• Natural Product Sciences
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• v.22 no.4
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• pp.287-292
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• 2016

Aqueous extraction of Citrus unshiu peels (AECUP) is mainly comprised with pro-angiogenichesperidin and narirutin. In this study, we report approaches to increasing the yields of extracted hesperidin and narirutinfrom Citrus unshiu peels using proper solvents. Significantly improved yields of both compounds were obtained using methanol and dimethyl sulfoxide (DMSO) compared to acetonitrile, ethyl acetate, ethanol, and isopropyl alcohol. Especially, effect of DMSO was by far the better of the two solvents in extraction of hesperidin. In addition, the DMSO extracted hesperidin significantly induced the pro-angiogenic effects of human umbilical vein endothelial cells (HUVECs) and markedly up-regulated phosphorylation of the ERK1/2 signaling pathway. These results demonstrate that pro-angiogenic inducer; hesperidin and narirutin can be simply, easily, and effectively extracted from Citrus unshiu peels.

• Korean journal of food and cookery science
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• v.26 no.1
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• pp.88-94
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• 2010

This study was carried out to investigate the total polyphenol and flavonoid contents and antioxidative activities of the methanol extracts of Citrus sunki, C. unshiu and C. natsudaidai peels before and after drying. Total polyphenolic content was high in the citrus peels before drying compared to the dried peels, and highest in the order of C. sunki, C. natsudaidai and C. unchiu. On the other hand, flavonoid content was high in the dried citrus peels than in the citrus peels before drying, and was highest in the order of C. unshiu, C. natsudaidai, C. sunki, but in dried peels it was highest in the order of C. natsudaidai, C. unshiu, C. sunki. DPPH radical scavenging activity was highest in the order of C. natsudaidai, C. unchiu, C. sunki, and that in the citrus peels before drying was higher than in the dried peels. Inparticular, C. natsudaidai peels before drying showed higher activity than vitamin C in 0.5 or 1.0 mg/100 g. Hydrogen peroxide scavenging activity was highest in the order of C. unshiu, C. natsudaidai, and C. sunki in the citrus peels before drying. The dried peels were highest in the order of C. unshiu, C. natsudaidai, C. sunki at 0.5 mg/100 g, but high in order of C. natsudaidai, C. unshiu and C. sunki at more than 1.0 mg/100 g. Inparticular, all C. natsudaidai peels displayed high activity more than 87% at 2.0 mg/100 g. Clear patterns in alkyl radical scavenging activity could not be confirmed in Citrus species whether before or after drying of peels. Hydroxyl radical scavenging activity was highest in the order of C. natsudaidai, C. unshiu and C. sunki but was relatively low compared to the scavenging activity of other activated oxygen species.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.1
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• pp.1-7
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• 2010

This study was carried out to investigate total polyphenol contents, total flavonoid contents and antioxidative activities of the methanol extracts from dried Citrus sunki and C. unshiu peels. The dried C. sunki peels displayed higher total polyphenol and flavonoid contents for older dried peels. In contrast, the dried C. unshiu peels displayed higher total polyphenol contents for more recently dried and displayed high total flavonoid contents by order of 2007, 2008 and 2006. DPPH radical scavenging activities of dried C. sunki peels were high by order of 2007 (0.25 mg/mL exception), 2006 and 2008, but C. unshiu peels could not confirm clear regularity. In particular, the dried C. sunki (2008, exception) and C. unshiu peels displayed very high activities of more than 86% in 1.0 mg/mL. Alkyl radical scavenging activities of dried C. sunki peels were higher for older dried peels (2007, 1.0 mg/mL exception), and that of dried C. unshiu peels were higher for more recently dried in below 0.5 mg/mL but were higher for older peels in 1.0 mg/mL. Hydrogen peroxide scavenging activities of dried C. sunki peels were higher for older peels (2007, 2.5 mg/mL exception), on the other hand, dried C. unshiu were higher for more recently dried. In particular, dried C. unshiu peels displayed high activities of more than 85% in 2.5 mg/mL. Hydroxyl radical scavenging activities of dried C. sunki and C. unshiu peels displayed low activities compared to other reactive oxygen species as the range of $49.9\pm2.2\sim63.5\pm0.9$% in 1.0 mg/mL.

• Journal of Applied Biological Chemistry
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• v.44 no.3
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• pp.143-146
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• 2001

Eight flavonoids, including rutin, naringin, hesperidin, quercetin, hesperetin, nobiletin, 3,5,6,7,8,3',4'-methoxylated flavone, and tangeretin, in the peels of satsuma mandarin (Citrus unshiu) species of Halla, Gungcheon, Hungjin, Namgam-20, Illnam-1, and Chungdo harvested between August and December were analyzed through HPLC. Hesperidin content of Halla harvested during early maturation was 28.70 mg/g, and was the highest among the tested citrus fruits. Rutin content of Hungjin harvested during early maturation was 2.66 mg/g. Naringin in all citrus species and hesperetin in Halla, Gungchun, Namgam-20, and Chungdo were only detected in the peel of fruits harvested during early maturation. Hesperidin and rutin were detected mainly in all citrus species, and other flavonoids in trace. Flavonoid content in the peel of fruits was high during early maturation. Flavonoid contents in the peels of all fruit samples were generally high in the early stage of maturation, which then decreased rapidly.

• Natural Product Sciences
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• v.26 no.2
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• pp.176-181
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• 2020

Two new compounds, 3-methyl-but-2-en-1-yl-1-O-β-xylopyranosyl-(1"→2')-O-β-glucopyranoside (1) and 1-O-β-glucopyranosyl-6-hydroxy-2-methyl-hep-2-enoic acid (2), along with sixteen known terpenoids were isolated from the peels of Citrus unshiu Markov. Their structures were elucidated based on extensive NMR analyses (¹H NMR, ¹³C NMR, DEPT, COSY, HMQC, and HMBC) and high-resolution mass spectrometry. In addition, all isolates (1 - 18) were tested their effects on nitric oxide (NO) production in RAW264.7 cells. Limonin (15) showed to inhibit LPS-induced NO production in a concentration-dependent manner without cytotoxicity.

• Korean journal of food and cookery science
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• v.26 no.1
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• pp.18-25
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• 2010

This study was carried out to investigate the total polyphenol and flavonoid contents and antioxidative activities of enzymatic digests from dried Citrus unshiu and C. grandis peels. The yields of digests from dried C. unshiu and C. grandis peels were high in viscozyme (a carbohydrase) and kojizyme (a protease), and enzymatic digests from dried C. grandis peels appeared highly comparable to those of C. unshiu. Total polyphenol contents were high in ultaflo (a carbohydrase) and alcalase and flavourzyme (proteases), and the digests from dried C. unshiu peels appeared high in comparison to C. grandis. Total flavonoid contents were high in ultaflo, alcalase, and water extract. DPPH radical scavenging activities appeared very high in digests from dried C. grandis peels in comparison to C. unshiu, and was the highest in viscozyme and kojizyme. The viscozyme digest displayed particularly high activity. Hydrogen peroxide scavenging activities increased somewhat with increasing amounts of digests, but displayed very high activity, more than 91%, except kojizyme the digest from dried C. unshiu peel, at 2.0 mg/mL. Alkyl radical scavenging activities increased rapidly with increasing amounts of digest, and all enzyme digests from dried C. unshiu and C. grandis peels displayed very high activities at more than 0.5 mg/mL. Hydroxyl radical scavenging activities increased rapidly with increasing amounts of digests, and all enzymatic digests from dried C. unshiu and C. grandis peels displayed relatively low activities in comparison to other activated oxygen species.

• 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.

• The Korea Journal of Herbology
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• v.23 no.4
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• pp.159-170
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• 2008

Objectives: This study was carried out to evaluate the quality of the peels of various Citrus species. Method: The contents of hesperidin from fruit peels used as Citri Pericarpium such as C. natsudaidai, C. grandis, C. unshiu, and C. sunki, were analyzed by HP-TLC, HPLC, and essential oils of those were analyzed by GC/MS. Results: HPLC analysis showed that the hesperidin from the peel of C. unshiu and C. reticulata was satisfied the standard of Korean Pharmacopoeia. The essential oil was analyzed by GC/MS. As a result, limonene, furfural, 5-methyl-2-furfural, linalool oxide(cis), linalool oxide(trans), terpinen-4-ol, $(-)-{\alpha}$-terpineol, germacrene D, 4-methyl-2,6-di-tert-butylphenol was detected in all 4 kinds of Citrus species. Conclusions: As a result of chemotaxonomical similarity analysis with essential oils, the peels of C. natsudaidai and C. grandis are closely related, while C. unshiu is distantly related to the others.

• Journal of Life Science
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• v.24 no.7
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• pp.750-756
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• 2014

Citrus, yield of which is the highest among fruits produced in Korea, is extensively consumed for processed food items. The amount of by-products of citrus produced from the processing within a short period after the harvest is tremendous. These by-products are mostly dumped into land or neglected because of cost involved in processing them. The aim of the present study was to explore the usefulness of the by-products as a new material by examining the anti-inflammatory activity of fermented extracts of citrus peels. The peels of 'unshu' (Citrus unshiu) was fermented with Aspergillus niger and their extracts before or after fermentation were analyzed using HPLC. The analysis showed that neohesperidin level considerably increased and the two new compounds were synthesized after fermentation. The anti-inflammatory activity of the fermented extracts was examined on RAW 264.7 murine macrophage cells stimulated with lipopolysaccharide. Fermented unshu extracts significantly enhanced the decrease of nitric oxide (NO) production, iNOS and COX-2 expression, comparing with those of unfermented extracts. Also TNF-${\alpha}$ and IL-6 production, both of which are pro-inflammatory cytokine, were more inhibited in fermented extracts. These results showed that the fermentation and promotion of the function of the by-products of citrus peels will help find a new application.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.9
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• pp.1580-1583
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• 2004

The effect of far-infrared (FIR) radiation on the antioxidant activity of extracts from Citrus unshiu peels (CPs) was evaluated. CPs (5 g) were placed in Pyrex petri dishes (8.0 cm diameter) and irradiated at 150$^{\circ}C$ for 10, 20, 30, 40 or 50 min with a FIR heater. After FIR irradiation, 70% ethanol extract of CPs were prepared and total phenol contents (TPC), radical scavenging activity (RSA) and reducing power of the extracts were determined. FIR radiation of CPs at 150$^{\circ}C$ for 30 min increased the TPC and RSA of ethanol extract from 71.9${\mu}$M to 133.9 ${\mu}$M and from 29.64% to 51.27%, respectively, and reducing power was increased from 0.451 to 0.675, compared to those of non-irradiated control. These results indicated that FIR radiation onto CPs could liberate and activate covalently bound phenolic compounds that have antioxidant activities.