• YAKHAK HOEJI
• /
• v.34 no.5
• /
• pp.291-295
• /
• 1990

A modified method was investigated for the determination of benzo(a)pyrene metabolites generated by the rat liver microsomes based on the HPLC technique with radioactive flow detection. By adding $[^3H]-dexamethasone$ to the B(a)P metabolites mixture metabolized by the microsome, the poor yield of solvent extaction of B(a)P metabolites was compensated.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 1999.10a
• /
• pp.110-117
• /
• 1999

A new lignan named as hibiscuside, (+) pinoresinol 4-O-[-glucopyranosyl (12) -rhamnoside] (1), and a known lignan, syringaresinol (2) were isolated from the root bark of Hibiscus syriacus together with two feruloyltyramines (3,4) and three known isoflavonoids (5,6,7). The structures of these compounds have been established on the basis of their NMR, Mass, UV spectra. Among these phenolic compounds,6-O-acetyl daidzin (5), 6-O- acetyl genistin (6), and 3-hydroxy daidzein (7) with IC50 values of 8.2, 10.6, and 4.1 M, respectively, significantly inhibited lipid peroxidation in rat liver microsomes Hibiscuside (1), E and Z-N-feruloyl tyramines (3,4) exhibited moderate antioxidant activity.

• Archives of Pharmacal Research
• /
• v.28 no.2
• /
• pp.164-168
• /
• 2005

The EtOAc extract of Youngia koidzumiana significantly inhibited the diacylglycerol acyltransferase (DGAT) from rat liver microsomes. Bioactivity-guided fractionation led to the isolation of nine compounds, the structures of which were established using physicochemical and spectral data. Of the isolated compounds, oleanolic acid (2), methyl ursolate (7) and corosolic aicd (8) inhibited DGAT, with $IC_{50}$ values of 31.7, 26.4, and $44.3{\mu}M$, respectively. However, sesquit-erpenoids showed only weak inhibitory effects toward DGAT.

• YAKHAK HOEJI
• /
• v.43 no.6
• /
• pp.736-742
• /
• 1999

Antioxidative and cytoprotective effects of tectorigenin and glycitein isolated from the pueraria thunbergiana and its derivative, genistein, were determined. Among these three compounds, tectorigenin and glycitein bearing 6-methoxyl groups in both isoflavones showed significant free radical scavenging activities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and xanthine/xanthine oxidase (XOD) generating superoxide anion radical. Tectorigenin only showed a slight inhibitory effect on XOD. We further studied the inhibitory effects of these isoflavones on the lipid peroxidation in rat liver microsomes induced by enzymatic and non-enzymatic methods. Each of them exhibited inhibitory effect on both ascorbic $acid/Fe^{2+}-{\;}and{\;}ADP/NADPH/Fe^{+3}-induced$ lipid peroxidation. Moreover, tectorigenin exhibited the highest protection of hydrogen peroxide damage on HepG2 and Vero cells among the three isoflavones, in the cytoprotective assay. It was suggested that the pattern of antioxidative and cytoprotective effect of isoflavones could be crucially by the aromatic substitution of oxygen-containing groups.

• Preventive Nutrition and Food Science
• /
• v.4 no.4
• /
• pp.221-225
• /
• 1999

Antioxidative compounds contained in roasted safflower seeds were investigated. Six phenolic compounds, N-feruloylserotonin, N-(p-coumaroyl) serotonin, matairesinol, 8'-hydroxyarctigenin, acacetin 7-Ο-β-D-glucoside(tilianine) and acacetin were isolated and identified from the extract of seeds. The inhibitory effects of six phenolic compounds on 1,1-dipheny1-2-picrylhydrazyl(DPPH) radical and lipid peroxidation induced by H₂O₂/FeSO₄in rat liver microsomes were determined. Two serotonins showed more potent DPPH radical scavenging activity, and a stronger inhibitory effect on the lipid peroxidation than that of α-tocopherol. In addition, acacetin and matairesinol also considerably inhibited lipid peroxidation, while 2-hydroxy-arctigenin and tilianine were inactive. These results suggest that phenolic compounds, including serotonins, lignans and flavonoids in the roasted safflower seeds can be used as potential dietary natural antioxidants.

• Bulletin of the Korean Chemical Society
• /
• v.20 no.7
• /
• pp.819-823
• /
• 1999

Antioxidant activities of various mushroom fruiting bodies were investigated in vitro. Among the mushroom extracts examined, Armillariella mellea, Daedalea dickinsi, Fomitella fraxinea and Pleurotus cornusopiae markedly exhibited inhibition on lipid peroxidaton of rat liver microsomes. Ergosterol peroxide (5,8-epidioxy-5α,8α-ergosta-6,22E-dien-3β-ol), antioxidant from A. mellea, was isolated by solvent extraction, silica gel column chromatography and recrystallization. The structure of the compound was determined by NMR, GC/MS and X-ray crystallography. Ergosterol peroxide showed potent inhibition on lipid peroxidation and exhibited higher antioxidant activity than well-known antioxidants, α-tocopherol and thiourea.

• Biomolecules & Therapeutics
• /
• v.24 no.4
• /
• pp.446-452
• /
• 2016

Pharmacokinetic interaction of chrysin, a flavone present in honey, propolis and herbs, with caffeine was investigated in male Sprague-Dawley rats. Because chrysin inhibited CYP1A-selective ethoxyresorufin O-deethylase and methoxyresorufin O-demethylase activities in enriched rat liver microsomes, the pharmacokinetics of caffeine, a CYP 1A substrate, was studied following an intragastric administration with 100 mg/kg chrysin. In addition to the oral bioavailability of chrysin, its phase 2 metabolites, chrysin sulfate and chrysin glucuronide, were determined in rat plasma. As results, the pharmacokinetic parameters for caffeine and its three metabolites (i.e., paraxanthine, theobromine and theophylline) were not changed following chrysin treatment in vivo, despite of its inhibitory effect on CYP 1A in vitro. The bioavailability of chrysin was found to be almost zero, because chrysin was rapidly metabolized to its sulfate and glucuronide conjugates in rats. Taken together, it was concluded that the little interaction of chrysin with caffeine might be resulted from the rapid metabolism of chrysin to its phase 2 metabolites which would not have inhibitory effects on CYP enzymes responsible for caffeine metabolism.

• Journal of Nutrition and Health
• /
• v.25 no.6
• /
• pp.492-500
• /
• 1992

The rate of vitamin K-dependent carboxylation of endogenous liver microsomal proteins and an exogenous peptide substrate for carboxylase were measured to test the effects of excess vitamin A on vitamin K function in rats. In vitro vitamin A incubation in normal rat microsomes of vitamin K-sufficient ras did not influence the carboxylation rates of either endogenous prothrombin precursors or a peptide substrate added, Similarly vitamin A incubation in micro-somes from control and excess vitamin A-fed rats that were on vitamin K-free diet did not change the rate significantly within the respectively groups ; however the rates of endogenous protein carboxylation from excess vitamin A-fed rats tended to be increased by the in vitro vitamin A addition compared to that of control rats. Excess vitamin A-fed rats had 2- to 3- fold higher carboxylase activites of endogenous protein carboxylation either with or without the invitro vitamin A incubation than did control rats. In an in vivo study carboxyalase activites with an added exogenous peptide substrate were not influenced by excess intake of vitamin excess vitamin A-fed rats than for control rats. Carboxylase activites tended to be increased amounts of vitamin A on endogenous protein carboxylation appeareed as early as one week post-initiation of the diet. The results of this study indicate that excess vitamin A produces toxic effect rapidly and that excess dietary vitamin A increase the rate of carboxylation of endogenous protein mainly prothrombin precursors which is an indication of vitamin K defi-ciency.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.1
• /
• pp.21-26
• /
• 2005

Although the sesame lignans, sesamol, have been shown to possess antioxidative activity, less is known about the metabolism and antioxidative properties of sesamol, a major constituent of sesame oil. To determine the ability of sesamol to act as an antioxidant in vivo, we fed rats a diet containing 0.5% sesamol for 3 wk and studied its metabolism and its effects on oxidative stress. Body weight gain and weight of liver, kidneys were significantly higher in the rats fed sesamol than in rats fed the control diets. GST and GST-Px activities in rat liver microsomes were higher in rats fed sesamol and CAT activities were found to be significantly increased in rats fed sesamol. The formation of TBARS was decreased in the liver of rat fed the 0.5% sesamol diet than in controls. We detected sesamol metabolites in liver and kidneys of rats fed sesamol and its metabolites were present as conjugated glucuronides and sulfates. In contrast, not detected sesamol peak in other organs such as colon, small intestine and pancreas.

• Journal of Life Science
• /
• v.13 no.2
• /
• pp.168-174
• /
• 2003

The chemical compositions and antioxidant activity of green tea extracts in medilite-extraction water were compared to that of distilled water(DW). Antioxidant activity was fetermined by the formation of thiobarbituric acid reactive substances (TBARS) in rat liver homogenates and microsomes and the scavenging activity of free radicals by DPPH ($\alpha$, $\alpha$'-diphenyl-$\beta$-picrylhydrazyl). The order of total polyphenolic compounds and extracted yield by extracts was medilite 325 mesh-extraction water, medilite 600 mesh-extraction water and distilled water(DW). The ranges of scavenging activity of green tea extracts in DPPH method were 60.95% - 64.51%. The inhibition ratios of TBARS formation in the rat liver homogenates and microsomal fractions were significantly lower with green tea extracts by DW-extraction than with both medilite 325 mesh and 600 mesh-extraction water. The concentration of iron ion of water containing medilite 325 mesh and green tea extracts and of water containing medilite 600 mesh and green tea extracts were significantly higher compared to DW. Therefore, this result suggested that enhanced concentration of iron ion in green tea extracts by medilite-extraction water containing high iron ion content was associated with enhanced peroxidation of the rat liver microsomal fractions. These results showed that total polyphenolic compounds, the % of yield and mineral compounds of green tea extracts were increased using medilite 325 mesh and 600 mesh-extraction water.