Researchers at Michigan State University and the Czech Academy of Sciences identified six enzymes that build the core of diterpenoid alkaloids, compounds with toxic reputations and medical promise.

Larkspur and wolfsbane are beautiful and dangerous. Their tall spikes of blue and purple flowers decorate gardens across the Northern Hemisphere, but the plants are laced with compounds potent enough to kill livestock and people. Wolfsbane, also called monkshood, has a reputation stretching back to ancient poison lore.

Yet those same compounds have a long medical history. “These plants have been used in different forms of medicine throughout the world for thousands of years,” said Garret Miller, an assistant professor of biotechnology at the University of Michigan-Flint who worked on the study as a researcher at Michigan State University (MSU).

Now Miller and colleagues at MSU and the Czech Academy of Sciences have worked out how the plants begin making these molecules. Writing in Molecular Plant, they describe the entry steps in the biosynthesis of diterpenoid alkaloids, a chemically complex family of compounds with potential uses against pain, malaria, cancer and crop pests.

A chemical puzzle

Diterpenoid alkaloids are among the most intricate molecules found in plants. They are built on a framework of 20 carbon atoms folded into multiple interlocking rings and studded with nitrogen and oxygen. That complexity makes them hard to make in a laboratory.

Aconitine, the best-known compound in the group and the main toxin in wolfsbane, was isolated nearly 200 years ago. Chemists have still not managed to synthesize it. Without a reliable way to produce such compounds, studying them as potential drugs depends on extracting them from plants, which yields variable amounts and limits the chemical modifications researchers can make.

Aconitine acts on sodium channels, the molecular gates that allow nerve and heart cells to fire. By holding those channels open, it can cause numbness, dangerous heart rhythms and, in high enough doses, death. That same ability to interfere with nerve signaling is part of what makes related compounds interesting as potential painkillers, if their effects can be controlled.

“Plants are the best chemists around, upgrading their arsenal of natural compounds over millions of years,” said Björn Hamberger, the James K. Billman Endowed Professor in MSU’s Department of Biochemistry and Molecular Biology and an author of the study.

Hunting for the right genes

To find out how the plants assemble these molecules, the team searched the genetic material of multiple species of larkspur and wolfsbane. They tracked thousands of genes, looking for those that were switched on in the right tissues at the right times to be involved in making the alkaloids.

Biosynthetic pathways work like assembly lines, with each enzyme performing one step before passing its product to the next. Miller explained why finding every enzyme matters. “If you have ten steps in a row needed to build a finished product, and suddenly one quits, the next steps can’t happen,” he said.

Candidate genes then had to be tested. The researchers used tobacco plants as biofactories, introducing the genes from larkspur and wolfsbane to see whether the tobacco would begin making the expected compounds. When the right combination was in place, the tobacco produced a compound called atisinium, an early intermediate in the pathway.

Tobacco plants, particularly the species Nicotiana benthamiana, are widely used as a test system in plant biology. Researchers can quickly introduce genes into its leaves using bacteria, and within days the leaves begin making the corresponding enzymes. That makes it possible to test combinations of candidate genes far faster than by growing modified versions of the original plants.

Six enzymes and a surprise

The work revealed that six distinct enzymes are needed for these entry steps. Together they shape the complex structure at the heart of the molecules. The team also found that the plants draw on an unexpected source of nitrogen to build them, an atom that defines the compounds as alkaloids.

Co-first authors of the study were Miller and Lana Mutabdžija, a graduate student at the Czech Academy of Sciences who works in the lab of Tomáš Pluskal.

From poison to medicine

Many important drugs have come from toxic plants. Digoxin, used to treat heart conditions, comes from foxglove. The cancer drug paclitaxel was first found in the bark of the Pacific yew. In both cases, the dose determines whether a compound harms or heals.

Diterpenoid alkaloids may follow a similar path. Some have been studied for their effects on pain and inflammation, and extracts of wolfsbane are still used in traditional medicine in parts of Asia, although poisonings from improperly prepared remedies remain a concern.

“In an ideal scenario, this could eventually help create new drugs inspired by these natural products,” Mutabdžija said.

The current work covers only the beginning of the pathway. Many more steps are needed to turn atisinium into the complex compounds that give larkspur and wolfsbane their medical and toxic properties, and those enzymes remain to be identified. But knowing the first steps gives researchers a foundation for engineering microbes or plants to produce the molecules, and possibly to make modified versions with better safety profiles.

A similar strategy has worked before. Researchers have engineered yeast to produce artemisinic acid, a precursor of the antimalarial drug artemisinin, and have pieced together the long pathways plants use to make compounds such as the painkiller precursors found in opium poppies. Each success started with identifying the enzymes involved, one step at a time.

Hamberger sees the work as part of a broader shift toward producing complex medicines biologically rather than by chemical synthesis or harvesting wild plants. “Our vision is to provide green, sustainable tools that will allow us harness these plants’ natural power,” he said.

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Notes

1. “Characterization of the entry steps in diterpenoid alkaloid biosynthesis.” Molecular Plant, 2 June 2026. DOI: 10.1016/j.molp.2026.05.022.
2. Michigan State University. “Two deadly flowers have big medical potential.” EurekAlert!, 31 July 2026. https://www.eurekalert.org/news-releases/1138435.

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