• The Korean Journal of Food And Nutrition
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• v.23 no.2
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• pp.233-239
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• 2010

Phenolic acid concentrates of rice bran(RB-ex) and hydroxycinnamic acids were investigated for their anti-hyperglycemic activities through glucose uptake and glucokinase activity using HepG2 cells and stimulatory effects on insulin secretion using HIT-T15 cells. RB-ex was prepared as an ethylacetate extract after alkaline hydrolysis and hydroxycinnamic acids, found as major compositions of RB-ex, such as ferulic acid(FA), sinapic acid(SA) and p-coumaric acid(p-CA) were investigated to compare with the properties of RB-ex. The properties of glucose uptake in HepG2 cells were examined in the absence of insulin and two different glucose concentrations(5.5 mM and 25 mM). RB-ex and FA showed anti-hyperglycemic activities through the increase of glucose uptake and the stimulation of glucokinase activity in HepG2 cells. RB-ex exhibited higher glucose uptakes with higher glucose concentrations, whereas FA exhibited the same increasing effects on both concentrations of glucose. RB-ex and FA exhibited doubled glucokinase activities relative to control. In the presence of insulin in the 25 mM glucose-containing medium, the levels of glucose uptake were increased in all treatments compared with control. As stimulatory effects of samples on insulin secretion were estimated, RB-ex and FA stimulated insulin secretion at a concentration of 25 ${\mu}g/m{\ell}$ and in particular, FA showed the highest amount of insulin-release in HIT-T15 cells. Antioxidative effects on HIT-T15 cells, RB-ex and hydroxycinnamic acids, excluding p-CA, showed inhibitory activities of 78% to 80% at a concentration of 100 ${\mu}g/m{\ell}$. On the basis of these results, we conclude that RB-ex and FA could help decrease blood glucose levels and prevent the cell damages via antioxidant activity.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.226.1-226
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• 2003

최근 쌀 소비량이 감소되고 쌀중심 식생활의 영양적 우수성을 인식하지 못하여 쌀은 주식으로서 위치가 흔들리고 있다. 그동안 쌀의 영양특성에 관한 연구로서 주로 탄수화물 급원으로서의 당질에 관한 연구와 미강을 중심으로한 식이섬유, 미강유등에 관한 연구결과들이 발표되었다. 특히 미곡 부산물인 미강으로부터 다양한 유효성분들이 확인되어 그 효능이 보고되고 있으며 일부가 기능성 소재로서 제품화되기도 하였다. 그러나 실제 우리의 식생활에서 섭취되고 있는 백미 또는 현미상태에서의 유효성분의 분포 및 함량에 대한 연구는 미진한 상태이다. 본 연구에서는 쌀의 영양적우수성을 규명하고자 유효성분 중 phenolic acid와 폴리페놀 함량을 품종 및 도정도에 따라 조사하였다. 조생종인 오대와 만생종인 남평 품종으로부터 현미와 7분도, 10분도 및 12분도로 도정도를 달리한 백미, 도정도별 미강을 각각 제조하였다. Ferulic acid 등 쌀과 미강에 존재하는 phenolic acid 는 알칼리로 추출한 후 pH를 조정하고 에틸아세테이트로 반복 추출하여 HPLC로 분석하였다. 현미에 함유된 phenolic acid는 ferulic acid가 가장 많아 50％ 내외를 차지하였으며 p-coumaric acid, benzoic acid, sinapinic acid 순으로 검출되었다. 오대 현미의 총 phenolic acid 함량은 65.9 mg%로서 남평 현미의 57.2 mg%보다 높았으며 도정도가 증가할수록 백미 중의 총 phenolic acid 함량은 감소되었다. 미강 중에는 백미의 10배 량에 해당하는 phenolic acid가 검출되었고 benzoic acid와 m-hydroxy benzoic acid는 미강 시료에서만 검출되었다. 도정한 백미 중의 phenolic acid는 28.8∼51.7 mg%, 미강에서 321.4∼438.4 mg% 범위로 나타났다. 현미, 백미 및 미강에 함유된 총 폴리페놀의 함량을 표준 페놀화합물로 카테친을 사용하고 비색법에 의하여 측정하였을 때 오대 현미의 폴리페놀 함량은 78.4 mg%, 남평 현미 88.8 mg% 였다. 도정한 백미 중의 총 폴리페놀 함량은 30.3∼56.9 mg%, 미강이 541.5∼472.6 mg%의 범위였다. 이상과 같이 쌀에는 phenolic acid 및 총 폴리페놀이 상당량 함유되어 있으며 특히 배유보다는 강층에 많이 존재하므로 이들 성분의 효율적인 이용을 위한 쌀의 섭취방안이 필요한 것으로 나타났다.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.4
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• pp.259-264
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• 1993

Allelopathic chemicals exudated from plants stimulate or inhibit crops directly or indirectly. To prove the effects of allelochemics, we isolated and identified the compounds by bioassays on the monoculture and crosscropping cultre systems. p-Coumaric acid were exudated on all of the test crops such as tomato, red pepper, lettuce, chinese cabbage and sesame, but pyrogallol and phenylacetic acid on tomato. hydroquinone on red pepper and egg plant, pyrogallol on lettuce, and vanillic acid on chinese cabbage. The highest total concentration of allelochemics was $5,883{\mu}g$ on tomato, lowest was $220{\mu}g/g$ dry plant weight on sesame. On the cross-cropping culture of tomato-egg plant, tomato-red pepper, chinese cabbage-egg plant, chinese cabbage-red pepper and chinese cabbage-sasame, the plant height, aerial dry weight and total dry weight of the tomato and the chinese cabbage were inereased contrast with monoculture, but decreased greatly on red pepper and sesame. Growth rate of both crops on the cross-cropping culture of tomato-chinese cabbage declined, while that of chinese cabbage was increased but lettuce decreased on the chinese cabbage-lettuce cross-cropping culture contrast with monoculture.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.1
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• pp.89-98
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• 2019

The aim of this study was to evaluate the change of phenolic compounds after bordeaux mixture treatment on Cheorwon onion. Onion is a perennial plant belonging to the lily family. It is native to Persia of Southwest Asia. It is cultivated much in the temperate regions of the world. Onion is a good name for the 'Okchong' to drop blood cholesterol and cardiovascular blood flow to increase the prevention of adult diseases. Cheorwon area is inland, but it has high continental climate due to its high altitude. After the treatment with bordeaux mixture, the weight, width and plant height of the onion were affected to some extent. In the phenolic compounds, caffeic acid, ferulic acid, rutin, and kaempferol except benzoic acid, p-coumaric acid and quercetin were similar to or less than the control. Therefore, it was concluded that the treatment with bordeaux mixture had some effect on onion growth and phenolic compound contents.

• Preventive Nutrition and Food Science
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• v.2 no.4
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• pp.316-320
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• 1997

Phenolic acids are regarded as harmful materials in food and environment science but recently, as useful materials, and thus adsorption is recommended as an effective separation technique to recover or remove phenolic acids from diluted solution. If the adsorbed phenolic compounds were useful materials, the materials should be recovered through desorption. Desorption using supercritical carbon dioxide(SC-$CO_2$) was tried to separate food-borne phenolic acids from charcoal in single solute system. In the comparisons of desorption amounts, gallic acid had the lowest lolubiligy to SC-$CO_2$. Gallic acid has more hydroxy functional groups than the other phenolic acids, which was immiscible with nonpolar SC-$CO_2$. Ferulic acid was yielded more than p-coumaric acid, because ferulic acid had much bigger molecular weight, which was affected more by van der Waas force. It was found that the most affecting factor on desorption amounts was the solubility of phenolic acids to SC-$CO_2$. The second affecting factor was van der Waals force. Response surface methodology(RSM) was conducted to read the trend of desorption. Increasing density of SC-$CO_2$ raised solubility of phenolic acids.

• Korean Journal of Food Science and Technology
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• v.53 no.3
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• pp.252-259
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• 2021

Barley contains health-beneficial compounds, such as phenolic acids, flavonoids, lignans, and tocopherols. The antioxidant activities of pearled and wholegrain hull-less, premature, and black barley harvested in Jeju were investigated by measuring total phenolic content (TPC), total flavonoid content (TFC), phenolic compounds, tocopherols (T), and tocotrienols (T3), along with their in vitro antioxidant activities. Consequently, TPC and TFC in wholegrain barley groups were higher than those in pearled barley. Gallic acid (1.55-2.98 ㎍/g) and protocatechuic acid (0.67-2.84 ㎍/g) were the predominant phenolic compounds in barley. Total T and T3 concentrations of wholegrain barley groups were significantly higher than those of pearled barley (p<0.05). Except for the metal chelating effect and reducing power, the in vitro antioxidant activities of wholegrain barley were significantly higher than those of pearled barley. These results indicate that wholegrain Jeju barley can be used as a natural antioxidant source in the food industry.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.1
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• pp.22-28
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• 2001

The induction of enzymes and the accumulation of their end products associated with self-defense mechanism in rice were investigated. When rice leaves were irradiated with UV light, activities of diterpene cyclase, phenylalanine ammonia-lyase (PAL), and cinnamic acid 4-hydroxylase (CA4H) were induced and rice phytoalexin, momilactone A was accumulated. The content of p-coumaric acid in rice leaves was closely correlated with self-defense or allelopathic potential against barnyardgrass. UV-challenged rice leaves gave rise to the inhibition of barnyardgrass growth.

• Journal of Ginseng Research
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• v.36 no.4
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• pp.425-429
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• 2012

In this study, hydroponically-cultivated ginseng leaves, fruits, and roots were respectively extracted with ethanol. The contents of 12 ginsenosides and three phenolics in the extracts were quantitatively analyzed and the free radical scavenging activities were measured and compared. Hydroponically-cultivated ginseng leaves contained higher levels of gensenosides (Rg1, Rg2+Rh1, Rd, and Rg3) and p-coumaric acid than the other parts of the ginseng plants. The 2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid radical scavenging activities of leaves were also the highest. Accordingly, hydroponically-grown ginseng leaves were shown to hold promise for use as an environmentally-friendly natural anti-oxidant.

• Natural Product Sciences
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• v.16 no.1
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• pp.10-14
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• 2010

Phytochemical examination of the barks of Pinus densiflora Siebold et Zuccarini has led to the isolation of one phenylpropanoid, one lignan, one flavonoid, one flavan 3-ol and two procyanidins : 4-O-$\beta$-D-glucopyranosyl-p-coumaric acid (1), 2,3-dihydro-2-(4-methoxy)-7-hydroxy-3-hydroxymethyl-5-(3-hydroxy propyl)-benzofuran 3-O-$\alpha$-D-glucopyranoside (2), taxifolin 3'-O-$\beta$-D-glucopyranoside (3), (+)-catechin (4), procyanidin B1 (5) and epicatechin-($4{\beta}$-8)-catechin-($4{\alpha}$-8)-catechin (6). Among them, Compound 4, 5 and 6 showed potent anti-oxidative activities and these anti-oxidative activities were significantly different compared with ascorbic acid as positive control.

• Korean Journal of Agricultural Science
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• v.15 no.1
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• pp.95-113
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• 1988

In order to find out changes of chemical components related to browning of dried jujube, four varieties were subjected to the proximate analysis. Boeun, one of the major varieties in Korea, was sun-dried and stored for 12 months and analyzed periodically for one year. Browning, titrable acidity, pH, contents of ascorbic acid, organic acid, total amino acid, free amino acid, free sugar, hydroxymethylfurfural (HMF) and phenolic compounds were determined and compared with those of fresh jujube. The results obtained are summarized as follows; 1. In comparison with other similar fruits, jujube was high contents of ascorbic acid (62-79mg%) and carbohydrate (22-28%) excluding fiber. 2. Browning was increased in both steam-treated and nontreated plot together as storage period was prolonged. 3. Ascorbic acid content of fresh jujube was as high as 297.4mg% DB, but it was decreased to 20.2mg% DB, after 12 months storage. Therefore, loss of ascorbic acid was very great up to 93% of its original content. 4. Five kinds of organic acid, oxalic, succinic, fumaric, malic and citric acid were identified as major organic acids. It was interesting that only fumaric acid content was increased while others decreased during storage. 5. Seventeen kinds of amino acid were identified in the analysis of total amino acid content. Major amino acids were found to be proline, threonine, glutamic acid and lysine. During 12 months storage, 30% of original total amino acid was decreased and this was mostly accounted for free amino acids. 6. Threonine, proline, alanine and valine were identified as free amino acids which showed 85% decrease after 12 months storage. 7. Free sugars of jujube were composed of fructose, glucose and sucrose. They showed 24% decrease after 12 months storage, Especially sucrose was not detected after 4 months storage. 8. HMF of dried jujube was isolated and identified. Its content was increased up to great extent as storage period prolonged. 9. Caffeic, ferulic and P-coumaric acid were identified as jujube phenolic compounds which were significantly decreased during storage. In conclusion, non-enzymatic browning was thought to be more important than enzymatic reaction in the dried jujube. Amino-carbonyl reaction, ascorbic acid oxidation and reaction between phenolic compounds and sugar or nitrogen compounds were observed to be related to this browning.