Category: Sciencebase

I’ve got a bottle of absinthe, at the back of a shelf in our store-cupboard. Unopened this bottle of green uber-liquor languishes untested awaiting an appropriate occasion when a drink containing 70 percent alcohol (140 proof) is required. It’ll probably be the day our cat dies…

Anyway, while my bottle languishes, new research suggests that the psychedelic mythology surrounding this exotic green aperitif and its purported mind-altering effects are due to nothing more than the high concentration of alcohol, plain, old EtOH like you find in wine, beer, and spirits.

The likes of van Gogh, Degas, Toulouse-Lautrec and Picasso quaffed large quantities of the stuff in the hope that its claimed hallucinogenic effects would enhance creativity. However, analysis of the contents of old bottles of the stuff by scientists in Europe and the US show that there were no psychotropic agents contained in the spiritual brew. Moreover, they found negligible quantities of thujone, a bicyclic compound with a three-membered ring that was widely believed responsible for absinthe’s effects. The results are detailed in the mid-May issue of the Journal of Agricultural and Food Chemistry.

The results brought to mind a high-school dance, when one particularly boastful and eccentric classmate (named Keith) was duped by some older boys into smoking common or garden tea leaves in the mistaken belief that they’d given him a spliff and then swaggered brazenly around the school hall under flashing disco lights claiming everything was, “Sooooo cooooooo, maaaaaan! I can almost picture van Gogh swigging the green grog, slicing off an ear and being endowed with a similar swaggering disposition (albeit in Dutch and with a large wad of surgical dressing pressed to the side of his head).

Absinthe took on legendary status in late 19th-Century Paris among bohemian artists and writers. They believed it expanded consciousness with psychedelic effects and called it the “Green Fairy” and the “Green Muse”.

The laboratory tests, unfortunately for Bohemians everywhere, found no compound other than ethanol that could explain absinthe’s effects nor its potent toxicity. “All things considered, nothing besides ethanol was found in the pre-ban absinthe samples that was able to explain the syndrome of absinthism,’ the researchers say. And, there I was hoping for a good drowning of sorrows when our cat has used him his full nonet of lives.

Check out my interview with chemical blogger Egon Willighagen, one of the new breed of chemists who are using the information tools of our age–the blogs, wikis, and online social media–to further their chemistry and benefit the wider chemical community.

By day, Willighagen is a postdoc at the Wageningen University & Research Center in the Netherlands. He participates in, amongst many other activities, Bioclipse, CDK, and Jmol as well as running the http://chem-bla-ics.blogspot.com blog. He also established the Chemical blogspace site, which collects data from dozens of scientific chemistry blogs and then does useful and interesting things with them.

Read the full interview in Reactive Profiles

Russian biathlete Tatiana Moiseeva tested positive for the banned drug dexamethasone (dex), according to a recent report from news agency Allsport. The news was followed up by CNN, which mentioned little of the drug’s activity.

Dexamethasone is a fluorinated corticosteroid (11b,16a)-9-fluoro-11,17,21-trihydroxy-
16-methylpregna-1,4-diene-3,20-dione, to be precise. It acts as an antiinflammatory and an immunosuppressant and as such is used in rheumatoid arthritis, in surgery to prevent rejection of artificial components, and in oncology to ameliorate the effects of chemotherapy. It also has efficacy in altitude sickness. In sport, it’s antiinflammatory action, of course, allows athletes to train harder and work through injuries faster.

Moiseeva meanwhile, is holding out hope that her “B” sample will show negative and that the result reported on her “A” sample was a false positive.

The structure of an active component of herbal remedy Gingko biloba is causing controversy among chemists apparently related to InChI strings and such matters.

Structural controversies may become a moot point given recent research that seems to suggest that one of the main benefits of taking this herbal remedy – memory improvement – is not valid.

A three-year study involving 118 people age 85 and older with no apparent memory problems was carried out by Hiroko Dodge and colleagues in the Department of Public Health and Center for Healthy Aging Research at Oregon State University in Corvallis. Half of the participants took Ginkgo biloba extract three times a day and half took a placebo. During the course of the study, 21 people developed mild memory problems, or questionable dementia: 14 of those took the placebo and seven took the ginkgo extract. Although there was a trend favoring ginkgo, the difference between those who took gingko versus the placebo was not statistically significant.

More on this from the American Academy of Neurology

A newly discovered diterpene quesnoin with a novel ring structure, bridged by a single oxygen atom, has been isolated from 55 million-year-old amber from the Eocene geological period by Akino Jossang and colleagues at the National Museum of Natural History in Paris.

According to a report in Chemistry World, Jossang said that, “It is very difficult to isolate pure known compounds in amber, so to discover a new structure was unexpected and exceptional.” The biosynthesis is intriguing but whether or not the quesnoin has any potential applications is a different matter.

The compound is related to one from a tree found today only in the Amazon rainforest adding to the weight of evidence that Paris was once a tropical region. Anyone who has spent an August there will know how that might have been.

Spinneret host Tony Williams tells me that he used the new ChemSpider manual deposition scheme to add this new compound to the database. “We are about to rollout the ability for anyone to deposit structures on ChemSpider. This one took me 5 mins…about 3.5 of that drawing the structure!” The entry description includes the DOI of the original paper and links directly to it.

This week’s Spinneret post actually points you to my latest Alchemist column on ChemWeb.com but also goes into a little more detail on one of the items reported there regarding pesticide contamination.

First off, Environmental research gets a boost from NIH in the form of a $6.8million grant to establish three DISCOVER centers to study the effects of environmental pollutants. Crystallography reveals the cellular machinations of the humble hydrogen peroxide molecule in The Alchemist this week, while fatty samples suggest that all of us harbor at least one pesticide or other persistent organic compound in our tissues. In environmental news, researchers have turned to gold to help them convert biomass into a useful chemical feedstock, while in theoretical studies it still matters, relatively, that electrons and nuclei are massively and speedily different. Finally, crystals behaving badly in supramolecular chemistry could herald new approaches to technological problems.

Read current issue of The Alchemist here.

Anyway, back to the contentious item on global contamination, which referred to news that almost everyone in Spain, and putatively the world, may be contaminated with at least one pesticide. I did have some misgivings about reporting on this and my concerns were brought into sharp relief by an Alchemist reader friend who happens to be a retired organic chemist with a great deal of experience.

He points out that the item on finding persistent organics in blood serum should really be put into perspective. “The fact that many of these studies find mainly halogenated compounds may well simply reflect the exquisite sensitivity of the detectors used in capillary gas chromatography to halogen,” he says, “these devices will pick up nanomolar concentrations of compounds containing chlorine or bromine.” He also asks whether strict controls were used by the investigators in this research and points out that work in this area submitted for regulatory filing requires stringent controls beyond simply showing a peak that has roughly the same Rf as a suspected pollutant.

More to the point, however, he questions the significance of finding traces of DDT or even DDE in serum. “If this were truly perilous the landscape should be littered with victims,” he says.

Levels of cholesterol in the membranes of hair cells in the inner ear can affect your hearing according to an article in the Journal of Biological Chemistry. There are two types of sensory hair cells in the inner ear called the inner and outer hair cells. It is the outer hair cells that are affected by cholesterol levels and produce the inaudible sounds in the ear canal.

SOURCE: Baylor College of Medicine

A detailed structure of a potassium ion channel protein has been obtained by a Nobel team in the US. The structure shows the channel in a more natural state, revealing how attendant lipid molecules within the cell membrane influence channel function by their interaction with the proteinaceous Mickey Mouse ears that protrude from the protein into the lipid layer and act as a voltage sensor.

Membrane-bound proteins are among the most fascinating molecules in biology but are notoriously difficult to crystallise and study in detail in their natural, or even near-natural state. Now, Nobel scientist Roderick MacKinnon and colleagues at Rockerfeller University, have developed a new technique, lipid-detergent-mediated crystallization, which could open the door to studying the hundreds of membrane proteins previously inaccessible in their natural environment to crystallography.

More in the latest issue of SpectroscopyNOW crystallography ezine

One of the very first articles I wrote for Elemental Discoveries (Issue 3 in March 1997, it was) was on the subject of a novel class of anticancer compound that had been isolated from soil bacteria. The article (archived now on Sciencebase) discussed the discovery of a total synthesis for the archetypal epothilone. Well, more than a decade since, and two decades after their initial discovery, the epothilones are about to enter the pharmaceutical market under the Bristol-Myers Squibb marque.

The epothilones that Gerhard Höfle and Hans Reichenbach discovered in myxobacteria block the somatic cell components known as microtubules, inhibiting cell division causing tumors to shrink or even disappear.

Bristol-Myers Squibb acquired the license for epothilone B for clinical testing. As of this month, US oncologists can prescribe epo B, under the tradename Ixempra, for metastatic breast cancer. European approval is anticipated for 2008.

InChIKEY: QXRSDHAAWVKZLJ-PVYNADRNBK