• Korean Journal of Pharmacognosy
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• v.22 no.1
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• pp.1-12
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• 1991

Nearly 50 highly sweet substances have been isolated and structurally characterized from green plants, and such compounds comprise mainly various types of terpenoids, flavonoids, and proteins. Among the sweet substances that have been studied as constituents of North and South American medicinal plants are the sesquiterpene, hernandulcin, the triterpene glycosides, abrusosides A-D, the steroidal saponins, polypodosides A and B, and the dihydroflavonol, dihydroquercetin-3-acetate. In addition, safety studies have been performed on the potently sweet substance, stevioside, from the 'sweet herb of Paraguay' (Stevia rebaudiana), a compound now produced on a commercial scale.

• Natural Product Sciences
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• v.4 no.2
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• pp.53-57
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• 1998

Leaves of Crataegus sinaica Boiss, contain the new C-glycosyl flavone $3"',4”’-di-O-acetyl-2“-O-{\alpha}-rhamnosylvitexin$, together with the hitherto unknown, dihydroflavonol 3-O-xyloside, (2R:3R)-dihydroquercetin-$3-O-{\beta}-xylopyranoside$. The known compounds (+)-catechin, (-)-epicatechin, vicenin-II, $2"-O-{\alpha}-rhamnosylvitexin$, and $4"'-O-acetyl-2"-O-{\alpha}-rhamnosylvitexin$ were also characterized. Structures were established by conventional methods of analysis and confirmed by $^1H-,\;^{13}C-NMR$, and ESI-MS.

• Preventive Nutrition and Food Science
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• v.10 no.1
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• pp.103-110
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• 2005

Opuntia ficus-indica, commonly known as prickly pear cactus, is commercially grown as a food and medicinal plant in Jeju Island, Korea. The crushed pads and fruits of Opuntia ficus-indica were dried in a freeze-dryer and ground into flour to be used for food materials. The major components of proximate compositions were part of a nitrogen free extract. The major minerals were Ca (4391.2-2086.9㎎%), K (1932.1-2608.7㎎%), and Mg (800.6-1984.8㎎%). The major amino acid was glutamic acid, comprising 16.3% of total amino acids in fruit and 25.2% in pad. Dihydroflavonols were identified as (+)-trans-dihydrokaempferol and (+)-trans-dihydroquercetin. Citric acid methyl esters extracted from fruits showed inhibitory activities against monoamine oxidase-B. The presence of trimethyl citrate has been reported in other plants, but 1,3-dimethyl citrate and 1-monomethyl citrate have not been previously reported. The results of pharmacological efficacy tests, including serum biochemical and hematological parameters, autonomic nervous system, anti-inflammatory, analgestic activity, anti-diabetic activity, antithrombotic, anticoagulant, dopamine beta-hydroxylase, monoamine oxidase activity, hyperlipidemia, the respiratory system, antigastic, and anti-ulcerative actions indicate that the fruit and pad of the Opuntia ficus-indica are rich sources of food and medicinal materials.

• YAKHAK HOEJI
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• v.49 no.5
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• pp.416-421
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• 2005

Cudrania tricuspidata Bereau (Moraceae) have been used for anti-inflammatory, anti-hepatotoxic, anti-hyper­tensive and anti-diabetic activities. In order to investigate the efficacy of antioxidant activity, the bio-activity guided fraction and isolation of Biologically active substance were performed. $H_{2}O,\;30\%,\;60\%,\;100%$ MeOH and acetone fractions were examined on the antioxidant activity by DPPH method. It was shown that $30\%,\;60\%,\;100\%$ MeOH fractions have sig­nificantly antioxidant activity. From $30\%$ MeOH fraction, two dihydroflavonoid glycosides dihydroquercetin 7-O-$\beta$-D-glu­copyranoside (I), dihydrokaempferol 7-O-$\beta$-D-glucopyranoside (V) were isolated and $60\%$ MeOH fraction, six flavonoids including quercetin 3-O-$\alpha$-L-rhamnopyranosyl($1\rightarrow6$)-$\beta$-D-glucopyranoside (II), quercetin 3-O-$\beta$-D-glucopyranoside (III), quercetin 7-O-$\beta$-D-glucopyranoside (IV), kaempferol 3-O-$\alpha$-L-rhamnopyranosyl($1\rightarrow6$)-$\beta$-D-glucopyranoside (VI), kaempferol 3-O-$\beta$-D-glucopyranoside (VII), kaempferol 7-O-$\beta$-D-glucopyranoside (VIII) were isolated. To investigate the antioxidant activities of each compounds, we measured radical scavening activity with DPPH method and anti-lipid per­oxidative efficacy on low density lipoprotein (LDL) with TBARS assay. Four compounds of quercetin glycosides (I, II, III, IV) showed significant antioxidant activity.

• Nutritional Sciences
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• v.7 no.4
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• pp.201-207
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• 2004

The current study examined the effects of freeze-dried mulberry fruit on disaccharidase activity in the small intestine and the lowering of blood glucose in streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley male rats were randomly assigned to one normal and three streptozotocin (STZ)-induced diabetic groups. The diabetic groups were fed a mulberry fruit-free diet (DM-group), 0.3% mulberry fruit diet (DM-F group) or 0.6% mulberry fruit diet (DM-2F group). After they were fed the experimental diets for three weeks, diabetes was induced with an intraperitoneal injection of streptozotocin 50 mg/kg b.w before sacrificing 9 days later using the same experimental treatments. Analyses of anthocyanins, flavonoid and 1-deoxynojirimycin (DNJ) of lyophilized mulberry fruit were carried out and the major anthocyanins were rutin (142.5 mg), isoquercitrin (10.3 mg), quercetin (5.8 mg), morin (1.6 mg) dihydroquercetin (3.83 mg), cy-3-O-glucopyranoside (230.45 mg) and cy-3-O-rutinoside (131.5 mg) on the basis of 100 g dry weight. Total DNJ content was 2.39 mg/g dry weight of lyophilized mulberry fruit. Blood glucose level decreased in the diabetic mts fed the mulberry fruit supplement. The content of the liver glycogen increased in the diabetic mts fed the mulberry fruit supplement. Disaccharidase activity in the proximal part of the intestine, such as that of maltase, sucrase and lactase in the mulberry fruit supplementation groups, were lower than that of the DM group. These results suggest that mulberry fruit possess a suppressive effect on hyperglycemia, possibly by inhibiting the activity of disaccharidase in the small intestine of rats.

• Molecules and Cells
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• v.26 no.6
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• pp.536-547
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• 2008

Anthocyanidin synthase (ANS, leucoanthocyanidin oxygenase), a 2-oxoglutarate iron-dependent oxygenase, catalyzed the penultimate step in the biosynthesis of the anthocyanin class of flavonoids, from the colorless leucoanthocyanidins to the colored anthocyanidins. The full-length cDNA and genomic DNA sequences of ANS gene (designated as GbANS) were isolated from Ginkgo biloba for the first time. The full-length cDNA of GbANS contained a 1062-bp open reading frame (ORF) encoding a 354-amino-acid protein. The genomic DNA analysis showed that GbANS gene had three exons and two introns. The deduced GbANS protein showed high identities to other plant ANSs. The conserved amino acids (H-X-D) ligating ferrous iron and residues (R-X-S) participating in 2-oxoglutarate binding were found in GbANS at the similar positions like other ANSs. Southern blot analysis indicated that GbANS belonged to a multi-gene family. The expression analysis by real-time PCR showed that GbANS expressed in a tissue-specific manner in G. biloba. GbANS was also found to be up-regulated by all of the six tested abiotic stresses, UV-B, abscisic acid, sucrose, salicylic acid, cold and ethylene, consistent with the promoter region analysis of GbANS. The recombinant protein was successfully expressed in E. coli strain with pET-28a vector. The in vitro enzyme activity assay by HPLC indicated that recombinant GbANS protein could catalyze the formation the cyanidin from leucocyanidin and conversion of dihydroquercetin to quercetin, suggesting GbANS is a bifunctional enzyme within the anthocyanidin and flavonol biosynthetic pathway.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.63-63
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• 2003

Opuntia ficus-indicavar. saboten Makino (Cactaceae) is a tropical or subtropical plant that has been widely used as folk medicine for the treatment of diabetes, asthma, burn, edema and gastritis. The purposes of the present study were to identify antioxidant constituents from fruits and stems of the plant cultivated in Cheju island, Korea, and examine their in vitro neuroprotective activities. Using a chromatographic fractionation method, ten chemical constituents were isolated from ethyl acetate extracts. By means of chemical and spectroscopic methods, those were identified as eight flavonoids such as kaempherol (a), quercetin (b), kaempferol 3-methyl ether (c), quercetin 3-methyl ether (d), narcissin (e), dihydrokaernpferol (f), dihydroquercetin (g) and erioclictyol (h), and two terpenoids such as 3-oxo-${\alpha}$-ionol-${\beta}$-d-glucopyranoside (i) and roseoside (j). Among the isolated compounds, comrounds c~e and h~j were those reported for the first titre from the plant. Compounds b, d and g showed DPPH free radical scavenging activities with IC$\sub$50/ values of 28, 19 and 31, ${\mu}$M respectively. Compounds d and g also inhibited iron-dependent lipid peroxidation with IC$\sub$50/ values of 2.4 and 3.5 ${\mu}$M. In a primary rat cortical neuronal cell culture system, compounds b, d and g inhibited xanthine/xanthine oxidase-induced (IC$\sub$50/ values of 18.2, 2.1 and 54.6 ${\mu}$M) and H$_2$O$_2$-induced (IC$\sub$50/ values of 13.6, 1.9 and 25.7 ${\mu}$M) cytotoxicities. In addition, compounds d and g inhibited NMDA-induced excitotoxicity by 21 and 33%, and only compound d inhibited growth factor withdrawal-induced apoptosis by 31% at a tested concentration of 3 ${\mu}$M. The results suggest that the antioxidant constituents with in vitroneuroprotective activities may serve as lead chemicals for the development of neuroprotective agent.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.2
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• pp.210-219
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• 2017

This study aimed to establish an optimal extraction process and high-performance liquid chromatography (HPLC)-photodiode array (PDA) analytical method for determination of marker compounds, dihydrokaempferol (DHK) and 3-O-methylquercetin (3-MeQ), as a part of materials standardization for the development of health functional foods from stems of Opuntia ficus-indica var. saboten (OFS). The quantitative determination method of marker compounds was optimized by HPLC analysis, and the correlation coefficient for the calibration curve showed very good linearity. The HPLC-PDA method was applied successfully to quantification of marker compounds in OFS after validation of the method in terms of linearity, accuracy, and precision. Ethanolic extracts from stems of O. ficus-indica var. saboten (OFSEs) were evaluated by reflux extraction at 70 and $80^{\circ}C$ with 50, 70, and 80% ethanol for 3, 4, 5, and 6 h. Among OFSEs, OFS70E at $80^{\circ}C$ showed the highest contents of DHK and 3-MeQ of $26.42{\pm}0.65$ and $3.88{\pm}0.29mg/OFS100g$, respectively. Furthermore, OFSEs were determined for their antioxidant activities by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and lipid peroxidation (LPO) inhibitory activities in rat liver homogenate. OFS70E at $70^{\circ}C$ showed the most potent antioxidant activities with $IC_{50}$ values of $1.19{\pm}0.11$ and $0.89{\pm}0.09mg/mL$ in the DPPH radical scavenging and LPO inhibitory assays, respectively. To identify active components of OFS, various chromatographic separation of OFS70E led to isolation of 11 flavonoids: dihydrokaempferol, dihydroquercetin, 3-O-methylquercetin, quercetin, isorhamnetin 3-O-glucoside, isorhamnetin 3-O-galactoside, narcissin, kaempferol 7-O-glucoside, quercetin 3-O-galactoside, isorhamnetin, and kaempferol 3-O-rutinoside. The results suggest that standardization of DHK in OFSEs using HPLC-PDA analysis would be an acceptable method for the development of health functional foods.