: Natural substances can treat cancer, prolong life and trigger amazing hallucinations.
But although nature can make a remarkably wide variety of chemicals — far more than the best molecule-making robots — it does not always deliver them in bulk. Drug companies and medical researchers often turn to organic chemists when they need something that is too rare or too difficult to harvest from the wild.
Many researchers enjoy the challenge of building complicated molecules from scratch in their laboratories, testing their skills in service of a worthwhile goal. Duplicating Mother Nature isn't easy, and sometimes the journey is almost as impressive as the chemicals themselves.
Click through the gallery for some of the most remarkable chemicals that have been rebuilt in the lab.
: When the flu medication Tamiflu was on back order in 2005, fears arose that in the event of a pandemic there would not be enough of the medication to go around. The substance used to make the drug, shikimic acid, is found in Chinese star anise and was in short supply.
Years before the crisis, John Pawlak and Glenn Berchtold made the precious acid in their lab at MIT. But, while impressive, their approach was not commercially viable.
Luckily, over the last few years several labs have figured out
how to make the drug without using any shikimic acid. Time will tell whether the pharmaceutical companies will employ these techniques.
Credit: Arria Belli/flickr
: Drinking red wine in moderate amounts is supposedly good for you, but scientists don't know exactly why. Some of them think that resveratrol, a chemical found in the skin of grapes, makes the body operate as if it were on a low-calorie diet. Other researchers suspect that the health benefits come from antioxidants or procyanidins.
Any substance that might increase longevity is bound to attract interest. Thus a small army of scientists has been brewing batches of resveratrol, and similar chemicals, since it is believed to have life-extending properties.
Credit: Noël Zia Lee/flickr
: For some ailments the treatment of choice is medicinal marijuana. But its active ingredient, tetrahydrocannabinol (THC), is hard to make.
Many researchers have made the psychoactive substance, but their brews were often contaminated with chemicals that are slightly different from THC and don't have the same properties. Barry Trost and Kalindi Dogra at Stanford University were able to avoid that problem and other pitfalls in building the chemical
by using a molybdenum catalyst. They eventually produced the substance successfully.
Their research, funded by Merck and the National Institutes of Health, demonstrated the effectiveness of their catalyst, but growing marijuana is still by far the most-efficient way to produce THC.
: Eat the wrong fish and you will start to notice that cold things feel burning hot, and warm objects feel uncomfortably cold. This unusual ailment is caused by ciguatoxin, which may be the strangest poison on earth.
Ciguatoxin is a huge molecule, which is made by microbes and found in the flesh of predatory tropical fish — like these red snapper. Because of its size and complexity, organic chemists love the challenge of making ciguatoxin, but it's also essential to have a renewable supply on hand to test for a cure. Luckily, Masayuki Inoue and Masahiro Hirama, researchers at Tohoku University, have successfully built the molecule and its relatives.
: Diviner's sage is more powerful than any other natural hallucinogen, and it may have some antidepressant effects, too. Its active ingredient, Salvinorin A, can mess with your mind by triggering proteins called kappa opioid receptors which have been shown to effect mood, appetite, pain and addictive behaviors. The possible applications for the drug are unclear, but promising.
Steps to produce the drug synthetically are already well underway. Researchers at Niigata University made the drug from scratch
in a 20-step process.
Another team of scientists, led by Thomas Prisinzano at the University of Iowa, pioneered a method to make similar chemicals
, which could be used to study the nervous system. Each chemical has a slightly different effect on the mind, and animal testing has already lead to useful insights about Salvinorin A's use.
: Eat a deathcap mushroom, and your next stop is the morgue. It contains a chemical called amantin, which destroys the liver and kidneys.
But that's not all. It has another poison, called phalloidin, that sticks to the scaffolding of cells. That substance is less deadly and has a useful purpose: By attaching the toxin to a fluorescent dye, researchers can study the inner workings of cells, and watch how they divide. Those observations can shed some light on how cancer works and the way tissues grow.
Scott Lokey and Laura Schuresko, chemists at the University of California, Santa Cruz, made the deadly substance with a technique called solid-phase synthesis. Instead of mixing the chemicals in a flask and letting them float around freely, one of the chemicals is held in place during the reactions. That gives the researchers much more control during the complicated procedure.
: In the crater of the retired Berkeley Pit copper mine
, not far from the Montana Tech campus, sits a lake of poison. Its water is highly acidic, loaded with heavy metals and filled with exotic fungi.
It also contains a microbe that produces what might be a cure for ovarian cancer. The potentially lifesaving chemical produced by the microbe was discovered by Don and Andrea Stierle in 2006, and they named it Berkelic Acid after the mine.
Three years later, Barry Snider and his colleagues at Brandeis University made the precious substance from scratch. His 13-step recipe is not terribly efficient, but it does offer the world a way to make more of the potential medicine.
Credit: The Lebers/flickr
: One of the most powerful cancer drugs on the market — Taxol or, generically, paclitaxel — comes from the Pacific yew tree. It was discovered in the 1960s during a massive government program to find medications in plant extracts. It worked remarkably well in its first human trials, but environmentalists realized that harvesting more Taxol could drive the Pacific yew into extinction. The race to create the drug in a lab was on.
French researchers led by Pierre Potier learned in 1988 that they could make the drug by modifying a chemical from European yew trees, but their approach was too inefficient for mainstream production. Robert Holton, a medicinal chemist at Florida State University
, built upon their work and developed the first viable approach to making Taxol in the lab in 1994.
Other researchers have followed suit, and some have tried to improve upon the original drug with better delivery systems. Several cousins of the medicine, including Docetaxel, are on the market today and in clinical trials. Abraxane, which is Taxol wrapped in a protein nanoparticle, has been approved by the FDA. Another nano-packaged Taxol, Xyotax, is in Phase III clinical trials.
: A chemical called 225H, found in amphibians, is an ion-channel blocker. That means it can alter the main switches of the nervous system, which makes it useful for neuroscience researchers. It could also be used as a pain drug, or to help people quit smoking. The problem is that 225H is scarce in nature.
Enter Mark Trudell of the University of New Orleans. Trudell happens to specialize in two serendipitous fields of study. He makes chemicals that fight cocaine addiction, and he also synthesizes molecules from poisonous dart frogs.
By combining these two areas of expertise, he was able to create 225H in his lab — a process that involves transforming cocaine into the desired compound through a series of chemical reactions. Now testing of 225H need not be dependent on these cute-but-slimy creatures.
Photo: Strawberry poison dart frog.
: The unmistakable scent of rain comes from bacteria, not clouds.
As raindrops fall, they agitate the soil and bring out a chemical called geosmin, which is made by microbes in the dirt. It has an earthy aroma, and sometimes ruins the flavor of food — particularly water, wine, beets and fish — by making it taste dirty.
James Marshall and Alan Hochstetler were able to make the pungent substance at Northwestern University in 1968, but their batch was rather impure. David Cane and his colleagues at Brown University learned in 2003 that some microbes have a gene that lets them make geosmin from a relatively common chemical called farnesyl diphosphate.
With no clear motivating application, it took three decades of tinkering before other chemists learned how to prepare it with ease. Geosmin's future is uncertain — perhaps dirt-scented cologne
: Phil Crews' team from the University of California, Santa Cruz, identified a chemical in sea sponges in 2004 that can devastate tumors. They called it psymberin. Another group, led by George Pettit from the University of Arizona, found the same substance near the coast of Malaysia in a different sponge the same year.
The ocean is full of cancer drugs. More than two dozen chemicals from sea life, or inspired by it, have made their way into human clinical trails. Crews and his students extract promising exotic chemicals from sea creatures and then test their ability to kill cancer and fight other diseases.
Psymberin is a large, and somewhat complicated, molecule. But that did not stop organic chemists from making it in the lab by the summer following its discovery. And just this year, a team at the Schering-Plough Research Institute reported a new, improved way to make the experimental drug.
Credit: Sarah Robinson, Katie Watts/Crews lab
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