• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.310-314
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• 2016

The search for natural antioxidants as alternatives to synthetic products is growing. Microalgae have emerged as a source of natural antioxidants with significant and diverse health-promoting properties. In this study, the effects of hot-water extraction conditions on total polyphenol compounds (TPC) production were investigated for lipid extracted microalgae (LEA). In order to enhance the polyphenol productivity, the extraction variables including solvents, temperature, time and ethanol concentration were optimized. The results showed hot-water extraction provided a higher extraction efficiency than the organic solvents and extraction at high temperatures showed a better extraction efficiency. While hot-water extract showed a higher extraction efficiency compared to 98% ethanol extraction, the mixture of water and ethanol (40:60 v/v) showed the highest production of polyphenols. The maximum polyphenols of 3.35 mg GAE (gallic acid equivalent)/g DM were obtained at the optimized extraction time of 10 min, $100^{\circ}C$ and 40% ethanol, respectively. Although Tetraselmis KCTC 12236BP was preprocessed by hexane to remove lipid for bio-diesel production, the results showed LEA contains relatively high level of polyphenols compared to untreated microalgae which can be used in the production of value-added materials. The predictions obtained from the developed Peleg's model were compared with the experimental data under the same operating conditions. The predicted and experimental data were consistent, indicating the reliability of the model.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.957-964
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• 2008

Antioxidative, antidiabetes, antibacterial, anticancer and angiotensin-converting enzyme (ACE) inhibitory activities of methanol extracts of dried persimmon, fresh persimmon and persimmon leaves were investigated. Total polyphenol content of dried persimmon, fresh persimmon and persimmon leaves were 147.79, 301.45 and $315.90\;{\mu}g/mg$, respectively, of which fresh persimmon and persimmon leaves had significantly higher total polyphenol than dried persimmon. Activities of DPPH radical scavenging, lipid peroxidation inhibition and salivary $\alpha$-amylase inhibition were increased in persimmon leaves related to total polyphenol contents. Anticancer activities against AGS of fresh persimmon and persimmon leaves were $65{\sim}70%$; however, there were no significant differences between dried persimmon and fresh persimmon on free radical scavenging activity and inhibitory activity of salivary $\alpha$-amylase. Also, extracts of dried persimmon, fresh persimmon and persimmon leaves showed good ACE inhibitory activities. Dried persimmon and fresh persimmon showed antibacterial activities on E.coli O157:H7. Therefore, there are many difference activities by dried and parts of persimmon. From this result, it is suggested that persimmon leaves is believed to have possible antioxidative, antidiabetes and anticancer capacities by polyphenol, but further studies on the identification of the active compound(s) as antioxidant, antidiabetic, antihypertensive and antibacterial materials will be needed to develop a better understanding of its potency on persimmons.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.7
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• pp.813-818
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• 2007

For this study, extracts of Vitex rotundifolia stems were prepared using reflux water extraction (WE), reflux ethanol extraction (EE) and hot water extract under high pressure (HWE). The extracts were investigated for the total content of phenolic compounds, antioxidant activities, and inhibitory potencies for xanthine oxidase and tyrosinase. The EE extraction method yielded the highest content of polyphenol compounds (176.34 mg/g). The electron donating abilities (EDA) were 93.46${\sim}$96.92%, when extracts were assayed at 1.0 mg/mL. The superoxide dismutase (SOD)-like activity was the highest in the WE extract (47.32% at 1.0 mg/mL). The nitrite scavenging abilities (pH 1.2) were 84.61${\sim}$88.36% and the inhibition of xanthine oxidase were over 90% at 0.5 mg/mL. Tyrosinase inhibition of HWE and WE were 57.84% and 53.47% respectively. It implies that V. rotundifolia stems have potent physiological activities and their activities were differently exhibited depending on solvent fractions.

• Food Science and Preservation
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• v.13 no.5
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• pp.616-622
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• 2006

This study was intended to analyze the contents of polyphenol compounds and vitamin C, and the inhibitory activities of xanthine oxidase and tyrosinase to measure physiological efface of various extract of Lespedeza bicolor. The vitamin C content was $26.42{\pm}0.08mg/100g$. The content of phenolic compounds included in the flesh L bicolor was $1.14{\pm}0.02mg/g$. The ethanol extract by reflux method and water extracts by the microwave-assisted method showed the highest content as 154.95 mg/g and 145.17 mg/g, respectively. The xanthine oxidase inhibitory tate of water extracts was the highest value of 87.85% at the concentration of 1,000 ug/mL. All kinds of extracts showed the highest inhibitory activity for the xanthine oxidase at the concentration of 1,000 ug/mL and a decreasing pattern of the inhibitory race over the concentration of 1,000 ug/mL. The tyrosinase inhibitory rate was increased with an increment of the extract concentrations, and the activity of ethanol extracts was the highest as 55.22% at the concentration of 3,000 ug/mL.

• Food Science and Preservation
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• v.15 no.1
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• pp.133-138
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• 2008

This study investigated the antioxidant activities of extracts from Angelica dahurica roots after microwave-assisted extraction with different levels of energy (120, 240W) and extraction time (5, 10, 15 and 30 min). The highest extraction yield was 11.77 mg% in water at 240W for 30 min followed by 11.42 mg% in water at 120Wand 30 min. The highest total polyphenol contents was 32.36 mg/g in an ethanol extract, followed by 31.77mg/g in water extract at the same conditions of 240W, 30 min. The electron donating abilities both the ethanol extract obtained using 240W and 30 min and the water extract obtained employing 120W and 5min showed the highest values, 83.55% and 82.49% respectively at a concentration 1.0mg/mL. The highest superoxide dismutase (SOD)-like activity was 14.16% in ethanol extract at 120Wand 15min, followed by 13.22% in the water extract at 120W and 5 min. The best extraction yield and polyphenol content after microwave-assisted extraction were achieved with 240W and 30 min using water. The best condition for extraction of electron donating ability and SOD-like activity from A dahurica roots were 120W and 5 minutes using water.

• Korean Journal of Food Science and Technology
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• v.42 no.6
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• pp.750-754
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• 2010

The purpose of this study was to investigate the antioxidant and skin whitening effects of Rhamnus yoshinoi extracts. Rhamnus yoshinoi was extracted with 100% ethanol and water. The antioxidative and skin whitening effects of extracts were determined by in vitro assays using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and inhibitory effects against tyrosinase activity and melanogenesis in B16F1 melanoma cells. The radical scavenging activities of the Rhamnus yoshinoi extracts were tested by DPPH assay and showed high DPPH radical scavenging activities (SC50; 21.6 ppm in EtOH, 40.5 ppm in water). As for tyrosinase inhibitory activity, the Rhamnus yoshinoi ethanol extract had the highest inhibition activity ($IC_{50}$; 256.3 ppm). In B16F1 mouse melanoma cells, the Rhamnus yoshinoi ethanol extract significantly inhibited melanin synthesis by 53.36% at the concentration of 50 ppm. These results suggest that Rhamnus yoshinoi ethanol extract has significant antioxidant activity and whitening activity.

• Korean Journal of Food Science and Technology
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• v.48 no.1
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• pp.59-65
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• 2016

This study was carried out to investigate the total polyphenols, antioxidant activities, and melanin synthesis inhibition of several pear cultivars (Pyruspyrifolia). The total polypenolic content of five pear cultivars was high in the unripe developmental stage. Total polyphenolic content of the Chuwhangbae cultivar extract was higher than that of other pear cultivars regardless of the developmental stage. However, the total flavonoid content did not differ between cultivars or developmental stages. The phenolic compound, arbutin has an inhibitory effect on melanogenesis. Arbutin levels in pear cultivars declined as the fruit matured. The free radical scavenging activity of the extract also decreased as the fruit ripened. In B16F10 mouse melanoma cells, most of the cultivar extracts inhibited melanin synthesis by about 50% at a $100{\mu}g{\cdot}mL^{-1}$ concentration, except in the Gamcheonbae extract until 90 days after full bloom. We have confirmed that the extract of pear cultivars have antioxidant activity and skin-whitening effects.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1286-1290
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• 2006

The objectives of this study were to determine antioxidant activities and antioxidnat compounds of 13 imported and 4 domestic red wines and to investigate relationships between antioxidant activities and antioxidant compounds in the selected red wines. The concentrations of total polyphenolics and anthocyanins in the samples were investigated by spectrophotometric methods. ABTS (2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid) and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, and reducing power have been used to compare the relative antioxidant activities of the selected red wines. In this study, total polyphenolic contents of the red wines were ranged from 250 to 2,298 mg gallic acid equivalents/L and the anthocyanin contents were ranged from 11 to 349 mg cyanidin-3-glucoside equivalents/L, respectively. As expected, all the red wines exhibited excellent antioxidnat activities (ABTS and DPPH radical scavenging and reducing power) except three domestic red wines. The correlation coefficient between total polyphenolic content and their antioxidant activities, namely ABTS radical scavenging activity, DPPH radical scavenging activity and reducing power, were 0.9784, 0.9905 and 0.8580, respectively. No correlation was observed between total anthocyanin content and their antioxidant activities.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.102-102
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• 2018

중국유(中國柚)의 주요성분은 비타민 C가 레몬보다 10배나 많이 함유되어 있고 또한 과피 안쪽에 펙틴 성분이 다량으로 함유되어 있다. 특히 과피가 일반 감귤류 보다 10배 이상 두꺼워 비타민P의 ?량 또한 다량으로 함유되어 있다. 즉, 유기산, 비타민P와 비타민C가 매우 많이 함유되어 있어서 예로부터 중국에서는 감기와, 피부노화, 피로를 방지하는데 사용되어져 왔으며 이러한 효능은 유기산에서도 많이 발생되었다. 그 밖에 비타민B군과 당질, 단백질등이 다른 감귤류 품종보다 많고, 모세혈관을 보호하는 헤스페리딘(비타민P)이 다량으로 함유되어 있어서 심혈관 질환 장애와 뇌졸증, 뇌출혈 등을 억제하는 효과를 가지고 있다. 또한 몸 안에 쌓여 있는 노폐물 등을 밖으로 배출시켜주는 효과가 양호하여 피부미용에 효과가 있는 것으로 알려져 있다. 본 실험에서는 중국유(中國柚)의 항산화활성과 총 폴리페놀 함량을 조사하였던 바, 과육보다 과피에서 폴리페놀 함량이 높게 나타났으며 항산화 활성도 과피에서 매우 양호한 결과를 나타내었다. 중국유(中國柚)의 품종별로 보면 과피가 두껍고 과육이 붉은색을 띈 품종에서 항산화 효과가 더 양호한 반응을 나타내었다. 이러한 결과는 과육에 함유되어있는 안토시아닌의 함량의 차이인 것으로 생각된다. 특히 과피가 과육의 추출과정에서 에탄올보다 메탄올 추출물에서 더 양호한 결과를 보였다. 이러한 결과들로 미루어볼 때 중국유(中國柚)의 항산화 활성은 천연화장품의 신소재로서의 가치를 가지고 있다고 판단된다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.534-541
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• 2013

In the present study, the effects of heat treatments on the phenolic components and antioxidative activities of various rice cultivars (from Hwaseongbyeo, Keunnunbyeo, Hongjinjubyeo, and Heugkwangbyeo) were investigated. Each brown rice cultivar was heated at six temperatures (40, 60, 90, 120, 150, and $180^{\circ}C$) for 15 min. The total polyphenolic content (TPC) and total flavonoid content (TFC) of 70% ethanol extracts from heated brown rice were quantified using spectrophotometrical methods, and antioxidant activities determined using DPPH, ABTS radical scavenging activities and reducing power. Hongjinjubyeo had the highest TPC (6.50 mg GAE/g, DB) and ABTS radical scavenging activity (5.85 AAE/g, DB) at $60^{\circ}C$. Also, Heugkwangbyeo showed considerable values for TPC (6.57 and 6.89 mg GAE/g, DB) and ABTS radical scavenging activity (6.29 and 6.11 AAE/g, DB) at $40^{\circ}C$ and $180^{\circ}C$, respectively. Overall, the antioxidant activities of both Hongjinjubyeo and Heugkwangbyeo extracts had a strong positive correlation ($R^2{\geq}0.916$, ${\alpha}$=0.01) with TPC and TFC. These results indicate that heat treatment effectively enhances the antioxidant activity of Hongjinjubyeo and Heugkwangbyeo.