• Journal of Veterinary Science
• /
• v.23 no.1
• /
• pp.4.1-4.15
• /
• 2022

Background: Flavonoids are natural polyphenols found widely in citrus fruit and peel that possess anti-adipogenic effects. On the other hand, the detailed mechanisms for the antiadipogenic effects of flavonoids are unclear. Objectives: The present study observed the anti-adipogenic effects of five major citrus flavonoids, including hesperidin (HES), narirutin (NAR), nobiletin (NOB), sinensetin (SIN), and tangeretin (TAN), on AMP-activated protein kinase (AMPK) activation in palmitate (PA)-treated HepG2 cells. Methods: The intracellular lipid accumulation and triglyceride (TG) contents were quantified by Oil-red O staining and TG assay, respectively. The glucose uptake was assessed using 2-[N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-d-glucose (2-NBDG) assay. The levels of AMPK, acetyl-CoA carboxylase (ACC), and glycogen synthase kinase 3 beta (GSK3β) phosphorylation, and levels of sterol regulatory element-binding protein 2 (SREBP-2) and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) expression were analyzed by Western blot analysis. The potential interaction between the flavonoids and the γ-subunit of AMPK was investigated by molecular docking analysis. Results: The flavonoid treatment reduced both intracellular lipid accumulation and TG content in PA-treated HepG2 cells significantly. In addition, the flavonoids showed increased 2-NBDG uptake in an insulin-independent manner in PA-treated HepG2 cells. The flavonoids increased the AMPK, ACC, and GSK3β phosphorylation levels and decreased the SREBP-2 and HMGCR expression levels in PA-treated HepG2 cells. Molecular docking analysis showed that the flavonoids bind to the CBS domains in the regulatory γ-subunit of AMPK with high binding affinities and could serve as potential AMPK activators. Conclusion: The overall results suggest that the anti-adipogenic effect of flavonoids on PA-treated HepG2 cells results from the activation of AMPK by flavonoids.

• Analytical Science and Technology
• /
• v.14 no.4
• /
• pp.331-339
• /
• 2001

Methoxylated flavonoids (sinenstin, nobiletin, tangeretin) were isolated and identified by preparative HPLC, mass and NMR. Chung-pi(I) and Chung-pi(II) contained methoxylated flavonoids most richly. Methoxylated flavonoids in Chung-pi obtained from Korean Milgam increased with fruit maturity, while contents of the methoxylated flavonoids gradually decreased after mid of October.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.37 no.2
• /
• pp.43-48
• /
• 2018

Mulberry fruit is a new income product in Korea sericulture due to the increase of fruit consumption. However, flavonoids of Korean mulberry cultivar for fruit production did not reported yet. In this study, the typical mulberry cultivar, 'Daeshim' was analyzed using ultrahigh performance liquid chromatography coupled with diode array detection and quadrupole time-of-flight mass spectrometry (UPLC-DAD-QTOF/MS) technique for flavonoids analysis. Nine flavonoids were isolated and analyzed from Daeshim using UPLC-DAD-QTOF/MS chromatogram. According to quantitative analysis, rutin (66.1 mg/100g DW) and quercetin 3-O-(6"-O-malonyl) glucoside (26.7 mg/100g DW) were abundant in mulberry fruit. Our results might be used as basic information for mulberry consumption.

• Korean Journal of Pharmacognosy
• /
• v.51 no.2
• /
• pp.139-145
• /
• 2020

The leaves of Diospyros kaki Thunb. were used to treat heart disease and hypotension in traditionally East Asia. The purpose of this study is to simultaneously quantitiative analyze the content of flavonoids in leaves of D. kaki. The isolated flavonoids from the leaves of D. kaki, and the structure of the isolated flavonoids were analyzed based on ¹H and ¹³C NMR spectrum compared to literature data. Simultaneous quantitative analysis of the isolated flavonoids was validated using high performance liquid chromatography (HPLC). Results showed that the calibration curves of the flavonoid compounds were confirmed that they have a large linearity with a correlation coefficient (R²) of 0.99. In the intra-day and inter-day analysis, accuracy and precision of five compounds were measured that accuracy was 94.39 to 114.47% and precision was less than 3.00%. Content analysis showed hyperoside (1.30 ± 0.09%), astragalin (0.81 ± 0.06%), trifoline (1.58 ± 0.07%), quercetin (0.13 ± 0.02%) and kaempferol (1.33 ± 0.25%).

• Advances in Traditional Medicine
• /
• v.6 no.1
• /
• pp.65-67
• /
• 2006

In this study, a new extraction method was developed and two kinds of flavonoids were extracted from the mature fruit of Vaccinium uliginosum L. of China. These two kinds of flavonoids were analyzed by spectral and identified by high-performance liquid chromatography (HPLC) and UV/Vis. The extract of the fruit was total acid hydrolyzed. TLC chromatography was subsequently employed to identify the hydrolysate. Two kinds of aglycone flavonoids, quercetin and myricetin, were identified. At the same time PC chromatography was used to identify the monomer sugar in the flavonoids and it was verified as glucose. HPLC, UV/Vis, and Mass spectrum analyses revealed that the flavonoids were quercetin 3-monoglucosides and myricetin 3-monoglucosides.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.5
• /
• pp.791-794
• /
• 2006

Cyclosophoraose (cyclic $\beta-(1,2)-glucan$, Cys) isolated from Rhizobium meliloti, a soil microorganism, was used as a solubility enhancer for flavonoids. The complexes of the cyclic oligosaccharide with flavonoids were confirmed through $^1H$ nuclear magnetic resonance (NMR) spectroscopic analysis. Flavonoids solubilized by Cys were quantitatively analyzed through high-performance liquid chromatography (HPLC). Among the flavonoids tested, the solubility of naringenin was greatly enhanced by Cys, compared with other compounds. The solubility of naringenin was enhanced about 7.1-fold by adding 10 mM Cys, compared with a control. $^1H$ NMR spectroscopic analysis indicated that the H-6 and H-8 protons, which are located on the A ring of naringenin, were greatly shifted upfield upon the complexation with Cys. This result suggested that Cys showed a regioselective interaction with the naringenin molecule upon the complexation, resulting in the solubility enhancement of naringenin.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.41 no.2
• /
• pp.45-50
• /
• 2020

Morus alba has white and/or purple fruits with a very sweet taste and low acidity. Most Korean mulberry trees have purple fruits. However, Baekokwang is a unique mulberry genetic resource in Korea with white fruits. In this study, flavonoids contents of Baekokwang mulberry leaf and fruit were analyzed using ultrahigh performance liquid chromatography coupled with diode array detection and quadrupole time-of-flight mass spectrometry (UPLC-DAD-QTOF/MS) technique. UPLC-DAD-QTOF/MS chromatogram showed that 15 flavonoids and 9 flavonoids were isolated and identified from the mulberry leaf and fruit. Total flavonoids contents of Baekokwang leaves and fruits were 812.7 mg and 35.0 mg, respectively. Baekokwang leaves had 4 major flavonoids including quercetin 3-O-(6"-O-malonyl) glucoside, 235.3 ppm, kaempferol 3-O-(6"-O-malonyl) glucoside, 132.3 ppm, kaempferol 3-O-rutinoside (nicotiflorin), 108.1 ppm, and quercetin 3-O-rutinoside (rutin), 103.8 ppm. Baekokwang fruits had 3 major flavonoids including quercetin 3-O-(6"-O-malonyl) glucoside, 13.0 ppm, quercetin 3-O-rutinoside (rutin), 7.8 ppm, and kaempferol 3-O-rutinoside (nicotiflorin), 5.7 ppm. From the above results, mulberry leaves have rich flavonoids compared to its fruits.

• Korean Journal of Pharmacognosy
• /
• v.39 no.2
• /
• pp.123-126
• /
• 2008

The five flavonoids, isoqueritrin, juglanin, astragalin and 2-O-trans-p-coumaroyl astragalin were quantitatively analyzed in the leaves, unripe- and ripe fruits of four Korean Rubus species including Rubus crataegifolius, R. pungens var. oldhami, R. parvifolius, and R. coreanus belonging to the Rosaceae family. The HPLC analysis demonstrated that flavonoids are more abundant in the leaves than in the fruits. In the four Rubus species, ripe fruits generally contained similar or more amount of flavonoids than in unripe fruits. In particular, the quantity levels of total flavonoid (49.81${\pm}$0.50 mg/g) and isoquercitrin (35.08${\pm}$0.37 mg/g) were highest in the leaf of R. crataegifolius. In addition, the content of the flavonoids were quite low in the unripe fruits of R. coreanus that is most widely used as Rubi Fructus.

• Journal of the East Asian Society of Dietary Life
• /
• v.10 no.1
• /
• pp.42-47
• /
• 2000

Flavonoids in commerical green-yellow vegetables (carrot, mugwort, perilla leaf, leek and water dropwort) were analyzed by HPLC. Flavonoids analyzed in samples were myricetin, luteolin , qercetin, apigenin and kaempferol. When 2N HCI and a reaction period of 1 hours was used, quercetin and kaempferol could be detected in leek and water dropwort, luteolin and apigenin could be detected in perilla leaf. Increasing reaction period up to 6 hours with 2N HCI led a degradation of quercetin and kaempferol to approximately 90% in leek and water dropwort, but it led to a increasing of luteolin and apigenin of maximum 300% in perilla leaf. After the blanching process, the amount of the flavonoids increased whereas the components of the flavonoids were not changed.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.15
• /
• pp.6317-6325
• /
• 2015

Ginkgo biloba extract (GBE) is a popular phytomedicine and has been used for disorders of the central nervous system, cardiovascular, renal, respiratory, and circulatory diseases. Although GBE is a complex mixture of over 300 compounds, its major components are 24% flavonoids and 6% terpene lactones. In this study, we tested the inhibitory effects of the three major flavonoids (kaempferol, quercetin, and isorhamnetin) from GBE, independently and as mixtures, on aromatase activity using JEG-3 cells (human placental cells) and recombinant proteins (human placental microsome). In both systems, kaempferol showed the strongest inhibitory effects among the three flavonoids; the flavanoid mixtures exerted increased inhibitory effects. The results of exon I.1-driven luciferase reporter gene assays supported the increased inhibitory effects of flavonoid mixtures, accompanied by suppression of estrogen biosynthesis. In the RT-PCR analysis, decreased patterns of aromatase promoter I.1 mRNA expressions were observed, which were similar to the aromatase inhibition patterns of flavonoids and their mixtures. The present study demonstrated that three flavonoids synergistically inhibit estrogen biosynthesis through aromatase inhibition, decrease CYP19 mRNA, and induce transcriptional suppression. Our results support the usefulness of flavonoids in adjuvant therapy for breast cancer by reducing estrogen levels with reduced adverse effects due to estrogen depletion.