Green tea catechins(GTC) were studied for its inhibitory effect on human platelet aggregation in vitro, for its antithrombotic effect in mice in vivo, and for bleeding and clotting time in rats. The catechins were isolated and purified from green tea, which were composed of (-)-epigallocatechin gallate, (-)-epigallocatechin, (-)-epicatechin gallate and (-)-epicatechin. GTC produced a potent inhibition of human platelet aggregation in a dose-dependent manner against the stimulants such as ADP, collagen, epinephrine and ristocetin in vitro. GTC also prevented death due to the formation of pulmonary thrombosis by platelet aggregates in mice in a dose-dependent manner in vivo. GTC increased the bleeding time, whole blood clotting time and plasma clotting time in rats, too. These results suggest that GTC is a promising antithrombotic agent.
The objective of this study is to investigate the direct effects of green tea catechins(GTC) on vascular smooth muscle tension and ^(46)Ca^(2+) uptake in rat aorta. The methods used in this study are isometric tension measurements using physiograph, Lanthanum method for ^(46)Cac^(2+) (2 uCi/ml) uptake measurement in rat aorta. GTC modified tension induced by 40 mM KCl or 1 uM norepinephrine in rat aorta. Low concentrations of GTC($lt;0.5 mg/m increased tension by 40 mM KCl or 1 tM norepinephrine, individually. However, high concentrations of GTC($gt; 0.5 mg/ml) inhibited tension by 40 mM KCl or 1 uM norepinephrine, individually. GTC increased ^(45)Ca uptake induced by 40 mM KCl in a dose-dependent manner. From these results, GTC has the dual actions in vascular smooth muscle in vitro. Low concentrations of GTC augments tension by K or norepinephrine. However, high concentrations of GTC inhibits tension by K or norpeinephrine. GTC may have Ca^(2+) channel activation action, which may result in unphysiological vasodilation by Ca^(2+) overload in vascular smooth muscle.
This study was carried out to determine the pesticide residues in rice bran, crude rice bran oil and the oil of various stages of refining process. Each samples were analyzed for 41 pesticide residues by multiclass multiresidue methods with GC-ECD, NPD and identified by GC-MSD. Rice bran were detected cypermethrin, diazinon, dichlofluanid, and its level were ranged from 0.01-0.122 ppm. Crude rice bran oil were detected cypermethrin, diazinon, dichlofluanid, dimethoate, etrimfos, flucythrinate, and its level were ranged from 0.015-0.654 ppm. Crude rice bran oil has the higher level of pesticide residues and more varieties of pesticides than rice bran. But pesticide residues in the crude rice bran oil was found to be almost removed when pigment was decolorized by absorption using active carbon and clealy removed by thermolysis for deodorization.
An attempt was made to determine the residual distribution of organochlorine and organophosphorus pesticides in the various kinds of Korean tea which were purchased from the market. The organochlorine pesticides investigated in this study were BHC, DDT and dicofol and the organophosphorus pesticides were diazinon, EPN, fenitrothion and parathion. The pesticide residues were determined by GC-ECD and NPD. Only BHC was detected in all the samples and it's level were ranged from 0.00064 ppm to 0.05995 ppm and it's average was 0.00682 ppm and DDT, dicofol and organophosphorus pesticides were not detected in all samples. The organophophorus pesticides were detected(0.0035-0.0983 ppm) in raw materials but were not in the manufactured material and it is considered that the largely components of the pesticides is removed by drying and high temperature while the tea was manufactured. The recovery tests of the pesticides gave satisfactory results showing an average yield of 97.6% with organochlorine pesticides and 92.5% with organophosphorus pesticides and the detection limits level were 0.00008 ppm to 0.0010 ppm.
The distribution of Listeria spp. in various foods and its fatty acid composition were examined. A total 60 samples of dairy products(15), seafoods(20), meat products(18), factory wastes(2), and salades(5) were tested. Listeria spp. was found 10 samples, showing about 16. 7% detection ratio; dairy products 0(0%), seafoods 1(5%), meat product 7(38.9%), factory wastes 2(100%) and salades 0(0%). L. monocytogenes was isolated from 6 samples(10%); seafood 1(5%), meat products 3(16.7%) and factory wastes 2(100%). L. innocua was isolated from meat products 7(38.9%) and factory wastes 2(100%). Whereas L. welshimeri was isolated from meat product 1(5. 6%) and factory wastes 1(50%). The cellular fatty acid composition determined by gas chromatography was found not to differ among L. monocytogenes and L. innocua. Twenty three strains of L. monocytogenes and twenty two strains of L. innocua isolated from foods has similar fatty acid profiles when grown at 30℃, 24 hrs on the tryptic soy plate with C_(15) and _(17)' anteiso branched acids accounting for about 80% of total.
In order to compare the suppressive effect of quercetin and several its glycosides, such as quercitrin (quercetin-3-rhamnoside), isoquercitrin (quercetin-3-gluooside), hyperin (quercetin-3-galactoside) and rutin (quercetin-3-rhamnosyl glucoside), on the genotoxicity by Nmethyl-N-nitrosourea(MNU), in vitro sister chromatid exchange(SCE) test using mouse spleen lymphocytes and in viuo micronucleus test using mouse peripheral blood were performed. MNU-indured SCEs in vitro were not decreased by the simultaneous treatment of teat compounds. Among them, quercetin and hyperin showed significant suppressive effects at high dose(10^(-5)M). On the other hand, MNU-induced micronucleated reticulocytes(MNRETs) in vivo were aignificantly decreased with good dose-dependent manner in all compounds tested. However, there were not significant differences between quercetin aglycone and its glycosides in the suppressive effects under experimental condition of this study. These results suggest that both of queroetin aglycone and its glycosides may act as an antigenotoxic agent in vivo and may be useful as a chemopreventive agent of alkylating agent.
The isolation and chemical characterization of yellow food pigments from Monascus purpureus were studied according to the compositions of media. Monascus yellow pigments were isolated and purified by solvent fractionation, silicagel column chromatography, TLC and HPLC. The retention time of Monascus yellow pigments isolated by HPLC was respectively 5 min(I) and 9 min(II) at the yeast malt extract agar(YMA) media and was respectively 4.6 min(III), 5 min(I) 5.7 min(IV), 8.3 min(V), 9 min(II) and 10.7 min(VI) at the malt extract agar (MEA) media. The structure of monascin(I), ankaflavin(II), 6,11-dihydrorubropunctatin(III), 6,11-dihydromonascorubrin(V) and unknown compounds(IV, VI) was elucidated by EI-Mass, H' and C'9 NMR, UV-visible spectrnmeter. Therefore, it was suggested that 6,11-dihydrorubropunctatin (III) and 6,11-dihydromonascorubrin(V) are new intermediates of Monascus yellow pigments.
Recently, as concern about the residual antibiotics in milk increase, the detection methods of residual antibiotics used extensevely at the present time were investigated and compared to their properties and the detection limits of variable antibiotics. At first, comparative tests of the detectable sensitivity of 4 teat organisms, B.cereus, B.subtilis, M.luteus, B. stearothermophilus C-953, were performed by disc assay. As a result, B.stearotleermoph.ilus was the most sensitive strain of all other strains and showed the detect limit of 5-50 ppb for penicillins (PCs). And also, B.subtilis was showed the more effective detection limit, 200-400 ppb, for aminoglycosides (AGs) and M.luteus was showed predominant sensitivity , 50-500 ppb for macrolides(MLs) and B.cereus was the most sensitive strain for tetracyclines (TCs) and showed the detection limit of 100-400 ppb. Therefore, each test strains were showed a different sensitivity in the detection of the different antibiotic families. When the detection limit of disc assay and other methods were compared, TTCmethod was less sensitive than other methods showing 5-50 ppb detectable lebel for PCs. Also, for the detection of other antibiotic families TTC method was showed the worst sensitivity and Delvo and Charm Farm tests were similar to the detectable properties of AGs and MLs. Although disc assay was showed the similar detection limit for PCs with Delvo and Charm Farm, it was more widely effective for the detection of kanamycin, erythromycin, chlortetracycline, doxycycline, verginiamycin and so on than Delvo or Charm Farm. CharmII test was showed the best sensitivity for the most of antibiotics except neomycin and gentamycin. But it was necessary that different tests must be performed to each antibiotic family and so it was regarded that the effectiveness of that method was low.
In order to grasp status of trace metals contained and corelation analysis between cereal and soils, the samples which have been collected from four myeons in Ulju-ku Ulsan-city were 48 for cereal and 48 for soils. The average Hg containing level' of samples is 0.006 ppm for cereal and 0.062 ppm for soil, Pb is 0.302 ppm for cereal and 1.137 ppm for soil, Cd is 0.012 ppm for cereal and 0.027 ppm for soil, Cu is 2.01 ppm for cereal and 0.885 ppm for soil, and Zn is 7.853 ppm for cereal and 2.366 ppm for soil. Corelation analysis between cereal and soils showed statistical significance for Hg, Pb and Cu, but it didn't show any significance for Cd and Zn.
This study was carried out to determine and confirm of Dapsone in vegetables and fruits which were illegally used for freshness. We have developed a simple, rapid and precise method that Dapsone can be analyzed in the cabbages, grapes and strawberry by HPLC with photodiode array detector. Experimental subjects were included 15 cases of cabbages, 10 cases of grapes and 10 cases of strawberries purchased in Kangwon, Chungchong province and the Seoul area. The results were obtained that Dapaone in the experimental subject was separated completely within 10 min. Detection limit of Dapsone was 0.5 ng. Aberage recoveries from cabbages, grapes and strawberries were 93.3±0.26%, 92.5±0..37%, 91.4±0..65% respectively. 4 cases of cabbages were detected Dapsone and the amount was below the 0.3 ppm. There was not detected Dapsone in any grape and strawberry samples.
A procedure for the determination of Aflatoxins in food and grains which utilizes reversed phased liquid chromatographic (LC) analysis with postcolumn derivatization by an electrochemical cell and determination with a fluorescence detector has been evaluated. The LC mobile phase was water-acetonitrile-methanol (6+2+2) with 1mM KBr and 1 mM HNO₃ which gave baseline separation for the four Aflatoxins (AfB₁, AfB₂, AfG₁, AfG₂). The electrochemical cell set at 7V, generated bromine and derivatized aflatoxins B₁ and G₁, The derivatives were detected by the fluorescence detector. The aflatoxins in naturally contaminated corn samples were isolated by three different cleanup procedures: the AOAC method I column (CB method), a rapid filtrate column (Romer's column), and an immunoaffinity column. The final extract were quantitated with fluorodensitometric TLC and the LC postcolumn derivatization techniques. The results were quite similar, however the LC technique showed less interferences and could be automated. Samples of corn, raw peanuts, peanut butter and dried dates were also analyzed successfully with this procedure.
The antilipidperoxidative and hepatopreventive effects of Aloe water extract (30 mg, 50 mg, 100 mg) were investigated at the levels of liver-total homogenates and the sera of SDrats intoxicated with CCl₄, (0.5 cc/100 g) and 50% ethanol. We measured MDA (Malondialdehyde) in the liver homogenate, AST (L-Aspartate-2-oxoglutarate aminotransferase) and ALT(L-Alanine-2-oxo-glutarate aminotransferase) in the serum. The analysis of the measurement indicated that Aloe water extract reduced MDA, ALT and AST significantly and their reduction was in relation to dose dependence. In rat liver homogenate intoxicated with ethanol and CCl₄, Aloe treatment group markedly inhibited lipidperoxidation by 30%-70%. In rat serum intoxicated with ethanol and CCl₄, Aloe treatment group inhibited AST, ALT by 40%-90%. In these data Aloe may be used to inhibit or prevent the hepatic toxicity which results from the environmental and alcoholic factors through the further study of its exact antihepatotoxic mechanism.