• 농업과학연구
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• 제49권2호
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• pp.227-237
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• 2022

Amyloid beta (Aβ) is produced from an amyloid precursor protein by the activation of the amyloidogenic pathway, and it is widely known to cause Alzheimer's disease (AD). In this study, we investigated the neuroprotective effects of three flavonoids, quercitrin, isoquercitrin, and afzelin, from Acer okamotoanum against Aβ-induced neurotoxicity in SH-SY5Y neuronal cells. Aβ_25-35 treatments resulted in decreased cell viability and increased levels of nuclei condensation and fragmentation. However, an isoquercitrin treatment dose-dependently increased cell viability and decreased nuclei condensation and fragmentation levels. SH-SY5Y cells treated with Aβ_25-35 showed increased reactive oxygen species (ROS) production compared to that from cells not treated with Aβ_25-35. However, treatment with the three flavonoids significantly inhibited ROS production compared to an Aβ_25-35-treated control group, indicating that the three flavonoids blocked neuronal oxidative stress. For a closer examination of the neuroprotective mechanisms, we measured the expressions of the non-amyloidogenic pathway-related proteins of a disintegrin and metalloprotease 10 (ADAM10) and the tumor necrosis factor-α converting enzyme (TACE). An isoquercitrin treatment enhanced the expressions of ADAM10 compared to the control group. In addition, the three flavonoids activated the non-amyloidogenic pathway via the upregulation of TACE. In conclusion, we demonstrated neuroprotective effects of three flavonoids from A. okamotoanum, in particular isoquercitrin, on neurotoxicity by the regulation of the non-amyloidogenic pathway in Aβ_25-35-treated SH-SY5Y cells. Therefore, we suggest that flavonoids from A. okamotoanum may have some potential as therapeutics of AD.

• Parasites, Hosts and Diseases
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• 제61권4호
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• pp.449-454
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• 2023

Free-living amoebae (FLA) rarely cause human infections but can invoke fatal infections in the central nervous system (CNS). No consensus treatment has been established for FLA infections of the CNS, emphasizing the urgent need to discover or develop safe and effective drugs. Flavonoids, natural compounds from plants and plant-derived products, are known to have antiprotozoan activities against several pathogenic protozoa parasites. The anti-FLA activity of flavonoids has also been proposed, while their antiamoebic activity for FLA needs to be emperically determined. We herein evaluated the antiamoebic activities of 18 flavonoids against Naegleria fowleri and Acanthamoeba species which included A. castellanii and A. polyphaga. These flavonoids showed different profiles of antiamoebic activity against N. fowleri and Acanthamoeba species. Demethoxycurcumin, kaempferol, resveratrol, and silybin (A+B) showed in vitro antiamoebic activity against both N. fowleri and Acanthamoeba species. Apigenin, costunolide, (-)-epicatechin, (-)-epigallocatechin, rosmarinic acid, and (-)-trans-caryophyllene showed selective antiamoebic activity for Acanthamoeba species. Luteolin was more effective for N. fowleri. However, afzelin, berberine, (±)-catechin, chelerythrine, genistein, (+)-pinostrobin, and quercetin did not exhibit antiamoebic activity against the amoeba species. They neither showed selective antiamoebic activity with significant cytotoxicity to C6 glial cells. Our results provide a basis for the anti-FLA activity of flavonoids, which can be applied to develope alternative or supplemental therapeutic agents for FLA infections of the CNS.

• Applied Biological Chemistry
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• 제44권2호
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• pp.122-128
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• 2001

감귤류 유래 플라보노이드인 hesperidin 및 naringin과 이들의 agIycone 형태인 hesperetin 및 naringenin의 생리기능 활성에 대하여 동물(흰쥐 및 햄스터)실험을 통한 지질대사,인체 간종양 세포주 HepG2 세포를 이용한 암세포 생육 및 지질대사, 노화와 질병의 원인이 되는 불포화 지방산의 지질 과산화 억제 작용을 중심으로 고찰하였다. 이들 감귤류 플라보노이드는 흰쥐에서의 콜레스테롤 농도 저하작용 및 햄스터에서의 중성지질 농도 저하작용을 나타내었다. 이러한 대사 기작으로서 콜레스테를 및 중성지질 합성의 중요 조절효소로 알려진 acyl-CoA: cholesterol acyltransferase(ACAT) 및 phosphatidate phosphohydrolase(PAP) 활성이 in vivo 및 in vitro 실험계에서 현저히 저해되었으며, 특히 aglycone 형태의 플라보노이드에서 그 효과가 강하게 나타났다. 또한,이들 플라보노이드는 인체 간종양 세포주 HepG2 세포를 이용한 실험에서 암세포 생육 억제 및 세포내 콜레스테롤과 중성지질 농도를 저하시키는 효과도 인정되었다. Hesperetin은 실험적으로 유도한 간질환을 개선시켰다. 노화 및 질병의 발생과 깊이 관련된 것으로 알려진 불포화지방산 과산화 반응을 억제시키는 항산화 효과도 확인되었는데, hesperetin에서 좋은 효과를 나타내었다. 이상의 결과에서 감귤류 유래 플라보노이드는 동물의 혈중 콜레스테롤 및 중성지질 억제작용에 의한 혈관계 질환 개선효과, 지방간을 비롯한 간질환 개선효과, 암세포 증식억제 작용, 노화 및 질병의 원인이 되는 지질 과산화 억제 작용 등 건강에 관련된 다양한 생리기능 활성이 존재하는 것을 확인하여 기능성 성분의 연구로 일정의 효과를 얻었다. 따라서 이러한 감귤류 유래의 생리활성 성분의 연구목적은 건강증진 효과를 높이는 식품의 개발과 식품 첨가물의 신규 수요를 증대시켜 국민의 건강을 향상시키는데 있다.

• Animal Bioscience
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• 제34권3_spc호
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• pp.434-442
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• 2021

Objective: This study aims to evaluate the influence of dietary flavonoids on the growth performance, blood and intestinal profiles, and carcass characteristics of broilers by employing a meta-analysis method. Methods: A database was built from published studies which have reported on the addition of various levels of flavonoids from herbs into broiler diets and then monitored growth performance, blood constituents, carcass proportion and small intestinal morphology. A total of 42 articles were integrated into the database. Several forms of flavonoids in herbs were applied in the form of unextracted and crude extracts. The database compiled was statistically analyzed using mixed model methodology. Different studies were considered as random effects, and the doses of flavonoids were treated as fixed effects. The model statistics used were the p-values and the Akaike information criterion. The significance of an effect was stated when its p-value was <0.05. Results: Dietary flavonoids increased (quadratic pattern; p<0.05) the average daily gain of broilers in the finisher phase. There was a reduction (p<0.01) in the feed conversion ratio of the broilers both in the starter (linear pattern) and finisher phases (quadratic pattern). The mortality rate tended to decrease linearly (p<0.1) with the addition of flavonoids, while the carcass parameter was generally not influenced. A reduction (p<0.001) in cholesterol and malondialdehyde concentrations (both linearly) was observed, while super oxide dismutase activity increased linearly (p<0.001). Increasing the dose of flavonoids increased (p<0.01) the villus height (VH) and villus height and crypt depth (VH:CD) ratio (p<0.05) in the duodenum. Similarly, the VH:CD ratio was elevated (p<0.001) in the jejunum following flavonoid supplementation. Conclusion: Increasing levels of flavonoids in broilers diet leads to an improvement in growth performance, blood constituents, carcass composition and small intestinal morphology.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1990년도 Proceedings of International Symposium on Korean Ginseng, 1990, Seoul, Korea
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• pp.49-57
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• 1990

It has been well known that extended exposure to reactive oxygens causes severe damage to susceptible biomolecules. In this study, the effects of flavonoids including trifling and kaempferol from Ginseng leaves on single oxygen induced photohemolysis of erythrocytes and free radical scavenging activities were investigated . Each flavonoid aglycone (5-50UM) such as kaempferol, quercetin or baicalein exhibited a high protective effect against the photohemolysis. They protected the cells by scavenging 102 and free radicals. Although the free radical scavenging activities of the flavonoid glycosides were not much lower than those of their corresponding aglycones, their insolubility into lipid bilayers of membrane made them less effective in preventing the photohemolysis induced by 1O2. The 102 and free radical scavenging activities of flavonoids were estimated by the decomposition of the flavonoid by 1O2 and the bleaching of free radicals by the flavonoid, respectively. The solubilization of the flavonoid into micelle or erythrocytes was deduced from spectrophotometric and microscopic observations. The cooperation of L-ascorbic acid and a flavonoid, and a possible involvement of lipoxygenase or cyclooxygenase in the photohemolysis mechanism were discussed. Keywords Panax ginseng C.A Meyer, ginseng leaves, flavonoids, singe1 oxygen, Photohemolysis.

• 한국식품영양과학회:학술대회논문집
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• 한국식품영양과학회 2004년도 Annual Meeting and International Symposium
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• pp.24-36
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• 2004

Polyphenolic flavonoids are among a wide variety of phytochemicals present in the human diet. Basic research, animal model, and human studies suggest flavonoid intake may reduce the risk of several age-related chronic diseases. The vast number of flavonoids and mixtures of their subclasses, including flavonols, flavones and flavanones, and the variety of agricultural practices that affect their concentration in foods have presented a challenge to the development of adequate food composition databases for these com-pounds. Nonetheless, dietary assessments have been applied to cohort and case-control epidemiological studies and several reveal an inverse association with risk of some forms of cancer, cardiovascular disease, and other chronic conditions. Those observational studies that have examined these relationships with regard to flavonols, flavones, and flavanones are reviewed. The requirement for caution in interpreting these studies is discussed with regard to the limited information available on the bioavailability and biotransformation of these flavonoids. As the totality of the available evidence on these flavonoids suggests a role in the prevention of cancer and cardiovascular disease, further research is warranted, particularly in controlled clinical trials.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 춘계학술대회
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• pp.255-255
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• 1996

Flavonoids are the large class of plant-derived polyphenolic compounds with a broad spectrum of biological actions including anti-inflammatory, anti-allergic and anti-asthmatic activities. It has been reported that quercetin and some other flavonoids inhibit the histamine release from mast cells. Disodium cromoglycate, a kind of biflavonoid, have been used as a anti-asthmatic agent. Therefore, the following study was undertaken to characterize tile structure-activity relationships of flavonoids in the inhibition of histamine release, from IgE-sensitized mast cells. Flavonoid acetate were synthesized by addition of acetic anhydride to the flavonoids dissolved in pyridine. According In the Mota method, IgE-rich serum was made in rats sensitized with Pertussis vaccine and ovalbumin. Rat abdominal mast cells were harvested and purified over tile discontineous Percoll gradients, Mast cells were preincubated in RPMI with IgE-rich serum and further incubated with flavonoids. Histamine contents released from mast cells were determined fluorospectrophotometrically after stimulation with ovalbumin. (omitted)

• Natural Product Sciences
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• 제11권4호
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• pp.233-239
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• 2005

The aerial parts of Gomphocarpus sinaicus Boiss. yielded four flavonoids that were identified as isorhamnetin 3-O-rhamnoglucoside (1), luteolin-7-O-glucoside-3-O-rhamnoside (2), rutin (3) and rutin-7-O-rhamnoside (4). All of the isolated flavonoids were identified by spectroscopic methods (UV, FAB-MS, $^1H-NMR\;&\;^{13}C-NMR$) and in comparison with the literature data. The isolated flavonoids 1, 2 and 4 are reported here for the first time from Gomphocarpus sinaicus Boiss. Three sets of experiments were carried out using the defatted alcoholic extract of Gomphocarpus sinaicus Boiss: the $1^{st}$ experiment indicated that the $LD_{50}$ was 49.82 mg/100 g b.wt. of intraperitoneally (i.p.) injected mice. The toxic signs were recorded within the first 24 hr post-injection. The $2^{nd}$ experiment revealed that the extract of the plant exhibited significant anti-inflammatory effects in normal rats. The $3^{rd}$ experiment was found that the tested doses of the extract in diabetic rats induced a significant decrease in serum glucose, AST, ALT, triglycerides, cholesterol and LDL, while HDL caused a significant increase.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.539-542
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• 2007

Glycosyltransferase family 1 (UOT) uses small chemicals including phenolics, antibiotics, and alkaloids as substrates to have an influence in biological activities. A glycosyltransferase (XcGT-2) from Xanthomonas campestris was cloned and consisted of a 1,257 bp open reading frame encoding a 45.5 kDa protein. In order to use this for the modification of phenolic compounds, XcGT-2 was expressed in Escherichia coli as a glutathione S-transferase fusion protein. With the E. coli transformant expressing XcGT-2, biotransformation of flavonoids was carried out. Flavonoids having a double bond between carbons 2 and 3, and hydroxyl groups at both C-3' and C-4', were glycosylated and the glycosylation position was determined to be at the hydroxyl group of C-3', using nuclear magnetic resonance spectroscopy. These results showed that XcGT-2 regiospecifically transferred a glucose molecule to the 3'-hydroxyl group of flavonoids containing both 3' and 4'-hydroxyl groups.

• Archives of Pharmacal Research
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• 제27권11호
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• pp.1114-1119
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• 2004

This paper describes the quantitative determination of flavonoids, tannins and ellagic acid in the leaves from wild and cultivated variations of Rubus L. species (Rosaceae): raspberry (2 wild and 13 cultivars) and blackberry (3 wild and 3 cultivars). The content of flavonoids was analyzed using spectrophotometric (the Christ-M llers method) and HPLC analysis after acid hydrolysis. The content of tannins was determined by the weight method, with hide powder, described by German Pharmacopoeia 10 (DAB 10). Ellagic acid content was examined using the HPLC method after acid hydrolysis. Flavonoid content, determined using the Christ-Muller's method was higher for the blackberry leaves than for the raspberry leaves and varied between 0.46% and 1.05%. Quercetin and kaempferol were predominant in all samples analyzed using the HPLC method. The highest flavonoid content was found in the leaves of R. nessensis (1.06%); with results in all of the examined samples varying between 0.27% and 1.06%. The concentration of ellagic acid in all species was determined after acid hydrolysis and ranged from 2.06% to 6.89%. The leaves of raspberries are characterized by greater amounts of tannins (varying between 2.62% and 6.87%) than the leaves of other species. The results from this study indicate that the analyzed species are a rich source of flavonoids, ellagic acid and tannins, which may be used for the quality assessment of Rubus L. species leaves.