• Food Science and Biotechnology
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• v.17 no.1
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• pp.151-155
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• 2008

Oxidation of low density lipoprotein (LDL) is regarded to play an important role in the development of atherosclerosis. In the present study, salad vegetables with a remarkable DPPH radical-scavenging activity were extracted with methanol, and the methanol extracts were evaluated for the inhibition of $Cu^{2+}$-induced oxidation of human LDL. Separately, the amount of total phenolics was determined colorimetrically using Folin-Ciocalteu reagent. The vegetable extracts, expressing a strong inhibition of LDL oxidation ($IC_{50}$ values, <$100\;{\mu}g/mL$), were from angelica, dandelion, mustard leaf, and water spinach, which contained relatively high level of polyphenol content. Noteworthy, a highly positive correlation was observed between inhibition of LDL oxidation and amount of total polyphenol (p<0.01). Based on these results, it is suggested that salad vegetables, especially angelica, dandelion, and mustard leaf, may be used as easily accessible sources of natural antioxidants, especially in anti-atherosclerosis.

• Journal of Applied Biological Chemistry
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• v.59 no.1
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• pp.19-23
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• 2016

A phenol substance was extracted from Pinus koraiensis Siebold et Zucc leaf extracts and its biological efficacy was measured. The highest content of the phenol substance contained in Pinus koraiensis Siebold et Zucc leaves was 13.5 mg/g, which was obtained when it was extracted with 80% ethanol. At a concentration of 200 mg/mL, the phenolic substances extracted with 80% ethanol and water showed antimicrobial activities against Helicobacter pylori, producing clear zones of 10 and 12 mm diameter, respectively. Pinus koraiensis Siebold et Zucc. leaf extracts were separated using a Sephadex LH-20 column and 4 fractions were obtained (fractions A-D). Fractions C and D showed the greatest inhibitory activity against Helicobacter pylori producing 10.1 and 12.3 mm clear zones, respectively. These two fractions were purified using a Sephadex LH-20 and MCI-gel column ($H_2O{\rightarrow}100%$ ethanol). Purified compounds A and B were identified as syringic acid and compound C was identified as p-coumaric acid based on $^1H$-nuclear magnetic resonance (NMR), $^{13}C$-NMR, and fast atom bombardment mass spectrometry spectra. When two or more purified compounds were mixed, a synergistic effect of anti-Helicobacter pylori activity was evident. This result indicates that extracts of Pinus koraiensis Siebold et Zucc leaves could be considered a functional food because of their high antimicrobial properties.

• Korean Journal of Medicinal Crop Science
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• v.24 no.1
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• pp.27-30
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• 2016

Background : This text was conducted to evaluate the distribution, shape characteristics and habitat condition of Crypsinus hastatus in Buyeo Korea. Methods and Results : In Buyeo, Crypsinus hastatus was distributed at an altitude of 31.2 m, a slope of 82.5% and a distance from river water of 27.2 m. The leaf blade was oblong, 2.7 cm long, 1.2 cm wide with a petiole length of 2.3 cm. The total population comprised 2,100 individuals, with the highest proportion being individuals with a leaf blade of length 0.5 - 1 cm. The temperature and light intensity of the growth point were lower, but the humidity higher, than that of growth around. The chemical properties of the soil were as follows: pH 4.42, organic matter 77.99 g/kg, electrical conductivity 0.50 dS/m, nitrate nitrogen 20.50 mg/kg and available phosphate 165.7 mg/kg. Exchangeable cation content of potassium, magnesium, sodium and calcium was 0.35, 0.70, 0.09 and $2.04cmol^+/kg$, respectively. Conclusions : In Buyeo, Crypsinus hastatus was distributed in $5.3m^2$ area of Nakhwaam, Naeseongri and Jeongamri. However, the population of the medicinal resources seemed to decrease owing to the poor environmental conditions of the habitat.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.165-165
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• 2017

Abiotic stress is one of the major serious limiting factors in rice (Oryza sativa) and caused rice production losses. It is important to precisely screen valuable genetic resources for improving stress tolerance and understanding tolerance mechanism to abiotic stresses. Because there are differences of experiment designs for screening of tolerant plant in several studies related to abiotic stress, this study has performed to provide the rapid and efficiency screening method for selection of tolerance rice to drought and salinity stresses. Two week-old rice seedlings that reached about three leaf stage were treated with drought and salinity stresses and examined tolerant levels with tolerant and susceptible control varieties, and transgenic plants. To determine the optimum concentration for the selection of drought and salinity condition, tolerant, susceptible and wild-type plants were grown under three soil moisture contents (5, 10 and 20% water contents) and three NaCl concentrations (100, 200 and 250 mM) for 10 days at seedling stage. 200 mM NaCl concentration and 5% moisture content soil were determined as the optimum conditions, respectively. The described methodologies in this study are simple and efficiency and might help the selection of drought and salinity tolerance plants at the 3,4-leaf-seedling stage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.4
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• pp.314-321
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• 2018

Durum (Triticum turgidum L. ssp. durum) is a major crop species cultivated for human consumption worldwide. In Tunisia, salt stress is one of the main problems that limit crop production. 'Mahmoudi' was selected as the most salt-sensitive out of 11 Tunisian durum cultivars. Using the salt-tolerant cultivar 'Om Rabia', resistant and susceptible cultivars were evaluated to compare genetic responses under salt stress. At the fully expanded third leaf stage, salt stress was applied by submerging the pots in 500 mM NaCl for 5 min every day for saline water irrigation in the greenhouse. The treatment was applied for 1 week and salt stress tolerance was determined by changes of growth parameters to the control condition. The salt tolerance trait index and salt tolerance index were calculated and used as selection criteria. The expression levels of TdHKT1;4, TdHKT1;5, and TdSOS1 were examined using qPCR. For further evaluation of physiological responses, salt stress (150 mM NaCl) was additionally applied for 48 h at the fully expanded third-leaf stage. Increased expression of the genes responsible for salt tolerance and proline content in tolerant durum can be used to broaden genetic diversity and provide genetic resources for the durum breeding program.

• Korean Journal of Food Science and Technology
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• v.39 no.5
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• pp.515-520
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• 2007

To establish the roasting conditions of dandelion leaves for the manufacture of processed foods such as beverages and tea, we investigated the physicochemical and sensory characteristics of dandelion leaves and their hot water extracts by roasting treatment. As the number of roasting times increased, the free sugar content of the roasted dandelion leaves decreased, and in particular, free amino acid and total polyphenol content decreased greatly after only 1 roasting treatment. The amino nitrogen and total polyphenol contents of the roasted dandelion leaf hot water extracts also decreased greatly, and their L-, a-, and b-values showed much lower values than those of the raw leaf extracts. However, a greater amount of reducing sugars was extracted in the roasted leaves than in the raw leaves, suggesting that the roasting process allows for easier extraction of the compounds in dandelion leaves. Five sensory characteristics, including astringent taste, bitter taste, peen flavor, burnt taste, and sweet odor, were deduced through quantitative descriptive analysis of the hot water extracts. Among them, astringent taste, bitter taste, and green flavor showed significant differences between roasting treatments. The sensory evaluation results show that as the number of roasting times increased, the palatability of the hot water extracts increased greatly, in terms of color and taste.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.255-261
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• 2016

The present study was conducted to characterize physiological responses of aerial part according to soil water stresses in 'Mihong' peach trees. Discolorations, wilting and falling of leaves were observed in chronological order as response for waterlogging and no irrigation and the phenomena started from basal to end of shoots. Shoot growth in elongation and thickness decreased and fallen leaves were severe in waterlogged trees. Function of water uptake by roots and photosynthesis and leaf respiration decreased by waterlogging. Leaf chlorophyll contents decreased in both treatments. In waterlogging treatment, decrease of chlorophyll was observed in normal leaves with waterlogging using light microscopy. Starch content was lower in both treatment and carbohydrate content was lower in root with waterlogging. These results demonstrated that waterlogging weakened the function of soil water uptake and movement and decreased photosynthesis and fallen leaves. Finally the peach trees would wither or suffer low temperature damage through the shortage of reserve accumulations. We suggested that waterlogging damage in peach trees could be reduced to take notice of irrigation and install drainage facility to improve soil condition.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.3
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• pp.177-183
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• 2008

Sodium is known to reduce a plant growth and yields. However, the relationships between physiological response of seedling and salinity stress caused by growing media are not well understood yet. We conducted experiments to investigate change of some parameters including Na, EC, moisture content in media under different air temperature ($15^{\circ}C$, $25^{\circ}C$), and the response of fruit-vegetables such as cucumber, oriental melon on saline conditions originated from horticultural substrate. Volumetric moisture content of media at $15^{\circ}C$ was 70%, but at $25^{\circ}C$ was decreased by 45% within 22 hrs, showing below optimal matric potential, approximately. During reaction time, the increase of Na concentration was significantly greater in saline substrate than in control. The decrease rate of Na concentration according to supplying irrigation water was higher in saline substrate than in control. $CO_2$ assimilation rate and transpiration rate of Korea melon grown in low temperature were decreased with a Na/cation ratio in hydroponic solution. Water saturation deficit was also increased significantly at $15^{\circ}C$ as compare to $25^{\circ}C$. Saline stress during nursery stage induced a reduction of seedling quality, growth and cucumber yield. The results suggest that the relationship between uncontrolled Na uptake of seedling from saline substrate and meteological condition is responsible for saline stress.

• Korean Journal of Plant Resources
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• v.21 no.5
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• pp.408-412
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• 2008

This research was designed to investigate the antioxidant activities and tyrosinase inhibitory effects of guava (Psidium guajava L.) leaf. Total phenol content was obtained from guava leaf extract of 19.0 (g/100g, D.W.). The crude extract exhibited significantly antioxidant activities (IC50value $102.5{\mu}g/ml$, free radical scavenging; $49.4{\mu}g/ml$, SOD like activity). The crude extract of guava leaf was fractionated into four partition layers; hexane (G-H), ethyl acetate (G-E), butanol (G-B) and water (G-W) layer. The extracts of G-E, G-B, G-W showed high radical scavenging activities of over 50% at $100{\mu}g/ml$. SOD like activities of G-E, G-B, G-W were revealed, as 81.8%, 84.7%, 65.3% at $100{\mu}g/ml$, while those of G-H did not showed the effectively. The crude extract of guava leaf showed high tyrosinase inhibitory effect as 60.8% at 1mg/ml, the measurement of G-E, G-B, G-W were 65.2%, 62.8%, 51.6% and that of G-H was not effective. These results indicate that useful bioactive substances exist in the guava leaf extracts, especially G-E, G-B. And the guava leaf has the potential of being developed into health related products.

• Journal of agriculture & life science
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• v.45 no.4
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• pp.105-112
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• 2011

Nutritional components and antioxidant activities of commercial loquat leaf tea (CLLT) were evaluated. Proximate compositions were as follows; moisture 5.34%, crude protein 8.38%, crude fat 13.26%, nitrogen free extract 46.21%, crude fiber 19.24% and crude ash 7.57%, respectively. Ascorbic acid and total phenolics content of CLLT was 0.47 mg/100 g and 42.55 mg/GAE g, respectively. Mineral elements were Ca 1,624.01 mg/100 g, K 1,099.66 mg/100 g, and Mg 192.70 mg/100 g, respectively. Amino acid contents of CLLT were very rich in glutamic acid 565.98 mg/100 g and deficient in cystine 12.97 mg/100 g. The 2,2'-azino-bis (3-ethylbenzthiazoline-6- sulfonic acid) diammonium salt (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities of hot water extract from CLLT were 72.51% and 90.11%, respectively at a concentration of $1,000{\mu}g/mL$. Reducing power and ferric reducing antioxidant power (FRAP) of hot water extract from CLLT were increased in a dose dependent manner. Therefore, these results suggest that the hot water extract of CLLT possess antioxidant activities and thus it has great potential as a source for functional food such as natural antioxidant.