• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.36-43
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• 2010

The purpose of this study was to investigate the phenolic acid, proanthocyanidin (PAs), and flavonol glycoside contents, as well as the antioxidant activities of pine needle extracts from six species of young pine trees. The extracts were prepared from Section Pinus (Diploxylon): P. densiflora, P. sylvestris, P. pinaster and P. pinea, and Section Strobus (Haploxylon): P. koraiensis and P. strobus. Phenolics were extracted from pine needles with 80% acetone to obtain the soluble free fraction, and insoluble residues were digested with 4 M NaOH to obtain bound ethyl acetate and bound water fractions. Phenolics were analyzed by HPLC, and the hydrophilic antioxidant activity was measured using oxygen radical absorbance capacity (ORAC). Total phenolic and flavonoid contents of the soluble free fraction were higher than those of the bound ethyl acetate and bound water fractions. The main phenolics were monomers and polymers of PAs in the soluble free fraction, and phenolic acids and flavonol glycosides in bound ethyl acetate fraction. Flavonol glycosides found in different species of pine needles were qualitatively similar within fractions, but composition varied among Pinus sections. High levels of kaempferol arabinoside and an unknown compound were present in all Strobus species. The soluble free fraction had the highest antioxidant activity, followed by bound ethyl acetate and bound water fractions.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.37-46
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• 2004

The analysis of enzymes associated with metabolism of phenolics by Stenotrophomonas maltophilia LK-24 was conducted. To identify metabolites of phenol and phenol compound, we investigated enzymes of S. maltophilia LK-24 associated with degradation of phenolics. We found that phenol hydrolase, catechol-2.3-dioxygenase, 2-hydroxymuconic semialdehyde dehydrogenase, 2-hydroxymuconic semialdehyde hydroxylase and acetaldehyde dehydrogenase were activated. The results showed that phenolics were gone through the meta-pathway ring cleavage. The results will contribute greatly to understand metabolic pathways of phenol and it is possible to make some assessment of the feasibility of using S. maltophilia LK-24 for the treatments of phenolic-contaminated waste streams.

• Journal of Society of Preventive Korean Medicine
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• v.13 no.1
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• pp.59-67
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• 2009

Objectives : This research aimed to evaluate the effects of Rubus coreanus $M_{IQ}$. Methods: These extracts from fresh R. coreanus $M_{IQ}$. were investigated with radical scavenging activity, the content of total phenolics, ferric thiocyanate method and flavonoid contents Results: These results revealed that the ethyl acetate extract from fresh R. coreanus $M_{IQ}$. possesses remarkable radical scavenging activity. The content of total phenolics of the ethanol extract from dried R. coreanus $M_{IQ}$. ($IC_{50}$=155.87${\pm}$8.8${\mu}$g/mL) is the highest among all of the samples. The stronger radical-scavenging activity ($IC_{50}$=77.72${\pm}$2.1${\mu}$g/mL) of ethyl acetate extract from dried R. coreanus $M_{IQ}$. should be related to its phenolic content as measured by gallic acid test. Conclusion: These results suggest that dried R. coreanus $M_{IQ}$. may act as a potential antioxidant agent.

• Food Science and Biotechnology
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• v.14 no.5
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• pp.700-703
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• 2005

Eight edible mushrooms grown in Korea were extracted with ethanol at room temperature for 24 hr. The extracts were investigated for their antioxidant activities as measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation scavenging activities. Among the mushroom extracts evaluated in this study, the ethanolic extracts from Ganoderma lucidum and Pleurotus eryngii showed the greatest potential antioxidant activity, by producing 85 and 88% inhibition in DPPH radical scavenging method and 219 and 165 mg ascorbic acid equivalent antioxidant capacity (AEAC), respectively. Total phenolics and total flavonoids in the ethanolic extracts were determined by spectrophotometric method. Positive correlations were found between total phenolic contents in the extracts and their antioxidant activities, suggesting that phenolic contents in the mushrooms extracts are mainly responsible for their antioxidant activities.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.88-97
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• 2017

This study explored the physicochemical and nutritional changes associated with storage duration of fresh tomatoes. Fruits of the 'TY Megaton' and 'Yureka' tomato cultivars were harvested at the pink stage and stored at $12^{\circ}C$ for 20 days. During storage, firmness, weight loss, skin color (Hunter L, a, b, a / b values), soluble solids content (SSC), titratable acidity (TA), pH, antioxidant contents (lycopene, ascorbic acid, and total phenolics) and antioxidant activity were evaluated. Firmness was above the minimum marketable limit and fresh weight loss was below maximum acceptable weight loss after 3 weeks of storage, and no deleterious effect on antioxidant contents or activities were observed. Significant differences in SSC, TA, and pH were seen between varieties, but not between fruits stored for different durations. In both varieties, Hunter a values increased more than five-fold after 8 days of storage; this correlated with a more than four-fold accumulation of lycopene after two weeks of storage. The antioxidant activity of tomatoes was highest at the beginning of the storage period, likely because of the effective DPPH - reducing power of ascorbic acid and total phenolics. Antioxidant activity increased after 12 days of storage because of increasing lycopene content. Hence, this study indicates that pink - stage tomatoes may be stored at $12^{\circ}C$ for up to 3 weeks without affecting marketability or nutritional value.

• Preventive Nutrition and Food Science
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• v.9 no.4
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• pp.289-294
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• 2004

The antioxidant activity of forty two kinds of salad vegetables grown in Korea was evaluated. Methanol extract of freeze-dried vegetable was assayed by radical scavenging activity using 1,2-diphenyl-2-picrylhydrazyl (DPPH) and Fe^{2+}$-catalyzed lipid peroxidation inhibition by TBA method. Total phenolics were determined colorimetrically using Folin-Ciocalteu reagent. The highest radical scavenging activity was expressed by perilla leaf, followed by dandelion leaf, red and green leafy lettuce, of which $IC_{50}$ was less than 0.10 mg/mL. Angelica leaf showed the highest inhibitory action for lipid peroxidation with $95\%$, and then dandelion leaf, water spinach, and perilla leaf inhibited over $80\%$. However, lettuce (Iceberg) and young Chinese cabbage exhibited the lowest antioxidant activity based on both assay methods. Highly positive correlations between antioxidative activities and total phenolics were observed (p < 0.001). The results suggested that salad vegetables, especially perilla leaf, leafy lettuce, dandelion or angelica, could be used for easily accessible sources of natural antioxidants.

• Preventive Nutrition and Food Science
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• v.9 no.3
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• pp.199-205
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• 2004

The effect of chitosan on enzymatic activities and on bioactive compounds was characterized during germination at $25^{\circ}C$ for 7 days to search for a method to produce a germinated black rice. The germination rate was reduced by the addition of lactate and chitosan. The rotting rate was greatly decreased by chitosan, suggesting that the addition of chitosan into a germination solution might be an effective method for controlling fungal contamination during the germination of cereals. The addition of 100 and 200 ppm chitosan increased $\alpha$-amylase activity after 7 days by up to 152 % and 197 %, respectively. The activities of $\beta$-amylase and $\beta$-glucosidase were lower with 200 ppm chitosan than in distilled water and 100 ppm lactate. The amount of total soluble phenolics and total flavonoids decreased rapidly for four days and thereafter remained constant until the seventh day. The antioxidant activity of germinated black rice, in terms of hydrogen-donating activity, increased slowly and did not correspond to the changes of total soluble phenolics and total flavonoids. The amount of phytic acid was reduced by the addition of 200 ppm chitosan compared to distilled water, indicating that chitosan could be used as an elicitor for the increase of phytase activity during the germination of black rice.

• Korean Journal of Plant Resources
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• v.21 no.6
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• pp.413-419
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• 2008

Phenolics level, total flavonoid content, and antioxidant were determined from the methanol extracts of the eight medicinal plants using roots. Total phenolics were found as the highest levels in the methanol extracts of Arctium lappa, and followed by Youngia sonchifolia and Cirsium japonicum. Total amount of the each phenol compounds were detected in C. japonicum extracts ($319.2\;mg\;kg^{-1}$) as the greatest component, and followed by A. lappa ($96.3\;mg\;kg^{-1}$) and Y. sonchifolia ($22.9\;mg\;kg^{-1}$). Total flavonoid content showed the highest amount in methanol extracts from A. lappa (68.1 mg $100\;g^{-1}$) and followed by Y. sonchifolia (11.2 mg $100\;g^{-1}$) Lycoris radiate extracts (87.2%) had the highest nitrite scavenging activity and followed by A. lappa (81.5%) and Y. sonchifolia (77.5%). Methanol extracts of A. lappa at 25 mg $100\;g^{-1}$ exhibited the highest DPPH radical scavenging activity by 90.8%, even though less activity than synthetic antioxidants Vitamin C or butylated hydroxytoluene (BHT). Level of polyphenols was highly correlated with anti oxidative activity ($r^2$ = 0.85). The results suggest that several medicinal plants selected had the potent biological activities, and that their activities were differential depending on plant species.

• Mycobiology
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• v.51 no.6
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• pp.445-451
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• 2023

Shiitake mushroom (Lentinula edodes) hold high nutritional and medicinal value as they contain an abundance of health-promoting compounds. However, the effect of long-term postharvest storage on the variation in the levels of health-promoting compounds has not been extensively studied. In this study, we investigated the changes in the levels of phenolic compounds, antioxidants, eritadenine, and ergothioneine in shiitake mushrooms stored at three different temperatures (1, 3, and 5 ℃) for 4 weeks. Compared to mushrooms stored at lower temperatures, those stored at 5 ℃ exhibited a higher level of total phenolics in their pileus after 2 weeks of storage; however, storage at 5 ℃ also increased the deterioration of the fruiting body of these mushrooms. In mushrooms stored at all temperatures, the eritadenine content in the pilei tended to increase up to 2 weeks of storage. In contrast, the ergothioneine content in the pileus decreased during storage, with a significantly lower level detected in mushrooms stored at 5 ℃ for 4 weeks. Together, these results suggest that the mechanisms underlying the accumulation of phenolics and eritadenine may be related to mushroom deterioration during storage. Our findings indicate that the levels of health-promoting compounds in shiitake mushrooms are influenced by storage temperature, suggesting the potential to control adjustments of specific bioactive compounds by regulating storage conditions.

• Korean Journal of Plant Resources
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• v.26 no.1
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• pp.60-67
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• 2013

A laboratory experiment was conducted to determine the content of phenolics and flavonoids, antioxidant activity and antioxidant enzyme activity for the extracts from cowpea seed and sprouts. Plant length and weight of cowpea sprouts were significantly increased until 7 days after seeding. Total phenolics level [mg chlorogenic acid equivalents (CAE) $kg^{-1}$ DW] was highest in dry seed (DS) extracts of cowpea ($63.9mg\;kg^{-1}$), followed by imbibed seed (IS) ($56.8mg\;kg^{-1}$) and 1-day-old sprout (1DOS) extracts ($46.4mg\;kg^{-1}$), and significantly reduced with increase of sprout age (p < 0.05). The antioxidant activity of the methanol extracts from all the samples showed same tendency to the results of total phenolics level, and dose-dependently increased. DPPH (1,1-diphenyl-2-picryl hydrazyl radical) free radical scavenging activity was higher in DS (87.3%) and IS (41.2%) than in cowpea sprouts from 1DOS to 7DOS, ranging from 17.1 to 30.4%. Antioxidant enzymes, APX, POX, and POX activities were highest in 7DOS and lowest in DS. SOD activity showed much higher activity in sprouts and in seeds. Correlation coefficient between physiological-active substance and the activity was highest between APX and CAT activities ($r^2$= 0.9574). Especially, total phenolics content was more highly correlated with antioxidant or with antioxidant enzyme activities than was total flavonoid level.