• Nutrition Research and Practice
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• v.6 no.4
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• pp.286-293
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• 2012

Resveratrol (3,4,5-trihydroxy-trans-stilbene), a phytoalexin found in grape skin, grape products, and peanuts as well as red wine, has been reported to have various biological and pharmacological properties. The purpose of this study was to investigate the anti-obesity effect of resveratrol-amplified grape skin extracts on adipocytes. The anti-obesity effects of grape skin extracts were investigated by measuring proliferation and differentiation in 3T3-L1 cells. The effect of grape skin ethanol extracts on cell proliferation was detected by the MTS assay. The morphological changes and degree of adipogenesis of preadipocyte 3T3-L1 cells were measured by Oil Red-O staining assay. Treatment with extracts of resveratrol-amplified grape skin decreased lipid accumulation and glycerol-3-phosphate dehydrogenase activity without affecting 3T3-L1 cell viability. Grape skin extract treatment resulted in significantly attenuated expression of key adipogenic transcription factors, including peroxisome proliferator-activated receptor, CCAAT/enhancer-binding proteins, and their target genes (FAS, aP2, SCD-1, and LPL). These results indicate that resveratrol-amplified grape skin extracts may be useful for preventing obesity by regulating lipid metabolism.

• Preventive Nutrition and Food Science
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• v.7 no.3
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• pp.231-237
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• 2002

This study was conducted to determine biological activities, such as lipid peroxidation inhibition, cytotoxicity, sun blocker, inhibition of tyrosinase, and antioxidative effect, of ethanol extracts, and of solvent fractionated ethanol extracts obtained from grape seeds and skins. The strongest lipid oxidative inhibition of 66.9% and 67.6% was observed respectively, in the presence of 20 $\mu\textrm{g}$/$m\ell$ of both ethanol extract and water fraction of grape seeds. Overall, the ethanol extracts and their fractions of grape seeds exhibited stronger lipid oxidative inhibition than that of skin extracts. On the other hand, the ethanol extracts of grape skins showed stronger cytotoxicity than that of seeds on MCF-7, Hep3B, and A549 cancer cell lines. However, the water fraction of seed ethanol extracts showed the strongest cytotoxic effect of 76.52% and 67.01% on MCF-7 and Hep3B, respectively among their fractions. Ethanol seed extracts obtained at 3$0^{\circ}C$ had the strongest absorbance both at UVA region (350 nm) and UVB region (308 nm) and the chloroform fraction showed the strongest absorbance at W region and butanol fraction at UVA region among their tractions, respectively. In the meantime, the ethanol extracts obtained at 3$0^{\circ}C$ and butanol fraction showed the strongest tyrosinase inhibitory effect of 39.4% and 37.6%, respectively. This study shows that ethanol extracts and their fractions of grape seeds and skins could be potential good materials for functional food and cosmetic products.

• Food Science and Preservation
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• v.22 no.1
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• pp.12-18
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• 2015

The objective of this research was to investigate the antioxidant and antimicrobial activities of muscadine grape extracts. Three different cultivars of muscadine grapes including Higgings, Jumbo, and Noble were selected. The skin/pulp and seed parts of three selected muscadine grape cultivars were used for extraction. The total phenolic contents of muscadine grape extracts were expressed as gallic acid equivalents (GAE). The antioxidant activity of muscadine grape extracts were determined by scavenging activity of diphenylpicrylhydrazyl (DPPH) radical and expressed as effective concentration ($EC_{50}$), which represented the concentration of the extract exhibiting 50% DPPH radical scavenging. The antimicrobial activity against E. coli K12 was determined and expressed as the minimum inhibition concentration (MIC). The seed extracts exhibited greater total phenolic contents than the skin/pulp extracts, ranging from 231.24 to 294.81 mg/mL GAE. The seed extracts exhibited greater antioxidant activities than the skin/pulp extracts ($EC_{50}$ of Higgins seed extract=0.026 mg/mL). However, the skin/pulp extracts exhibited greater antimicrobial activities than the seed extracts, exhibiting the minimum inhibition concentration (MIC) in Higgins skin/pulp extract (MIC=4.0 mg/mL). This research indicated that the seed part and skin/pulp parts of the muscadine grapes possessed antioxidant activity and antimicrobial activity, respectively. Therefore, it was concluded that muscadine grapes possess the potential to be utilized as functional foods or nutraceuticals.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.8
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• pp.961-966
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• 2006

This study was worked out to investigate antioxidant activity of solvent extracts from wild grape skin by measuring electron donating ability (EDA), reducing power, superoxide dismutase (SOD)-like activity, thiobarbituric acid reactive substances (TBARS) and nitrite scavenging ability. Total phenolic compound and flavonoids contents were the highest in ethyl acetate extract, $54.4{\pm}1.18\;mg/100\;g$ and $645.1{\pm}5.05\;mg/100\;g$, respectively. The EDA and reducing power of solvent extracts from wild grape skin were proportionally increased with concentration and ethyl acetate extract $(79.2{\pm}0.06%)$ showed the stronger than BHT $(74.1{\pm}0.15%)$ at concentration of $100\;{\mu}g/mL$, especially. SOD-like ability of ethyl acetate $(25.1{\pm}0.41%)$ and butanol $(20.2{\pm}0.13%)$ extracts were stronger than other extracts at concentration of $100\;{\mu}g/mL$. TBARS of ethyl acetate extract was higher than ascorbic acid. Nitrite scavenging ability of solvent extracts from wild grape skin (pH 2.5, $1000\;{\mu}g/mL$) were in order of ethyl acetate $(90.5{\pm}0.75%)$>butanol $(65.9{\pm}2.16%)$>hexane $(58.1{\pm}1.74%)$>chloroform $(55.4{\pm}1.02%)$>water $(40.9{\pm}0.35%)$. Antioxidant activity of solvent extracts from wild grape skin was the highest in ethyl acetate extract from the results of our experiments.

• Food Science and Preservation
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• v.9 no.3
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• pp.338-344
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• 2002

This study was conducted to determine biological activities, such as lipid peroxidation inhibition and cytotoxic effect of ethanol extracts of Black Olympia grape seeds and skins, and of organic solvent fractionated ethanol extracts obtained from grape seeds and skins at different temperatures. Among different extraction temperatures, the ethanol extract of grape seed obtained at 30$\^{C}$ had the strongest lipid oxidation inhibition of 60.1%, while the strongest lipid oxidation inhibitory effect of 71.2% was observed in the presence of 20 $\mu\textrm{g}$/㎖ ethylacetate fraction obtained from ethanol extract of grape seeds at 30$\^{C}$. The ethanol extract of grape seeds showed more strong lipid oxidation inhibition than that of skin extracts. Similar results were observed in cytotoxic effects. The ethanol extract of grape seeds at 30$\^{C}$ exhibited more strong cytotoxicity than that of skin extracts on MCF-7, Hep3B, and A549 cell lines. Among organic solvent fractions extracted from the ethanol extracts of gape seeds and skins, the hexane fraction showed the strongest cytotoxic inhibition of 75.15% and 62.50% on MCF-7 and Hep3B cell in the presence of 1.0 $\mu\textrm{g}$/㎖ respectively. On the other hand, the water fraction showed the strongest cytotoxic inhibition of 65.41% on A549 cell in the presence of 1.0 $\mu\textrm{g}$/㎖. Overall, the ethanol extracts and their fractions of Black Olympia grape seeds showed strong lipid oxidation inhibition and cytotoxicity than those of grape skins.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2002.04a
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• pp.72.2-72
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• 2002

• Food Science and Biotechnology
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• v.16 no.6
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• pp.884-888
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• 2007

The aim of this study was to analyze the antioxidant properties of different cultivars of grape skin extract in an in vitro system. The extracts were prepared from eight grape cultivars: 'Campbell Early' (CE), 'Kyoho' (K), 'New Kyoho' (NK), 'Muscat of Alexandria' (MOA), 'Seibel' (S), 'Morgen Schow' (MS), 'Gold Finger' (GF), and 'Meru' (M). The total phenolic acid contents were highest in MS and K. Resveratrol content was high in NK (50.88 mg/l g of coat), and quercetin content was significantly higher in K (0.68 mg/l g of coat) than in the other grape species (0.21-0.44 mg/l g of coat). The K and MS grape species, in which total phenol content was comparatively high (K: $24.15\;{\mu}g/mL$, MS: $25.52\;{\mu}g/mL$), also showed a high level of electron donating activity (K, 53%; MS, 59%). The hydrogen radical scavenging activity of M (50.36%) was significantly higher than the other grape species, including the S (50.21%), MS (49.43%), and K (49.06%) cultivars. Antioxidant activity varied depending on grape species, but overall it was highest in the MS and K cultivars.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.121-124
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• 2003

Optimal extraction condition and free radical scavenging effect of ethanol extracts of Olympia grape (Vitis labruscana L.) seeds and skins were determined. Extraction yield of grape seeds increased with increasing extraction temperature increased, but was not affected by ethanol concentration in grape skins. Highest extraction yields obtained with 100% ethanol concentration at $78^{\circ}C$ were 36 and 49.5% in seeds and skins, respectively. Ethanol extract of grape seeds obtained at $78^{\circ}C$ showed stronger $RC_{50}\;(409.7\;{\mu}g/mL)$ than that of grape skins. Among organic solvent fractions, ethylacetate fraction obtained from ethanol extract of grape seed showed the strongest $RC_{50}\;(136.7\;{\mu}g/mL)$. Overall, ethanol extracts of grape seeds and their organic fractions showed significantly stronger free radical scavenging effect than those of skin extracts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.115-118
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• 2003

This study was conducted to determine optimal extraction condition and free radical scavenging effect of ethanol extracts of Campell Early grape seeds and skins at different temperatures, and of organic solvent fractionated from ethanol extracts of grape seeds and skins. The free radical scavenging effect was tested using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and expressed as dose required for a 50% reduction of DPPH radical (RC$_{50}$). The extraction yields were increased with increasing the extraction temperature but it was not related with ethanol concentrations. The ethanol extract of grape seeds obtained at 5$0^{\circ}C$ showed the more stronger RC$_{50}$ (16.8 $\mu\textrm{g}$/mL) than those of both 3$0^{\circ}C$ and 78$^{\circ}C$. The ethylacetate fraction obtained from ethanol extract of grape seed showed the strongest RC$_{50}$ (15.4 $\mu\textrm{g}$/mL). Overall, both ethanol extracts and their fractions of grape seeds showed significantly stronger free radical scavenging effect than those of skin extracts.racts.

• KSBB Journal
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• v.24 no.5
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• pp.477-482
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• 2009

Anthocyanin and origomeric proanthocyanidin (OPC) fractions showing antioxidizing activity are present in grape extracts. Grape extracts are widely used in cosmetic applications as functional ingredients. The aim of our study is to isolate the antioxidant fraction from waste of grape products. The extraction was done using soxhlet apparatus. Next, the extraction was subjected for identification of antioxidants by using HPLC. Antioxidant assay was performed by using 2,2-diphenyl-picryl-hydrazyl (DPPH) and superoxide dismutase (SOD) method. Antioxidizing activity was found to be higher in grape seed extract when compared to grape skin extract. Using the extract, a novel formula with multi lamella emulsion structure has been developed and its safety and stability were confirmed by standard protocols.