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Biomedical subjects

L Jahodár

Publications and source records attributed to L Jahodár.

At least 19 recordsLinked to original sources
PubMed2006

[Plant metabolites as nootropics and cognitives].

Nowadays several millions of people suffer from Alzheimer's disease and other types of dementia. Etiology of these diseases is not known very well. There occur different levels of neurotransmitters, the level of acetylcholine in the brain is decreased and pathological changes affect the brain tissue. Organic and toxic damage of the brain, free radicals, and other changes participate in the development of these diseases. Drugs as nootropics, cognitives, and neuroprotectives are commonly used to treat these diseases. Some of these drugs have often side and undesirable effects. In recent years some natural substances (galanthamine, huperzine A, vinpocetine), and standardized plant extracts (Ginkgo biloba L., Centella asiatica L.) Urban, Bacopa monniera L., Evolvulus alsinoides L.) are often used. These plant preparations produce fewer undesirable effects and the same effectiveness as the classic therapy, or these preparations are used as a supplement to the classic therapy.

Alzheimer Disease↗
PubMed2005

Evaluation of in vitro effects of natural substances of plant origin using a model of protein glycoxidation.

In an in vitro model with purified porcine aspartate aminotransferase (AST, EC 2.6.1.1) as the protein, the effects of phenolic antioxidants of plant origin (arbutin, methylarbutin, ferulic and isoferulic acids, o-coumaric and p-coumaric acids, quinic acid), flavonoids (baicalin and baicalein), and of hydroxycitric acid (HCA) at 0.5-50 mM concentration on the enzyme activities and on its glycation by 50 mM D-fructose as the glycating agent were studied. During incubation with AST at 37 degrees C up to 24 days, fructose alone decreased AST activities as a result of protein glycation. In the absence of fructose, 50 mM phenolic compounds gradually decreased AST activity, while no or a weak effect of individual compounds was found at 3 mM concentration. A direct negative effect on AST was pronounced with ferulic acid. On the other hand, beneficial influences of phenolic compounds on glycation of AST by fructose were found mostly at 3 mM concentration. Effects on glycation were vague at 50 mM concentration, probably due to a combination of direct negative influences and antiglycation effects of individual compounds. No effect, neither positive nor negative, on AST activity and protein glycation, was found with quinic acid. The flavonoid baicalin and its aglycon baicalein rapidly decreased the in vitro activity of the enzyme in all concentrations used (0.5-3 mM), and no beneficial effects of the compounds on glycation of the enzyme by fructose were found. The influence of HCA on glycation was concentration-depended, ranging from beneficial inhibition of glycation at 2.5 mM concentration to a strong decrease in AST activity at 10 mM HCA. Both the beneficial and undesirable effects of natural antioxidants should be considered in case they are used as antiglycation factors. The results obtained can contribute to the evaluation of quality of various generally recommended antioxidants.

Animals↗
PubMed2005

[Arbutin, salicin: the possibilities of their biotechnological production].

The paper aimed to transform exogenous precursors with in vitro cultures of Datura meteloides, Coronilla varia, Leuzea carthamoides and Schisandra chinensis. These cultures were added the precursors of arbutin and salicin (phenylalanine, cinnamic, p-coumaric, p-anisoic, o-coumaric, salicylic acids, salicylaldehyde, helicin), not yet tested by the present authors. The culture of Schisandra chinensis was also added, besides the above-mentioned precursors, hydroquinone, because this culture had not been employed for biotransformation purposes yet. The precursors tested were used in a concentration of 100 mg x l(-1) and the period of their action was 6; 12; 24; 48, and 168 hours. Positive results (both TLC and HPLC) in arbutin production were obtained in the culture of Schisandra chinensis after an addition of hydroquinone. The largest amount of arbutin in callus cultures was measured after a week's cultivation with hydroquinone (5.08 %). In this experimental variant, arbutin was released also to the culture medium. Our results revealed salicylaldehyde to be the optimal precursor of salicin. It was transformed by the culture of Datura meteloides after 6; 24, and 168 hours and by the culture of Coronilla varia after 6 hours. In comparison with arbutin, its amount was smaller.

Arbutin↗
PubMed2005

[Xanthium spinosum L.--a phytochemical study].

The paper deals with the isolation of the constituents of Xanthium spinosum L. and the determination of its biological activity (toxicity). The taxon which is found also in our flora has not been studied from this aspect yet. The used methodology is of a bioassay-guided separation character. The Tubifex tubifex test (TT test) served as the basic biological test. From the methanol extract of the aerial part, ent-kaurane diterpene atractyloside was isolated, from the acetone extract of the aerial part, xanthumin and deacetylxanthumin, two derivatives of xanthanolides--sesquiterpene lactones, were isolated, and from the ethanol extract, phytosterols--beta-sitosterol and stigmasterol. From the acetone extract of fruits, fatty acids were obtained.

Xanthium↗
PubMed2004

Phototoxic activity and the possibilities of its testing.

The photodynamically active compounds have been attracting an attention of specialists for relatively long time. The most fruitful period of their research has been probably the last decade. The structures of the photosensitizers are very different. The biological activity is based on a formation of free reactive radicals after an excitation of the molecules of the phototoxins by e.g. UV radiation. Some photosensitizers are used for treatment of various diseases in dermatology and oncology. Since the substances can occur in plants, food or cosmetics, the photodynamic activity of these compounds is necessary to be studied under various conditions. Now e.g. some photochemical reactions, cell cultures, cultures of microorganisms, suspensions of erythrocytes, and different species of animals are used to the research of the photodynamic activity of the substances.

Animals↗
PubMed2004

Antiradical activity of petals of Philadelphus coronarius L.

2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay and nitroprusside assay were used for in vitro study of antiradical/scavenger activity of Philadelphus coronarius petal substances. The results obtained can be used as the basis for further studies of this type of the biological effects in the plant.

Animals↗
PubMed2004

Tubifex tubifex Müll.--photosensitive organism.

The worm Tubifex tubifex Müll. (Tubificideae, Oligochaeta) is a suitable organism for the research of the biological effect of various pollutants. This pilot study deals with the responds of the organism to the treatments of two photosensitizers (bengal rose B, quinidine) and UVA radiation. The activity of the photosensitizers was evaluated by the comparison of the surfaces of tested worms and dark controls. The results showed that T. tubifex Müll. could be a suitable organism for the studies of phototoxicity. This species demonstrated relatively strong sensitivity to the effect of the selected photodynamically active substances.

Animals↗
PubMed2003

[Chalcones (1,3-diarylpropen-1-ones) and their analogs as potential therapeutic agents in cardiovascular system diseases].

At the beginning of a new millennium, several important questions have come to the fore connected with the utilization of natural resources for the investigation of new medicaments (necessity of cooperation of both highly developed and developing countries in the protection of natural resources, necessity to justly evaluate and reward the contributions of the individual cultures in the case that a knowledge of traditional medicine was employed in the development of a new medicament, necessity to achieve the maximal chemical variety of real and virtual libraries of substances from which potential drugs are selected for screening tests). The research of chalcones and its analogues which are relatively easily available not only by isolation from natural material, but also by the methods of classical and combinatorial synthesis should not be substantially affected by the above-described changes. The present communication links up with previous papers (Opletalová, V., Sedivý, D.: Ces. slov. Farm. 48, 252 (1999); Opletalová, V.: Ces. slov. Farm. 49, 278 (2000); Opletalová, V. et al.: Folia Pharm. Univ. Carol. 25, 21 (2000)) and is devoted to the stabilizing action of chalcones on the vascular wall, vasodilating and anti-aggregating effects, and a favourable effect of their antioxidative activity on the functions of the cardiovascular system. The introduction also briefly discusses the nomenclature of this group of compounds.

Animals↗
PubMed2001

[Bergenia crassifolia (L.) Fritsch in vitro].

Sterile germinating plants were used to derive a tissue culture. The greatest stimulating effect on the growth of the culture was exerted by NAA cultures in all concentrations tested, by IAA in concentrations of 1.0 and 10.0 mg.l-1, by IBA in a concentration of 0.1 mg.l-1, and by the combination of IBA + K. The difference between the values of growth on these media was statistically insignificant. TLC analysis of callus extracts demonstrated the presence of bergenin, arbutin, hydroquinone, and methylarbutine. HPLC analysis confirmed the findings (arbutin 0.25%, hydroquinone 0.05%, methylarbutin 0.28%). The results of biotransformation tests show that the highest increase in arbutin took place after addition of 4-hydroxybenzoic acid and withdrawal of the sample after 24 hours (3.82%). No transformation of arbutin or 4-methoxyphenol to produce methylarbutin took place in the culture under the given conditions. The highest increase in the summary content of phenolic substances occurred with the use of the elicitor Pseudomonas aeruginosa--88% (conc. 0.0001 g/100 ml, 12-hour action).

Arbutin↗
PubMed1997

Evidence for the anti-hyperlipidaemic activity of the edible fungus Pleurotus ostreatus.

The effects are described of adding either the dried fruiting bodies of the oyster fungus Pleurotus ostreatus, or an ethanolic extract of it, to the diet of normal Wistar male rats and a strain with hereditary hypercholesterolaemia. Addition of the dry oyster fungus to the diet significantly increased, by more than two-fold, the triacylglycerol (TAG) level in the plasma of both groups of rats compared with their respective controls. In contrast, the ethanolic extract did not significantly change TAG levels. Values for total cholesterol and its high- and low-density lipoprotein fractions in the plasma, as well as the calculated atherogenic index, did not show any significant change. Levels of liver cholesterol were significantly lowered by the dried oyster fungus in both hypercholesterolaemic and normal groups of rats, and by the ethanolic extract in normal rats. A significantly increased phospholipid-to-cholesterol ratio in the aortas of both groups of rats, after the administration of either dried oyster fungus or the ethanolic extract of it, suggests a favourable anti-atherogenic effect for both.

Animals↗
PubMed1994

[CADISO (Cardiovascular Diseases and Stability of the Organism): 10 years of integrated research on natural substances at the Charles University Pharmacy School in Hradec Králové].

The research project CADISO (Cardiovascular Diseases and Stability of the Organism--Phytotherapeutical Possibilities) is an alliance board associating approximately 20 professional institutions, its centre and coordinating laboratory being the Department of Pharmaceutical Botany and Ecology, Faculty of Pharmacy, Charles University, Hradec Králové. It aims at the prevention (additives in food industry) and therapy of diseases of the circulatory apparatus using phytotherapeutic agents and substances isolated from higher plants and fungi. The project is divided into three systems of investigation: ADAPRETE, i.e. the substances increasing the nonspecific resistance of the organism (adaptogenes of plant origin, immunostimulants), DIACORD, dealing with the substances acting on the cardiovascular system in a mediated way, i.e. treating the diseases the eventual action of which alters the heart and vessels (antihypercholesterolemics, antihyperlipidemics, antidiabetics, anti-oxidants and quenchers of free radicals, hepatoprotectives, anti-aggregating agents), and CORCORAN studying the taxons and substances isolated from them which act directly on the circulatory system (cardiotonic, anti-arrhythmic and vasodilating agents). To achieve a real purpose of the project, the linking-up of the phytochemical, pharmacological-toxicological, pharmaceutical-technological fields, production of raw materials and legislation is ensured.

Cardiovascular Diseases↗
PubMed1993

[Plants with hypoglycemic effects].

Diabetes mellitus is a metabolic disorder which has affected several millions of population all over the world. It is characterized by an excess of sugar in the blood and urine, hunger, thirst and gradual loss of weight. Insulin is a hormone which regulates the carbohydrate and triacylglyceride metabolism through its action at several sites and facilitates the entry of glucose accumulation in the blood. Insulin also stimulates the synthesis of glucokinase and moderates the degree of gluconeogenesis. In the diabetic patient, there is an aberration in the functioning of insulin. Prior to the 1950s, control of diabetes was based entirely on insulin therapy. Unfortunately, some patients developed complications and thus need for some other therapy was realized. Presently control of NIDDM relies on compounds from two classes--sulphonylureas and biguanides. Although these drugs are widely accepted as being efficacious in treating some diabetics, they are ineffective in many others. Consequently, testing of many chemicals and plant extracts has continued. The object of the present paper is to bring up-to-date information on the hypoglycemic activity of plants, above all the plants occurring in our country, and those who se hypoglycemic activity has been scientifically documented in a more detailed way. Recent theories on the mechanism of action of these plants are also discussed.

Diabetes Mellitus↗