Evaluation of the rodenticidal effect of Conium maculatum plant extract under laboratory conditions

For centuries, humans have sought ways to manage the populations of house mice, small rodents that can cause significant damage to crops and spread disease. While chemical poisons have long been the standard solution, they often leave behind persistent residues in the environment and can harm other wildlife. This has driven scientists to look toward nature for alternatives, specifically to plants that produce their own chemical defenses. Many plants create toxic compounds called alkaloids, which are nitrogen-based molecules that can disrupt the nervous systems of animals that eat them. The idea is that if a plant can naturally deter or kill pests, its extracts might offer a safer, more biodegradable way to control rodent populations without the long-term environmental baggage of synthetic chemicals.

In a recent study, researchers investigated the potential of a plant known as spotted hemlock, or Conium maculatum, to serve as such a natural rodenticide. This plant, native to regions including the Caucasus, is famous for containing potent alkaloids that are toxic to many animals. The scientists wanted to see if extracts made from this plant could effectively kill house mice, and whether the method used to pull these chemicals out of the plant mattered. They prepared two different versions of the extract: one using alcohol and another using water. They then fed these extracts to mice in a controlled laboratory setting to observe how quickly the poison took effect and what physical signs appeared before the animals died.

The researchers collected the spotted hemlock from the wild in Azerbaijan, drying the plant parts before processing them. For the alcohol-based extract, they soaked the dried plant material in 95% ethanol for two weeks, creating a solution that was stored for eight years before being used in the experiment. For the water-based extract, they boiled the plant roots in distilled water for three hours. They mixed these liquids into small food pellets made of flour and oil, which they offered to ten mice. The mice were divided into groups, with some receiving the alcohol extract, some receiving the water extract, and a control group receiving no extract. The scientists watched the animals closely, recording their behavior, movement, and survival over the next two days.

The results showed that both types of extracts were deadly, but they worked in very different ways. The mice that ate the water-based extract became sick much faster. Within six hours of eating the poisoned food, these animals stopped moving around, began to tremble, and huddled motionless in the corners of their cages. All the mice in this group died within 24 hours. In contrast, the mice that ate the alcohol-based extract took longer to show signs of poisoning. It was not until 24 hours after eating that they began to move weakly and tremble, and they did not die until 48 hours had passed. Despite the difference in speed, the outcome was the same for both groups: the extracts caused severe neurotoxic effects that paralyzed the animals and led to their death.

The study suggests that the speed of the poison depends heavily on how it was extracted. The water-based extract likely contained chemicals that dissolve easily in the stomach and enter the bloodstream quickly, causing a rapid shock to the nervous system. The alcohol-based extract, which had been stored for eight years, may have contained different chemical forms that are absorbed more slowly or accumulate in the body over time, leading to a delayed but equally fatal effect. Interestingly, the mice did not seem to avoid the poisoned food. Even after eating a small amount and stopping, they eventually consumed the rest of the pellets, even as the food dried out. This behavior indicates that house mice do not have a strong instinct to stop eating once they taste something bitter or toxic, making them vulnerable to plant-based poisons.

These findings confirm that spotted hemlock extracts are powerful neurotoxins for house mice, capable of killing them through central nervous system failure. The study highlights that the choice of solvent—whether water or alcohol—drastically changes how quickly the poison works, a factor that would be crucial if someone were to develop this into a practical tool for pest control. While the research was conducted in a laboratory and does not yet prove how these extracts would perform in the wild or over the long term, it provides a clear scientific basis for further exploration. The work supports the idea that plant-derived toxins could offer a viable, environmentally friendly alternative to current chemical methods, provided future studies can optimize the dosage and ensure safety for the wider ecosystem.