Compatibility of fosfomycin with different commercial peritoneal dialysis solutions.

For treatment of peritoneal dialysis-related peritonitis, intraperitoneal administration of antibiotics remains the preferable route. For home-based therapy, patients are commonly supplied with peritoneal dialysis fluids already containing antimicrobial agents. The present study set out to investigate the compatibility of fosfomycin with different peritoneal dialysis fluids, namely, Extraneal®, Nutrineal®, Physioneal® 1.36% and Physioneal® 2.27%, under varying storage conditions. The peritoneal dialysis fluid bags including 4 g fosfomycin were stored over 14 days at refrigeration temperature (6°C) and room temperature (25°C) and over 24 h at body temperature (37°C). Drug concentrations over time were determined by using high-performance liquid chromatography coupled to a mass spectrometer. In addition, drug activity was assessed by a disk diffusion method, diluent stability by visual inspection and drug adsorption by comparison of the measured and calculated concentrations. Blank peritoneal dialysis fluids and deionized water were used as comparator solutions. Fosfomycin was stable in all peritoneal dialysis fluids and at each storage condition investigated over the whole study period. The remaining drug concentrations ranged between 94% and 104% of the respective initial concentrations. No significant drug adsorption was observed for any peritoneal dialysis fluid at any storage condition. No relevant reduction of antimicrobial activity was observed. Fosfomycin is compatible with Extraneal®, Nutrineal® and Physioneal® for up to two weeks at refrigeration or room temperature and may be used for home-based therapy. No dose adjustment is needed due to adsorption or degradation.

The influence of different peritoneal dialysis fluids on the in vitro activity of ampicillin, daptomycin, and linezolid against Enterococcus faecalis.

Intraperitoneal administration of antibiotics is recommended for the treatment of peritoneal dialysis-related peritonitis. However, little data are available on a possible interference between peritoneal dialysis fluids and the activity of antimicrobial agents. Thus, the present in vitro study set out to investigate the influence of different peritoneal dialysis fluids on the antimicrobial activity of ampicillin, linezolid, and daptomycin against Enterococcus faecalis. Time-kill curves in four different peritoneal dialysis fluids were performed over 24 h with four different concentrations (1 × MIC, 4 × MIC, 8 × MIC, 30 × MIC) of each antibiotic evaluated. Cation-adjusted Mueller-Hinton broth was used as the comparator solution. All four peritoneal dialysis fluids evaluated had a bacteriostatic effect on the growth of Enterococcus faecalis. Compared to the cation-adjusted Mueller-Hinton broth comparator solution, the antimicrobial activity of all antibiotics tested was reduced. For ampicillin and linezolid, no activity was found in any peritoneal dialysis fluid, regardless of the concentration. Daptomycin demonstrated dose-dependent activity in all peritoneal dialysis fluids. Bactericidal activity was observed at the highest concentrations evaluated in Dianeal® PDG4 and Extraneal®, but not in concentrations lower than 30 × MIC and not in Nutrineal® PD4 and Physioneal® 40. The antimicrobial activity of ampicillin and linezolid is limited in peritoneal dialysis fluids in vitro. Daptomycin is highly effective in peritoneal dialysis fluids and might, thus, serve as an important treatment option in peritoneal dialysis-related peritonitis. Further studies are needed to evaluate the clinical impact of the present findings.

The Herbal Drug Melampyrum pratense L. (Koch): Isolation and Identification of Its Bioactive Compounds Targeting Mediators of Inflammation.

Melampyrum pratense L. (Koch) is used in traditional Austrian medicine for the treatment of different inflammation-related conditions. In this work, we show that the extracts of M. pratense stimulated peroxisome proliferator-activated receptors- (PPARs-) α and - γ that are well recognized for their anti-inflammatory activities. Furthermore, the extract inhibited the activation of the proinflammatory transcription factor NF- κ B and induction of its target genes interleukin-8 (IL-8) and E-selectin in vitro. Bioassay-guided fractionation identified several active flavonoids and iridoids including melampyroside and mussaenoside and the phenolic compound lunularin that were identified in this species for the first time. The flavonoids apigenin and luteolin were distinguished as the main components accountable for the anti-inflammatory properties. Apigenin and luteolin effectively inhibited tumor necrosis factor α (TNF- α )-induced NF- κ B-mediated transactivation of a luciferase reporter gene. Furthermore, the two compounds dose-dependently reduced IL-8 and E-selectin protein expression after stimulation with lipopolysaccharide (LPS) or TNF- α in endothelial cells (ECs). The iridoids melampyroside and mussaenoside prevented the elevation of E-selectin in LPS-stimulated ECs. Lunularin was found to reduce the protein levels of the proinflammatory mediators E-selectin and IL-8 in ECs in response to LPS. These data validate the ethnomedical use of M. pratense for the treatment of inflammatory conditions and point to the constituents accountable for its anti-inflammatory activity.

Selected Extracts of Chinese Herbal Medicines: Their Effect on NF-κB, PPARα and PPARγ and the Respective Bioactive Compounds.

Chinese herbal medicinal (CHM) extracts from fourteen plants were investigated in cell-based in vitro assays for their effect on nuclear factor κB (NF-κB), a key regulator of inflammation, as well as on peroxisome proliferator-activated receptors (PPARs) being key regulators of genes involved in lipid and glucose metabolism. 43% of the investigated CHMs showed NF-κB inhibitory and 50% PPARα and PPARγ activating effects. Apolar extracts from cortex and flos of Albizia julibrissin Durazz. and processed rhizomes of Arisaema sp. and Pinellia ternata (Thunb.) Breit. that effectively inhibited TNF-α-induced NF-κB activation and dose-dependently activated PPARα and PPARγ were further investigated. Bioassay-guided fractionation and analysis by GC-MS led to the identification of fatty acids as PPAR agonists, including linoleic and palmitic acid.

Yarrow (Achillea millefolium L. s.l.): pharmaceutical quality of commercial samples.

Yarrow (Achillea millefolium L. s.l.) is traditionally used against inflammatory and spasmodic gastrointestinal complaints, hepato-biliary disorders, as an appetite enhancing drug, against skin inflammations and for wound healing due to its antiphlogistic, choleretic and spasmolytic properties. The main pharmacologically active principles were shown to be the essential oil (antimicrobial), proazulenes and other sesquiterpene lactones (antiphlogistic), dicaffeoylquinic acids (choleretic) and flavonoids (antispasmodic). In order to assess the pharmaceutical quality of the drug we evaluated the content of these bioactive compounds in 40 commercial drug samples. The essential oil and the proazulenes were analysed according to the European Pharmacopoeia, whereas the content of dicaffeoylquinic acids and flavonoids was determined by solid phase extraction (SPE)-HPLC. This comprehensive survey revealed that the quality of the drug material was very heterogenous, and only 50% of the samples met the standards of the European Pharmacopoeia. Moreover, this study gives information about the content of phenolic compounds in the drug and allowed to establish tentative reference values which may be used as additional parameters in the quality control of the drug.

Sulfation of resveratrol in human liver: evidence of a major role for the sulfotransferases SULT1A1 and SULT1E1.

Sulfation of resveratrol, a polyphenolic compound present in grapes and wine with anticancer and cardioprotective activities, was studied in human liver cytosol. In the presence of 3'-phosphoadenosine-5'-phosphosulfate, three metabolites (M1-3) whose structures were identified by mass spectrometry and NMR as trans-resveratrol-3-O-sulfate, trans-resveratrol-4'-O-sulfate, and trans-resveratrol-3-O-4'-O-disulfate, respectively. The kinetics of M1 formation in human liver cytosol exhibited an pattern of substrate inhibition with a K(i) of 21.3 +/- 8.73 microM and a V(max)/K(m) of 1.63 +/- 0.41 microLmin(-1)mg(-1) protein. Formation of M2 and M3 showed sigmoidal kinetics with about 56-fold higher V(max)/K(m) values for M3 than for M2 (2.23 +/- 0.14 and 0.04 +/- 0.01 microLmin(-1)mg(-1)). Incubation in the presence of human recombinant sulfotransferases (SULTs) demonstrated that M1 is almost exclusively catalysed by SULT1A1 and only to a minor extent by SULT 1A2, 1A3 and 1E1, whereas M2 is selectively formed by SULT1A2. M3 is mainly catalysed by SULT1A2 and 1A3. In conclusion, the results elucidate the enzymatic pathways of resveratrol in human liver, which must be considered in humans following oral uptake of dietary resveratrol.

Metabolism and biliary excretion of the novel anticancer agent 10-hydroxycamptothecin in the isolated perfused rat liver.

10-hydroxycamptothecin (HCPT), a natural analog of the alkaloid camptothecin (CPT), is a promising anticancer agent currently undergoing preclinical trials. Though HCPT is less toxic and more active in various human cancer cell lines and in animal tumor models than the clinically approved CPT-analog topotecan, little is known about its biotransformation products and their route of elimination. To investigate the metabolism and biliary excretion, livers of male Wistar rats were perfused with HCPT (5 microM). Bile and perfusate samples were collected for 60 min and quantified by reversed-phase high-performance liquid chromatography (HPLC). Besides HCPT, three metabolites, namely HCPT glucuronide (M1), hydroxyHCPT glucuronide (M2), and hydroxyHCPT (M3) could be identified by enzymatic hydrolysis with beta-glucuronidase and mass spectroscopy. Biliary secretion of HCPT and M1-M3 reached a peak secretion of 1532+/-124, 75+/-16, 5.8+/-1.6 and 2.1+/-0.5 pmoles/g liver.min, respectively, after 25 min. The total amount of HCPT and M1-M3 excreted into bile during the time of perfusion (60 min) was low and represented a mean of 9.9+/-3.2%, 0.44+/-0.17%, 0.041+/-0.010%, and 0.022+/-0.004% of the initial HCPT dose, respectively. In the perfusate, besides HCPT M1 and M2 but not M3 could be detected (maximum concentrations after about 20 min: 3248+/-210, 16.8+/-2.8 and 1.0+/-0.4 pmoles/g liver.min, respectively). The cumulative efflux of HCPT and M1 and M2 into the perfusate was 21.1+/-3.9%, 0.145+/-0.036% and 0.018+/-0.004% of the initial dose, respectively, indicating a preferable non-biliary secretion for HCPT and a predominant biliary elimination for conjugated HCPT biotransformation products. In conclusion, HCPT is biotransformed in a rat liver model to three metabolites, mainly excreted into bile, which may be of clinical relevance during cancer therapy.

Morphogenetic variability of faradiol monoesters in marigold Calendula officinalis L.

The main compounds of lipophilic extracts of flower heads of marigold (Calendula officinalis L.) are triterpendiol esters, mainly faradiol laurate, faradiol myristate and faradiol palmitate. These faradiol-3-O-monoesters have been quantified for the first time by means of reversed phase HPLC with internal standardisation in different parts of C. officinalis plants, namely ray florets, disk florests, involucral bracts, receptacles, levaes and seeds. The amounts of the esters were highest in ray florets, approximately 10 times lower in disk florets than in the ray florets, and approximately 10 times lower in involucral bracts than in the disk florets. In the leaves only traces of the esters could be detected, and in the receptacles no esters could be detected at all. Quantification in the seed was not possible using this method because of interfering fatty compounds. Concerning the faradiol esters, the dried ray and disk florets only should be preferred as primary products for remedies as demanded in the recently published supplement of the Pharmacopoiea Europaea (1999). Breeding work should focus on varieties with a greater number of ray florets in order to improve the quality of herbal medicinal products derived from marigoid.

Percutaneous absorption of the montoterperne carvone: implication of stereoselective metabolism on blood levels.

The purpose of this study was to determine whether an enantioselective difference in the metabolism of topically applied R-(-)- and S-(+)-carvone could be observed in man. In a previous investigation we found that R-(-)- and S-(+)-carvone are stereoselectively biotransformed by human liver microsomes to 4R,6S-(-)- and 45,6S-(+)-carveol, respectively, and 4R,6S-(-)-carveol is further glucuronidated. We therefore investigated the metabolism and pharmacokinetics of R-(-)- and S-(+)-carvone in four healthy subjects using chiral gas chromatography as the analytical method. Following separate topical applications at a dose of 300 mg, R-(-)- and S-(+)-carvone were rapidly absorbed, resulting in significantly higher Cmax levels for S-(+)-carvone (88.0 vs 23.9 ng mL(-1)) and longer distribution half-lives (t(1/2alpha)) (19.4 vs 7.8 min), resulting in 3.4-fold higher areas under the blood concentration-time curves (5420 vs 1611 ng min mL(-1)). The biotransformation products for both enantiomers in plasma were below detection limit. Analysis of control- and beta-glucuronidase pretreated urine samples, however, revealed a stereoselective metabolism of R-(-)-carvone to 4R,6S-(-)-carveol and 4R,6S-(-)-carveol glucuronide. No metabolites could be found in urine samples after S-(+)-carvone application. These data indicate that stereoselectivity in phase-I and phase-II metabolism has significant effects on R-(-)- and S-(+)-carvone pharmacokinetics. This might serve to explain the increased blood levels of S-(+)-carvone.

Stereoselective metabolism of the monoterpene carvone by rat and human liver microsomes.

The large amounts of carvone enantiomers consumed as food additives and in dental formulations justifies the evaluation of their biotransformation pathway. The in-vitro metabolism of R-(-)- and S-(+)-carvone was studied in rat and human liver microsomes using chiral gas chromatography. Stereoselective biotransformation was observed when each enantiomer was incubated separately with liver microsomes. 4R, 6S-(-)-Carveol was NADPH-dependently formed from R-(-)-carvone, whereas 4S, 6S-(+)-carveol was produced from S-(+)-carvone. Metabolite formation followed Michaelis-Menten kinetics exhibiting a significant lower apparent Km (Michaelis-Menten Constant) for 4R, 6S-(-)-carveol compared with 4S, 6S-(+)-carveol in rat and human liver microsomes (28.4+/-10.6 microM and 69.4+/-10.3 microM vs 33.6+/-8-55 microM and 98.3+/-22.4 microM). The maximal formation rate (Vmax) determined in the same microsomal preparations yielded 30.2+/-5.0 and 32.3+/-3.9 pmol (mg protein)(-1) min(-1) in rat liver and 55.3+/-5.7 and 65.2+/-4.3 pmol (mg protein)(-1) min(-1) in human liver microsomes. Phase II conjugation of the carveol isomers by rat and human liver microsomes in the presence of UDPGA (uridine S'-diphosphogluaronic acid) only revealed glucuronidation of 4R, 6S-(-)-carveol. Vmax for glucuronide formation was more than 4-fold higher in the rat liver compared with human liver preparations (185.9+/-34.5 and 42.6+/-7.1 pmol (mg protein)(-1) min(-1), respectively). Km values, however, showed no species-related difference (13.9+/-4.1 microM and 10.2+/-2.2 microM). This study demonstrated stereoselectivity in phase-I and phase-II metabolism for R-(-)- and S-(+)-carvone and might be predictive for carvone biotransformation in man.

Clinical pharmacokinetics and metabolism of paclitaxel after polychemotherapy with the cytoprotective agent amifostine.

BACKGROUND: Cytoprotection of healthy cells represents a new approach in cancer chemotherapy, but a pharmacokinetic drug interaction between the cytostatic and the cytoprotectant is undesired. METHODS: The purpose was to evaluate the clinical pharmacokinetics (PHK) of paclitaxel (PACLI) and its metabolites under cytoprotection in patients suffering from breast cancer. PACLI was administered alone and in a second cycle in combination with amifostine (AMI) as a paired cross over. RESULTS: In both treatment schedules the steady state of PACLI occurred after 3 hours, the tmax of metabolites between 3 and 4 hours. The mean steady-state concentration was cmax = 5432 +/- 1238 ng/ml in the control group and cmax = 5140 +/- 2407 ng/ml in the AMI group. For the serum metabolites, the findings were very similar: 6-OH-PACLI: cmax 413 +/- 153 ng/ml versus 432 +/- 304 ng/ml, 3"-OH-PACLI: cmax 99 +/- 103 ng/ml versus 123 +/- 98 ng/ml, 3",6-DiOH-PACLI: cmax 43 +/- 55 ng/ml versus 75 +/- 85 ng/ml. AUC values of metabolites were slightly higher in the AMI group, but PHK seemed equal. CONCLUSION: The results gave evidence, that cytoprotection with AMI has no clinical consequences on PACLI pharmacokinetics and biotransformation.

Saponins from Hacquetia epipactis.

Four new estersaponins were isolated from hacquetia epipactis. Using GC-MS, FAB-MS and various 2D-NMR techniques they were identified as 3-O-[beta-D-glucopyranosyl-(1-->2)-[alpha-L-arabinopyranosyl-(1--> 3)]- beta-D-glucuronopyranosyl-(1-->)]-21-acetyl-22-(2-methylbutyryl)- barringtogenol C (hacquetiasaponin 1), the corresponding 21-(2-acetoxy-2-methylbutyryl)-22-acetyl-derivative (hacquetiasaponin 2), 3-O-[beta-D-glucopyranosyl-(1-->2)-[alpha-L-arabinopyranosyl- (1-->3)]-beta-D-glucuronopyranosyl-(1-->)]-21-acetyl-22-(2-methylb utyryl)- R1-barrigenol (hacquetiasaponin 3) and its corresponding 21-(2-acetoxy-2-methylbutyryl)-22-acetyl-derivative (hacquetiasaponin 4).

A triterpene saponin from Herniaria glabra.

A new acetylated triterpene saponin was isolated from Herniaria glabra. GC, GC-MS, FAB-MS analysis and the use of 2D NMR techniques allowed the elucidation of its structure as 28-O-(beta-D-glucopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)- [beta-D-glucopyranosyl-(1-->3)]-4-acetyl-beta-D-fucopyranosyl(1-->))- medicagenic acid-3-O-beta-D-glucuronide.

[Isolation and structure elucidation of further new saponins from Solidago canadensis]. / Isolierung und Struktur weiterer neuer Saponine aus Solidago canadensis.

Four new main saponins (canadensis-saponins 5-8) (compounds 5-8) were isolated from Solidago canadensis L. (Asteraceae). Using GC/MS, FAB-MS, and mainly 2D-NMR techniques their structures were identified as 3-O-[beta-D-glucopyranosyl(1----3)-beta-D- glucopyranosyl]-28-O-[beta-D-galactopyranosyl(1----2)-alpha-L- rhamnopyranosyl-(1----3)-beta-D-xylopyranosyl-(1----4)-[beta-D- xylopyranosyl-(1----3)]-alpha-L-rhamnopyranosyl-(1----2)-[beta-D-apio -D- furanosyl-(1----3)]-beta-D-6-deoxyglucopyranosyl-(1----)]-bayog enin(5),3-O- [beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranosyl]-28-O-[beta-D- galactopyranosyl-(1----2)-alpha-L-rhamnopyranosyl-(1----3)-beta-D- xylopyranosyl-(1----4)-[beta-D-xylopyranosyl-(1----3)]-alpha-L- rhamnopyranosyl-(1----2)-[beta-D-apio-D-furanosyl-(1----3)]- arabinopyranosyl-(1----)]bayogenin(6),3-O-[beta-D-glucopy ran osyl-(1----3)- beta-D-glucopyranosyl]-28-O-[beta-D-galactopyranosyl-(1----2)- alpha-L-rhamnopyranosyl-(1----3)-beta-D-xylopyranosyl-(1----4)-[beta-D- xylopyranosyl-(1----3)]-alpha-L-rhamnopyranosyl-(1----2)-[alpha-L- rhamnopyranosyl-(1----3)]-beta-D-6-deoxyglucopyranosyl-(1----)]-++ +bayogenin (7), and 3-O-[beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranosyl]-28-[O- beta-D-galactopyranosyl-(1----2)-alpha-L-rhamnopyranosyl-(1----3)-beta-D - xylopyranosyl-(1----4)-[beta-D-xylopyranosyl-(1----3)]-alpha-L- rhamnopyranosyl-(1----2)-[alpha-L-rhamnopyranosyl-(1----3)]arabinopyr anosyl - (1----)[-bayogenin (8).

Four major saponins from Solidago canadensis.

Four new bisdesmosidic saponins each containing eight carbohydrate units were isolated from Solidago canadensis. GC, GC-MS, FABMS analysis and mainly the use of 2D NMR techniques allowed their identification as bayogeninglycosides (canadensissaponins 1-4) 3-O- [beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranosyl]-28-O-[alpha-L- rhamnopyranosyl-(1----3)-beta-D-xylopyranosyl-(1----4)-[beta-D- xylopyranosyl-(1----3)]-alpha-L-rhamnopyranosyl-(1----2)-[beta-D- apio-D-furanosyl-(1----3)]-beta-D-6-deoxyglucopyranosyl- (1----]-bayogenin; -(1----2)-[beta-D-apio-D-furanosyl-(1----3)]-ara- binopyranosyl-(1----]-bayogenin; -[alpha-L-rhamnopyranosyl-(1----3)]-beta- D-6-deoxyglucopyranosyl-(1----]-bayogenin and - [alpha-L-rhamnopyranosyl- (1----3)]-arabinopyranosyl-(1----]-bayogenin.