• Natural Product Sciences
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• v.17 no.2
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• pp.65-79
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• 2011

Reactive oxygen species potentially cause damage to cellular components including lipids, protein and DNA; this oxidative damage plays a key role in the pathogenesis of neurodegenerative disease, cardiovascular disease, metabolic disease and cancer. On the basis of the oxidative stress hypothesis, a number of studies have been performed to search for an efficient and safe antioxidant. Although in vitro studies have provided promising results, only a limited number of natural and synthetic antioxidants have been developed for clinical application due to their low efficacy and side-effects. Thus, the discovery of new antioxidants with marked efficacy and safety has attracted worldwide attention in recent decades. Since plants are recognized as important sources of natural antioxidants, our research has focused on the discovery of new naturally occurring antioxidants from medicinal plants. The purpose of this review is to open a new prospect in the field of search for natural antioxidants from medicinal plants by summarizing our recent findings. Using in vitro bioassay systems such as 2,2-diphenyl-1-picrylhydrazyl, superoxide radical scavenging tests and lipid peroxidation models, we have tested over than 350 species of medicinal plants for their antioxidant activity and selected several of them for further investigation. During the research on the discovery of effective natural antioxidants from the medicinal plants selected, we have isolated several new and known antioxidant compounds that include stilbene glycosides, phenolic glycosides, flavonoids, oligostilbenes, and coumarins. Our results suggest that the presence of antioxidant compounds in the medicinal plants might be associated with the traditional use to treat inflammation, cardiovascular disease and various chronic diseases.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.25-30
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• 1989

Effects of cooking and drying methods on the composition of glycolipids and phospholipids of shrimp, Metapenaeus joyneri, were investigated. Major components of the glycolipids were esterified steryl glycosides, monogalactosyl diglycerides and steryl glycosides. Hot air drying enhanced the esterified steryl glycosides content substantially with the reduction of the monogalactosyl diglycerides content. However, reversed pattern was shown for freeze drying. Main components of the phospholipids were phosphatidyl ethanolamines, phosphatidyl cholines, phosphatidic acids, phosphatidyl inositols and phosphatidyl serines. Phosphatidic acids content for hot air and freeze dried shrimp without tooting was 8.3% and 5.9%, respectively. On the other hand, freeze dried shrimp with microwave heating was higher in phosphatidyl ethanolamines contents but lower in phosphatidyl cholines contents than hot air dried shrimp. Major fatty acids of the glycolipids and phospholipids fractions were pentadecanoic acid, palmitic acid, oleic acid, nervonic acid and eicosapentaenoic acid in fresh shrimp.

• Toxicological Research
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• v.25 no.1
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• pp.23-28
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• 2009

Some of the edible plants like apricot kernel, flaxseed, and cassava generate hydrogen cyanide (HCN) when cyanogenic glycosides are hydrolyzed. Rhodanese (thiosulfate: cyanide sulfurtransferases of TSTs; EC: 2.8.1.1) is a sulfide-detoxifying enzymes that converts cyanides into thiocyanate and sulfite. This enzyme exists in a liver and kidneys in abundance. The present study is to evaluate the conversion of apricot cyanogenic glycosides into thiocyanate by human hepatic (HepG2) and colonal (HT-29) cells, and the induction of the enzymes in the rat. The effects of short term exposure of amygdalin to rats have also been investigated. Cytosolic, mitochondrial, and microsomal fractions from HepG2 and HT-29 cells and normal male Spraque-Dawley rats were used. When apricot kernel extract was used as substrate, the rhodanese activity in liver cells was higher than the activity in colon cells, both from established human cell line or animal tissue. The cytosolic fractions showed the highest rhodanese activity in all of the cells, exhibiting two to three times that of microsomal fractions. Moreover, the cell homogenates could metabolize apricot extract to thiocyanate suggesting cellular hydrolysis of cyanogenic glycoside to cyanide ion, followed by a sulfur transfer to thiocyanate. After the consumption of amygdalin for 14 days, growth of rats began to decrease relative to that of the control group though a significant change in thyroid has not been observed. The resulting data support the conversion to thiocyanate, which relate to the thyroid dysfunction caused by the chronic dietary intake of cyanide. Because Korean eats a lot of Brassicaceae vegetables such as Chinese cabbage and radish, the results of this study might indicate the involvement of rhodanese in prolonged exposure of cyanogenic glycosides.

• Korean Journal of Pharmacognosy
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• v.23 no.4
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• pp.201-210
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• 1992

Scutellariae plants contain a large number of flavonoids and in addition, many of them are with unusual A- and/or B-ring substitutions. The total number of flavonoids reported up to the middle of 1991 are 137 including 89 of flavones, flavonols and their glycosides including 3 C-glycosides$(1{\sim}89)$, 39 of flavanones, dihydroflavonols and their glycosides $(90{\sim}128)$, 8 of chalcones $(129{\sim}136)$ and one biflavonoid, 8, 8'-bibaicalein(137). More than half of the flavonoids are with either unusual 5-metboxy(2'-methoxy in case of chalcones) in A-ring and/or 2'-oxygenation(2-oxygenation in case of chalcones) in B-ring substitutions. Four flavones, four flavanones and two chalcones are with methylation at 5-OH(2'-OH in case of chalcones) and six of them also have 2'-oxygenations(2- in case of chalcones). Sixtyeight out of total 137 flavonoids have oxygenated substitution at 2'-(2- in case of chalcones) position of B-ring and in addition, 27 of them have another oxygen function at 6'-(6- in case of chalcones) and 18 of them have additional oxygen substitutions either at 3'-, 5'-,3',6'-or 3', 4', 5'-(3, 4, 5- in case of chalcones) positions. The distribution and isolation of flavonoid components of Scutellariae plants are tabulated with references.

• Korean Journal of Pharmacognosy
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• v.47 no.4
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• pp.295-300
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• 2016

Flavonoids are widely reported to be beneficial to human health. Among flavonoids, in general, flavonoid aglycons have better biological activities than flavonoid glycosides, in that aglycons can easily penetrate through cell membrane because of their low polarity. Therefore, kaempferol, quercetin and various their glycosides were evaluated for their abilities to inhibit NO and $PGE_2$ productions in LPS-induced RAW 264.7 cells. Of these flavonoids and flavonoid glycosides, kaempferol-7-O-${\beta}$-D-glucoside(kp-7-glu) which possesses a glycoside at C-7 position of the A ring in kaempferol, potently inhibited NO, $PGE_2$ and $TNF-{\alpha}$, $IL-1{\beta}$, IL-6 productions in LPS-induced RAW 264.7 macrophages.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.36-43
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• 2010

The purpose of this study was to investigate the phenolic acid, proanthocyanidin (PAs), and flavonol glycoside contents, as well as the antioxidant activities of pine needle extracts from six species of young pine trees. The extracts were prepared from Section Pinus (Diploxylon): P. densiflora, P. sylvestris, P. pinaster and P. pinea, and Section Strobus (Haploxylon): P. koraiensis and P. strobus. Phenolics were extracted from pine needles with 80% acetone to obtain the soluble free fraction, and insoluble residues were digested with 4 M NaOH to obtain bound ethyl acetate and bound water fractions. Phenolics were analyzed by HPLC, and the hydrophilic antioxidant activity was measured using oxygen radical absorbance capacity (ORAC). Total phenolic and flavonoid contents of the soluble free fraction were higher than those of the bound ethyl acetate and bound water fractions. The main phenolics were monomers and polymers of PAs in the soluble free fraction, and phenolic acids and flavonol glycosides in bound ethyl acetate fraction. Flavonol glycosides found in different species of pine needles were qualitatively similar within fractions, but composition varied among Pinus sections. High levels of kaempferol arabinoside and an unknown compound were present in all Strobus species. The soluble free fraction had the highest antioxidant activity, followed by bound ethyl acetate and bound water fractions.

• Natural Product Sciences
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• v.8 no.2
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• pp.35-43
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• 2002

Glycosides of herbal medicines, such as glycyrrhizin, ginsenosides, kalopanaxsaponins, rutin and ponicirin, were studied regarding their metabolic fates and pharmacological actions in relation to intestinal bacteria using germ-free, gnotobiotic and conventional animals. When glycyrrhizin (GL) was orally administered, $18{\beta}-glycyrrhetinic\;acid\;(GA)$, not GL, was detected in plasma and intestinal contents of gnotobiotic and conventional rats. However, GA could not be detected in germ-free rats. When GL was incubated with human intestinal bacteria, it was directly metabolized to GA (>95%) or via $18{\beta}-glycyrrhetinic\;acid-3-{\beta}-D-glucuronide$(>5%). Orally administered GL was effective in gnotobiotic and conventional rats for liver injury induced by carbon tetrachloride, but was not effective in germ-free rats. When ginseng saponins were orally administered to human beings, compound K in the plasma was detected, but the other protopanxadiol saponins were not detected. The compound K was active for tumor metastasis and allergy. When kalopanaxsaponins were incubated with human intestinal microflora, they were metabolized to kalopanaxsaponin A, kalopanaxsaponin I and hederagenin. These metabolites were active for rheumatoid arthritis and diabetic mellitus while the other kalopanxsaponins were not. When flavonoid glycosides were orally administered to animals, aglycones and/or phenolic acids were detected in the urine. The metabolic pathways proceeded by intestinal bacteria rather than by liver or blood enzymes. These metabolites, aglycones and phenolic acids, showed antitumor, antiinflammatory and antiplatelet aggregation activities. These findings suggest that glycosides of herbal medicines are prodrugs.

• Preventive Nutrition and Food Science
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• v.8 no.4
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• pp.365-371
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• 2003

The potential of seven flavonoid glycosides to induce quinone reductase (QR), an anticarcinogenic marker enzyme, in murine hepatoma cells (hepalc1c7) and its mutant cells (BPRc1) was evaluated. Among test compounds, kaempferol-3-O-glucoside, luteolin-6-c-glucoside, and quercetin-3-O-glucoside (Q-3-G) induced QR in hepalc1c7 cells in a dose-dependent manner. However, in BPRc1 cells lacking arylhydrocarbon receptor nuclear translocator (ARNT), only Q-3-G caused a significant induction of quinone reductase at the concentration range of 0.5 to 8 ug/mL, suggesting that it is a monofunctional inducer. Q-3-G induced not only phase 2 enzymes, including QR and glutathione-S-transferase, but also nitroblue tetrazolium reduction activity in HL-60 cells, a biochemical marker for cell differentiation promoting agents. In conclusion, Q-3-G merits further study to evaluate its cancer chemopreventive potential.

• Journal of Ginseng Research
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• v.20 no.3
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• pp.269-273
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• 1996

We investigated the effects of ginseng glycosides and their aglycones on processes of single ion channel formation and channel properties. The glycosides, Rg, and Rb, , and their aglycones, 20-(S)-protopanaxatriol (PT) and 20-(S)-protopanaxadiol (PD) increased the membrane permeability for ions. PT, PD, Rg1, and Rb1; at concentrations of 0.5, 3.0, 10.0 and 30.0 $\mu\textrm{g}$/ml respectively; Induced single ion channel fluctuations with the life times in the range of 0.1~1005 in open states and conductances from 5 to 30 pS in 1 M KCI. At high concentrations of these substances, rapid fluctuations of transmembrane ion current with amplitude from hundred pS to dozen nS were observed. Against other substances, ginsenoside Rbl began to increase the membrane conductance at concentration of about 60 $\mu\textrm{g}$/ml without fluctuation of single ion channel. Membranes treated with PT, PD, Rg1 and Rb1 are more permeable to K+, than to Cl while zero current membrane potentials with 10 gradients of KCI were 12, 16, 8, 25 mV respectively. Key words : Membrane conductance, single ion channel, ginsenosides.

• Archives of Pharmacal Research
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• v.27 no.7
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• pp.751-756
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• 2004

Flavonoids have been demonstrated to exhibit a wide range of biological activities including anti-inflammatory and neuroprotective actions. Although a significant amount of flavonoids has been identified to be present as glycosides in medicinal plants, determinations of the biological activities of flavonoids were mainly carried out with aglycones of flavonoids. Therefore, the exact role of the glycosidation of flavonoid aglycones needs to be established. In an attempt to understand the possible role of glycosidation on the modulation of the biological activities of flavonoids, diverse glycosides of kaempferol, quercetin, and aromadendrin were examined in terms of their anti-inflammatory activity determined with the suppression of lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV2 microglial cells. The results indicated that glycosidation of aglycones attenuated the suppressive activity of aglycones on LPS-induced NO production. Although attenuated, some of glycosides, depending on the position and degree of glycosidation, maintained the inhibitory capability of LPS-induced NO production. These findings suggest that glycosidation of flavonoid aglycones should be considered as an important modulator of the biological activities of flavonoids.