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Biomedical subjects

E F Elstner

Publications and source records attributed to E F Elstner.

At least 37 records · Page 2Linked to original sources
PubMed1999

Biochemical activities of extracts from Hypericum perforatum L. 4th Communication: influence of different cultivation methods.

Extracts from the herb "St. John's wort" (Hypericum perforatum L.), know since ancient times as medical plant, besides other activities such as wound healing, antighout, antirheumatic and diuretic properties, is used in the treatment of mild to moderate depression. Increasing application continuously makes cultivation under controlled conditions of Hypericum perforatum L. more important. This report shows the results of three-years cultivation experiments with Hypericum perforatum L. The findings indicate that N-fertilizing yields more plant material but results in a drug with less quantity of secondary metabolites. Important components of the drug were quantified by HPLC and their activities were analyzed with the aid of biochemical test systems. Narrowleaved and broadleaved varieties of Hypericum perforatum L. show differences both in activity and quality. In this experiments the most active extract was a methanolic extract derived from non-fertilized, broadleaved plants.

Anthracenes↗
PubMed1999

Inhibition of biochemical model reactions for inflammatory processes by plant extracts: a review on recent developments.

All processes of oxygen activation include very reactive intermediates. Therefore, aerobic cells must cope with- and to some extent also adapt to- oxidative stress provoked for example by infections or intoxications, where these reactive intermediates accumulate. Dependent on the strength of these impact, several symptoms indicate the deviation from normal, steady-state-metabolism. Intrinsic radical scavenging processes or compounds administered with food thus have to warrant metabolic control within certain limits. Antioxidants which in many cases are free radical scavengers or quenchers of activated states comprise a wealth of classes of organic molecules including phenolics, probably as the most prominent ones. In this communication mechanisms of protection from oxidative damage are discussed. Furthermore, examples of antioxidative functions of a few important natural products in certain diseases are reported.

Antioxidants↗
PubMed1999

Enhancement by glucose of low density lipoprotein-oxidation by peroxynitrite.

Oxidation of low density lipoprotein (LDL) by copper ions is not influenced by glucose in a concentration range between 1 and 20 mM. LDL-oxidation by peroxynitrite or the simultaneous action of nitrogen monoxide and superoxide, produced by morpholino-sydnonimine (SIN-1) is considerably enhanced by typical hydroxyl-radical scavengers such as formate or mannitol and by glucose. Since both free radicals, nitrogen monoxide and superoxide, are produced by activated leukocytes and endothelial cells the presented reaction might represent a simple model for the cooperative function of reactive oxygen species (ROS) and glucose in certain diabetic blood vessel diseases such as atherogenesis and retinopathy.

Glucose↗
PubMed1999

Studies on the chemical identity and biological functions of pangamic acid.

Pangamic acid (6-O-(dimethylaminoacetyl)-D-gluconic acid) has been detected 1938 and described as a natural, universally occurring substance with multiple biological and medical functions. In this respect pangamic acid has been worldwide on the market since decades as a drug stimulating cellular respiration. In addition to the natural pangamic acid, diisopropylammonium dichloroacetate (DIPA), a synthetic product not found in biological material, is on the market requesting similar biological functions. In commercially available drugs on the German market declared as pangamic acid three separate substances can be found by chemical identification of pangamic acid, namely: gluconic acid, glycine and diisopropylamonium dichloroacetate. As biological functions have been found in vitro inhibition of Cu-dependent LDL oxidation by glycine due to chelation of Cu2+ ions and deterioration of mitochondrial respiratory control due to an increased state IV oxygen consumption rate at high concentrations of DIPA.

Animals↗
PubMed1998

Modulation of the production of reactive oxygen species by pre-activated neutrophils by aminoadamantane derivatives.

Aminoadamantane derivatives (AAD) such as amantadine or memantine have been used for the treatment of Morbus Parkinson and Morbus Alzheimer. In this communication, we report on the immunomodulatory activities of AAD. Luminol-dependent chemiluminescence of zymosan-, N-formylmethionylleucylphenylalanine(FMLP)- or experimental Ca2+-ionophore(A 231879)-preactivated polymorphonuclear leukocytes (PMN) was strongly enhanced by submicromolar concentrations of AAD and inhibited at higher concentrations than 0.1 mM. Light emission by phorbol-12-myristate-acetate(PMA)-preactivated cells was not further stimulated but inhibited by the elevated concentrations, just as with the other, above-mentioned activators. Ethylene formation from alpha-keto-methylthiobutyrate (KMB) as an indicator for production of OH.-type reactive oxygen species by the NADPH-oxidase ("respiratory burst") was augmented by AAD and completely inhibited by superoxide dismutase. In contrast, ethylene release from 1-amino-cyclopropyl-l-carboxylic acid (ACC) as relatively specific indicator for the myeloperoxidase reaction after degranulation was not influenced by AAD. As documented by several model reactions, AAD per se did not act as scavengers or quenchers of activated oxygen species such as superoxide, OH.-radical, hydrogen peroxide or hypochlorite. Altogether, these results suggest that submicromolar concentrations of AAD upregulate the respiratory burst, but apparently not the degranulation of prestimulated polymorphonuclear leukocytes. At higher concentrations of AAD, both respiratory burst and degranulation are inhibited, however. These effects can also be shown in complete blood samples.

Amantadine↗
PubMed1997

Biological durability and oxidative potential of a stonewool mineral fibre compared to crocidolite asbestos fibres.

Experiments are described concerning the differences in redox properties and biodurability of natural asbestos fibres and an experimental stonewool fibre incubated in Gamble solution and reconstructed surfactant fluid. Crocidolite exhibits a significantly higher oxidative potential compared to the tested stonewool fibres. The oxidative activity of both types of fibres is not constant during incubation over several weeks, but rather shows a sinoidal curve including reactivities much higher than those at the beginning of the incubation. A continuous loss of mass is concluded not to be definitively connected with a continuous loss of toxicity.

Asbestos, Crocidolite↗
PubMed1996

Interactions of different extracts of propolis with leukocytes and leukocytic enzymes.

Extracts of the "bee glue" propolis exhibit well-known antioxidative and anti-inflammatory properties. However, the biochemical mechanisms of propolis effects in wound healing and inflammatory processes are not yet fully understood. Therefore the effects of different ethanolic and aqueous extracts on leukocytes and some of their most important enzymes namely myeloperoxidase, NADPH oxidase and lipoxygenase were investigated. Only high concentrations of propolis extracts inhibited these enzymatic activities but especially the water-soluble derivatives showed stimulatory effect on the activity of commercially available human myeloperoxidase. Leukocytic myeloperoxidase and NADPH oxidase activities were clearly inhibited by propolis extracts probably indirectly due to their excellent radical scavenging properties.

Animals↗
PubMed1996

Effects of extracts from Populus tremula L., solidago virgaurea L. and Fraxinus excelsior L. on various myeloperoxidase systems.

Extracts from Populus tremula, Solidago virgaurea and Fraxinus excelsior are used as anti-inflammatory drugs. The effects of these extracts on myeloperoxidase (MPO), an enzyme liberated by activated granulocytes and known to produce the destructive agent hypochloric acid, were investigated. Populus and Fraxinus inhibited this enzyme, Solidago was without effect. These results were obtained concordantly with four different MPO-assays (H2O2/MPO; X/XOD/MPO; activated PMN; and elastase/alpha 1-PI-MPO). Fractionation of Populus and Fraxinus extracts showed that this inhibition is due to several different compounds. Well known or wide spread substances as e.g. rutin, salicylic acid, chlorogenic acid etc. had no or only little effect on the enzyme.

Amino Acids↗
PubMed1995

Gas chromatographic differentiation between myeloperoxidase activity and Fenton-type oxidants.

Several pathological situations are characterized by the production of reactive oxygen species (ROS), whereby different sources such as activated leukocytes and xanthine oxidase seem to be mainly responsible. The contribution of immigrating activated neutrophils to symptom development during inflammatory processes or after reperfusion of ischemic tissues is a matter of continuing discussion. We present a simple method for the differentiation between oxygen activating reactions in which neutrophil-derived myeloperoxidase is involved. The method is based on the gas chromatographic detection of ethylene, which is formed by the reaction of alpha-keto-gamma-methylthiobutyric acid (KMB) or 1-amino-cyclopropane-1-carboxylic acid (ACC) with ROS. In the presence of OH-radical-type oxidants, only KMB yields ethylene whereas ACC is fragmented by myeloperoxidase-derived species (OCl-, chloramines). The amounts of ethylene may be used as an indicator for the relative contribution of Fenton-type or myeloperoxidase-catalyzed reactions.

Amino Acids↗
PubMed1995

Biological and biochemical effects of air pollutants: synergistic effects of sulphite.

Air pollution has become a major public and political concern since the beginning of industrialization, particularly motor exhaust over the past three decades. Epidemiological studies, together with clinical trials and experiments in exposition chambers (including biochemical model reactions), have contributed to our knowledge of potential dangers and increased our understanding of the corresponding mechanisms and dose-response effects. Comparison of the threatening reports that appear almost daily in the press with the digest of over 800 scientific publications allows the statement that the impact of ozone and nitric oxide on the health and performance of plants and animals is widely overestimated and appears to be used as a political instrument. In contrast, the combination of SO2 with soot and asbestos particles may represent an underestimated toxic potential. In this communication, we shall concentrate on basic redox mechanisms involving SO2 and important target molecules, as well as looking at the cooperative effects of sulphite and soot particles.

Air Pollutants↗
PubMed1995

Sedative action of extract combinations of Eschscholtzia californica and Corydalis cava.

The herbal drug Phytonoxon N (abbreviated as PN) is indicated in nervousness induced insomnia, agitation and/or anxiety. It is composed of alcoholic drug extracts of the plants Corydalis cava (20%) and Eschscholtzia californica (80%). Both plants are rich in isoquinoline alkaloids derived from tyrosine metabolism. Recent research shows that they may influence the neurotransmitter metabolism.

Alkaloids↗
PubMed1995

Modulation of key reactions of the catecholamine metabolism by extracts from Eschscholtzia californica and Corydalis cava.

Aqueous-alcoholic extracts from Eschscholtzia californica inhibit the enzymatic degradation of catecholamines as well as the synthesis of adrenaline, whereas aqueous-ethanolic extracts from Corydalis cava enhance the chemical oxidation of adrenaline and the synthesis of melanine from dihydroxyphenylalanine (DOPA). Both extracts dramatically shorten the lag phase in the catalysis of phenolase probably due to their o-diphenol content, where the Corydalis extracts are 10 times more active than the Eschscholtzia preparations. Dopamine beta-hydroxylase and monoamine oxidase (MAO-B) are especially inhibited by Eschscholtzia extracts. Diamine oxidases are inhibited by both preparations to a similar extent. The results of this study may be interpreted as a cooperative function of the two preparations in establishing and preserving high catecholamine levels thus explaining their sedative, antidepressive and hypnotic activities.

Alkaloids↗
PubMed1995

Effects of ethanolic extracts from Eschscholtzia californica and Corydalis cava on dimerization and oxidation of enkephalins.

The endogenous pentapeptides, met-enkephalin and leuenkephalin, similar to their parent structures, beta-endorphin or dynorphin, bind to opioid receptors of the nociceptive system thus provoking analgesic responses. Peroxidases and phenolases (tyrosinase, catecholase) were shown to dimerize these pentapeptides thus possibly modulating their activity and/or lifetime. Extracts from plants from the order of the Papaverales contain isoquinoline alkaloids. Since the benzoisoquinolines are known to possess sedative-hypnotic activities, the potential effects of extracts from two species from this plant group, Eschscholtzia californica (Papaveraceae) and tyrosinase-catalyzed dimerization and/or oxidation of met-enkephalin were investigated. The results of the study show that the peroxidase-catalyzed dimerization via the tyr-residues is especially inhibited by the C. cava extract. The tyrosinase-catalyzed reaction yields five different products A-E, according to their HPLC-retention times. Consisting of the 4:1 (v/v) combination of the extracts from E. californica and C. cava, Phytonoxon N (abbreviated as PN) stimulates the formation of minor products A, B and E, whereas the formation of the major products C and D is inhibited. Only products C and D exhibit properties similar to the peroxidase-derived dimer. Product A is likely to be identical to DOPA-enkephalin.

Alkaloids↗
PubMed1995

A combination of Populus tremula, Solidago virgaurea and Fraxinus excelsior as an anti-inflammatory and antirheumatic drug. A short review.

Anti-inflammatory properties of Populus tremula are mainly deduced from its components, the well investigated salicylates. Solidago extracts have spasmolytic, antihypertensive and diuretic effects. Fraxinus excelsior itself has hardly been investigated, but its coumarin components proved to have a variety of pharmacological properties, i.e. inhibition of T-cell activation and of the arachidonic acid cascade. Phytodolor N (abbreviated as PD) is a combination of the above mentioned plants. Various in vitro and especially in vivo studies proved its anti-inflammatory and antirheumatic properties, often comparable to non-steroidal anti-inflammatories, but with little or no side effects.

Animals↗
PubMed1995

Inhibition of dihydrofolate reductase activity by alcoholic extracts from Fraxinus excelsior, Populus tremula and Solidago virgaurea.

Aqueous-ethanolic extracts of Fraxinus excelsior, Populus, tremula and Solidago virgaurea in a combination of 1: 3: 1 (v/v/v) are the components of the plant drug Phytodolor N (abbreviated as PD), which exhibits antipyretic, analgesic and antirheumatic activity. Similar to a broad variety of synthetic non-steroidal anti-inflammatories the mentioned plant extracts inhibit dihydrofolate reductase. The following concentrations as percentage in the test volumes represent the individual I50-values: F. excelsior = 0.26% (v/v); P. tremula = 0.46% (v/v) and S. virgaurea = 0.6% (v/v). The combined extracts in PD exhibit an I50 at 0.3% (v/v). Testing the activity of the water-soluble compounds of corresponding dry extracts, the activity of F. excelsior with an apparent I50-value of 0.008% (w/v) by far dominates the inhibitory overall effect of the combination (I50 = 0.014%, w/v).

Animals↗
PubMed1995

Antioxidative properties of alcoholic extracts from Fraxinus excelsior, Populus tremula and Solidago virgaurea.

Aqueous-ethanolic extracts from Fraxinus excelsior, Populus tremula and Solidago virgaurea inhibit biochemical model reactions representing inflammatory situations to various extents. These model reactions include xanthine oxidase, diaphorase in the presence of the autoxidizable quinone juglone, lipoxygenase and photodynamic reactions driven by riboflavin or rose bengal. The tested extracts are the components of the phytomedicine Phytodolor N (abbreviated as PD) which possesses antipyretic, analgesic, antiinflammatory and antirheumatic activity. Since several reactive oxygen species produced by the mentioned model systems are also involved in inflammatory processes, the beneficial activities of the complete drug may at least in part be due to the reported antioxidative functions of the individual components.

Animals↗
PubMed1994

The influence of magnesium-pyridoxal-5'-phosphate-glutamate in comparison with probucol, alpha-tocopherol and trolox on copper-induced oxidation of human low density lipoprotein in vitro.

Low density lipoprotein (LDL) in the presence of magnesium-pyridoxal-5'-phosphate-glutamate (MPPG), pyridoxal-5'-phosphate (PP), alpha-tocopherol, probucol or trolox is more resistant against copper-induced oxidation as control-LDL in vitro. The efficiency of the drugs is: probucol > MPPG > trolox > alpha-tocopherol > PP. LDL oxidation is determined by its increasing negative surface charge, fragmentation of apolipoprotein B-100 and changes of the fatty acid content of LDL. The protection of the drugs depends on their concentration and incubation time. Different experiments point to the fact that copper-induced oxidation of LDL in vitro starts with the binding of copper at the apolipoprotein B-100, resulting in an increasing negative surface charge and fragmentation of the apolipoprotein B-100. Afterwards a decrease of LDL-bound linoleic acid (18:2) is measurable.

Arteriosclerosis↗