Steviosid aus Süßkraut

The diterpene glycoside stevioside is the most abundant among a group of sweet steviol glycosides, present in sweetleaf (Stevia rebaudiana), which is naturally occurring in Paraguay. It has already been used by the Guarani Indians as a sweetener. Since 2011 such “steviosides” have an EU approval as sweeteners E 960. They taste ca. 250 times sweeter than sucrose. Meanwhile, they have got a significant recognition, not least due to their use in Coca Cola life®. We describe the isolation of stevioside and rebaudioside A from dried leaves of the sweetleaf plant. The complete set of spectra for stevioside is reported. Based on students' laboratory work this project is a follow up of the book “Classics in Spectroscopy” by S. Berger und D. Sicker (Wiley‐VCH 2009).     

Eucalyptol aus Eukalyptusöl

Eucalyptol (1,8‐cineol), a cyclic monoterpenoid ether, is the dominant portion of eucalyptus oil, an essential oil of Eucalyptus globulus, accessible by steam distillation of its leaves. Some herbs and spices such as basil and cardamom also contain it as characterising flavour compound. Eucalyptus is a very diverse genus of Myrtaceae naturally occurring in Australia to whom the species have adapted in evolution. Planting Eucalyptus trees outside Australia has both benefits for poor populations and drawbacks. Especially, the enormous water consumption has been criticized. The total impact is doubtful. Eucalyptol is used in flavorings, fragrances, confectionery, cosmetics, cough suppressants, and insect repellents. Higher than normal doses are a hazard. A convenient isolation of eucalyptol from eucalyptus is reported. All analytical spectra were recorded and are reproduced and interpreted either in the main part or in the supporting information. The project is a follow up of the recent book “Classics in Spectroscopy” by S. Berger und D. Sicker (Wiley‐VCH 2009).     

Diosgenin aus Yams als Hormonvorstufe

Diosgenin as a sapogenin is the aglycone of the saponine dioscin. It is occuring in plants such as yam, from which it is isolated on industrial scale since the 1940ies. Plant diosgenin is a starting substance for the synthesis of human, i.e. animal, hormones and “the pill”, which as a hormonal contraception represents a revolution in the control of human sexuality. History, isolation and spectroscopy of this complex sapogenin are reported. This article extends the briskly discussed feature “50 years pill in Germany” (Streller & Roth, ChiuZ, 2011 [( 1 ) ]) by a particular compound example. It belongs to the series on isolation and spectroscopy of natural products in this journal.     

Raffinose + Raffinase = Raffinade: Raffiniert!

Raffinose has been obtained by extraction with 50% ethanol from the seeds of the Sweet Blue Lupine and purified first via a Cation exchange column and finally by analytical HPLC using a RI‐detector. All analytical spectra were recorded and are reproduced either in the main part or in the supporting information. The NMR‐ and mass‐spectra have been interpreted and compared with theoretical calculations of the ¹³C chemical shifts. The project is a follow up of the recent book “Classics in Spectroscopy” by S. Berger und D. Sicker (Wiley‐VCH 2009).     

Über Rosmarin und Rosmarinsäure

Rosmarinic acid, a tan from Lamiaceae, is found in rosemary and many other plants such as thyme, painted nettle, savory, sage, oregano, or lemon balm, from which it has been isolated here. It is a caffeic acid ester and a chiral, aromatic natural product. Rosmarinic acid tastes bitter, which may be attractive for rosemary as spice. Due to the catechol subunit the acid is an antioxidant. Using rosmarinic acid as a cure is possible due to manyfold physiological effects which are still under investigation. The rosmarinic acid biosynthesis pathway was completely elucidated at the painted nettle. This led to attempts to produce the acid biotechnologically by plant cell cultures in high yields. The preparation of a spectroscopically pure sample is challenging. All analytical spectra were recorded and are reproduced and interpreted either in the main part or in the supporting information.     

Chlorophyll

Chlorophyll exists since ca. 3 billion years and is at begin of the evolution. This chiral, green Mg‐porphyrin‐complex absorbs as a photosensitizer in the antennas of the light‐harvesting complexes of chloroplasts all parts of visible light except of green light. This energy is transferred to the reaction centres of oxygenic photosynthesis. By this redox reaction carbon dioxide and water are transformed into carbohydrates and oxygen. We describe how the structures of chlorophylls were elucidated, discuss structure‐property relations, the relationship to heme of blood, everyday uses, and how Green has influenced our language. The isolation of pure chlorophyll a from spinach is an experimental challenge, which we report in detail. All analytical spectra were recorded and are reproduced and interpreted either in the main part or in the supporting information.     

Mit der Eberesche vom Heimatlied zur Frühstücksmagarine

The mountain ash (rowan tree) belongs to the adaptable trees of pioneer vegetation. Its fruits are edible and can be used for dishes and beverages. Appropriate knowledge is, however, required to avoid dissapointments. Their use in folk medicine is also known. In the German Ore Mountain region there is a special folk song as a song of praise for the tree. Typical chemical ingredients are the constituents parasorboside ( 1 ), a glucoside, parasorbinic acid ( 2 ), a lactone, and sorbinic acid ( 3 ), an unsaturated carboxylic acid. It is chemically accessible from 2 and used as a preservative. In more than 100 years, the structures were determined by renowned chemists. The access to 1 , 2 , and 3 based on the mountain‐ash rowan berries is described. All analytical spectra were recorded and are reproduced and interpreted either in the main part or in the supporting information.     

γ‐Conicein und Coniin aus Geflecktem Schierling

Socrates is the most famous victim of hemlock poisoning by drinking the cup of hemlock after being condemned to death in Athens in 399 BC. Lethal poisons are γ‐coniceine and coniine, the two most abundant Conium alkaloids which smell like mouse urine. It causes a shudder that the victim is gradually paralyzed under consciousness and that there is no antidote. Poison hemlock is also strongly poisonous to range animals. Therefore, agriculture suppresses hemlock. Coniine was the first alkaloid made synthetically (Ladenburg, 1866). Today, hemlock poisons have no medical use. We describe the isolation of γ‐coniceine and coniine from home‐grown and wild poison hemlock. Their set of spectra is reported and interpreted. Based on students laboratory work and this time on our own preparative commitment as academic supervisors this project is a follow up of the book “Classics in Spectroscopy” by S. Berger und D. Sicker (Wiley‐VCH 2009).     

Thymochinon – das Gelbe vom Öl

Thymoquinone has been obtained by steam distillation from the yellow cold pressed oil of the seeds of Nigella sativa L. and purified by column chromatography. All analytical spectra were recorded and are reproduced either in the main part or in the supporting information. The NMR‐ and mass‐spectra have been interpreted and compared with theoretical calculations of the ¹³C chemical shifts. The project is a follow up of the recent book “Classics in Spectroscopy” by S. Berger und D. Sicker (Wiley‐VCH 2009).     

Sinensetin

Sinensetin was isolated from cold pressed orange peel oil and recrystallized from ethanol. All analytical spectra were recorded and are reproduced either in the main part or in the supporting information (www.chiuz.de). The NMR‐ and mass‐spectra have been interpreted and compared with theoretical calculations of the ¹³C chemical shifts. The project is a follow up of the book “Classics in Spectroscopy” by S. Berger und D. Sicker (Wiley‐VCH 2009).