• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.11
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• pp.1681-1684
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• 2016

Oats (Avena sativa L.) are well known for having high contents of bioactive compounds and health benefits. The objective of this study was to evaluate the antioxidant compounds and antioxidant activities of methanolic extracts from milling fractions and whole grains of oat. The contents of total polyphenolics and flavonoids were analyzed by spectrophotometric methods. ABTS radical and DPPH radical scavenging activities and reducing power were used to compare relative antioxidant activities of milling fractions from oat. Total polyphenolics and flavonoids were much more abundant in oat bran extract than in extracts from whole grain and endosperm. In addition, high levels of ABTS radical (42.34 mg Trolox equivalent antioxidant capacity (TEAC)/100 g sample) and DPPH radical (24.18 mg TEAC/100 g sample) scavenging activities and reducing power ($A_{700}=0.76$) were detected in oat bran. The results of this study indicate that oat bran has significantly higher antioxidant activities and appears to have significant health benefits.

• 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.

• Korean Journal of Food Science and Technology
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• v.48 no.1
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• pp.86-91
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• 2016

Oxidative stress caused by reactive oxygen species is ascribed to many neurodegenerative diseases like Alzheimer's disease. Phenolic antioxidants can reduce the oxidative stress. In this study, ripe fruits of Opuntia ficus-indica var. saboten (OFS) were extracted using 80% (v/v) aqueous ethanol. Total phenolic and flavonoid contents of the OFS fruits (100 g) were 409.9 mg gallic acid equivalents and 72.2 mg catechin equivalents, respectively. The OFS fruits had antioxidant capacity at 381.2, 298.2, and 3,219.9 mg vitamin C equivalents/100 g in ABTS, DPPH, and ORAC assays, respectively. The OFS fruits showed protective effects on PC-12 cells against oxidative stress in a dose-dependent manner, partly due to decrease of intracellular oxidative stress. Furthermore, the OFS fruits inhibited both acetylcholinesterase and butyrylcholinesterase. Consequently, these results suggest that the OFS fruits might be served as a source of functional materials to reduce oxidative stress in neuronal cells and to inhibit cholinesterases.

• Korean Journal of Food Science and Technology
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• v.52 no.2
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• pp.130-137
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• 2020

The present study was undertaken to compare the effects exerted by different extraction solvents on the extraction of active components, such as polyphenols and flavonoids, from the dried leaves of Artemisia annua L. Different extracts were prepared using a heating mantle. The extraction solvents used were distilled water, and 20, 40, 60, 80, and 99.5% ethanol solution. It was observed that the 40% ethanol solution yielded the most significant results in the extraction of various phytochemicals with phenol concentration of 154.8±0.28 mg of gallic acid equivalent/g and flavonoid content of 25.28±0.01 mg quercetin equivalent/g. However, based on the extraction solvent used, varying trends were observed in the antioxidant, enzyme inhibition, and bacterial inhibition analyses. It was concluded that the extraction solvent should be selected based on the purpose of use of the dried leaves of A. annua L.

• Korean Journal of Plant Resources
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• v.31 no.4
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• pp.312-321
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• 2018

Angelica tenuissima, also known as Ligusticum tenuissimum, is classified as a food-related plant and has been used as traditional medicines treating headache and anemia in Asia. However, its anti-melanogenic effect has not been reported in detail. When the extract of Angelica tenuissima (ATE) was prepared by the extraction with 70% EtOH at $80^{\circ}C$ (final yield = 22%), the contents of decursin and Z-ligustilide in ATE were determined 0.06% and 8.43%, respectively. Total flavonoid and phenolic content in mg ATE were $5.52{\pm}0.07{\mu}g$ quercetin equivalents and $237.27{\pm}13.24{\mu}g$ gallic acid equivalents, respectively. Antioxidant capacity of ATE determined by DPPH and ABTS assay was increased with a dose dependent manner up to $1000{\mu}g/m{\ell}$. The amount of melanin synthesis followed by ${\alpha}-melanocyte$ stimulating hormone on B16F10 cells were significantly reduced in the presence of ATE (250 to $1000{\mu}g/m{\ell}$, p<0.05). ATE (125 to $1000{\mu}g/m{\ell}$, p<0.05) suppressed the tyrosinase activity but did not show any significant effect on ${\alpha}-glucosidase$ activity at the same condition. Taken together, ATE possesses tyrosinase inhibitory potential with significant antioxidant capacities. These effects of ATE might be involved in suppression of melanin synthesis, at least, in B16F10 cells. The anti-melanogenic potential of ATE will provide an insight into developing a new skin whitening product.

• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.600-608
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• 2019

The aim was to determine the physiological activity and antioxidant activity by lipid peroxidation inhibitory action of turmeric (Curcuma longa L.). Bioactive compound of total carotenoid $1.581{\pm}0.005mg$ ${\beta}$-carotene equivalents (BCE)/g dry weight. Total phenol content was the highest in the ethyl acetate (EA) extract, followed by chloroform:methanol (CM, 2:1, v/v) and 70% methanol extracts. Antioxidant effects (nitrogen oxide radical scavenging activity, nitrite scavenging activity, ${\beta}$-carotene bleaching assay, and lipid peroxidation inhibition action) of 70% methanol, CM, and EA extract of turmeric. Turmeric extracts yield were 70% methanol 16.54%, CM 5.64%, and EA 4.14%, respectively. Antioxidant activity of the samples exhibited a dose-dependent increase. However, in the current study, none of the samples evaluated showed activity as strong as the BHA (butylated hydroxyanisole) and trolox. Further, nitrite scavenging activity was the highest for the EA extract. As a result of this experiment, indicating their commercial value and potential applications in food and nutraceuticals.

• Korean Journal of Plant Resources
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• v.32 no.3
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• pp.220-227
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• 2019

Stevia rebaudiana (Asteraceae), a perennial plant, has been used as a low-calorie sweetener and is being developed as a therapeutic agent for diabetes, hypertension, myocardial diseases, and microbial infections. Despite the common use of its leaves and stem, the bioavailability of the components present in S. rebaudiana flowers, when used as ingredients of cosmetics, has not been well investigated. Herein, we investigated the antioxidative and antimelanogenic effects of an aqueous extract of S. rebaudiana flowers (Stevia-F). Total flavonoid and phenolic content in Stevia-F were determined to be $8.64{\pm}0.23mg$ of quercetin equivalents/100 g and $631.5{\pm}2.01mg$ of gallic acid equivalents/100 g, respectively. The $IC_{50}$ values of Stevia-F for reducing power, and 2,2-diphenyl-1-picryl-hydrazyl-hydrate radical, hydrogen peroxide, and nitric oxide scavenging activities were 5541.96, 131.39, 466.34, and $10.44{\mu}g/mL$, respectively. Stevia-F showed inhibitory effects on the tyrosinase ($IC_{50}=134.74{\mu}g/mL$) and ${\alpha}$-glucosidase ($IC_{50}=114.81{\mu}g/mL$) activities. No significant cytotoxicity of Stevia-F was observed in B16F10 cells, treated with up to $100{\mu}g/mL$ of the extract for 24 and 48 h (p > 0.05). Stevia-F ($1-100{\mu}g/mL$) suppressed ${\alpha}$-melanocyte stimulating hormone-induced melanin production in B16F10 cells (p < 0.05) and also inhibited the cellular tyrosinase activity (p < 0.05). Overall, our results show that Stevia-F possesses potential for inhibiting tyrosinase and ${\alpha}$-glucosidase activities and has significant antioxidant capacity. The antimelanogenic potential of Stevia-F should extend the usage of S. rebaudiana flowers in the development of skin-whitening products.

• Korean Journal of Food Science and Technology
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• v.51 no.4
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• pp.356-360
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• 2019

To evaluate antioxidant capacities and total phenolic, flavonoid, and catechin contents of pure green tea packaged in tea bags, green tea bags of 10 commercial brands were purchased and analyzed. Considering commonly used infusion methods, green tea bags were extracted using 150 mL of spring water at $70^{\circ}C$ for 2 min. Ten brands of green tea showed a wide range of total phenolic content (46.3-93.9 mg gallic acid equivalents/g), total flavonoid content (10.3-21.7 mg catechin equivalents/g), and antioxidant capacities (88.8-175.6 mg and 87.9-183.5 mg vitamin C equivalents/g for DPPH and ABTS assays, respectively). Total catechin content of green tea ranged from 33.8-74.7 mg/g, which corresponded to 43.0-108.3 mg/150 mL of cup. Collectively, these results suggest that daily consumption of 3.8-12.5 cups of green tea packaged in tea bags meets the recommended daily intake of catechins in green tea extract as a health functional foods in Korea.

• Journal of Life Science
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• v.29 no.10
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• pp.1111-1119
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• 2019

Prunus mume, known as maesil in Korea, has been widely cultivated in East Asia and used as medication and food. However, because most of the previous studies concerning P. mume had been investigated its under extract state, detailed studies are still required for its extensive utilization. In this study, we evaluated the antioxidant and ${\alpha}-glucosidase$ inhibitory activities of solvent fractions of P. mume ethanol extracts. The ethyl acetate fraction showed higher DPPH radical scavenging activity, ABTS radical scavenging activity, reducing power, and hydrogen peroxide scavenging activity than other fractions. The DPPH radical scavenging activities of ethyl acetate fraction was 67.79%; ABTS radical scavenging activity was 60.03%; reducing power ($OD_{670}$) was 1.26; and hydrogen peroxide scavenging activity was 93.18% at $500{\mu}g/ml$. Also, the ethyl acetate and methanol fraction showed effective levels of ${\alpha}-glucosidase$ inhibition activity (69.25% and 72.29% at $500{\mu}g/ml$). Total polyphenol contents and total flavonoid contents of the ethyl acetate fraction were 88.28 mg/g (gallic acid equivalent) and 70.38 mg/g (quercetin equivalent), respectively. These results suggest that the physiological activities of the ethyl acetate fraction are associated with its polyphenol and flavonoid contents. Therefore, this study can be used as basic data for developing natural antioxidants and potential functional material using P. mume.

• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.821-829
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• 2019

This study was conducted to evaluate the applicability of the extracts from nipa palm, molokhia, and finger root in functional cosmetics as a natural active ingredient. The extracts were obtained through the processes of heating under reflux with ethanol, filtration, concentration, and freeze-drying. UV absorption and blocking effects of the extracts were examined by using the UV-vis spectrophotometer equipped with an integrating sphere. Antioxidant activity and its stability between the extracts were compared using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Also, total polyphenol content in the extracts was determined quantitatively using the Folin-Ciocalteu reagent, with gallic acid as the standard. Antibacterial activity of the extracts was investigated by the disc diffusion test against Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative). Finally, collagenase inhibitor assay was performed to examine the anti-wrinkle effect of the extracts. From the results of this study, the extract of nipa palm showed the potential for use in cosmetics as an antioxidant and anti-wrinkle agent, and the extract of finger root as a sunscreen and antibacterial agent.