Nature’s way of making chemicals

With a mortar, pestle and a little bit of the South American native barbasco root, you can make a natural piscicide, or fish killer. The active compound? Rotenone. It is an archaic yet effective method of fishing for some tribal cultures.

This root is not the only source of rotenone. It is found in plants in North and South America, southeast Asia, the southwest Pacific Islands and even southern Africa.

Research has shown that when humans are exposed to rotenone through injection or inhalation, they develop tremors similar to those experienced by Parkinson’s patientsThat’s why its use as a pesticide has been banned in the United States. 

“I’m interested in natural product biosynthesis, which is just a jargon way of saying the process by which nature makes chemicals.” – Dr. Matthew Siebert

So is it safe to eat fish that died of rotenone exposure?

“It has to get in your bloodstream,” said Dr. Matthew Siebert, assistant professor of chemistry. “If it’s going through your digestive system, there’s little risk.”

Siebert and graduate student Adam Kirkpatrick conducted a series of experiments to identify the final few steps in the development of rotenone. During this study, which was later published in the Journal of Physical Chemistry A, they concluded there are two ways rotenone is created naturally.

“The way nature makes chemicals – that’s organic chemistry,” said Siebert.

Once you understand how the pieces of a puzzle fit together, it is easier to solve. Similarly, noted Siebert, when scientists make a discovery about how a process like this works, they are able to use that knowledge to develop antidotes for combatting harmful chemicals. His study, he noted, has the potential to assist in the development of new pharmaceuticals to fight Parkinson’s and other disorders.


The barbasco root can be found in the Amazon region.

Fighting cancer

Boeravinone, one of the compounds in the same class as rotenone, has been a focus for Siebert in research experiments. These projects, which he’s conducted alongside Kirkpatrick and Cailin Weber, an undergraduate student, have great potential to help cancer patients who have built resistance to treatment.

“What we are able to say is the way the chemical wants to react is this way or that.” – Dr. Matthew Siebert

“These compounds inhibit that resistance. They knock out that cancer’s defense, which makes treatments that had become unhelpful an option again,” said Siebert.

Since this compound has such profound possibilities, Siebert’s team examined the processes by which boeravinone was created, and the viability of one path over another.

They discovered the most likely path for boeravinone creation was through the use of free radicals. Since free radicals are usually considered harmful in the body – they form due to environmental factors as well as stress, poor diet, stress or smoking – this was a surprising finding.

“As humans, we try to ingest antioxidant-rich foods to get rid of free radicals,” said Siebert. “But there are plenty of human processes that use free radicals, so it was interesting to see that mirrored in this plant.”

To make these determinations, Siebert looks at the type of atoms in the molecule, how many electrons are present and the energy determining factor inside the molecule.

Their studies, he said, are trying to reveal the “energetically favorable thing to do,” or the most likely way a reaction occurs.

When Siebert decided to investigate the very first step into rotenone development, he was surprised: Nobody had ever tried to understand it.

Rotenone molecule

Model representation of rotenone. Photo by Kevin White

Anything but basic

Siebert calls himself an applied theoretical organic chemist, which means you won’t find him concocting chemical brews in test tubes. Instead he’s using quantum mechanics as he’s creating models, providing insight into chemical reactions and carrying out reactions in the virtual world.

“When we publish work, that’s the collection of several hundred individual experiments.” – Dr. Matthew Siebert

“A lot of scientific research these days is done through computer programs and modeling software to help us see what we can’t see with the naked eye,” said Weber. “I like that we are using the forefront of technology to perform research.”

Although it sounds anything but basic, Siebert said it’s, “basic science. It’s like the old saying that says we’re standing on the shoulders of giants.”

In a field that tries to explain natural reactions, it seems that the possibilities are endless.


People go to local restaurants and pick up used fryer oil to convert to diesel. Since most passenger vehicles don’t run on diesel, it has limited use. But Dr. Matthew Siebert and Zach Wilson, graduate student, presented research at American Chemical Society about how to get gasoline from biodiesel.

Further reading

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