• Natural Product Sciences
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• v.2 no.2
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• pp.106-114
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• 1996

Four polymethoxyfavones were isolated from the leaves of Citrus deliciosa, three of which (nobiletin, 5-O-demethylnobiletin, and tangeritin) are bioactive. The fourth (7,4'-dihydroxy-5,6,8,3'-tetramethoxyflavone) is reported for the first time in the genus Citrus and is a potential chemotaxonomic marker. The structures of these flavones were confirmed by analysing their spectral data and comparison with similar compounds. The previously reported $^{13}C$ NMR assignment of 5-O-demethylnobiletin has been revised on the basis of 2D NMR experiments (HETCOR, COSY, and COLOC). The chemotaxonomic value of the present finding is verified.

• Journal of the Korean Chemical Society
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• v.65 no.5
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• pp.327-332
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• 2021

Shiranuhi is a fruit of Citrus species widely cultivated in Jeju Island, Korea. From an extract of Shiranuhi tree branches were identified five polymethoxyflavones possessing anti-inflammatory effects; nobiletin (1), sinensetin (2), tetramethylscutellarein (3), 6-hydroxy-5,7,3',4'-tetramethoxyflavone (4) and 5-desmethylsinensetin (5). Evaluation of the activities was conducted by monitoring the production of nitric oxide (NO), prostaglandin E₂ and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) as well as the levels of iNOS and COX-2 protein expression in LPS-induced RAW264.7 cells. Among the isolates, the compound 4 exhibited the most significant NO inhibition, and suppressed the levels of iNOS and related cytokines. Therefore, it was suggested that the extract and constituents from Shiranuhi tree branches could be useful as anti-inflammatory ingredient.

• Journal of Life Science
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• v.32 no.7
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• pp.542-549
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• 2022

Polymethoxyflavones (PMFs) are flavonoids mainly found in citrus fruits and have been reported to exhibit a wide range of bioactivities, including anti-obesity, anti-cancer, and anti-inflammatory actions. To utilize PMFs as functional materials, it is necessary to develop a simple method of obtaining PMFs from citrus tissues containing a large amount of PMFs. It has been reported that Jinkyool (C. sunki Hort ex. Tanaka) peel contained a large amount of PMFs, but there are no studies on PMFs isolated from its leaves. In this study, we established a simple procedure for obtaining the PMF-rich fraction (PRF) from the leaves of Jinkyool and investigated the effects of PRF on lipid metabolism in 3T3-L1 cells. PRF inhibited lipogenesis during the differentiation of 3T3-L1 preadipocytes. It decreased the expression of peroxisome proliferator-activated receptor gamma (PPAR𝛾) and CCAAT/enhancer binding protein alpha (CEBP𝛼), FAS, and adipocyte fatty-acid-binding protein 2 (aP2). In mature 3T3-L1 adipocytes, PRF increases the phosphorylation of protein kinase A (PKA)/hormone-sensitive lipase (HSL), which are key factors involved in lipolysis. Moreover, it increases the phosphorylation of the AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) involved in fatty acid oxidation. These results suggest that PRF from Jinkyool leaves can be used as an anti-obesity agent with the action of inhibiting lipogenesis and promoting lipolysis and fatty acid oxidation in 3T3-L1 adipocytes.

• Journal of Applied Biological Chemistry
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• v.57 no.3
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• pp.211-218
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• 2014

Polymethoxyflavones (PMFs) are a group of polymethoxylated bioactive flavones with diverse biological activities, including anticancer, anti-inflammatory, antibacterial, and antiviral activities. PMFs are found from various plants such as orange, tangerine, and krachaidum. To establish the simple quantitative analytical methods for PMFs, chromatographic analysis was applied to the selected krachaidum foods because krachaidum contains diverse PMFs compared to other PMF-containing foods. Krachaidum is the rhizome of Kaempferia parviflora, and many commercial krachaidum products, such as tea, juice and wine, are commercially available and consumed as health functional foods in Asian countries. Apart from the claimed health promoting benefits, reliable quality assurance and legal guideline for the registration of these products are not available yet. Twelve PMFs were analyzed from the commercial krachaidum foods by GC-FID and HPLC-DAD. No single chromatographic method could not analyze 12 PMFs simultaneously. HPLC-DAD method was found more sensitive to detect PMFs. Based on our analysis data, we proposed 5,7-dimethoxyflaone and 5,7,4'-trimethoxyflavone as index components for the food products.

• Journal of Nutrition and Health
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• v.42 no.3
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• pp.278-290
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• 2009

This study aims to evaluate the changes of flavonoid contents and antioxidants activity of Jeju native citrus fruits juice according to the harvest date. Flavonoids such as quercatagetin, narirutin, hesperidin and neohesperidin were contained most plentifully in the juice of Jigak (Citrus aur-antium) by 573.73 mg/100 mL, Sadoogam (C. pseudogulgul) by 393.99 mg /100 mL, Soyooja by 29.63 mg/100 mL and Jigak (C. aurantium) by 201.23 mg/100 mL in the late August, respectively. The highest contents of nob-iletin, sinensetin and tangeretin among polymethoxyflavones were found in the juice of Hongkyool (C. tachibana) by 7.39 mg/100 mL, 2.24 mg/100 mL, 0.63 mg/100 mL in the late August, respectively. 3,5,6,7,8,3',4'- Heptamet- hoxyflavone recorded the highest amount in Punkyool (C. tangerina) by 0.27 mg/100 mL in the late August, but the other polymethoxyflavones including 3',4',7,8-tetramethoxyflavone, 3',4'-dimethoxyflavone, 4'-methoxyflavone, 5,6,7,3',4',5'-hexamethoxyflavone, scutellarein tetramethylether were observed only trace amount in all the citrus fruits. Flavonoid contents in the citrus fruit juices were the highest during early maturation and decreased rapidly while ripening. Total polyphenol contents were the highest in the late August and decreased with ripening. However from the late December, the contents were increased again. Antioxidant activities of the fruits were evaluated as electron donating ability and were the lowest in the late September and increased with the fruit ripening. These results suggest that quercetagetin among all the flavonoids was most plentiful in Jigak and Dangyooja (C. grandis), so that the fruits could be used for industrial material of flavonoids and antioxidant agents.