Determination of cranberry phenolic metabolites in rats by liquid chromatography-tandem mass spectrometry

The glycosides of flavonoid, anthocyanins and A type proanthocyanidins in cranberry concentrate were characterized and quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Cranberry concentrate (1 g/body weight) was orally gavaged to Fischer-344 rats (n = 6), and blood and urine samples were collected over 24 h periods. Quercetin, 3'-O-methylquercetin (isorhamnetin), myricetin, kaempferol, and proanthocyanidin dimer A2, together with thirteen conjugated metabolites of quercetin and methylquercetin and intact peonidin 3-O-galactoside and cyanidin 3-O-galactoside were identified in the rat urine after cranberry treatment. Very low levels of isorhamnetin (0.48 ± 0.09 ng/mL) and proanthocyanidin dimer A2 (0.541 ± 0.10 ng/mL) were found in plasma samples after 1 h of cranberry administration. Although no quercetin was detected in plasma, MRM analysis of the methanolic extract of urinary bladder showed that chronic administration of cranberry concentrate to rats resulted in accumulation of quercetin and isorhamnetin in the bladder. These results demonstrate that cranberry components undergo rapid metabolism and elimination into the urine of rats and are present in the urinary bladder tissue potentially allowing them to inhibit urinary bladder carcinogenesis.     

Cranberries and cranberry products: powerful in vitro, ex vivo, and in vivo sources of antioxidants

Cranberry products and especially cranberry juice (CJ) have been consumed for health reasons primarily due to their effect on urinary tract infections. We investigated the quantity of both free and total (after hydrolysis) phenolic antioxidants in cranberry products using the Folin assay. The order of amount of total polyphenols in cranberry foods on a fresh weight basis was as follows: dried > frozen > sauce > jellied sauce. On a serving size basis for all cranberry products, the order was as follows: frozen > 100% juice > dried > 27% juice > sauce > jellied sauce. High fructose corn syrup (HFCS) is a major source of sugar consumption in the U.S. and contains both glucose and fructose, potential mediators of oxidative stress. We investigated the effect of the consumption of HFCS and ascorbate with CJ antioxidants or without CJ (control) given to 10 normal individuals after an overnight fast. Plasma antioxidant capacity, glucose, triglycerides, and ascorbate were measured 6 times over 7 h after the consumption of a single 240 mL serving of the two different beverages. The control HFCS caused a slight decrease in plasma antioxidant capacity at all time points and thus an oxidative stress in spite of the presence of ascorbate. CJ produced an increase in plasma antioxidant capacity that was significantly greater than control HFCS at all time points. Postprandial triglycerides, due to fructose in the beverages, were mainly responsible for the oxidative stress and were significantly correlated with the oxidative stress as measured by the antioxidant capacity. Cranberries are an excellent source of high quality antioxidants and should be examined in human supplementation studies.     

Increased salicylate concentrations in urine of human volunteers after consumption of cranberry juice

The aim of this study was to assess whether regular consumption of cranberry juice results in elevations in urinary salicylate concentrations in persons not taking salicylate drugs. Two groups of healthy female subjects (11/group) matched for age, weight, and height consumed 250 mL of either cranberry juice or a placebo solution three times a day (i.e., 750 mL/day) for 2 weeks. At weekly intervals, salicylic acid and salicyluric acid (the major urinary metabolite of salicylic acid) concentrations were determined in urine by HPLC with electrochemical detection. Concentrations of salicylic acid in plasma were also determined. Consumption of cranberry juice was associated with a marked increase (p < 0.001) of salicyluric and salicylic acids in urine within 1 week of the intervention. After 2 weeks, there was also a small but significant (p < 0.05) increase in salicylic acid in plasma. The regular consumption of cranberry juice results in the increased absorption of salicylic acid, an anti-inflammatory compound that may benefit health.     

Metabolism by rats of 2-dodecylcyclobutanone, a radiolytic compound present in irradiated beef

Alkylcyclobutanones (2-ACBs) are suspected cancer promoters and clastogens, which have raised concerns about the safety of irradiated foods. Currently there are few data on the metabolism of 2-ACBs, which makes it very important to study this aspect of 2-ACBs to evaluate their safety. The objectives of this experiment were to quantify 2-dodecylcyclobutanone (2-DCB; formed from palmitic acid) in the feces and adipose tissue of rats and to check for metabolites of 2-DCB in the urine. Six female Sprague-Dawley rats were administered 2-DCB (5 mg/day) in corn oil for 5 days via gavage. Six control rats did not receive 2-DCB. Feces and urine were collected daily, whereas adipose tissue was collected upon euthanasia. Hexane extracts of feces and adipose tissue were analyzed by gas chromatography-mass spectroscopy (GC-MS). Urine with and without added beta-glucuronidase was monitored for glucuronide complexes by hexane extraction and GC-MS. The total amount of 2-DCB recovered in feces was 1.78 +/- 0.63 mg at the end of 5 days, which represents between 3 and 11% of the total 2-DCB administered. The total amount recovered in the adipose tissue was 0.08 +/- 0.01 mg, which was approximately 0.33% of the total 2-DCB administered. No metabolites were recovered in any of the urine extracts. The results show that at most 11% of the 2-DCB was recovered unchanged in the feces and adipose tissue. This indicates that either most of 2-DCB is metabolized and rapidly eliminated from the body or stored at sites other than adipose tissue.     

Content of the flavonols quercetin, myricetin, and kaempferol in 25 edible berries

The amounts of quercetin, myricetin, and kaempferol aglycons in 25 edible berries were analyzed by an optimized RP-HPLC method with UV detection and identified with diode array and electrospray ionization mass spectrometry detection. Sixteen species of cultivated berries and nine species of wild berries were collected in Finland in 1997. Quercetin was found in all berries, the contents being highest in bog whortleberry (158 mg/kg, fresh weight), lingonberry (74 and 146 mg/kg), cranberry (83 and 121 mg/kg), chokeberry (89 mg/kg), sweet rowan (85 mg/kg), rowanberry (63 mg/kg), sea buckthorn berry (62 mg/kg), and crowberry (53 and 56 mg/kg). Amounts between 14 and 142 mg/kg of myricetin were detected in cranberry, black currant, crowberry, bog whortleberry, blueberries, and bilberry. Kaempferol was detected only in gooseberries (16 and 19 mg/kg) and strawberries (5 and 8 mg/kg). Total contents of these flavonols (100-263 mg/kg) in cranberry, bog whortleberry, lingonberry, black currant, and crowberry were higher than those in the commonly consumed fruits or vegetables, except for onion, kale, and broccoli.     

Lingonberry (Vaccinium vitis-idaea) and European cranberry (Vaccinium microcarpon) proanthocyanidins: isolation, identification, and bioactivities

European, small-fruited cranberries (Vaccinium microcarpon) and lingonberries (Vaccinium vitis-idaea) were characterized for their phenolic compounds and tested for antioxidant, antimicrobial, antiadhesive, and antiinflammatory effects. The main phenolic compounds in both lingonberries and cranberries were proanthocyanidins comprising 63-71% of the total phenolic content, but anthocyanins, hydroxycinnamic acids, hydroxybenzoic acids, and flavonols were also found. Proanthocyanidins are polymeric phenolic compounds consisting mainly of catechin, epicatechin, gallocatechin, and epigallocatechin units. In the present study, proanthocyanidins were divided into three groups: dimers and trimers, oligomers (mDP 4-10), and polymers (mDP > 10). Catechin, epicatechin, A-type dimers and trimers were found to be the terminal units of isolated proanthocyanidin fractions. Inhibitions of lipid oxidation in liposomes were over 70% and in emulsions over 85%, and in most cases the oligomeric or polymeric fraction was the most effective. Polymeric proanthocyanidin extracts of lingonberries and cranberries were strongly antimicrobial against Staphylococcus aureus, whereas they had no effect on other bacterial strains such as Salmonella enterica sv. Typhimurium, Lactobacillus rhamnosus and Escherichia coli. Polymeric fraction of cranberries and oligomeric fractions of both lingonberries and cranberries showed an inhibitory effect on hemagglutination of E. coli, which expresses the M hemagglutin. Cranberry phenolic extract inhibited LPS-induced NO production in a dose-dependent manner, but it had no major effect on iNOS of COX-2 expression. At a concentration of 100 μg/mL cranberry phenolic extract inhibited LPS-induced IL-6, IL-1β and TNF-α production. Lingonberry phenolics had no significant effect on IL-1β production but inhibited IL-6 and TNF-α production at a concentration of 100 μg/mL similarly to cranberry phenolic extract. In conclusion the phenolics, notably proanthocyanidins (oligomers and polymers), in both lingonberries and cranberries exert multiple bioactivities that may be exploited in food development.     

Metabonomics approach to determine metabolic differences between green tea and black tea consumption

The purpose of this study was to compare the effects of black and green tea consumption on human metabolism. Seventeen healthy male volunteers consumed black tea, green tea, or caffeine in a randomized crossover study. Twenty-four-hour urine and blood plasma samples were analyzed by NMR-based metabonomics, that is, high-resolution 1H NMR metabolic profiling combined with multivariate statistics. Green and black tea consumption resulted in similar increases in urinary excretion of hippuric acid and 1,3-dihydroxyphenyl-2-O-sulfate, both of which are end products of tea flavonoid degradation by colonic bacteria. Several unidentified aromatic metabolites were detected in urine specifically after green tea intake. Interestingly, green and black tea intake also had a different impact on endogenous metabolites in urine and plasma. Green tea intake caused a stronger increase in urinary excretion of several citric acid cycle intermediates, which suggests an effect of green tea flavanols on human oxidative energy metabolism and/or biosynthetic pathways.     

Metabolism of furametpyr. 2. (14)C excretion, (14)C concentrations in tissues, and amounts of metabolites in rats

14C-Labeled furametpyr [N-(1,3-dihydro-1,1, 3-trimethylisobenzofuran-4-yl)-5-chloro-1, 3-dimethylpyrazole-4-carboxamide, Limber] was dosed to male and female rats at 1 (low dose) and 200 or 300 mg/kg (high dose). Elimination of furametpyr was rapid, and the dosed (14)C was substantially excreted within 7 days (45.5-53.3% in feces, 44.1-53. 8% in urine, and 0.01% in expired air). However, (14)C excretion rate showed sex- and dose-related differences, more rapid in males at low dose. (14)C concentrations in tissues decreased rapidly to generally low levels at 7 days (<0.004 ppm with the low dose and <1. 1 ppm with the high dose). Forty metabolites were detected, and 13 metabolites and 4 glucuronides were identified. A small amount of unchanged furametpyr was detected in feces (0.1-0.5% of the dose). The major metabolites in tissues were N-demethylated metabolites. In a bile study, 52.5-54.2% of the dosed (14)C was rapidly excreted into bile within 2 days. The absorption ratio was estimated to be >93.7% for the low dose (1 mg/kg). Major metabolites in bile were glucuronic acid conjugates of furametpyr hydroxides. On the basis of the results, furametpyr is substantially absorbed from the gastrointestinal tract after oral administration, rapidly distributed to tissues, extensively metabolized, and excreted into urine and bile or feces.     

Oxidative metabolism of the soy isoflavones daidzein and genistein in humans in vitro and in vivo.

The soy isoflavones daidzein and genistein are found in high concentrations in human plasma and urine after soy consumption. However, in vitro and in vivo data regarding the oxidative metabolism of isoflavones in humans are scarce. Therefore, we have studied the oxidative metabolites of these compounds formed in human liver microsomes and excreted in urine of male and female humans ingesting soy products for 2 days. Human liver microsomes transformed the soy isoflavone daidzein to three monohydroxylated and three dihydroxylated metabolites according to GC/MS analysis. On the basis of a previous study with rat liver microsomes and with the help of reference substances, these metabolites were identified as 6,7,4'-trihydroxyisoflavone, 7,3',4'-trihydroxyisoflavone, 7,8,4'-trihydroxyisoflavone, 7,8,3',4'-tetrahydroxyisoflavone, 6,7,8,4'-tetrahydroxyisoflavone, and 6,7,3',4'-tetrahydroxyisoflavone. Significant amounts of the same metabolites except 6,7,8,4'-tetrahydroxyisoflavone were also found in urine of female and male volunteers after soy intake. Genistein was metabolized by human liver microsomes to six hydroxylation products. The main metabolites were the three aromatic monohydroxylated products 5,6,7,4'-tetrahydroxyisoflavone, 5,7,8,4'-tetrahydroxyisoflavone and 5,7,3',4'-tetrahydroxyisoflavone. The aliphatic monohydroxylated metabolite 2,5,7,4'-tetrahydroxyisoflavone and two aromatic dihydroxylated metabolites, 5,7,8,3',4'-pentahydroxyisoflavone and 5,6,7,3',4'-pentahydroxyisoflavone, were formed in trace amounts. The same hydroxylated genistein metabolites except the aliphatic hydroxylated one could also be detected in human urine samples. Methylated forms of the catechol metabolites, which were generated by incubations with catechol-O-methyltransferase in vitro could be detected only in trace amounts in the urine samples. This implies that this reaction does not play a major role in the biotransformation of the hydroxylated daidzein and genistein metabolites in vivo. Most of these oxidative metabolites are described as human in vivo metabolites for the first time. Their biological significance remains to be established.     

Red mold dioscorea has greater hypolipidemic and antiatherosclerotic effect than traditional red mold rice and unfermented dioscorea in hamsters

Monascus-fermented red mold dioscorea (RMD) was proven to produce higher monacolin K levels than red mold rice (RMR) in our previous study. The goal of this study is to investigate whether the novel RMD had more hypolipidemic and antiatherosclerotic effect than traditional red mold rice. The daily dose of RMR for adults was recommended as 1 g, which corresponded to 96 mg/kg/day for hamsters. Therefore, high cholesterol diet-induced hyperlipidemic hamsters were daily administrated with a 0.5-fold (48 mg/kg/day), a 1-fold (96 mg/kg/day), or a 5-fold dose (480 mg/kg/day) of RMD for 8 weeks. Furthermore, a 1-fold dose of RMR (96 mg/kg/day) and unfermented dioscorea (96 mg/kg/day) were also respectively used to evaluate the effect of hypolipidemic and antiarteriosclerosis. The results indicated that only needing a 0.5-fold dose of RMD was able to significantly lower total cholesterol (by 13.78%, p<0.001), triglyceride (by 38.74%, p<0.01), and low-density lipoprotein cholesterol levels (by 43.11%, p<0.05) as well as maintain a high-density lipoprotein cholesterol level, as compared to the hyperlipidemic group. RMD including a higher monacolin K level and a dioscorea substrate was able to exhibit a more significant difference in the hypolipidemic effect than RMR or unfermented dioscorea. Both RMR and dioscorea exhibited potent in vitro antioxidative ability and in vivo protection against hypolipidemia-induced oxidative stress. Therefore, the antioxidative ability of RMD provided by Monascus metabolites (dimerumic acid, tannin, phenol, etc.) as well as dioscorea was able to perform more antiatherosclerotic effects on increasing total antioxidant status, catalase, and superoxide dismutase activity and repressing lipid peroxidation and atherosclerotic plaque than RMR and dioscorea.     

Comprehensive assessment of the quality of commercial cranberry products. Phenolic characterization and in vitro bioactivity

Cranberry (Vaccinium macrocarpon) products have been widely recommended in traditional American medicine for the treatment of urinary tract infection (UTI). A total of 19 different commercial cranberry products from American and European markets have been analyzed by different global phenolic methods and by UPLC-DAD-ESI-TQ MS. In addition, in vitro antioxidant capacity and uropathogenic bacterial antiadhesion activity tests have been performed. Results revealed that products found in the market widely differed in their phenolic content and distribution, including products completely devoid of flavan-3-ols to highly purified ones, either in A-type proanthocyanidins (PACs) or in anthocyanins. The product presentation form and polyphenolic profile widely affected the antiadhesion activity, ranging from a negative (nulel) effect to a MIC = 0.5 mg/mL for cranberry powders and a MIC=112 mg/mL for gel capsule samples. Only 4 of 19 products would provide the recommended dose of intake of 36 mg total PACs/day. Of most importance was the fact that this dose would actually provide as low as 0.00 and up to 205 μg/g of procyanidin A2, indicating the lack of product standardization and incongruence between global and individual compound analysis.     

Effects of cocoa extract on glucometabolism, oxidative stress, and antioxidant enzymes in obese-diabetic (Ob-db) rats

In this present study, we investigated the effects of cocoa extract containing polyphenols and methylxanthines prepared from cocoa powder on the biochemical parameters of obese-diabetic (Ob-db) rats. Obese-diabetic (Ob-db) rats were developed using a high-fat diet (49% fat, 32% carbohydrate, and 19% protein from total energy, kcal) for 3 months, followed by a low dose (35 mg/kg body weight) streptozotocin (STZ) injection. Cocoa extract (600 mg/kg body weight/day) was given to the rats for 4 weeks. The results indicated that there were no significant differences in fasting plasma glucose and insulin level after 4 weeks of cocoa extract administration. Oral glucose tolerance test revealed that cocoa supplementation in Ob-db rats significantly (p < 0.05) reduced plasma glucose at 60 and 90 min compared to unsupplemented Ob-db rats. Plasma free fatty acid and oxidative stress biomarker (8-isoprostane) were significantly (p < 0.05) reduced after cocoa supplementation. Superoxide dismutase activity was enhanced in Ob-db compared to that in nonsupplemented rats. However, no change was observed in catalase activity. The results showed that cocoa supplementation had an effect on postprandial glucose control but not for long term (4 weeks). Moreover, cocoa supplementation could reduce circulating plasma free fatty acid and 8-isoprostane and may enhance the antioxidant defense system.     

Inhibition of uropathogenic Escherichia coli by cranberry juice: a new antiadherence assay

A combination of microplate technology and turbidity assessment for testing the adherence of P-fimbriated Escherichia coli to human uroepithelial cell line T24, validated with the addition of the known inhibitor 4-O-alpha-D-galactopyranosyl-alpha-D-galactopyranose (galabiose), resulted in a high-throughput, biologically relevant assessment of cranberry (Vaccinium macrocarpon). P-fimbriated ATCC E. coli strains 25922, 29194, and 49161 were inhibited by galabiose. ATCC 29194, a representative urine isolate containing the papGII allele (Class II fimbrial adhesin) and demonstrating the most significant inhibition in the presence of galabiose, was chosen for further testing. In this assay, a low-polarity fraction of cranberry juice cocktail demonstrated dose-dependent inhibition of E. coli adherence. Reported here, for the first time in V. macrocarpon, are 1-O-methylgalactose, prunin, and phlorizin, identified in an active fraction of cranberry juice concentrate. This in vitro assay will be useful for the standardization of cranberry dietary supplements and is currently being used for bioassay-guided fractionation of cranberry juice concentrate.     

Gas chromatographic determination of avilamycin total residues in pig tissues, fat, blood, feces, and urine

A gas chromatographic (GC) procedure is presented for the determination of residues of avilamycin and all its metabolites/conjugates which can be converted to the common moiety dichloroisoeverninic acid (DIA). The method involves alkaline hydrolysis to DIA, cleanup by partitioning with chloroform, acidification of the aqueous phase, and partitioning of DIA into methylene chloride. After methylation of DIA, the product, 3,5-dichloro-4,6-dimethoxy-2-methylbenzoic acid methyl ester, is cleaned up on a silica gel column prior to the final determination by electron capture GC. The method is sensitive to 0.1 mg/kg avilamycin equivalent. Overall average recoveries were 85.4%, with a standard deviation of 9.1% for n = 20. Analyses of feces, urine, tissues, and fat of pigs treated with avilamycin demonstrated that 93% of the administered substance is excreted in feces and urine, within 72 h after treatment, and that no residues (less than 0.01 mg/kg) can be found in the tissues and fat of the animals at any time between 0 and 7 days after treatment with medicated feed.     

Metabolism of N-[(R)-1-(2,4-dichlorophenyl)ethyl]-2-cyano-3,3-dimethylbutanamide (Delaus, S-2900) and its isomer, N-[(S)-1-(2,4-dichlorophenyl)ethyl]-2-cyano-3,3-dimethylbutanamide (S-2900S), in rats. 1. Identification of metabolites in feces and urine

Rats were orally dosed with a 1:1 diastereomixture of N-[(R)-1-(2,4-dichlorophenyl)ethyl]-2-cyano-3,3-dimethylbutanamide (Delaus, S-2900) and N-[(S)-1-(2,4-dichlorophenyl)ethyl]-2-cyano-3,3-dimethylbutanamide (S-2900S), both labeled with 14C, at 200 mg/kg/day for 5 consecutive days, and 16 metabolites in urine and feces were purified by a combination of several chromatographic techniques. The chemical structures of all isolated metabolites were identified by spectroanalyses (NMR and MS). Several of them were unique decyanated and/or cyclic compounds (lactone, imide, cyclic amide, cyclic imino ether forms). Major biotransformation reactions of the mixture of S-2900 and S-2900S in rats are proposed on the basis of the metabolites identified in this study.     

The persistence and degradation of chlorothalonil and chlorpyrifos in a cranberry bog

The effect of a spray-tank adjuvant on the persistence, distribution, and degradation of two pesticides, chlorothalonil and chlorpyrifos, was studied in a commercial cranberry bog. Pesticides were applied according to label instructions to cranberry plants in paired plot studies. Dislodgeable foliar and whole fruit residues of both pesticides and several degradation products were assessed over a growing season. Residues were also assessed in soil samples collected at fruit harvest. Adjuvant increased both fruit and foliar residues but did not significantly alter the dissipation rate or metabolism of either pesticide. The dissipation of dislodgeable foliar chlorothalonil and chlorpyrifos residues followed first-order kinetics, with estimated half-lives of 12.7 and 3.5 d, respectively. All residue levels on harvested fruit were well below the current U.S. EPA tolerances for fresh cranberries. Chlorothalonil (58%) was the major residue in fruit at harvest (76 d post-chlorothalonil application), with 4-hydroxy-2,5,6-trichloroisophthalonitrile and 1,3-dicarbamoyl-2,4,5,6-tetrachlorobenzene accounting for 26% and 6% of the total residues, respectively. Degradation products accounted for 88% of the total chlorothalonil residues in soil at fruit harvest. The products 1,3-dicarbamoyl-2,4,5,6-tetrachlorobenzene, 1-carbamoyl-3-cyano-4-hydroxy-2,5,6-trichlorobenzene, 2,5,6-trichloro-4-methylthioisophthalonitrile, and 2,4,5-trichloroisophthalonitrile have not been previously identified in cranberry bog environments. Chlorpyrifos was detected in fruit at harvest (62 d post-chlorpyrifos application), but no metabolites were found. Chlorpyrifos-oxon and 3,5,6-trichloro-2-pyridinol, however, were detected in earlier fruit samples and in foliage and soil samples.     

Urolithins Are the Main Urinary Microbial-Derived Phenolic Metabolites Discriminating a Moderate Consumption of Nuts in Free-Living Subjects with Diagnosed Metabolic Syndrome

Walnuts ( Juglans regia L.), hazelnuts ( Corylus avellana L.), and almonds ( Prunus dulcis Mill.) are rich sources of ellagitannins and proanthocyanidins. Gut microbiota plays a crucial role in modulating the bioavailability of these high molecular weight polyphenols. However, to date there are no studies evaluating the capacity to produce nut phenolic metabolites in subjects with metabolic syndrome (MetS), a pathology associated with an altered gut bacterial diversity. This study applied a LC-MS targeted approach to analyze the urinary excretion of nut phenolic metabolites in MetS subjects following 12 weeks of nut consumption, compared to sex- and age-matched individuals given a nut-free control diet. Metabolites were targeted in both hydrolyzed and nonhydrolyzed urine by LC-PDA-QqQ-MS/MS analysis, and identification of metabolites lacking available standards was confirmed by LC-ESI-ITD-FT-MS. Ellagitannin-derived urolithins A and B significantly increased after the nut-enriched-diet, urolithins C and D were also detected, and a complex combination of urolithin-conjugated forms was observed in nonhydrolyzed urine, confirming an extensive phase II metabolism after absorption. In contrast, no significant increases in proanthocyanidin microbial metabolites were observed in urine following nut consumption. Because the intestinal microbiota of the subjects in this study could catabolize ellagitannins into a wide range of urolithins, further research is strongly warranted on the in vivo potential of these microbial metabolites in reducing cardiometabolic risk.     

3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid, an active principle of kimchi, inhibits development of atherosclerosis in rabbits

The effects of 3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid (HDMPPA) originating from Korean cabbage kimchi were investigated, showing an antioxidant effect on the prevention of atherosclerosis in hypercholesterolemic rabbits. Twenty-one 3-month-old rabbits were fed an atherogenic diet containing 0.5% (w/w) cholesterol and 10% (w/w) coconut oil, whereas another two groups were given an atherogenic diet with intravenous injection of either HDMPPA or simvastatin (0.33 mg/kg/day) for 4 weeks. HDMPPA inhibited the oxidative modification of low-density lipoprotein (IC 50 = 1.4 microg/mL) and increased 2,2'-diphenyl-1-picrylhydrazyl radical scavenging activity (IC 50 = 0.78 microg/mL) in a dose-dependent manner. In hypercholesterolemic rabbits, the thickness of intima of aorta of the HDMPPA group was significantly reduced (control versus HDMPPA, 42%; simvastatin, 38%) without a plasma cholesterol-lowering effect. Thiobarbituric acid reactive substance formation in the plasma of the HDMPPA group was significantly decreased compared to that of the control group. Furthermore, the generation of vascular reactive oxygen species in HDMPPA group was suppressed as the cyclooxygenase-2 protein level decreased. These findings suggest that HDMPPA prevents the development of aortic atherosclerosis in high-cholesterol-fed rabbits. The antiatherosclerotic effect of HDMPPA may be due to an antioxidative effect at a low dose without cholesterol-lowering effects.     

玉米秸秆在土壤中腐解的动态变化及其对Cu(Ⅱ)、Cd(Ⅱ)吸附-解吸的影响

通过室内培养和吸附-解吸试验,研究玉米秸秆腐解后石灰性褐土对Cu2+、Cd2+吸附-解吸的影响。结果表明,玉米秸秆腐解量随培养时间的延长而增加,到第7周时,腐解总量可达45%,添加常规量秸秆处理(S1)与加倍量处理(S2)的腐解量差别不明显;常规量秸秆处理(S1)的腐解速率大于加倍量处理(S2),但均随培养时间的延长而减少。土壤对Cu2+的吸附量随秸秆培养时间的延长表现为先升高后降低,吸附量在第21天时达到最大值;Cu2+浓度为1 000mg/L时土壤对Cu2+吸附量显著高于Cu2+浓度为600mg/L处理;而Cu2+的解吸量在秸秆腐解前期变化不明显,到培养第21天后迅速降低。在相同的Cu2+浓度下,Cu2+的吸附量和解吸量受Cd2+浓度影响均不明显。Cd2+浓度为1mg/L时,土壤对Cd2+的吸附量随秸秆培养时间的延长变化不明显,但随Cu2+浓度的增加而减小;而Cd2+浓度为10mg/L时,在Cu0处理和Cu1000处理时,不同培养时间土壤对Cd2+吸附量影响不明显,但Cu600处理下,在培养的第21天后,土壤对Cd2+的吸附量显著增加。土壤Cd2+的解吸量均随秸秆培养时间的延长表现为先升高后降低,在第21天时达最小值,而Cd2+的解吸量随共存Cu2+浓度的增加而先增加后降低。     

Improvement of mitochondrial function in muscle of genetically obese rats after chronic supplementation with proanthocyanidins

The aim of this study was to determine the effect of chronic dietary supplementation of a grape seed proanthocyanidin extract (GSPE) at a dose of 35 mg/kg body weight on energy metabolism and mitochondrial function in the skeletal muscle of Zucker obese rats. Three groups of 10 animals each were used: lean Fa/fa lean group (LG) rats, a control fa/fa obese group (OG) of rats, and an obese supplemented fa/fa proanthocyanidins obese group (POG) of rats, which were supplemented with a dose of 35 mg GSPE/kg of body weight/day during the 68 days of experimentation. Skeletal muscle energy metabolism was evaluated by determining enzyme activities, key metabolic gene expression, and immunoblotting of oxidative phosphorylation complexes. Mitochondrial function was analyzed by high-resolution respirometry using both a glycosidic and a lipid substrate. In muscle, chronic GSPE administration decreased citrate synthase activity, the amount of oxidative phosphorylation complexes I and II, and Nrf1 gene expression, without any effects on the mitochondrial oxidative capacity. This situation was associated with lower reactive oxygen species (ROS) generation. Additionally, GSPE administration enhanced the ability to oxidize pyruvate, and it also increased the activity of enzymes involved in oxidative phosphorylation including cytochrome c oxidase. There is strong evidence to suggest that GSPE administration stimulates mitochondrial function in skeletal muscle specifically by increasing the capacity to oxidize pyruvate and contributes to reduced muscle ROS generation in obese Zucker rats.