Antioxidant dehydrotocopherols as a new chemical character of Stemona species
| Autor: | Otmar Hofer, Thomas Pacher, Markus Hartl, Franz Hadacek, Srunya Vajrodaya, Christoph Seger, Harald Greger, Brigitte Brem |
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| Rok vydání: | 2004 |
| Předmět: |
Stemona collinsae
Magnetic Resonance Spectroscopy Antioxidant Stemona Free Radicals Double bond DPPH Stereochemistry medicine.medical_treatment Tocopherols Plant Science Horticulture Biochemistry Antioxidants chemistry.chemical_compound Stemonaceae Botany medicine Tocopherol Stemona burkillii Molecular Biology Chromatography High Pressure Liquid chemistry.chemical_classification Molecular Structure biology food and beverages General Medicine biology.organism_classification chemistry Stemona kerrii lipids (amino acids peptides and proteins) Stemona tuberosa |
| Zdroj: | Phytochemistry. 65:2719-2729 |
| ISSN: | 0031-9422 |
| DOI: | 10.1016/j.phytochem.2004.08.023 |
| Popis: | From the roots of various Stemona species four new dehydrotocopherols (chromenols) were isolated and their structures and stereochemistry elucidated by spectroscopic methods. The double bond between C-3 and C-4 proved to be a typical chemical character of the genus found in most of the species. Various C-methylations of the aromatic ring reflect differences in methyltransferase activities and agreed with the current species delimitations showing an exclusive accumulation of dehydro-delta-tocopherol for the Stemona tuberosa group, whereas different provenances of Stemona curtisii were characterized by dehydro-gamma-tocopherol accompanied by small amounts of dehydro-alpha-tocopherol. From Stemona collinsae all four tocopherols were isolated with a clear preponderance of dehydro-delta-tocopherol accompanied by smaller amounts of the rare dehydro-beta-tocopherol. Stemona burkillii and a group of unidentified species showed a weak accumulation trend towards dehydro-alpha-tocopherol, whereas Stemona cochinchinensis and especially Stemona kerrii clearly differed by a preponderance of chromanol derivatives. In Stemona cf. pierrei no tocopherols could be detected at all. Based on TLC tests and microplate assays with the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH*) the antioxidant capacities of all chromenol derivatives were comparable with that of alpha-tocopherol showing no significant differences among each other, except for a more rapid kinetic behaviour of the 5,7,8-methylated dehydro-alpha-tocopherol. |
| Databáze: | OpenAIRE |
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