Does rooibos tea (Aspalathus linearis) support regeneration of rat liver after intoxication by carbon tetrachloride?

This study evaluates the effect of rooibos tea (RT, Aspalathus linearis) on biochemical and histological parameters during rat liver regeneration after intoxication by carbon tetrachloride (CCl4). From the 10th week, when the administration of CCl4 was terminated, the liver tissue began to regenerate. Seven days later in the regeneration phase, the animals treated by RT during whole period of the experiment, and those which drunk RT only during the regeneration period, exhibited a trend for decrease in the activity of alanine aminotransferase and significant decrease in the activity of aspartate aminotransferase and in total bilirubin content when compared with the water-drinking group. At the same time, the concentration of plasma albumin was elevated and that of tissue malondialdehyde decreased in the both groups drinking RT. After 42 days of regeneration, all biochemical parameters in all three groups reached the level of control healthy animals. In both groups treated with RT, the extent of fibrotic tissue was lower than in the group which received water. We conclude that RT can be recommended not only for the prevention but also as a co-adjuvant for the therapy of liver diseases.

Effect of rooibos tea (Aspalathus linearis) on Japanese quail growth, egg production and plasma metabolites.

1. Birds have been proposed as a suitable model for studies on ageing because of their long life in comparison with similar-sized mammals. However, some weak fliers, such as Galliformes, are the exception to this rule. The aim of the present study was to determine the effects of the treatment with rooibos tea (Aspalathus linearis), a natural source of flavonoid antioxidants and compounds with phyto-oestrogenic activity, on postnatal development and egg production of aged Japanese quail (Coturnix coturnix japonica). 2. Substitution of drinking water with traditional rooibos tea or diet supplementation with ground rooibos tea affected body weight of Japanese quail up to 100 d of age. The body weight of males drinking rooibos tea or eating rooibos-supplemented food decreased significantly. There was a trend toward increased body weight of tea drinking females and a significant increase in the body weight of hens fed the rooibos-supplemented diet. Although rooibos treatment did not significantly increase egg production in young hens, the decrease in egg production of rooibos-treated aged hens (360 d of age) was significantly reduced, regardless of the egg production levels (high - 80%; low - 20%) before the treatment. 3. The results suggest that treatment with rooibos tea positively affected body weight and egg production in quail hens and prolonged the productive period of aged animals. Further studies would be needed to address the question whether these effects are due to the antioxidant or phyto-oestrogenic activities of rooibos.

Rooibos tea (Aspalathus linearis) partially prevents oxidative stress in streptozotocin-induced diabetic rats.

The aim of this study was to investigate the effects of rooibos tea as a natural source of a wide scale of antioxidants on the prevention and treatment of oxidative stress in streptozotocin-induced diabetic rats. Expected significant changes of biochemical parameters characteristic for experimental diabetic state were found in plasma and tissues eight weeks after single dose streptozotocin application. Administration of aqueous and alkaline extracts of rooibos tea (or N-acetyl-L-cysteine for comparison) to diabetic rats did not affect markers of the diabetic status (glucose, glycated hemoglobin and fructosamine). Besides the parameters characterizing hepatotoxic effect of streptozotocin, rooibos tea significantly lowered advanced glycation end-products (AGEs) and malondialdehyde (MDA) in the plasma and in different tissues of diabetic rats, particularly MDA concentration in the lens. From these results we can conclude that antioxidant compounds in rooibos tea partially prevent oxidative stress and they are effective in both hydrophobic and hydrophilic biological systems. Therefore, rooibos tea as a commonly used beverage can be recommended as an excellent adjuvant support for the prevention and therapy of diabetic vascular complications, particularly for protecting ocular membrane systems against their peroxidation by reactive oxygen species.

Regeneration of coenzyme Q9 redox state and inhibition of oxidative stress by Rooibos tea (Aspalathus linearis) administration in carbon tetrachloride liver damage.

The effect of rooibos tea (Aspalathus linearis) on liver antioxidant status and oxidative stress was investigated in rat model of carbon tetrachloride-induced liver damage. Synthetic antioxidant N-acetyl-L-cysteine (NAC) was used for comparison. Administration of carbon tetrachloride (CCl4) for 10 weeks decreased liver concentrations of reduced and oxidized forms of coenzyme Q9 (CoQ9H2 and CoQ9), reduced -tocopherol content and simultaneously increased the formation of malondialdehyde (MDA) as indicator of lipid peroxidation. Rooibos tea and NAC administered to CCl4-damaged rats restored liver concentrations of CoQ9H2 and alpha-tocopherol and inhibited the formation of MDA, all to the values comparable with healthy animals. Rooibos tea did not counteract the decrease in CoQ9, whereas NAC was able to do it. Improved regeneration of coenzyme Q9 redox state and inhibition of oxidative stress in CCl4-damaged livers may explain the beneficial effect of antioxidant therapy. Therefore, the consumption of rooibos tea as a rich source of natural antioxidants could be recommended as a market available, safe and effective hepatoprotector in patients with liver diseases.

Hepatoprotective effect of rooibos tea (Aspalathus linearis) on CCl4-induced liver damage in rats.

Hepatoprotective properties of rooibos tea (Aspalathus linearis) were investigated in a rat model of liver injury induced by carbon tetrachloride (CCl(4)). Rooibos tea, like N-acetyl-L-cysteine which was used for the comparison, showed histological regression of steatosis and cirrhosis in the liver tissue with a significant inhibition of the increase of liver tissue concentrations of malondialdehyde, triacylglycerols and cholesterol. Simultaneously, rooibos tea significantly suppressed mainly the increase in plasma activities of aminotransferases (ALT, AST), alkaline phosphatase and billirubin concentrations, which are considered as markers of liver functional state. The antifibrotic effect in the experimental model of hepatic cirrhosis of rats suggests the use of rooibos tea as a plant hepatoprotector in the diet of patients with hepatopathies.

The membrane potential of Methanobacterium thermoautotrophicum under different external conditions.

The membrane potential (delta psi) of whole cells of Methanobacterium thermoautotrophicum strain delta H was estimated under different external conditions using a TPP(+)-sensitive electrode. The results show that the delta psi values of M. thermoautotrophicum at alkaline pHout (8.5) are comparable with delta psi values under slightly acidic conditions (pH 6.8; 230 and 205 mV, respectively). On the other hand, the size of colonies on Petri dishes was remarkably smaller at pH 8.5 than at 6.8. The delta psi was insensitive to relevant ATPase inhibitors. At pH 6.8, the protonophore 3,3',4',5-tetrachlorosalicylanilide (TCS) strongly inhibited delta psi formation and ATP synthesis driven by methanogenic electron transport. On the other hand, at pH 8.5 the CH4 formation and ATP synthesis were insensitive to TCS and a protonophore-resistant delta psi of approximately 150 mV was determined. The finding of a protonophore-resistant delta psi at pH 8.5 indicates that at alkaline pHout these cells can switch from H(+)-energetics to Na(+)-energetics, when the delta [symbol: see text] H+ becomes limited. The results strongly support the hypothesis that at alkaline pHout Na+ ions might fully substitute for H+ in these cells as the coupling ions.

Antihemolytic effect of Rooibos tea (Aspalathus linearis) on red blood cells of Japanese quails.

The antihemolytic activity of Rooibos and black tea on Japanese quail erythrocytes was studied. Peroxide and hypotonic hemolysis of the red blood cells of quails, either fed with Rooibos tea supplemented food or fed without tea, was performed. Long-term consumption of Rooibos tea did not change the erythrocyte fragility to either peroxide or hypotonia induced hemolysis. However, Rooibos and black teas decreased peroxide induced hemolysis of erythrocytes incubated with each of them, but not hemolysis induced by hypotonic NaCl solution. Stronger inhibition of hemolysis has been obtained when a boiled water extract of Rooibos tea was used for the inhibition. The degree of inhibition was comparable with the effect of ascorbic acid.

A study of the Na+/H+ antiport in the archaeon Methanobacterium thermoautotrophicum strain delta H.

The ability of the cells of Mb. thermoautotrophicum strain delta H to generate a proton gradient (driven by a concentration gradient of sodium ions) at pH 6.8 as well as at pH 8 was demonstrated. The electrogenic Na+/H+ antiport responsible for this process was shown to be inhibited by EIPA and also by DCCD. Artificially increasing of intracellular concentration of Ca2+ in these cells enhanced the Na+/H+ antiport activity, while the lowering of external Ca2+ by EGTA significantly decreased this activity. The apparent K(m) values for Na+ about 14 and 3 mM at pH 6.8 and 8, respectively, and Vmax about 214 (pH 6.8) and 155 (pH 8) delta Q/min per mg of cell proteins, respectively, were calculated. It is concluded that the described processes are mediated by the Na+/H+ antiporter which might be a clue to the adaptive bioenergetic behaviour of the cells of Mb. thermoautotrophicum strain delta H under the different physiological conditions.

Effect of Rooibos tea (Aspalathus linearis) on chick skeletal muscle cell growth in culture.

Rooibos tea (RT) extract contains natural antioxidants and scavenging agents. We investigated the effects of different concentrations of RT extract in medium on growth and changes of growth parameters of cultured chick embryonic skeletal muscle cells. Presence of 2, 10 and 100% of RT extract in the culture of primary cells significantly inhibited cell proliferation. The inhibition of cell growth reflected on decreased DNA, RNA and protein contents in primary cell culture and fibroblasts and myoblasts. The ability of the primary cells, fibroblasts and myoblasts to synthesize DNA and protein in the presence of RT extract, measured as an amount of [3H]thymidine and [3H]leucine incorporated into DNA and de novo synthesized protein, corresponded with decreasing DNA and protein contents in all three cell types. The inhibition effect of RT rose with increasing concentration of the tea extract in the culture medium. Ornithine decarboxylase activity was significantly affected only by 100% RT extract in every examined cell types. These results suggest that the inhibitory effect of RT extract on the growth of primary cells, fibroblasts and myoblasts is due to the potent scavenging activity of the RT extract.

Isolation and characterization of a neomycin-resistant mutant of Methanobacterium thermoautotrophicum with a lesion in Na+-translocating ATPase (synthase).

A mutant of Methanobacterium thermoautotrophicum with a lesion in membrane Na+-translocating ATPase (synthase) was isolated. The total ATPase activity in permeabilized cells of this mutant was elevated three-fold as compared with the wild-type strain. In contrast to wild-type cells, mutant ATPase was neither inhibited by DCCD nor stimulated by Na+ ions. The methane formation orate of the mutant cells at pH 7.5 under non-growing conditions was nearly twice that of the wild-type strain and was stimulated by sodium ions. On the other hand, the ATP synthesis driven by methanogenesis under the same conditions was lower that of the wild-type under the same conditions, and contrary to the wild-type was not stimulated by Na+ ions. ATP synthesis driven by a potassium diffusion potential in the presence of sodium ions was markedly diminished in the mutant cells. The membrane potential values of the wild-type and the mutant cells in the presence of 10 mM NaCl at pH 7.0 were comparable at energized conditions (-223 mV and -230 mV respectively). The Mg2+-dependent ATPase activity of the 10(5) x g supernatant of broken cells from the mutant cells was 30% higher than in the wild-type. On the other hand, two bands with Mg2+-dependent ATPase activity were identified by native PAGE in this fraction in both wild-type as well as in mutant. These data suggest that the binding of Na+-translocating ATPase (synthase) to the membrane spanning part is changed in the mutant strain.

The presence of H+ and Na+ -linked Ca2+ extruding systems in Methanobacterium thermoautotrophicum.

The effects of monovalent cations (Na+, K+ and choline+) and the uncoupler 3,3',4',5-tetrachlorosalicylanilide (TCS) were tested on 45Ca2+ uptake by non-energized cells of Methanobacterium thermoautotrophicum. 45Ca2+ uptake was stimulated by the addition of K+ and (less) by choline+ while Na+ slowed down and even reversed it, thereby mimicking the energization of cells. The uncoupler agent, TCS, suppressed 45Ca2+ uptake in non-energized cells in the presence or absence of Na+ but in cells energized in an atmosphere of CO2+H2 it exerted a stimulating effect. Uncoupled 45Ca2+ efflux was measured in cells pre-loaded with 45Ca2+ by means of the divalent ionophore A23187 following its washing out by buffer containing serum albumin. The efflux was temperature-dependent and was stimulated by external 40Ca2+ and Na+. In the absence of Na+, the uncoupled efflux was completely inhibited by TCS, whereas in the presence of Na+, TCS was without any effect. The results are in agreement with the model in which the Ca2+ influx pathway is represented by a membrane potential-driven uniport whereas Ca2+ efflux is mediated by two transport systems - Na+/Ca2+ and H+/Ca2+ antiporters - whose participation in the total efflux is dependent on the energy of the corresponding gradients of driving ions.

The presence of H+ and Na(+)-translocating ATPases in Methanobacterium thermoautotrophicum and their possible function under alkaline conditions.

Two ATPases with different apparent molecular masses of approx. 500 kDa and 400 kDa were identified in the EDTA extract of the cell membranes of Methanobacterium thermoautotrophicum. Western blotting with polyclonal antiserum reactive with beta-subunit of mitochondrial ATPase from rat liver and yeast was used for further analysis of these ATPases. A strong crossreactivity with a single protein band with an apparent molecular weight of about 53 kDa (similar to beta-subunit of F-type ATPase from other sources) was found in protein extracts of whole cells of Methanobacterium thermoautotrophicum strains delta H and Marburg, as well as of Methanospirillum hungatei. This indicates the presence of F-type ATPase in methanogens. ATP synthesis driven by membrane potential which was generated by artificially-imposed delta pH in the presence of protonophorous uncoupler and sodium ions was stimulated by bafilomycin A1, an inhibitor of V- and A-type ATPases, as well as by harmaline, an inhibitor of Na+/H+ antiporter. These results indicate that cells of Methanobacterium thermoautotrophicum strain delta H contain the F-type ATP synthase which is Na(+)-translocating in addition to V- or A-type ATP synthase which is H(+)-translocating.

Na(+)-driven ATP synthesis in Methanobacterium thermoautotrophicum and its differentiation from H(+)-driven ATP synthesis by rhodamine 6G.

Rhodamine 6G (3 microM) effectively inhibited delta pH-driven ATP synthesis in Methanobacterium thermoautotrophicum while delta pNA-driven ATP synthesis was not affected by it. Rhodamine 6G inhibited Mg(2+)-stimulated ATPase activity of membrane vesicles prepared from these cells but the ATPase catalytic sector detached from the membrane was insensitive to this inhibitor. Methanogenesis-driven ATP synthesis at pH 6.8 of the cells grown in the presence of 50 mM NaCl was inhibited by rhodamine 6G both in the presence of 5 mM and 50 mM NaCl. On the other hand, the methanogenesis-driven ATP synthesis at pH 8.0 of cells grown in the presence of 50 mM NaCl was slightly inhibited by rhodamine 6G in the presence of 5 mM NaCl and was not inhibited at all in the presence of 50 mM NaCl. The growth experiments have shown that cells of Methanobacterium thermoautotrophicum can grow under alkaline conditions even in the presence of rhodamine 6G and of high NaCl concentration when the growth media were inoculated with the cells which had been grown in the presence of 50 mM NaCl. These results indicate that sodium-motive force-driven ATP synthase in Methanobacterium thermoautotrophicum operates effectively at alkaline conditions and it might be the sole ATP synthesizing system when the proton motive force-supported ATP synthesis is inhibited by rhodamine 6G.

Na(+)-driven ATP synthesis in Methanobacterium thermoautotrophicum and its differentiation from H(+)-driven ATP synthesis by rhodamine 6G.

Rhodamine 6G (3 microM) effectively inhibited delta pH-driven ATP synthesis in Methanobacterium thermoautotrophicum while delta pNa-driven ATP synthesis was not affected by it. Rhodamine 6G inhibited Mg(2+)-stimulated ATPase activity of membrane vesicles prepared from these cells but the ATPase catalytic sector detached from the membrane was insensitive to this inhibitor. Methanogenesis-driven ATP synthesis at pH 6.8 of cells grown in the presence of 50 mM NaCl was inhibited by rhodamine 6G both in the presence of 5 mM and 50 mM NaCl. On the other hand, the methanogenesis-driven ATP synthesis at pH 8.0 of cells grown in the presence of 50 mM NaCl was slightly inhibited by rhodamine 6G in the presence of 5 mM NaCl and was not inhibited at all in the presence of 50 mM NaCl. The growth experiments have shown that cells of Methanobacterium thermoautotrophicum can grow under alkaline conditions even in the presence of rhodamine 6G and of high NaCl concentration when the growth media were inoculated with the cells which had been grown in the presence of 50 mM NaCl. These results indicate that sodium-motive force-driven ATP synthase in Methanobacterium thermoautotrophicum operates effectively in alkaline conditions and it might be the sole ATP synthesizing system when the proton-motive force-supported ATP synthesis is inhibited by rhodamine 6G.

Mode of sodium ion action on methanogenesis and ATPase of the moderate halophilic methanogenis bacterium Methanohalophilus halophilus.

Cells of Methanohalophilus halophilus swelled when exposed to hypotonic solutions of NaCl at pH 7.0. The swelling of the cells ceased in the presence of Mg2+. Methane formation by non-growing cells was strongly dependent on the NaCl concentration. Among other monovalent and divalent cations only Li+ and Mg2+ could partly substitute for a specific function of sodium ions. The artificial Na+/H+ antiporter, monensin, exerted a strong inhibitory effect on methane formation from methylamine. The membrane-bound Mg(2+)-stimulated ATPase of these cells was enhanced at low (40 mM) NaCl concentration while higher concentrations of this solute were inhibitory. The results obtained show that sodium ions are a prerequisite for optimal methane formation and ATPase activity in these cells. However, both of these processes required different sodium ion concentrations.

[Genetic markers in the blood and their relation to metabolic parameters in dairy cows]. / Genetické markery krvi a ich vztah k metabolickým parametrom dojníc.

A relationship between the genetic markers of blood (blood groups, serum polymorphic proteins) and the clinico-chemical parameters was studied in the dairy cows of the Slovak Pied breed. Antigens belonging to systems A, B, C, F, S, R, T, Z and the polymorphic traits genetically controlled from loci Tf, Cp, Am and Hb were identified in all the animals subjected to testing. The values of the parameters of acid-base balance and concentration of 13 metabolic components were repeatedly determined in the experimental period. The results of the F-test indicated that there were no significant differences in the values of any of the tested parameters between the phenotypes of the A, J, Am, Tf and Cp systems. Of the 21 parameters tested, statistically significant differences were found in 11 parameters between some alleles of the C, FV, T, Z and Hb systems.

The isolation and some properties of dairy cow liver mitochondria.

The problem of the isolation of intact mitochondria from dairy cow liver, which arises from the relative rigidity of this tissue for homogenization, was overcome by prehomogenizing the tissue in an Ultra-Turrax TP 18-10 apparatus, followed by homogenization in a Potter-Elvehjem homogenizer. The mitochondria isolated from such a homogenate displayed, on various substrates, ADP/O ratio and a respiratory control ratio (RCR) comparable with those of rat liver mitochondria. The specific activity of DNP-stimulated ATP-ase of mitochondria isolated from dairy cow liver exhibited about 60% of the activity of mitochondria isolated from rat liver; oligomycin inhibition in the two cases was the same. The transport properties of the inner mitochondrial membrane for phosphate, acetoacetate, D,L-3-hydroxybutyrate, malate, fumarate, succinate and citrate were comparable with those of rat liver mitochondria.

Citrate synthesis in intact rat-liver mitochondria is irreversible.

Rat-liver mitochondria were incubated with [1,5-14C]citrate in the presence of fluorocitrate to block its oxidation in the Krebs cycle. The reaction products were analysed enzymatically and by anion-exchange chromatography. Incorporation of 14C into acetyl-L-carnitine or ketone bodies via a backward action of citrate synthase was not observed. The optimal rate of citrate synthesis from pyruvate and malate in the presence of fluorocitrate was 15 nmol . mg-1 min-1. In the absence of fluorocitrate, but in the presence of malonate, citrate was oxidized to succinate at a rate of 4 nmol . mg-1 . min-1. We conclude that the synthesis of citrate by intact rat liver mitochondria is an irreversible process. The possible mechanism underlying this phenomenon and the consequence for metabolic regulation are discussed.