• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.12
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• pp.1628-1632
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• 2007

The present study describes the preliminary evaluation of antioxidant activities and antigenotoxic effect of Rhododendron mucromulatum Turcz. flowers (RMF). The samples were prepared by extracting RMF with four different solvents (methanol, ethanol, acetone, and water), and antioxidant properties were evaluated by determining total phenolic contents (TPC), DPPH radical scavenging activity (RSA), and reducing power (RP). Water extract showed the highest total phenol content (328.1 mg/g gallic acid equivalents). Acetone extract showed the most potent RSA and RP. The $IC_{50}$ for RSA and RP in the acetone extract were 78 mg/mL and 454 mg/mL, respectively. The 200 mM $H_2O_2$ induced DNA damage, measured by Comet assay, was inhibited with water, methanol and acetone extract in dose dependent manner in human leukocytes. The inhibition rates were 42, 62, and 52% at the concentrations of 50 mg/mL of water, methanol and acetone extracts, respectively. These results suggest that R. mucromulatum Turcz. has significant antioxidative activity and protective effect against oxidative DNA damage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.2
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• pp.313-318
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• 2010

This study was carried out to evaluate the antioxidant activity of stevia extracts from Stevia rebaudiana Bertoni leaves. Stevia extracts were prepared by three different methods including hot water extraction (HWE) at $120^{\circ}C$ for 4 hr, vacuum extraction (VE) at $65^{\circ}C$ for 4 hr under 0.08 MPa, and fermentation of hot water extract (FHWE) using Lactobacillus buchneri. The antioxidant activities measured by radical scavenging activity, ferric-reducing antioxidant potential ability, and thiobarbituric acid reactive substance showed the highest values in vacuum extract. Also, the antioxidant activities of all extracts were higher than those of stevioside and rebaudioside at the same concentrations, known as the major active components in stevia. To define the antioxidative compound in stevia extracts, the total phenol content was measured, and it was shown that the highest contents of total phenolic compounds were in vacuum extract. These results suggest that the antioxidant activity of stevia extract was due to the phenolic compound components. In addition, vacuum extraction was the proper method to prepare stevia extract with higher antioxidant activity.

• Korean Journal of Medicinal Crop Science
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• v.12 no.1
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• pp.79-84
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• 2004

To develop a new functional materials, angiotensin converting enzyme (ACE) inhibitory activity, antioxidant effect and total phenolic content of Hovenia dulcis Thunb. cortex were evaluated. Methanol and water extract of H. dulcis inhibited ACE by 81% and 76%, respectively, at the concentration of $4,000\;{\mu}g\;m{\ell}^{-1}$ which were similar level with that (85%) of commercial peptide-type ACE inhibitor. Superoxide radical scavenging activity of two extracts $(99.5%{\sim}99.9%)$ were stronger than that (69%) of ascorbic acid at the final concentration of $200\;{\mu}g\;m{\ell}^{-1}$. Among the solvent fractions, ether and ethylacetate fraction showed also potent scavenging activities (91% and 85%) for superoxide radical. Inhibitory activities of two extracts on oxidation of human low density lipoprotein (LDL) which were similar with that of ${\alpha}-tocopherol$, were higher than 80% at the concentration of $50\;{\mu}g\;m{\ell}^{-1}$. Total phenol contents of methanol and water extracts were 7.2% and 3.6%, respectively, and that of ethylacetate showed the highest value as 60.8% among the solvent fractions. Therefore, it has been suggested that H. dulcis cortex could be a effective anti-hypertention and antioxidant resource to develope a new functional material.

• Korean Journal of Microbiology
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• v.43 no.3
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• pp.217-221
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• 2007

The domestic cultured Campbell's Early and Geubong grapes were fermented far the production of red wines with the isolated wild yeast Saccharomyces cerevisiae IJ850. For the isolation of wild yeast, Geubong and Campbell's Early grapejuices were naturally fermented at room temperature for 6 days without adding stater culture. The strain isolated from Geubong which has 1.8 times higher fermentative ability than the strains isolated Campbell Early was selected. The selected strain was identified by using 26S rDNA sequencing. The strain showed 99.7% of similarity with Saccharomyces cerevisiae and thus identified as Saccharomyces cerevisiae IJ850. It was investigated the fermentative ability as the start culture. For the production of grapewine, the final sugar concentrations of grapejuices were adjusted to the $25^{\circ}Brix$ with anhydrous glucose. The grapejuices were fermented at room temperature for 10 days in the air-locked bottles filled with $CO_2$ gas. The final yield and alcohol concentration of Campbell's Early and Geubong grapewines fermented with the isolated wild yeast were 80.8%, 11.0% and 87.8%, 13.0%, respectively. Between the isolated wild yeast S. cerevisiae IJ850 and the commercial yeast S. cerevisiae EC1118, total acidities of grapewines produced with wild yeast were lower than those produced with the commercial yeast. The pH values and the values of color analysis of grapewines produced with both strains were similar. The total phenol contents of campbell's Early and Geubong wines produced with the isolated yeast and the commercial yeast were obtained in the range of 75 to 125mg/L. In conclusion, S. cerevesiae IJ850 isolated from the domestic cultured Geubong grape is able to use to produce grapewines as stater culture.

• Korean Journal of Plant Resources
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• v.26 no.4
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• pp.426-432
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• 2013

The results of the content of total polyphenol and flavonoid, DPPH (1-1-diphenyl-2-picryl-hydrazyl) radical scavenging activity, ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)] radical scavenging activity, nitrite scavenging activity and SOD-like activity of methanol extracts from immature cotton boll are follows. The contents of total polyphenol and flavonoid compound were higher in small size cotton boll, and DPPH and ABTS radical scavenging activity also showed a relatively high activity in the small size. These results indicate that there is a correlation between phenol content and DPPH radical scavenging, ABTS radical scavenging. The test concentrations of immature cotton boll extract for measuring DPPH and ABTS radical scavenging activities were set as 1.25, 2.5, 5, 10 and 20 mg/ml. Immature cotton boll has high radical scavenging activity at the concentration of 1.25~20 mg/ml and the result showed a tendency to increase in a concentration-dependent. The nitrite scavenging activity showed high activity in the pH 1.2, and the result in the pH 4.2 showed progressively less active, and in the pH 6.0 near neutral was confirmed that does not affect the nitrite scavenging. In addition, SOD-like activity showed somewhat lower activity compared with ascorbic acid, but tended to be higher when compared with the results of the other natural substances. Through this experiment, we confirmed that immature cotton boll was excellent antioxidant activity. Therefore, it is demonstrated that the cotton suggest the possibility of development of new material for cosmetic product or functional food in the future, and is expected to make a greater usability.

• Food Science and Preservation
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• v.22 no.1
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• pp.51-55
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• 2015

This study investigated the changes in the physicochemical characteristics and sensory evaluation of Aster scaber by blanching treatment time. Aster scaber was blanched with $100^{\circ}C$ hot water for 1~5 min. At $100^{\circ}C$ blanching, the total polyphenol contents of the sample blanched for 1~5 min ranged from 7.57 to 6.45% while the sample blanched for 5 min showed a severe loss of phenolic compounds. The sample blanched $at 100^{\circ}C$ for 5 min had the lowest $L^*$ and $b^*$ values (24.96 and 16.14, respectively) and the highest $a^*$ value (-10.39) among all the samples. With regard to the texture profile, the sample blanched at $100^{\circ}C$ for 5 min was the highest in texture. Significant reductions in the texture, color, and total phenol content were observed after blanching. In the sensory evaluation, the Aster scaber sample blanched with hot water at $100^{\circ}C$ for 2 min showed the highest color, appearance, and flavor while the sample heated with boiling water for 3 min had the highest sensory score in terms of texture and overall acceptability. In conclusion, the 3 min blanching of Aster scaber yielded the best sensory quality.

• Food Science and Preservation
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• v.22 no.5
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• pp.690-698
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• 2015

Effects of roasting on physical (weight, volume, density and color) and chemical properties (total phenol, caffeine, chlorogenic acid and antioxidant properties) of three Arabica coffee beans (Brazil Bourbon, Indonesia Mandheling and Kenya Tatu) were investigated. A steady weight loss, volume increase, and bean density decrease were observed during the roasting process. The $L^*$, $a^*$, and $b^*$ values tended to decrease as the roasting temperature and time increased. Caffeine level was approximately 0.73% in green beans, and increased to 40-67% for darker roasts. Green beans contained the highest chlorogenic acid content, which decreased as the roasting temperature and time increased. The light- and medium-roasted coffee showed the highest total phenolol contents. The antioxidant activities were measured using DPPH and ABTS. The light-roasted coffee beans showed the highest antioxidant activities, and an approximately 36-51% loss in antioxidant activity was observed after further roasting. The flavor patterns of roasted coffee beans were analyzed using an electronic nose system based on gas chromatography. This analysis demonstrated that an electronic nose system can be applied to identify the green bean variety and the degree of roasting.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.4
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• pp.405-409
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• 2008

This study was performed to investigate the physiological activities of Viola mandshurica. Antioxidant activity was evaluated by measuring total phenolic contents, reducing power, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-di-2-ethyl-benzthiazoline sulphonate (ABTS) radical scavenging activity while anti-diabetic activity was measured by inhibition activities on ${\alpha}$-amylase and ${\alpha}$-glucosidase. V. mandshurica extracts were prepared by extracting with four different solvents (methanol, ethanol, acetone, and water). The methanol extract showed the highest total phenol content (34.49 mg/g gallic acid equivalents) among the extracts. The water extract showed the highest reducing power (0.454) at the concentration of $1,000{\mu}g$/mL. The acetone extract showed the most potent radical scavenging activity. DPPH and ABTS radical scavenging activity of the acetone extract at the concentration of $1,000{\mu}g$/mL were 21.13% and 43.53%, respectively. The inhibitory activity of acetone extracts against ${\alpha}$-amylase and ${\alpha}$-glucosidase showed more than 100% at the concentration of $1,000{\mu}g$/mL. The results indicate that V. mandshurica might have potential antioxidant and anti-diabetic activities.

• Journal of Life Science
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• v.29 no.11
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• pp.1241-1250
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• 2019

Artemisia argyi H. has been used for centuries as a traditional medicine and food supplement in Asian countries. The objective of this study was to investigate the physiological activities of Artemisia argyi H. extracts prepared by butanol, chloroform, ethyl acetate, ethyl ether, hexane, and methanol extraction. We evaluated total phenol and flavonoid content, antioxidant activity, nitric oxide (NO) and reactive oxygen species (ROS) release, and osteoclastogenesis inhibition. The total phenolic and flavonoid contents were highest in the methanol extract (49.46 mg GAE/g and 24.32 mg QE/g, respectively). The methanol extracts also had the highest antioxidant activity (DPPH and ABTS radical scavenging ability and ferric reducing antioxidant power), while the hexane extract had the lowest. The release of NO and ROS was dose-dependently decreased by pre-treatment with all solvent extracts. At the same concentrations, the ethyl acetate and butanol extracts showed higher inhibition of NO and ROS production when compared with the other extracts. The butanol extract, at a concentration of $20{\mu}g/ml$, inhibited about 89% of the activity of the osteoclast marker, tartrate resistant acid phosphatase (TRAP). These results suggest that butanol extracts of Artemisia argyi H. may be effective natural medications for the prevention and treatment of osteoporosis.

• Journal of Food Hygiene and Safety
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• v.36 no.4
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• pp.353-362
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• 2021

Ecklonia stolonifera, which belongs to the family Laminariaceae, is an edible perennial brown marine alga that is widely distributed, and is rich in polyphenols, including dieckol. Here, we investigated the radical scavenging activities of E. stolonifera extract (ESE) using various in vitro models. We further evaluated the effect of ESE on the cholesterol secretion inhibition activity in HepG2 cells, as well as the hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase activity. Our results showed that the total phenol, total flavonoid, and dieckol contents of ESE were 9.64±0.04 mg GAE/g, 2.72±0.08 mg RE/g and 27.42±0.66 mg/g, respectively. The antioxidant activity of ESE increased in a dose-dependent manner. In addition, the ESE inhibited cholesterol secretion from HepG2 cells with anti-HMG-CoA reductase activity. These results suggested that ESE possesses antioxidant and anti-cholesterol activities, and can therefore be used as a preclinical bioresource for development of health functional foods.