• Archives of Pharmacal Research
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• v.22 no.6
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• pp.642-645
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• 1999

In a bioassay-guided search for anti-allergic compounds from higher plants of Korea, poly-methoxyflavones, 3',4',5,6,7,8-hexamethoxyflavone (I), 5-hydroxy-3',4',6,7,8-pentamethoxyflavone (II) and 3',4',5,7,8-pentamethoxyflavone (III) have been isolated from the immature peels of Citrus unshiu. Structures of these compounds were elucidated on the basis of spectroscopic techniques. Compounds I and II inhibited dose-dependent histamine release from the rat peritoneal mast cells activated by compound 48/80 or anti-DNP IgE.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1665-1672
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• 2012

An 80% ethanol extract of Hizikia fusiforme was obtained and followed by successive fractionation using the organic solvents n-hexane, ethyl acetate, and n-butanol to identify the antioxidative substance. The aqueous part of the nbutanol fractionation step, showing high antioxidative activity, was subjected to reverse-phase liquid chromatography. As a result, a substance purified from a BB-2 fraction showed high antioxidative activity. The m/z 419 [M+H] molecular ion peak in the fraction was observed by the analysis of the ESI-LC/MS spectrum. By the analysis of 1H NMR (500 MHz, DMSO-$d_6$) and $^{13}C$ NMR (125 MHz, DMSO-$d_6$) spectra, a unique compound of the fraction was biochemically identified as a 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone (5HHMF). We also investigated the effect of 5HHMF on human gastric AGS carcinoma cells. Western blot analysis suggested that the flavone substantially increased the levels of the death receptor-associated apoptosis mediators Fas, Fas L, FADD, TRADD, and DR4 in a concentration-dependent manner. The levels of Fas, Fas L, TRADD, and DR4 in the cells treated with 5HHMF ($5{\mu}g/ml$) were approximately 26.4-, 12.8-, 6.7-, and 9.8-times higher than those of non-treated cells, respectively. Of note, the level of FADD protein in the cells exposed to 5HHMF ($1{\mu}g/ml$) increased approximately 9.6-times. In addition, the cleavage of caspase-3, -8, and -9 in cultured AGS cells treated with 5HHMF was significantly confirmed. Therefore, our results suggest that 5HHMF from H. fusiforme is involved in the induction of death receptor-associated apoptosis mediators in human gastric AGS carcinoma cells.

• Food Science and Preservation
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• v.30 no.2
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• pp.235-246
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• 2023

Yellowball (Citrus hybrid cv. Yellowball ) is a new citrus hybrid between Haruka (C. tamurana × natsudaidai ) and Kiyomi (C. unshiu × sinensis) and is known to possess strong antioxidant activity. However, detailed information on the antioxidant components of its peel has not yet been reported. This study evaluated the antioxidant activity of the peel and identified the antioxidant components by fractionating a methanolic extract of Yellowball peels using liquid-liquid extraction with n-hexane, ethyl ether (ether), ethyl acetate (EA), butanol, and water. The phenolic contents and antioxidant activities of the n-hexane, ether, and EA fractions were higher than those of the other fractions, and these fractions were further separated by semi-preparative high-performance liquid chromatography (HPLC). Four antioxidant peaks, EA1, EA2, EA3, and He1, were isolated and analyzed using ultra-performance liquid chromatography-quadrupole-time- of-flight mass spectrometry (UPLC-Q-TOF MS). Sinapoyl glucoside and hesperidin were identified in EA2 and EA3, respectively, and a polymethoxylated flavone (PMF) complex (5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone, natsudaidain, tetrameth- oxyflavone, and tangeretin) was identified in He1. A compound in EA1 with m/z 223.0246 [M-H] could not be identified and was named unknown2. The antioxidant activity of unknown2 (IC₅₀=69.17 ㎍/mL) was similar to that of Trolox, which was noted as a major antioxidant in Yellowball peel. Further studies on the antioxidant capacity of Yellowball peel are required; however, these results provide a foundation for using Yellowball peel as an antioxidant.