Absorption and excretion of elderberry (Sambucus nigra L.) anthocyanins in healthy humans.

Pharmacokinetic variables of several dietary anthocyanins (potent natural antioxidants) following consumption of elderberry (Sambucus nigra L.) extract were evaluated in urine and plasma of six healthy volunteers. They were given a single oral dose of either 30 ml (278 mg total anthocyanins) or 200 ml (1852 mg total anthocyanins) of a commercially available elderberry extract. Within 7 h, the fraction of orally administered total anthocyanins (calculated as the sum of cyanidin-3-sambubioside and cyanidin-3-glucoside) excreted unchanged was 0.39% and 0.27% following ingestion of 30 and 200 ml, respectively. The elimination half-life of total anthocyanins was slightly lower following the consumption of 278 mg (1.85 h) than that after the consumption of 1852 mg (2.57 h). The renal clearance (median) of total anthocyanins was 196 and 169 ml/min, respectively. The peak and average systemic exposure to the major elderberry anthocyanidin glycosides in plasma as well as their renal excretion exhibited approximate dose-proportional characteristics within the administered range. The low dose-normalized area under the concentration-time curve (AUC) and the fraction of orally administered anthocyanins recovered unchanged in urine indicate a low bioavailability of these compounds.

Urinary pharmacokinetics of cyanidin glycosides in healthy young men following consumption of elderberry juice.

We investigated the urinary pharmacokinetics of monomeric anthocyanins in seven healthy volunteers. The volunteers were administered a single oral dose of 3.57 g total anthocyanins contained in 150 ml of a concentrated elderberry juice under fasting conditions. Within 24 h the urinary excretion of unchanged cyanidin-3,5-diglucoside (cyanidin-3-sambubioside-5-glucoside and cyanidin-3,5-diglucoside were calculated as cyanidin-3,5-diglucoside equivalents), cyanidin-3-glucoside, cyanidin-3-sambubioside and total anthocyanins (i.e., the sum of all quantifiable anthocyanidin glycosides) was 0.16, 0.06, 0.05 and 0.06% of the administered doses, respectively. Maximum excretion rates were determined within 1.0 h after intake. The estimates (arithmetic mean +/- SD) of t1/2 were 1.25 +/- 0.25, 1.53 +/- 0.36, 1.38 +/- 0.20 and 1.35 +/- 0.18 h for cyanidin-3,5-diglucoside, cyanidin-3-glucoside, cyanidin-3-sambubioside and total anthocyanins, respectively. The urinary excretion of intact anthocyanins was fast and the decline of excretion rates appeared to be monophasic, suggesting a one-compartment pharmacokinetic model. The low urinary excretion of dietary anthocyanidin glycosides with values below 1% indicates that a large proportion of these plant pigments consumed are metabolized before entry into the circulation.

Determination of some pharmacologically active phenolic acids in juices by high-performance liquid chromatography.

Several phenolic acids, e.g. caffeic acid, chlorogenic acid, ferulic acid, gallic acid and ellagic acid, which occur naturally, are inhibitors of carcinogenesis. In this paper we present a new method for the simultaneous determination of all of these compounds, except ellagic acid, in juices by reversed-phase high-performance liquid chromatography (HPLC) using ultraviolet detection and involving isocratic elution, and we have devised an HPLC method for the determination of ellagic acid in juices. The experimental results showed that cherry juice contains a high concentration of chlorogenic acid and the content of bound gallic acid in black and green grape juices is high compared to that of other phenolic acids.

Efficacy of benfotiamine versus thiamine on function and glycation products of peripheral nerves in diabetic rats.

In rats with streptozotocin (STZ) induced diabetes the effect of (watersoluble) thiamine nitrate and of (lipidsoluble) benfotiamine on peripheral nerve function (motor nerve conduction velocity) as well as on the formation of advanced glycation end-products in peripheral nerve tissue was studied. In one group of animals drug administration was started immediately after diabetes induction (prevention study) and in another group two months after diabetes induction (treatment study). Motor nerve conduction velocity (NCV) dropped by 10.5% in diabetic animals, carboxymethyl-lysine (CML) rose to a 3.5fold concentration, deoxyglucosone (3DG)-type AGE formation was increased 5.1fold compared with controls. After three months preventive administration of both vitamin B(1) preparations NCV had increased substantially compared with results in diabetic controls. It was nearly normal after six months with benfotiamine, while the administration of thiamine nitrate resulted in no further amelioration. NCV was nearly normalized after six months of benfotiamine application but not with thiamine. Furthermore, benfotiamine induced a major inhibition of neural imidazole-type AGE formation and completely prevented diabetes induced glycoxidation products (CML). Treatment with thiamine did not significantly affect AGE or cmL levels. Unlike treatment with water-soluble thiamine nitrate timely administration of liposoluble prodrug benfotiamine was effective in the prevention of functional damage and of AGE and cmL formation in nerves of diabetic rats.

Bioactive anthocyanins detected in human urine after ingestion of blackcurrant juice.

Anthocyanins are a group of very efficient bioactive compounds that are widely distributed in plant food. Several fruits (blackcurrant, blackberry, red grape) and some vegetables (eggplant, onion, red radish) are rich sources of these natural pigments. Extracts of some of them are used as food colorants as well as components of pharmaceutical preparations and functional foods. Anthocyanins, through their ability to inhibit radical reactions, are considered to exert several protective effects in the human body. Until now there has been only a small amount of data available on their capability, in intact or metabolized form, to reach the systemic circulation of humans. The present study was designed to determine the potential bioavailability in humans of the most important anthocyanins of blackcurrants: delphinidine-3-glucoside, delphinidine-3-rutinoside, cyanidine-3-glucoside, and cyanidine-3-rutinoside. Urinary samples from 4 healthy volunteers (2 women and 2 men) were collected before (baseline) and over a period of 5 hours with intervals of 30 minutes after the ingestion of 200 mL of blackcurrant juice (containing 153 mg of anthocyanins). Using high-performance liquid chromatography (HPLC), it was possible to quantify the 4 main anthocyanins of blackcurrants, excreted unchanged in the urine (0.020-0.050% of the oral doses). We present data on the bioavailability in humans of blackcurrant anthocyanins, which are dietary antioxidants with possible biological effects.

Bioavailability of anthocyanidin-3-glycosides following consumption of elderberry extract and blackcurrant juice.

Pharmacokinetic parameters and the bioavailability of several dietary anthocyanins following consumption of blackcurrant juice and elderberry extract were compared exploratorily in 6 healthy volunteers. They were given a single oral dose of either 137 ml of blackcurrant juice (144.8 mg total anthocyanins) or 30 ml of elderberry extract (147.3 mg total anthocyanins). Within 7 hours, the urinary excretion of total anthocyanins (i.e. the sum of all assayed anthocyanidin glycosides) was 0.04% and 0.37% of the administered dose following blackcurrant juice and elderberry extract ingestion, respectively. Pharmacokinetic parameters based on non-compartmental methods for plasma and urine concentrations exhibited higher variability in urinary excretion after ingestion of elderberry extract. Anthocyanin absorption was significantly greater following the intake of elderberry extract than after the intake of blackcurrant juice as shown by the 5.3- and 6.2-fold higher estimates of dose-normalized Cmax and AUC(0-tZ) of total anthocyanins, respectively. The geometric means of t(1/2) were not significantly different following elderberry extract (1.74 h) and blackcurrant juice ingestion (1.73 h, p > 0.05). The urinary excretion rate of intact anthocyanins was fast, appeared to be monoexponential for both blackcurrant juice and elderberry extract. However, in order to evaluate the contribution of anthocyanins to the health-protecting effects of blackcurrant juice and elderberry extract it will be necessary to perform further studies on the unchanged glycosides and their in vivo metabolites in human plasma and urine.

[Enzyme-histochemical behaviour of the tanycyte ependyma in the III. ventricle of the rat with thiamin deficiency (author's transl)]. / Das enzymhistochemische Verhalten des Tanycytenependyms im III. Ventrikel der Ratte bei Thiaminmangelernährung.

The influence of experimental thiamine deficiency in rats on enzyme-histochemical parameters was carried out in the diencephalon. The degree of thiamine deficiency was measured by the activity coefficient of transketolase in the red blood cells. The alpha-ETK of thiamine deficient animals was 1,45 +/- 0,36, of equal-fed animals 1,04 +/- 0.04 and of control animals 1,08 +/- 0,04. We got the following results: Lactatdehydrogenase, acid phosphatases and thiamine pyrophosphatase did not indicate any difference in enzyme activity between the groups of control, equal-fed and thiamine deficient rats. However, the enzyme activity of nonspecific lysosome-bound esterases in the tanycyte ependyma and in the investigated nuclear regions (nucleus supraopticus, ncl. paraventricularis, ncl. ventromedialis) of the thiamine deficient animals was significantly decreased in comparison to control and equal-fed animals. The possibility of a restriction of the hypophyseal-adrenal-cortex-system is discussed, since the results are similar to those obtained with bilaterally adrenalectomized rats.

The intrauterine turnover of thiamin in preterm and full-term infants.

In thirteen preterm infants, 45 full-term infants, and their mothers thiamin was analyzed in plasma from maternal veins, umbilical arteries, umbilical veins, and placental tissue. The blood flow in the umbilical veins was determined by pulsed Doppler ultrasonography. Thiamin-dependent transketolase was measured in erythrocytes from full-term infants and their mothers. Plasma thiamin concentrations in umbilical veins from preterm infants (227.0 +/- 85.0 nmol/L) and full-term infants (121.3 +/- 103.3 nmol/L) were seven times greater than maternal concentrations (p < 0.005). Maternal and umbilical thiamin concentrations were lower in the full-term group compared to the preterm group (p < 0.05). Arteriovenous concentration gradients were not feasible. The blood flow in the umbilical veins was higher in full-term compared to preterm infants (p < 0.05). However, intrauterine thiamin supply (plasma thiamin concentration times umbilical plasma flow) and placental thiamin concentrations were not different between preterm and full-term infants. Thiamin saturation of transketolase was greater in fetal than in maternal erythrocytes (p < 0.005); severe thiamin deficiency was not observed. Our findings suggest that thiamin turnover is similar in early and late pregnancy. Fetal tissue uptake of thiamin is not substantial. Transketolase activities suggest that thiamin status is sufficient even in late pregnancy.

Interactions between malnutrition and primaquine studied on Wistar rats. II. Complex vitamin B deficiency and thiamine deficiency.

The action of primaquine was investigated on male Wistar rats depleted on the vitamin B complex (approximately 50% of their requirement for optimal growth), on thiamine (approximately 50% of their requirement for optimal growth), and pair-fed control animals. There was only a marginal increase in adverse primaquine reactions in the malnourished, especially in the thiamine deficient rats.

High-performance liquid chromatographic (HPLC) analysis of thiamin pyrophosphokinase activity in rat liver.

A HPLC method for the determination of TPPK activity in rat liver is presented. The assay comprises an extraction of TPPK from the liver into sodium phosphate buffer, pH 7.3. TPP formed in the TPPK reaction from thiamin was converted to thiochrome and thiochrome was absorbed onto Shandon APS Hypersil. The mobile phase was acetonitrile/potassium phosphate buffer, pH 8.2, and elution was monitored spectrofluorometrically.

Bioavailability of water- and lipid-soluble thiamin compounds in broiler chickens.

The bioavailability of thiamin mononitrate, thiamin chloride-hydrochloride and benfotiamin was compared in broiler chickens. A thiamin-deficient diet was supplemented with either 1.8 and 1.5 mg/kg thiamin equivalent as water-soluble salts, or with 1.5 and 1.2 mg/kg thiamin equivalent as benfotiamin, respectively, and fed to 3 replicate groups/treatment for 21 days. Weight gain, feed consumption and feed conversion rate were not significantly affected by solubility or dietary level of thiamin. Likewise, using biochemical indices of thiamin status (erythrocyte transketolase activation coefficient, and thiamin concentrations in blood and liver), no differences were found between the water-soluble thiamin salts, indicating that they have identical potency. In contrast, biochemical indices of thiamin status showed a significantly higher bioavailability for benfotiamin than for the water-soluble sources.

[New methods for pharmacokinetic assessment of alcohol and its metabolites in male and female probands]. / Neue Methoden zur pharmakokinetischen Beschreibung des Alkohols und seiner Metaboliten bei weiblichen und männlichen Versuchspersonen.

The pharmacokinetics of ethanol and its metabolites were examined in 10 young healthy women and men after 1-hr intravenous ethanol application of 7.8 mmol/kg body weight. Therefore, a new pharmacokinetic model takes into account Michaelis-Menten-elimination kinetics of ethanol as well as kinetics of acetaldehyde and acetate, which are defined by first order processes. The metabolite-model adequately describes the ethanol and acetate concentration courses. In fact, the observed ethanol concentrations are so close to the model-predicted values, that the metabolite-model allows an evaluation of half-life-times of acetaldehyde and acetate. The analyses of ethanol infusion studies showed, that there are no sex differences in parameters of ethanol elimination: Maximal elimination velocity Vmax was 3.41 +/- 0.61 mmol/l.h in females and 3.98 +/- 0.69 mmol/l.h in males. Michaelis-Menten-constant kM was 1.49 +/- 0.44 mmol/l and 1.69 +/- 0.88 mmol/l, respectively. In the female group, the volume of distribution of ethanol V1 was with 38.4 +/- 5.0 l significant smaller than in males with 50.5 +/- 3.5 l. In conclusion, the new metabolite-model can be used as a basis for the investigation of the entire alcohol metabolism.

[New methods of pharmacokinetic evaluation of alcohol and its metabolites in female and male probands]. / Neue Methoden zur pharmakokinetischen Beschreibung des Alkohols und seiner Metaboliten bei weiblichen und männlichen Versuchspersonen.

The Pharmacokinetics of ethanol and its metabolites were examined in 10 young healthy women and men after 1-hr intravenous ethanol application of 7.8 mmol/kg body weight. Therefore, a new pharmacokinetic model takes into account Michaelis-Menten-elimination kinetics of ethanol as well as kinetics of acetaldehyde and acetate, which are defined by first order processes. The metabolite-model adequately describes the ethanol and acetate concentration courses. In fact, the observed ethanol concentrations are so close to the model-predicted values, that the metabolite-model allows an evaluation of half-life-times of acetaldehyde and acetate. The analyses of ethanol infusion studies showed, that there are no sex differences in parameters of ethanol elimination: Maximal elimination velocity Vmax was 3.41 +/- 0.61 mmol/l.h in females and 3.98 +/- 0.69 mmol/l.h in males. Michaelis-Menten-constant kM was 1.49 +/- 0.44 mmol/l and 1.69 +/- 0.88 mmol/l, respectively. In the female group, the volume of distribution of ethanol V1 was with 38.4 +/- 5.01 significant smaller than in males with 50.5 +/- 3.51. In conclusion, the new metabolite-model can be used as a basis for the investigation of the entire alcohol metabolism.