Publications by authors named "Tomas Siatka"

Article Synopsis
  • Vitamin B, specifically cobalamin, is essential for human health as it plays key roles in converting l-methylmalonyl coenzyme A to succinyl coenzyme A and in forming methionine from homocysteine.
  • Unlike prokaryotes, eukaryotes like animals and plants cannot synthesize vitamin B, so humans need to obtain it from dietary sources such as meat, dairy, fish, and eggs, putting vegetarians at risk for deficiency.
  • This review covers the biological aspects of vitamin B, its functions, causes and symptoms of deficiency, diagnostic methods, prevention and treatment approaches, as well as its pharmacological applications and potential toxicity.
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This review summarizes the current knowledge on essential vitamins B, B, B, and B. These B-complex vitamins must be taken from diet, with the exception of vitamin B, that can also be synthetized from amino acid tryptophan. All of these vitamins are water soluble, which determines their main properties, namely: they are partly lost when food is washed or boiled since they migrate to the water; the requirement of membrane transporters for their permeation into the cells; and their safety since any excess is rapidly eliminated via the kidney.

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Three new alkaloids, bersavine (3), muraricine (4), and berbostrejdine (8), together with seven known isoquinoline alkaloids (1-2, 5-7, 9, and 10) were isolated from an alkaloidal extract of the root bark of Berberis vulgaris. The structures of the isolated compounds were determined by spectroscopic methods, including 1D and 2D NMR techniques, HRMS, and optical rotation, and by comparison of the obtained data with those in the literature. The NMR data of berbamine (5), aromoline (6), and obamegine (7) were completely assigned employing 2D NMR experiments.

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Glycogen synthase kinase-3β (GSK-3β) is a multifunctional serine/threonine protein kinase that was originally identified as an enzyme involved in the control of glycogen metabolism. It plays a key role in diverse physiological processes including metabolism, the cell cycle, and gene expression by regulating a wide variety of well-known substances like glycogen synthase, tau-protein, and β-catenin. Recent studies have identified GSK-3β as a potential therapeutic target in Alzheimer´s disease, bipolar disorder, stroke, more than 15 types of cancer, and diabetes.

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Alzheimer's disease is an age-related, neurodegenerative disorder, characterized by cognitive impairment and restrictions in activities of daily living. This disease is the most common form of dementia with complex multifactorial pathological mechanisms. Many therapeutic approaches have been proposed.

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Objectives: The aim of this work was to assess the possible beneficial effects of aqueous extracts of Hibiscus sabdariffa L. calyces and anthocyanins isolated therefrom in an adenine-induced chronic kidney disease (CKD) model.

Methods: Rats were orally given, for 28 consecutive days, either adenine alone or together with either aqueous extract of H.

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Extracts of Hibiscus sabdarnffa calyces have been shown to have various medicinal properties, some of which have been reported to be due to anthocyanins present in the calyces. To study whether these claims are valid, it is necessary to produce an extract with a high anthocyanin content and to have available a method to identify and quantify the individual compounds in the product. A method of extraction and purification has been developed based on a polyamide column chromatographic purification step.

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Callus cultures of Juniperus virginiana L. (varieties 'Hetzii', 'Glauca', 'Grey Owl') were derived from fresh leaves of garden-grown trees on Schenk and Hildebrandt medium supplemented with 3.0 mg/L of α-naphthaleneacetic acid, 0.

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Extracts of the calyces of Hibiscus sabdariffa are widely used in folk medicine to combat many illnesses. The active constituents of the extracts have been shown on several occasions to be anthocyanins. In our current studies the biological activities of an extract of H.

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Alkaloid extracts of eight Narcissus (Amaryllidaceae) species and varieties were studied with respect to their acetylcholinesterase (HuAChE) and butyrylcholinesterase (HuBuChE) inhibitory activity and alkaloid patterns. Thirty alkaloids were determined by GC/MS, and twenty-five of them identified from their mass spectra, retention times and retention indexes. Promising HuAChE inhibition activity was demonstrated by six Narcissus taxa and HuBuChE inhibition by N.

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Effect of exogenously applied jasmonic acid (JA) in combination with calcium and verapamil (a calcium channels blocker) on the production of flavonoids and isoflavonoids in suspension cultures of Trifolium pratense L. was investigated. The culture was cultivated in Gamborg medium with an addition of 2 mg.

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The plant cell may respond to the excess of heavy metals in its environment by various mechanisms, including enhanced biosynthesis of secondary metabolites. In this study, zinc (0 to 1500 μM) and cadmium ions (0 to 100 μM) were tested as potential elicitors of the production of coumarins in angelica cell suspension cultures. In addition, the toxicity of both metals was assessed by evaluating their effect on cell growth (characterized by fresh and dry biomass at the end of a two-week subculture).

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The production of secondary metabolites in Trifolium pratense L. suspension culture of the family of legume plants (Fabaceae) is low, and therefore there was an attempt to increase it by elicitation. New synthetic substance, 2-(2-fluoro-6-nitrobenzylsulfanyl)pyridine-4-carbothioamide, was tested as elicitor--a substance that showed the best elicitation effect after 48-hour application of 1 μmol L⁻¹ concentration.

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Variations in total phenolic and flavonoid contents as well as antioxidant activity of Bellis perennis (common daisy) flowers were investigated. The flowers were collected monthly (from March to October, i.e.

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