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Rudolf Bauer

Publications and source records attributed to Rudolf Bauer.

25 records · Page 2Linked to original sources
PubMed2004

New constituents of Leontopodium alpinum and their in vitro leukotriene biosynthesis inhibitory activity.

Phytochemical investigations of the roots of Leontopodium alpinum Cass. resulted in the isolation and structure elucidation of six novel compounds and two known compounds. Novel constituents could be identified as the polyacetylenes 1-acetoxy-3-angeloyloxy-(4 E,6 E)-tetradeca-4,6-diene-8,10,12-triyne and its (6 Z)-isomer, the kaurenic acid derivative methyl ent-7alpha,9alpha-dihydroxy-15beta-[(2 Z)-2-methyl-but-2-enoyloxy]kaur-16-en-19-oate, the bisabolane derivative (1 R*,3 S*,4 R*,6 S*)-9-(acetoxy)-4-hydroxy-1-[(2Z)-2-methylbut-2-enoyloxy]bisabol-10(11)-ene and the lignans [(2 S,3 R,4 R)-4-(3,4-dimethoxybenzyl)-2-(3,4,5-trimethoxyphenyl)-tetrahydrofuran-3-yl]-methyl-(2 Z)-2-methylbut-2-enoate and its 3,4,5-trimethoxybenzyl derivative. Known compounds, reported here for the first time for the genus Leontopodium, were identified as ent-kaur-16-en-19-oic acid and T-cadinol. The obtained compounds were tested together with 15 previously described compounds of L. alpinum in an ex vivo leukotriene biosynthesis inhibition assay. The highest activities were determined for the bisabolane derivates (IC50: 7.7 to 11.4 microM), one lignan (IC50: 10.7 microM) and the ent-kaurenoate (IC50: 10.4 microM).

Asteraceae↗
PubMed2002

mRNA expression profiles for the response of human tumor cell lines to the antimalarial drugs artesunate, arteether, and artemether.

The antimalarial artemisinin derivatives artesunate (ART), arteether (ARE), and artemether (ARM) reveal remarkable antineoplastic activity. In the present investigation, we identified mRNA expression profiles associated with the response of tumor cells to ART, ARE, and ARM. We performed correlation and hierarchical cluster analyses of inhibition concentration 50% (IC(50)) values and basal mRNA expression levels of 464 genes deposited in the database of the National Cancer Institute, USA. Correlating IC(50) values of ART, ARE, and ARM and of 16 established antineoplastic drugs revealed that the artemisinin derivatives could not be assigned with a known class of drugs with defined mode(s) of action. The basal mRNA expression of 208 out of 464 genes (45%) correlated significantly with IC(50) values of at least one artemisinin derivative. These genes were from different classes (drug resistance genes, DNA damage and repair genes, apoptosis-regulating genes, proliferation-associated genes, oncogenes, tumor suppressor genes and cytokines). We identified two different gene clusters by hierarchical cluster analysis. One cluster contained predominately genes significantly correlated to all three artemisinin derivatives. This overlapping set of genes points to common molecular mechanisms of tumor inhibition by all three drugs in which genes affecting cellular proliferation may play an important role. The second cluster contained genes differentially associated with the response of artemisinin derivatives to cancer cells. The number of correlating drug resistance genes in this cluster increased in the order ART<ARE<ARM and was paralleled by increasing IC(50) values of the three drugs in the same order. The higher activity of ART in comparison to ARE and ARM may, thus, be explained by a lower number of drug resistance genes affecting ARTs action. The present analysis is a starting point for the generation of hypotheses on candidate genes and for a more detailed dissection of the functional role of individual genes for the activity of artemisinin derivatives in tumor cells.

Antimalarials↗
PubMed2002

Anti-inflammatory activity of two different extracts of Uncaria tomentosa (Rubiaceae).

We assessed in vivo the anti-inflammatory activity of two Cat's claw bark extracts, by comparing a spray-dried hydroalcoholic extract against an aqueous freeze-dried extract, to determine which extract was more effective. We used the carrageenan-induced paw edema model in mice. In addition, to assess the molecular mechanism of action, we determined the inhibition of NF-kappa B through the Electrophoretic Mobility Shift Assay (EMSA) and the effects on cycloxygenase-1 and -2. Results showed that the anti-inflammatory activity was significantly higher using the hydroalcoholic compared with the aqueous extract (P<0.05). The extracts also showed little inhibitory activity on cyclooxygenase-1 and -2. It cannot be excluded that the slight inhibitory activity on DNA binding of NF-kappa B is due to cytotoxic effects.

Animals↗
PubMed2002

Echinacea stimulates macrophage function in the lung and spleen of normal rats.

Echinacea plant extract has been used for immunostimulation for many years but the evidence supporting its therapeutic potential is still controversial. Using male Sprague-Dawley rats (425-475 g), an in vivo study was conducted to examine the immunomodulatory effects of preparations of Echinacea containing its components cichoric acid, polysaccharides and alkylamides in different concentrations. The rats were gavaged orally with these preparations, two times/day for 4 days. Phagocytic activity of alveolar macrophage was increased with increasing concentrations of the Echinacea components. A trend of increase in TNF-alpha and nitric oxide release by the alveolar macrophages following an in vitro stimulation with LPS was also evident. An enhanced release of cytokines (such as TNF-alpha and IFN-gamma) in response to Echinacea components, was also apparent in rat's spleen macrophage, but at higher concentrations. These results suggest that the Echinacea preparations containing optimal concentrations of cichoric acid, polysaccharides and alkylamides are potentially effective in stimulating an in vivo, non-specific immune response in normal rats.

Journal Article↗
PubMed2002

Alkylamides of Echinacea purpurea stimulate alveolar macrophage function in normal rats.

Echinacea plant extract is widely used for the prevention and the treatment of upper respiratory tract infections. However, the active components in the herb, their optimal dosages and their in vivo effects are still undefined. Using male Sprague-Dawley rats (425-475 g), an in vivo study was conducted to examine the immunomodulatory effects of various dose levels of three components, isolated and purified from Echinacea purpurea. The components were cichoric acid, polysaccharides and alkylamides. The rats were gavaged orally two times/day for 4 days with three different concentrations of each of the Echinacea components. Among the components, alkylamides at the dose level of 12 microg/kg body weight/day significantly increased the phagocytic activity as well as phagocytic index of the alveolar macrophages. The alveolar macrophages obtained from this group of rats also produced significantly more TNF-alpha and nitric oxide after an in vitro stimulation with LPS than any other active component or the control. None of the components at any concentration had any effect on the release of TNF-alpha, IFN-gamma and IL-2 by the splenocytes. These results suggest that the alkylamides are one of the active constituents of E. purpurea plant. At a dose level of approximately 12 microg/kg body weight/day they effectively stimulate alveolar macrophage function in healthy rats. The immunomodulatory effects of alkylamides appear to be more pronounced in lungs than in spleen.

Amides↗
PubMedDate not supplied

HPLC-MS trace analysis of atropine in Lycium barbarum berries.

The dried ripe fruits of Barbary wolfberry, Lycium barbarum L. are widely used in China for medicinal purposes and as a functional food. Previous investigations reported to have found atropine in Barbary wolfberries from India. These results have been questioned. Since then, however, there has been a discussion on whether the berries are suitable for human consumption. In order to determine the content of atropine, we have analysed eight samples of berries from China and Thailand for traces of atropine, using highly selective and sensitive HPLC-MS methods. Atropine was found in all examined samples in concentrations of maximally 19 ppb (w/w). Therefore, the content is far below toxic levels.

Atropine↗