• v.53 no.1
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• pp.63-71
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• 2021

In this study, a comparative analysis was carried out between the 'Beta Tiny' and 'TY Nonari' cherry tomato cultivars harvested at the pink and red stages. Samples of the red stage were stored at room temperature for 9 days, during which physicochemical qualities, antioxidant compounds, and activities were measured. As cherry tomato ripening and storage progressed, firmness was reduced, whereas the lycopene content increased. Total phenolic content and antioxidant activity showed no significant changes as ripening and storage progressed; however, total flavonoid content of 'Beta Tiny' showed a significant increase (p<0.05). The main polyphenols in the two cultivars were identified as chlorogenic acid, rutin, and (-)-epigallocatechin gallate, among which chlorogenic acid showed a significant decrease (p<0.05) as ripening and storage progressed. A strong correlation was found between total phenolic and flavonoid content (R=0.744), and ABTS radical scavenging activity (R=0.975). Additionally, a negative correlation was shown by lycopene and chlorogenic acid (R= -0.934).

• Food Science and Biotechnology
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• v.16 no.3
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• pp.349-354
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• 2007

The objectives of this study were to systemically identify phenolic compounds in roasted wild ginseng (Panax ginseng C.A. Meyer) leaves and investigate their radical scavenging activities. Seven phenolic compounds were identified by NMR (H, C, COSY, HMQC, HMBC) and mass (EI-MS, FAB-MS) analyses: 5-caffeoylquinic acid, kaempferol, quercetin, 3,4-dihydroxy-benzoic acid, 4-hydroxy-benzoic acid, 3-(3,4-dihydroxyphenyl)-2-propenoic acid, and 3-(4-hydroxy-3-methoxyphenyl)-2-propenoic acid. Their concentrations ranged from 0.4 (3,4-dihydroxy-benzoic acid) to 7.5 mg (kaempferol) per 100 g of roasted leaves. Among these compounds, 5-caffeoylquinic acid, kaempferol, and quercetin were found exclusively in the leaf portions of the ginseng plants. When their antioxidant activities were measured by DPPH and superoxide anion radical scavenging activity, quercetin, and kaempferol were most effective.

• Korean Journal of Pharmacognosy
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• v.43 no.4
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• pp.274-278
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• 2012

As part of ongoing study focused on the discovery of natural antioxidants from Korean plants by measuring the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging effect and superoxide quenching activity, ethanol extract of the aerial parts of Curcuma longa (Zingiberaceae) was found to show potent antioxidant activities. Subsequent activity-guided fractionation of the ethanol extract led to the isolation of two phenolic compounds, 1,2,3,4,6-penta-O-galloyl-${\beta}$-D-glucopyranoside (1) and gallic acid (2), as antioxidant compounds. Their structures were elucidated by spectroscopic studies. Compounds 1 and 2 were isolated for the first time from this plant. These compounds showed the significant antioxidative effects during the DPPH free radical scavenging test, and the riboflavin- and xanthine-originated superoxide quenching activity tests.

• Food Science and Biotechnology
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• v.15 no.1
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• pp.44-50
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• 2006

Contents of phenolic compounds in peel, flesh, and core of three Asian pear cultivars, Hosui, Niitaka, and Chuwhangbae, were determined at different stages of maturity. Antioxidant properties of methanol extracts of peels at various fruit maturity stages were also evaluated. Total phenolic content decreased with maturity. Arbutin, chlorogenic acid, and epicatechin were major phenolic compounds in young fruits. Catechin, 4-hydroxymethyl benzoic acid, and caffeic acid were detected in peel and core of immature and mature pears. 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activities of methanol extracts were 16.30 and $15.73\;{\mu}g$ in peel of immature Hosui and Chuwhangbae pears, respectively, and $11.59\;{\mu}g$ in mature Niitaka pears, which was significantly higher than those of other maturity stage in the same cultivar. Inhibitory activities on lipid oxidation of methanol extracts of three cultivars at all maturity stages were similar to that of ${\alpha}$-tocopherol.

• Nutritional Sciences
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• v.9 no.4
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• pp.330-334
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• 2006

Chemical composition of the Eucommia ulmoides bark, including extractives, proximate, mineral, fatty acid and monosaccharide compositions, was studied The most abundant mineral was calcium (533.17 mg/l00 g). $\alpha-linolenic$ acid (24.7%) and linoleic acid (24.3%), showed higher contents among the fatty acids. Major monosaccharides of E. ulmoides balk were arabinose (13.94 mg/g), xylose (18.91 mg/g) and glucose (119.7 mg/g). From the bark of E ulmoides, four compounds were isolated and their structures were elucidated as caffeic acid (I), kaempferol (II), quercetin (III) and isoquercitrin (IV) by spectroscopic analysis such as NMR and MS, including cellulose TLC and other chemical evidence such as hydrolyzation and acetylation. The antioxidant activities of four isolated compounds were evaluated by DPPH free radical scavenging, hydroxyl scavenging and reducing power assays. The results indicated that all the isolated compounds showed higher DPPH radical scavenging activity than $\alpha-tocopherol$ and BHT that were used as positive controls and these four compounds exhibited considerable reducing power and hydroxyl radical (OH) scavenging activity. Considering from the results above, it suggests that the E. ulmoides bark is a potential natural source of antioxidant material.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.495-510
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• 2017

This study was to investigate the antioxidant activities of Cryptomeria japonica leaves extracts such as essential oil, methanol extract and hot water extract and to evaluate its potential as a natural antioxidant. Antioxidant activities of extracts were evaluated by DPPH radical scavenging activity, FRAP activity, zanthin oxidase inhibitory activity, and iron ion chelate activity, comparing with the positive controls. According to the results, methanol and hot water extracts showed higher antioxidant activities than essential oil. This fact suggested that terpenoids have lower antioxidant effect than phenolic compounds which were found in methanol and hot water extracts. Especially, acetone and water soluble fractions of methanol extract and ethanol fraction of hot water extract contained a lot of phenolic compounds and hydroxyl group, indicating that many hydroxyl groups and glycosidic bonds showed higher antioxidant effect than the other fractions. These results can suggest that the phenolic compounds which contained hydroxyl group or glycosidic bonds have a certain role for effective antioxidant activities.

• The Korean Journal of Food And Nutrition
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• v.27 no.3
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• pp.348-357
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• 2014

This study was carried out to evaluate the yield of extract, antioxidant compounds (total phenolic and total flavonoid), antioxidant (DPPH assay, ABTS assay and reducing power), and antimicrobial activities of bracken (Pteridium aquilinum Kuhn), according to cooking methods (non-blanched, blanched and seasoned). The yield of seasoned bracken extracts showed a high value of (4.59%) followed by non-blanched bracken and blanched bracken with 2.69% and 0.30%, respectively. In the total polyphenol and flavonoid contents, seasoned bracken extracts showed higher antioxidant compounds ($96.11{\pm}0.34mg\;GAE$/100 g RW, $20.90{\pm}0.mg\;CE$/100 g RW) than non-blanched and blanched. The total antioxidant activities (DPPH assay, ABTS assay and reducing power) were shown to be in the order of seasoned bracken > non-blanched bracken > blanched bracken. In the antimicrobial activities, non-blanched bracken extracts showed antimicrobial activity against B. cereus, B. subtilis, E. cloacae, E. coli, S. enterica, and P. aeruginosa except for S. aureus. The non-blanched bracken extracts (5 and 10 mg/disc) especially showed strong antimicrobial activity against P. aeruginosa ($10.00{\pm}0.71$ and $10.25{\pm}0.35mm$). The inhibition zone diameter from the extracts of blanched bracken and seasoned bracken was not detected. Many seasonings added in the process of cooking can increase the antioxidant capacities. The overall results of this study demonstrate that the cooked bracken with seasoning would be the most efficient way of ingesting antioxidant compounds.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.85-91
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• 2000

Antioxidant activity and related components including tocopherols, phenolic compounds and carotenoids in the corn(Zea mays L.) kernels were measured to understand effects of fertilizer application. Hybrids used were Chalok 2, a waxy corn, and Suwon 19, a dent corn. The standard fertilizer level of N-P-K was 14.5-3-6 for Chalok 2 and 17.4-3-6.9 for Suwon 19. The treatments of the fertilizer levels were the standard level, half and two fold amounts of N, P, and K, and no fertilizer. The antioxidant activity was determined by measuring electron donating ability. The antioxidant activity of Chalok 2 was higher than Suwon 19. The antioxidant activity was the highest at the standard fertilizer treatment for Chalok 2, but was statistically not significant. The antioxidant activity and the related compounds content in Suwon 19, however, were the highest in the two fold nitrogen treatment, and the differences were significant. The contents of tocopherols, phenolic compounds and carotenoids were 30.0~38.1, 104.7~118.8, $0.1{\mu}gml^{-1}$, respectively for Chalok 2 and 16.7~20.1, 59.9~72.7, $35.5{\sim}50.0{\mu}gml^{-1}$, respectively for Suwon 19. The antioxidant activity was positively correlated with the grain yield in both cultivars. The shorter the ASI the higher the yield of the plant. The difference in genetic factors would affect greater influence than fertilizer effect on the antioxidant activity of corn.

• The Korean Journal of Food And Nutrition
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• v.29 no.3
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• pp.347-356
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• 2016

This study analyzed the antioxidant properties of Equisetum arvense and its effects on serum factor levels in mice fed a high-fat diet. The aim was to establish a new effective resource for biologically active materials. E. arvense stem and root extracts were obtained using deionized water at $95^{\circ}C$, and 70.5% ethanol at $85^{\circ}C$. These extracts were used to analyze the total phenolic compounds and antioxidant (ABTS, DDPH, and FRAP) activities. The effects of prepared ground samples were evaluated by feeding them to mice. E. arvense extracts showed strong antioxidant effects. The caffeic acid content was highest in the 70.5% ethanol extract of the vegetative stem, as determined by high-performance liquid chromatography. The blood concentrations of insulin and leptin were significantly lower in mice fed a high-fat diet supplemented with extracts of the root, reproductive stem, and vegetative stem of E. arvense than in mice fed only a high-fat diet. These results suggest that the polyphenolic compounds in E. arvense extracts exert various antioxidant effects. The stems and root of E. arvense can lower the blood levels of insulin and leptin, even after consumption of a high-fat diet.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.55-61
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• 2007

The antioxidant activities of water, ethanol, methanol, and chloroform extracts of Ulmus davidiana were evaluated using various antioxidant assays: DPPH (1,1-diphenyl-2-pricrylhydrazyl) free radical scavenging; hydroxyl radical scavenging; lipid peroxidation scavenging; and reducing power assays. All extracts, except the chloroform extract, demonstrated strong antioxidant activity in all assays. The chloroform extract had the highest hydroxyl radical scavenging activity, and its activity was equivalent to $\alpha$-tocopherol at a concentration of 0.5 mg/mL. Additionally, the antidiabetic activity of their extracts was also evaluated using a rat intestinal $\alpha$-glucosidase inhibition assay. Among all extracts investigated, the methanol extract had the highest $\alpha$-glucosidase inhibitory activity, although its activity was less than acarbose at $0.5\;{\mu}g/mL$. This result suggested that U. davidiana extracts may have antidiabetic activity. Total phenolic compounds and flavonoids were also measured. Phenolic compounds such as tannic acid, p-coumatric acid, and kaempferol were detected by high-performance liquid chromatography (HPLC). These results suggest that U. davidiana extracts may be useful as a potential source of antioxidant and antidiabetic materials.