Endothelium-dependent vasorelaxation induced by black currant concentrate in rat thoracic aorta.
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We investigated the effect of black currant (BC) concentrate on smooth muscle in rat thoracic aorta. BC concentrate dose-dependently relaxed the norepinephrine (0.1 microM)-precontracted aorta, and the response was abolished after endothelium removal. Both oxyhemoglobin (1 microM), a nitric oxide (NO) scavenger, and IH-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ, 0.5 microM), an inhibitor of guanylyl cyclase (GC), inhibited the relaxing effect of BC concentrate. NG-nitro-L-arginine methyl ester (L-NAME, 10 microM), a nitric oxide synthase (NOS) inhibitor, inhibited the relaxation, and the subsequent addition of L-arginine (1 mM), a NOS substrate, reversed the inhibitory effects of L-NAME. Neither indomethacin (10 microM), an inhibitor of cyclooxygenase, nor atropine (1 microM), an antagonist of muscarinic receptors, modified the effect of BC concentrate. Diphenhydramine (3 microM) and chlorpheniramine (2 microM), selective antagonists of H1-receptors, inhibited the relaxation, but cimetidine (0.3 mM), a selective antagonist of H2-receptors, did not affect the relaxation. These results indicate that, in the rat aorta, BC concentrate enhances synthesis of NO, which subsequently induces the endothelium-dependent vasorelaxation via the H1-receptors on the endothelium. (+info)
Effect of blackcurrant-, cranberry- and plum juice consumption on risk factors associated with kidney stone formation.
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OBJECTIVE: To evaluate the influence of plum-, cranberry- and blackcurrant juice on urinary stone risk factors. DESIGN: Investigations were carried out in 12 healthy male subjects aged 18-38 y. All subjects received a standardized diet formulated according to the dietary recommendations of the German Society of Nutrition. The subjects provided 24 h urine collections in a control, three loading phases. In each loading phase a neutral mineral water was substituted for 330 ml of the particular juice. RESULTS: Cranberry juice decreased the urinary pH, whereas the excretion of oxalic acid and the relative supersaturation for uric acid were increased. Blackcurrant juice increased the urinary pH and the excretion of citric acid. The excretion of oxalic acid was increased too. All changes were statistically significant. The plum juice had no significant effect on the urinary composition. CONCLUSION: It is concluded that blackcurrant juice could support the treatment and metaphylaxis of uric acid stone disease because of its alkalizing effect. Since cranberry juice acidifies urine it could be useful in the treatment of brushite and struvite stones as well as urinary tract infection. SPONSORSHIP: Funded by our own Division respectively the University. (+info)
Inhibitory effects of proanthocyanidins from Ribes nigrum leaves on carrageenin acute inflammatory reactions induced in rats.
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BACKGROUND: The anti-inflammatory effects of proanthocyanidins (PACs), isolated from blackcurrant (Ribes nigrum L.) leaves, were analysed using carrageenin-induced paw oedema and carrageenin-induced pleurisy in rats. RESULTS: Pretreatment of the animals with PACs (10, 30, 60 and 100 mg/kg, i.p.) reduced paw oedema induced by carrageenin in a dose and time-dependent manner. PACs also inhibited dose-dependently carrageenin-induced pleurisy in rats. They reduced (A) lung injury, (B) pleural exudate formation, (C) polymorphonuclear cell infiltration, (D) pleural exudate levels of TNF-alpha, IL-1beta and CINC-1 but did not affect IL-6 and IL-10 levels. They reduced (E) pleural exudate levels of nitrite/nitrate (NOx). In indomethacin treated rats, the volume of pleural exudate was low, its content in leukocytes and its contents in TNF-alpha, IL-1beta, IL-6 and IL-10 but not in NOx were reduced. These data suggest that the anti-inflammatory properties of PACs are achieved through a different pattern from those of indomethacin. CONCLUSION: These results suggest that the main mechanism of the anti-inflammatory effect of PACs mainly lies in an interference with the migration of the leukocytes. Moreover, PACs inhibited in vivo nitric oxide release. (+info)
New inhibitor against nuclear factor of activated T cells transcription from Ribes fasciculatum var. chinense.
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Two new compounds were isolated from the stem and twigs of Ribes fasciculatum var. chinense and their structures were identified to be threo-(7S,8R)-1-(4-hydroxyphenyl)-2-[4-(E)-propenylphenoxy]-propan-1-ol (1), and 5,4'-dihydroxy-7-methoxyflavone-3-O-[alpha-L-rhamnopyranosyl(1-->3)-O-alpha-L-rha mnopyranosyl(1-->6)-O-beta-D-glucopyranoside] (2). With nine other known components, they were tested on inhibitory activity against nuclear factor of activated T cells (NFAT) transcription factor. Compound 1 showed a potent inhibitory activity (IC50=15.6 microM), while compounds 4, 5 and 9 showed moderate inhibitory activity (IC50 22.4, 24.5 and 25.7 microM, respectively). (+info)
Aglycones and sugar moieties alter anthocyanin absorption and metabolism after berry consumption in weanling pigs.
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To investigate the absorption and metabolism of anthocyanins (ACNs) with different aglycones and sugar moieties, weanling pigs (11.4 +/- 3.8 kg) were fed, in a single meal, a freeze-dried powder of chokeberry, black currant, or elderberry at a single dose of 229, 140, or 228 mumol total ACN/kg body weight (BW), respectively. These berries provided ACNs with differences in aglycone as well as some unique differences in the sugar moieties. The relative proportions of the different metabolites depended upon concentrations, quantities consumed, and types of glycoside of ACNs in the berry. Delphinidin ACNs were not metabolized to any measurable extent. Cyanidin ACNs were metabolized via methylation and glucuronidation as well as by formation of both derivatives on the same ACN molecule. ACNs with either a di- or trisaccharide attached to them were excreted in the urine primarily as the intact form. Over 80% of the ACN compounds containing rutinose or sambubiose, which were excreted in the urine from black currant, elderberry, or Marion blackberry, were excreted as the intact molecule. The limited metabolism of these ACNs that did occur was via methylation. ACN monoglycosides other than the glucoside were metabolized via methylation and/or glucuronide formation. The monoglucuronide that formed represented a small proportion of the metabolites relative to the methylated or the mixed methylated and glucuronide forms of ACNs. The data clearly demonstrate that the aglycone and the sugar moieties can alter the apparent absorption and metabolism of ACNs. (+info)
HPLC determination of the composition and stability of blackcurrant anthocyanins.
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High-performance liquid chromatography with UV and mass spectrometry detectors are used to monitor the composition and stability of anthocyanins in blackcurrants harvested from different Ribes nigrum breeds at various ripeness phases. The highest amounts of pigments are found in overripe berries. The concentration of anthocyanins is higher in the berries of late blackcurrant breeds (Vakariai and Ben Alder). Delphinidin- 3-rutinoside is the dominant component in the reddish color berries (onset of ripening), and cyanidin-3-rutinoside is a major pigment in the black ones (ripe berries). Studies of the effect of temperature and light on the stability of the main pigments in blackcurrants show that aqueous solution prepared from a dry colorant is more stable when compared with the liquid water and ethanol extracts of coloring substances. Cyanidin-3-rutinoside is found to be the most thermally stable anthocyanin. (+info)
Phosphoenolpyruvate carboxykinase and its potential role in the catabolism of organic acids in the flesh of soft fruit during ripening.
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Previous studies of grapes and tomatoes have shown that the abundance of phosphoenolpyruvate carboxykinase (PEPCK) increases in their flesh at the start of ripening, and that this coincides with a decrease in its citrate and/or malate content. Thus, PEPCK might function in the catabolism of organic acid anions during the ripening of these fruits. In the present study, the abundance of PEPCK was determined in the flesh of blueberries, raspberries, red currants, and strawberries at different stages of their development. In addition, changes in the amounts of citrate, malate, soluble sugars, isocitrate lyase, NADP-malic enzyme, phosphoenolpyruvate carboxylase, and pyruvate, orthophosphate dikinase in the flesh were determined. PEPCK was not detected in strawberry flesh, in which there was no dissimilation of malate or citrate. In the flesh of the other fruits, the abundance of PEPCK increased during ripening to an amount that was similar to that in grapes and tomatoes. In the flesh of blueberries and red currants, PEPCK was most abundant when there was dissimilation of malate. In the flesh of raspberries, PEPCK was most abundant when there was dissimilation of malate and citrate. These results are consistent with PEPCK playing a role in the dissimilation of citrate and/or malate in the flesh of these fruits during ripening. However, PEPCK was also present in the flesh of blueberries, raspberries, and red currants when there was no dissimilation of malate or citrate, and this raises the possibility that PEPCK might have additional functions. Dissection of blueberries provided evidence that both PEPCK and phosphoenolpyruvate carboxylase were present in the same cells, and possible functions for this are discussed. (+info)
Immunostimulatory effects of a polysaccharide-rich substance with antitumor activity isolated from black currant (Ribes nigrum L.).
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The fruit juice of black currant was found to contain a polysaccharide-rich substance, which was designated cassis polysaccharide (CAPS), with macrophage-stimulating activity. Especially, its interleukin (IL)-1beta-inducing activity was remarkably high, compared with other fruit juice preparations. CAPS was found to consist of rhamnose, mannose, arabinose, galactose, xylose, and glucose in a molar ratio of 11.3:0.9:54.1:29.8:2.0:1.9. CAPS turned out to be partitioned into a soluble component (CAPS-l.m.) and a precipitable component (CAPS-h.m.) with mean MWs of 80,000 and 600,000 respectively in 45% (v/v) ethanol solution. At least in vitro, CAPS-l.m. rather than CAPS-h.m. appeared to play an important role in macrophage activation. Oral administration of black currant juice and CAPS to Ehrlich carcinoma-bearing mice retarded the growth of the solid tumor by 45% and 51% respectively. CAPS administration had a stimulatory effect on the release of IL-2, IL-10, interferon-gamma, and IL-4 from splenocytes in comparison with PBS treatment in tumor-bearing mice. The IL-4 level was, however, still lower than that exhibited by a group of normal mice. CAPS showed a certain cytotoxicity directly against tumor cells. (+info)