• Journal of Life Science
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• v.28 no.11
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• pp.1386-1395
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• 2018

Over recent years, it has become evident that the central nervous system bidirectionally interacts with the gastrointestinal tract along the gut-brain axis. A series of preclinical studies indicate that the gut microbiota can modulate central nervous system function through a multitude of physiological functions. Polyphenols are ubiquitous plant chemicals included in foods such as fruits, vegetables, tea, coffee and wine, and their consumption is directly responsible for beneficial health effects due to antioxidant, anti-inflammatory, antimicrobial, immunomodulatory, anticancer, vasodilating, and prebiotic-like effects. There is increasing evidence that dietary polyphenol can contribute to beneficial effects in neuronal protection acting against oxidative stress and inflammatory injury as well as in cognitive functions. In this paper, we overview the neuroprotective role of dietary polyphenols especially focusing on the neuroinflammation and neurovascular function by interaction with the gut microbiome. Polyphenol metabolites could directly act as neurotransmitters crossing the blood-brain barrier and modulating the cerebrovascular system or indirectly modulating gut microbiota. In addition, evidence suggests that dietary polyphenols are effective in preventing and managing neurological disorders, such as age-related cognitive decline and neurodegeneration, through a multitude of physiological functions. Dietary polyphenols are increasingly envisaged as a potential nutraceuticals in the prevention and treatment of neurological disorders, because they possess the ability to reduce neuroinflammation, to improve memory and cognitive function and to modulate the gut microbiota.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.5
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• pp.769-775
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• 2010

The genus Lespedeza belonging to Leguminosae is an annual or perennial herb, which has been used as a Chinese herbal medicine. Antioxidant activity on DPPH ((1,1)-diphenyl-2-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylenebenzothiazoline-6-sulfonic acid) radicals and the contents of total polyphenol and flavonoid were analyzed with 12 methanol extracts from six Lespedeza genus plants with different plant parts. The highest content of total polyphenol was detected in the leaves of Lespedeza$\times$robusta (194.6 mg GAE/g), while the highest content of total flavonoid existed in the aerial part of Lespedeza thunbergii var. intermedia (47.9 mg QE/g). Generally, the amounts of polyphenol and flavonoid compounds were higher in the leaves than in the stems. The $SC_{50}$ value of DPPH radical scavenging activity ranged from 10.16 to 90.94 ppm, of which the strongest activity was determined in the leaves of L. robusta. Most ABTS radical scavenging activities from the investigated methanol extracts were higher than that of L-ascorbic acid, implying the excellent antioxidant activity. The radical scavenging activity in this study showed high correlation with the amount of total polyphenol rather than that of total flavonoid. These data suggest that the methanol extracts from these Lespedeza spp. could be potential candidates for natural antioxidants.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.1
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• pp.111-115
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• 2000

This study was to investigate antiallergic contact hypersensitivity of the polyphenol fractons isolated from persimmon leaves (Diospyros kaki folum). The result of the allergic contact dermatitis is a common skin disease resulting from specific immunologic sensitization due to topically applied allergens. Here the contact hypersensitivity was assayed and obdominal skin morphological changes including mast cells were examined. At contact hypersensitivity assay, less right ear swelling occured in the polyphenol fraction I, II and III groups compared to the control group. The number of mast cells was significantly decreased in the sample groups than the control group.

• Bulletin of Food Technology
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• v.18 no.3
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• pp.31-38
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• 2005

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.4
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• pp.517-524
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• 2011

Eleven polyphenolic compounds, including procatechuic and chlorogenic acids, (+)-dihydroquercetin, rutin, isoquercitrin, quercitrin, (+)-dihydrokaempferol, trans-resveratrol, moracin, quercetin and 4-prenylmoracin were isolated and purified from the methanolic extract of defatted mulberry seed residue by a series of column chromatography including silica gel, Sephadex LH-20, and ODS-A, and their chemical structures were identified by spectral analysis. The antioxidant activities of the eleven isolated polyphenolic compounds were measured spectrophotometrically using DPPH radical. Among the eleven polyphenolic compounds tested, rutin ($IC_{50}=20.2\;{\mu}M$), isoquercitrin ($IC_{50}=22.5\;{\mu}M$), quercitrin ($IC_{50}=24.6\;{\mu}M$), quercetin ($IC_{50}=27.8\;{\mu}M$), (+)-dihydroquercetin ($IC_{50}=28.9\;{\mu}M$), and chlorogenic acid ($IC_{50}=30.6\;{\mu}M$) exhibited stronger antioxidant activity than L-ascorbic acid ($IC_{50}=31.5\;{\mu}M$) and ${\alpha}$-tocopherol ($IC_{50}=52.3\;{\mu}M$), whereas procatechuic acid ($IC_{50}=68.2\;{\mu}M$) showed lower activity. In addition, (+)-dihydrokaempferol ($IC_{50}=33.8\;{\mu}M$), trans-resveratrol ($IC_{50}=36.2\;{\mu}M$), moracin ($IC_{50}=47.6\;{\mu}M$), and 4-prenylmoracin ($IC_{50}=48.2\;{\mu}M$) exhibited moderate antioxidant activity. Furthermore, levels of the eleven polyphenolic compounds from three different types of mulberry seeds were quantified by HPLC, and their contents were as follows: rutin (311~60.0 mg/100 g)> quercitrin (7.2~34.2 mg/100 g)> (+)-dihydroquercetin (13.2~33.1 mg/100 g)> quercetin (15.8~19.5 mg/100 g)> 4-prenylmoracin (10.5~43.3 mg/100 g)> isoquercitrin (5.8~15.4 mg/100 g)> chlorogenic acid (0.0~15.3 mg/100 g)> moracin (4.7~7.2 mg/100 g)> procatechuic acid (0.0~11.6 mg/100 g)> (+)-dihydrokaempferol and trans-resveratrol (<0.1 mg/100 g). The 'Daesungppong' mulberry seeds among the three cultivars had higher flavonoid contents, such as rutin and quercetin derivatives, while the 'Iksuppong' seeds had the highest contents of phenolic acids and moracin derivatives. 'Cheongilppong' had lower amounts of polyphenolic compounds than the other two mulberry seeds. These results indicate that mulberry seeds containing antioxidant polyphenolic compounds may be potentially useful sources of anti-diabetic, anti-hypertensive, and anti-aging agents for functional foods and cosmetics.

• Korean journal of food and cookery science
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• v.30 no.6
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• pp.767-773
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• 2014

In vitro antioxidative activities and antioxidants of the lotus root, dried laver, and perilla leaf bugak, Korean traditional fried cuisine, were evaluated. The bugak was prepared with fermented glutinous rice batter and unroasted sesame oil for use in the pan-frying. The perilla leaf bugak showed the highest radical scavenging activity and reducing power, with the lowest in the lotus root bugak. The antioxidative activity of the blanched lotus root was lower than the dried laver or the perilla leaf. Polyphenol content was higher in the perilla leaf bugak than the lotus root or the dried laver bugak, and tocopherols were mainly derived from frying oil. The antioxidative activity of bugak was correlated well with polyphenol contents, but there was no correlation between tocopherol contents and the antioxidative activity.

• Food Science and Preservation
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• v.18 no.3
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• pp.328-334
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• 2011

Natural polyphenolic compounds such as catechin, epicatechin derivatives, quercetin, and resveratrol, have been reported to have a wide range of biological activities against carcinogen and reactive oxygen species. The compounds can act together in synergy or can independently affect the activity. Contents of four compounds in different grape cultivar groups with different skin color were determined through HPLC. There were not significant differences in content of four phenolic compounds among the different skin color groups of the same grape cultivar groups, but were among different grape cultivars within the same skin color groups. Totally, contents of catechin, epicatechin derivatives were much higher than those of quercetin and resveratrol. In each skin color group, Campbell Early in Black, Seneka in Green, and Benigard in Red group showed highest contents, respectively. Nothing or a very small amount of four phenolic compounds was detected in some cultivars. This information would be useful for grape breeders and manufactures.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.147-152
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• 1999

HPLC was used for determining polyphenols which are known as the functional compounds in the unripe apples Fuji and Aori. The changes in their contents caused by heat treatments were monitored. The carbohydrate contents in Fuji and Aori were 14.1% and 13.5% respectively. Both apple juices showed pH 3.2 and $8.0\;brix^{\circ}$, which were relatively low levels. The major polyphenols were composed of (+)-catechin, chlorogenic acid, (-)-epicatechin, and tannic acid. Total polyphenol contents in Fuji and Aori were 0.11, 0.12% by Folin-Denis method. HPLC analysis of polyphenols showed that four major components were contained by 0.06% in Fuji and 0.07% in Aori. Chlorogenic acid was three times higher in Fuji than in Aori. After water blanching, the area percent of polyphenols resulted in an increase by 3.54% in Fuji but a decrease by 2.93% in Aori. Pasteurization of juices led to decrease by 1.39% and 3.31% respectively. Blanching and pasteurization of unripe apple juices induced negligible changes in polyphenol contents during storage. During concentration, polyphenol contents increased in proportion to the concentration of unripe apple juices.

• Journal of Life Science
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• v.27 no.4
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• pp.476-481
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• 2017

Polyphenols are secondary metabolites produced by higher plants and have been used as antiallergic, anticancer, antihypertensive, antiinflammatory, antimicrobial and antioxidant agents. They are generally divided into flavonoids and non-flavonoids. The antimicrobial activity of flavonoids are stronger than that of non-flavonoids. The skeleton structures of flavonoids possessing antimicrobial activity are chalcone, flavan-3-ol (catechin), flavanone, flavone, flavonol and proanthocyanidin. The flavonols are shown antibacterial activity against several gram-positive bacteria (Actinomyces naeslundii, Lactobacillus acidophilus and Staphylococcus aureus) and gram-negative bacteria (Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella melaninogenica and Prevotella oralis). Among of non-flavonoids, caffeic acids, ferulic acids and gallic acids showed antimicrobial activity against gram-positive (Listeria monocytogenes and S. aureus) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). These are found to be more efficient against the E. coli, L. monocytogenes, P. aeruginosa and S. aureus than antibiotics such as gentamicin and streptomycin. The kaempferol and quercetin showed synergistic effect with ciprofloxacin and rifampicin against S. aureus and methicillin resistant S. aureus (MRSA). Epigallocatechin gallate (EGCG) acts synergistically with various ${\beta}-lactam$ antibiotics against MRSA. In particular, the epicatechin, epigallocatechin (EGC), EGCG and gallocatechin gallate from Korean green tea has antibacterial activity against MRSA clinical isolates and the combination of tea polyphenols and oxacillin was synergistic for all the clinical MRSA isolates.

• Journal of Life Science
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• v.21 no.11
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• pp.1631-1635
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• 2011

The capability of synthesizing polyphenol glycosides was examined using recombinant amylosucrase from the hyperthermophilic bacterium Deinococcus geothermalis. Based on the action mode of amylosucrase, sucrose and twenty-one polyphenols were used as a donor and acceptors respectively. The transglycosylation reaction by amylosucrase produced one or two major polyphenol glycosides depending on the type of polyphenols used. The synthesized polyphenol glycosides were detected by thin-layer chromatography. The structures of the newly synthesized polyphenol glycosides were predicted based on the transglycosylation mechanism of the enzyme. According to the acceptability of the polyphenols, the structural characteristics of polyphenol as an efficient acceptor were evaluated. The results indicate that amylosucrase is an efficient catalyst for the enzymatic synthesis of polyphenol glycosides, which have high potentials in food, cosmetics, and pharmaceutical industries.