• Food Science and Preservation
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• v.23 no.7
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• pp.1004-1011
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• 2016

Flavonoids, non-nutrient secondary metabolites of plants, are widely distributed in commonly consumed agro-food resources. Flavonoids include aglycones, and their glycosides are reported to have potential health-promoting compounds. The aim of this study was to investigate flavonoid glycosides in the fruit and leaves of Zizyphus jujuba var. inermis (Bunge) Rehder (jujube). A total of six flavonoids (five flavonols and one chalcone) were identified in jujube fruit and leaves by using ultra-performance liquid chromatography-diode array detector-quadrupole time of flight mass spectrometry along with chemical library and an internal standard. In positive ion mode, six flavonoids were linked to the C- and O-glycosides which were conjugated with sugar moieties based on kaempferol, quercetin, and phloretin aglycones. Total flavonoid contents of leaves (8,356.5 mg/100 g dry weight (DW)) was approximately 900-fold higher than that of fruit (fresh fruit, 13.6 mg/100 g dry DW; sun-dried fruits, 9.2 mg/100 g dry DW). Quercetin 3-O-rutinoside (rutin) and quercetin 3-O-robinobioside were the predominant flavonols in fruit and leaves of jujube. In particular, rutin had the highest content (6,735.2 mg/100 g DW) in leaves, and rutin is a widely reported bioactive compound. Phloretin 3',5'-di-C-glucoside (chalcone type) was detected only in leaves. The leaves of jujube contain a high content of flavonoids and the results of this study indicate that jujube leaves may be a source of bioactive flavonoids.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.6
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• pp.833-839
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• 2003

Quantitaties of flavonoids were determined by HPLC in three different ethanol extract (50, 70 and 95%, v/v) from Korean cherry. Antimicrobial activity of the ethanol extract and its solvent fraction (ethyl acetate and n-butanol fractions) against Staphylococcus aureus (ATCC 6538) and Staphylococcus epidermidis (ATCC 12228) was evaluated using MIC and disk test. Additionally, UV protective effect was also determined. The highest flavonoid quantity was found in 70% ethanol extract of Korean cherry. The quantities of quercitrin were 12.7 mg% and 2.1 mg% in ethyl acetate fraction and in buthanol fraction, respectively. In addition, the flavonoid in 70% (v/v) ethanol extract of Korean cherry included 14.9 mg% of quercitrin, 6.0 mg% of tannic acid and 5.2 mg% of catechin. Therefore, it was confirmed that main flavonoid of Korean cherry was quercitrin. For antimicrobial activity of ethanol extract of Korean cherry against Staphylococcus aureus (ATCC 6538) and Staphylococcus epidemidis (ATCC 12228), MIC and disk test using ethyl acetate fraction and butanol fraction were carried out. As a result, ethyl acetate fraction with higher quantity of flavonoid showed higher antimicrobial activity. Therefore, it was confirmed that the higher antimicrobial activity was brought about by flavonoid in Korean cherry. For UV protective effect of Korean cherry, ethanol extract showed the absorption zone of ultraviolet rays in 210∼380 nm including 290∼320 nm that is the wave length of UV-B harmful to the skin of human body. The pattern is the same as the absorption zone of 220∼300 nm in catechin and 210∼400 nm in quercitrin. Then, the functionalities of catechin and quercitrin were anticipated. It is expected that quercitrin in Korean cherry has the antimicrobial effect and UV protective effect related to the skin.

• Preventive Nutrition and Food Science
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• v.10 no.1
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• pp.1-5
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• 2005

Eight flavonoids, apigenin-6-C-β-D-glucopyranosy l-8-C-β-D-glucopyranoside (AGG), quercetin 7-O-β-D­glucopyranoside (QG), luteolin 7-O-β-D-glucopyranoside (LG), quercetin 7-O-(6'-O-acetyl)-β-D-glucopyranoside (QAG), luteolin 7-O-(6'-O-acetyl)-β-D-glucopyranoside(LAG), quercetin (Q), luteolin (L) and acacetin 7-O-β­D-glucuronide (AG) were determined by HPLC in the safflower (Carthamus tinctorius L.) leaf during growth and processing. During growth, levels of five flavonoid glycosides (AGG, QG, LG, QAG, & LAG) in the leaf increased progressively at over time according to growth stages, reached a maximum before June 11, and then decreased sharply, while those of three flavonoid aglycones (Q, L, & AG) increased greatly at the early stage of growth, reached a peak before May 28, and then decreased rapidly. During the steaming process, contents of five flavonoid glycosides increased rapidly with increased steaming time, reached a maximum after 5 min of steaming, and then decreased, whereas those of flavonoid aglycones except for AG decreased sharply with increased steaming time. During the roasting process, contents of three flavonoid glycosides decreased rapidly with increased roasting time, whereas those of two acetylflavonoid glycosides (QAG & LAG) and three flavonoid aglycones increased progressively with increased roasting time, reached a maximum after 3 min of roasting, and then decreased. These results suggest that appropriate steamed and roasted safflower leaves are a rich source of flavonoids, and may be a good source of bioactive components as a functional leaf tea.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.551-555
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• 1997

This experiment was carried out to elucidate the biological activity and absorption characteristics of flavonoids in Rhizobium and Bradyrhizobium and to obtain basic information on host specific nodulation by flavonoids in rhizobium-legume symbiosis. The purpose of the present study was to explore the biological activity and the flavonoid absorption indicates that host-specificity is induced by flavonoids in symbiotic nitrogen fixation. Biological activity increased by daidzein and genistein treatment on B. japonicum KCTC 1539 whereas decreased by luteolin treatment but increased by luteolin treatment on R. meliloti whereas decreased by daidzein and genistein treatment. Daidzein and genistein are absorbed by B. japonicum, KCTC 1539 at higher rate than other flavonoids. Especially, luteolin was absorbed at a least rate. Luteolin are absorbed by R. meliloti KCTC 2353 at higher rate than other flavonoids. Especially, daidzein and genistein was absorbed at a least rate.

• Korean journal of applied entomology
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• v.13 no.1 s.18
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• pp.33-39
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• 1974

For the investigations on the mechanism of blast disease resistance in the rice variety 'Toilg-il', Ihe chemical contents such as silicate, nitrogen and flavonoid in the leaf blades of tile variety were determined as compared to moderately susceptible variety 'Pung-kwang' A correlation between disease severity of rice blast and the chemical contents in the variety 'Pung-kwang' were also studied. The results showed that silicate and flavonoid contents were decreased inversely with application of nitrogen fertilizer, and negative correlation between silicate and flavonoid contents and disease severity in the field were observed. In the resistant variety 'Tong-il', these chemical contents and silicified cells were significantly higher than in the variety 'Pung-kwang' From these results, it seemed that the high contents of silicate and flavonoid in the leaf blades were related closely to the resistance of the variety 'Tong-il'.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.3
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• pp.338-346
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• 2015

This study was performed to elucidate the anti-proliferative and apoptotic mechanism of flavonoids in HT-29 human colon cancer cells. We investigated the anti-proliferative activity of flavonoids in HT-29 human colon cancer cells via cell viability assay (MTT assay), caspase-3 activity, RT-PCR, and western blotting. We cultured HT-29 cells in the presence of various flavonoids (apigenin, rutin, naringenin, and myricetin) at a concentration of $100{\mu}M$. In the MTT assay, naringenin showed the strongest effect on cell viability in HT-29 colon cancer cells. Caspase-3 activity, a marker of apoptosis, significantly increased upon naringenin treatment. For RT-PCR, myricetin significantly increased Bax protein levels, naringenin increased p53 protein levels, and rutin reduced expression of the anti-apoptotic protein Bcl-2. Western blotting of HT-29 colon cancer cells showed that myricetin increased cleaved caspase-3 protein levels, naringenin significantly increased poly (ADP-ribose) polymerase protein levels, and rutin increased E-cadherin protein levels. These results indicate that flavonoid exerts anticancer effects on human colon HT-29 cells through a caspase-dependent apoptotic pathway.

• Journal of Animal Science and Technology
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• v.62 no.5
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• pp.605-613
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• 2020

This study was conducted to evaluate the effects of dietary supplementation of plant flavonoid (quercetin) on immune parameters, growth performance, and nutrient digestibility in growing pigs challenged with Escherichia coli lipopolysaccharide (LPS). A total of 40 crossbred ([Landrace × Yorkshire] × Duroc) growing pigs; initial body weight (BW) of 26.95 ± 1.26 kg were used in a six-week experimental trial. Pigs were randomly allocated into one of four treatment groups in a 2 × 2 factorial arrangement with the following factors; without LPS challenge and with LPS challenge (day 21) supplemented with or without 0.1% flavonoid according to BW (2 replicate pens per treatment with 2 gilts and 3 barrows per pen). The single-dose LPS (100 ug / kg BW) injection showed trends tended to be increased in interleukin-6 (IL-6) after 2 h and 6 h of challenge compared with unchallenged pigs. However, other measured immune indices (white blood cell, immunoglobulin G, lymphocyte, and tumor necrosis factor), growth performance, and nutrient digestibility were not significantly different between challenged and non-challenged animals. The supplementation of flavonoid significantly increased (p < 0.05) average daily gain (ADG) during day 0-21, tended to increase dry matter and nitrogen digestibility, significantly reduced IL-6, increased Ig-G and WBC concentrations and increased lymphocytes percentage regardless of LPS challenge.

• Journal of Microbiology and Biotechnology
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• v.19 no.7
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• pp.709-712
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• 2009

Enzymatic glucosylation with glycosyltransferases can be used to regulate the water solubility of aglycone. The drawback of this process is the demand of UDP-glucose as a sugar donor. We made an in-frame fusion of the flavonoid O-glucosyltransferase (OsUGT-3) and sucrose synthase (AtSUS) genes. The resulting fusion protein, OsUGT3-AtSUS, was expressed in E. coli and purified. When sucrose and UDP were supplied, the fusion protein was able to convert quercetin into quercetin O-glucoside without the addition of UDP-glucose. In addition, UDP-glucose was recycled when sucrose was added to the reaction mixture. This fusion protein is useful for the enzymatic production of flavonoid O-glucosides.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6991-6995
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• 2013

Antioxidant activity, total phenolic, total flavonoid compounds and cytotoxicity to cancer cell lines of propolis extracts from two extraction methods were investigated in this study. Propolis was collected from Phayao province and extracted with 70% ethanol using maceration and sonication techniques. The antioxidant activity was evaluated by DPPH assay. Total phenolic and flavonoid compounds were also determined. Moreover, the cytotoxicity of propolis was evaluated using MTT assay. The percentage propolis yield after extraction using maceration (18.1%) was higher than using sonication (15.7%). Nevertheless, antioxidant and flavonoid compounds of the sonication propolis extract were significant greater than using maceration. Propolis extract from sonication showed antioxidant activity by $3.30{\pm}0.15$ mg gallic acid equivalents/g extract. Total phenolic compound was $18.3{\pm}3.30$ mg gallic acid equivalents/g extract and flavonoid compound was $20.49{\pm}0.62$ mg quercetin/g extract. Additionally, propolis extracts from two extraction methods demonstrated the inhibitory effect on proliferation of A549 and HeLa cancer cell lines at 24, 48 and 72 hours in a dose-dependent manner. These results are of interest for the selection of the most appropriate method for preparation of propolis extracts as potential antioxidant and anticancer agents.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4352-4360
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• 2011

A four dimensional quantitative structure activity relationship analysis was applied to a series of 50 flavonoid inhibitors of $p56^{lck}$ protein tyrosine kinase by the molecular comparative electron topological method. It was found that the -log (IC50) values of the compounds were highly dependent on the topology, size and electrostatic character of the substituents at seven positions of the flavonoid scaffold in this study. Depending on the negative or positive charge of the groups correctly embedded in these substituents, three-dimensional bio-structure to increase or decrease -log (IC50) values in the training set of 39 compounds was predicted. The test set of 11 compounds was used to evaluate the predictivity of the model. To generate 4D-QSAR model, the defined function groups and pharmacophore used as topological descriptors in the calculation of activity were of sufficient statistical quality ($R^2$ = 0.72 and $Q^2$ = 0.69). Ligand docking approach by using Dock 6.0. These compounds include many flavonoid analogs, They were docked onto human families of p56lck PTKs retrieved from the Protein Data Bank, 1lkl.pdb.