Siegfried Huneck

Bio: Siegfried Huneck is an academic researcher from Tokushima Bunri University. The author has contributed to research in topics: Depside & Depsidone. The author has an hindex of 21, co-authored 141 publications receiving 2479 citations. Previous affiliations of Siegfried Huneck include Duke University.

Identification of lichen substances

Abstract: The number of lichen substances with known structure is about 700. It is the aim of this book to help the lichenologist and the natural product chemist in the identification of this large group of plant metabolites. It comprises methods for the isolation and identification of lichen substances by physical and spectroscopic methods, microcrystallization, thin layer chromatography, high performance liquid chromatography, gas liquid chromatography and derivatization. The main part contains the formulae, molecular weights and data about the melting points, colour reactions, UV, IR, 1H-NMR, 13C-NMR and mass spectra, derivatives, TLC RF-values, microcrystallization, HPLC and the standard lichen (which contains the corresponding compound) with references of all lichen substances described in the literature up to 1995. Tables of molecular weights, melting points and reactions of lichen substances are further auxiliaries. Finally, a key for the identification of lichen substances is presented.

The significance of lichens and their metabolites.

Abstract: and Evernia prunastri are processed in the perfume industry, and some lichens are sensitive reagents for the evaluation of air pollution.

Analysis of secondary metabolites from Lichen by high performance liquid chromatography with a photodiode array detector

Abstract: Secondary metabolites from Lichen, mainly phenolic compounds, have been analysed and identified using high performance liquid chromatography with a photodiode array detector. Components of lichen thalli were detected by characteristic ultraviolet spectra and relative retention times. Some new minor components have been found in several lichens.

New Results on the Chemistry of Lichen Substances

Abstract: Lichen chemistry continues to be a flourishing branch of natural product chemistry. Since the last major review by Elix et al. in volume 35 of this series (274) many new and interesting lichen substances have been isolated and synthesized. This suggests that an update is desirable. As in the previous articles new methods for structure elucidation and synthesis, biosynthesis, chemotaxonomy and biological activities of lichen substances will be discussed. Some other relatively recent treatments of the subject need to be mentioned: A short chapter by Culberson and Elix (100) in Harborne’s Methods in Plant Biochemistry treated lichen constituents. Several minor reviews were published in 1984 (382), 1991 (385) and 1994 (386). Volume III of Galun’s Handbook of Lichenology (311) contains a chapter on chemical constituents of lichens including secondary metabolic products, storage products of lichens, carotenoids and phycobiliproteins.

Almost all about citrulline in mammals.

Abstract: Citrulline (Cit, C6H13N3O3), which is a ubiquitous amino acid in mammals, is strongly related to arginine. Citrulline metabolism in mammals is divided into two fields: free citrulline and citrullinated proteins. Free citrulline metabolism involves three key enzymes: NO synthase (NOS) and ornithine carbamoyltransferase (OCT) which produce citrulline, and argininosuccinate synthetase (ASS) that converts it into argininosuccinate. The tissue distribution of these enzymes distinguishes three “orthogonal” metabolic pathways for citrulline. Firstly, in the liver, citrulline is locally synthesized by OCT and metabolized by ASS for urea production. Secondly, in most of the tissues producing NO, citrulline is recycled into arginine via ASS to increase arginine availability for NO production. Thirdly, citrulline is synthesized in the gut from glutamine (with OCT), released into the blood and converted back into arginine in the kidneys (by ASS); in this pathway, circulating citrulline is in fact a masked form of arginine to avoid liver captation. Each of these pathways has related pathologies and, even more interestingly, citrulline could potentially be used to monitor or treat some of these pathologies. Citrulline has long been administered in the treatment of inherited urea cycle disorders, and recent studies suggest that citrulline may be used to control the production of NO. Recently, citrulline was demonstrated as a potentially useful marker of short bowel function in a wide range of pathologies. One of the most promising research directions deals with the administration of citrulline as a more efficient alternative to arginine, especially against underlying splanchnic sequestration of amino acids. Protein citrullination results from post-translational modification of arginine; that occurs mainly in keratinization-related proteins and myelins, and insufficiencies in this citrullination occur in some auto-immune diseases such as rheumatoid arthritis, psoriasis or multiple sclerosis.

The significance of lichens and their metabolites.

Abstract: and Evernia prunastri are processed in the perfume industry, and some lichens are sensitive reagents for the evaluation of air pollution.