An expert view on the poisonous plant
Ageratina altissima
Jiří Patočka, Matthew Chidozie Ogwu,
Zdeňka Navrátilová
Ageratina altissima (L.) King & H. Rob, also known as Eupatorium rugosum, is a perennial plant belonging to the Asteraceae family. This plant is native to North America, where it is also known by several indigenous names, such as „white snakeroot“, "snakeroot" or "richweed" (Davis et al., 2015). A. altissima can grow up to around 1.5 meters in height. Its leaves are alternate, long and have a bumpy surface. The inflorescences are composed of small white flowers and are known for their attractive appearance (Fig. 1). At the same time, however, it is important to emphasize that the white snakeroot is also considered a poisonous plant (Sang-Hun et al., 2019). It is often mentioned in connection with fatal poisonings (Stegelmeier & Davis, 2023). Its toxic properties are associated with the content of substances that harm human health and the environment (Davis et al., 2015). white snakeroot is an invasive and aggressive plant in most areas that are not native. It has been introduced as an ornamental plant in some parts of the world but has become a problem in many ecosystems due to its ability to spread rapidly and displace native species.
Figure 1. Flowering North American plant Ageratina altissima.
A. altissima contains several toxic components, among which are mainly pyrrolizidine alkaloids (Bischoff & Smith, 2011). These alkaloids are a group of chemical compounds that are also found in other plants (Smith & Culvenor, 1981). They are known for their hepatotoxic effect and their ability to cause toxic effects in humans, animals, and even insects that feed on these plants (Neuman et al., 2015).
Pyrrolizidine alkaloids harm liver function. The toxic effect is mainly caused by their biotransformation in the body into reactive metabolites that damage liver cells (Xu et al., 2019). These metabolites can react with DNA, proteins, and other cellular components, leading to loss of liver cell integrity, which disrupts normal liver function and can lead to chronic health problems. Consumption or contact with pyrrolizidine alkaloids can cause adverse effects on the digestive system, including nausea, vomiting, and diarrhea (Dubey et al., 2018). Some pyrrolizidine alkaloids are considered to be carcinogens, meaning they may increase the risk of cancer, especially liver cancer, and also have adverse effects on the digestive system (Li et al., 2011).
A substance called tremetol and its oxidation product tremetone are responsible for the acute toxicity of nettle to mammals (Davis et al., 2009, 2015).
Tremetol and tremetone affect the muscles, especially the heart, and cause their degeneration. Cardiac myopathy results in irregular heartbeat due to conduction abnormalities that can result in death. Tremetol accumulates in the milk of animals and reaches their young (cows, goats, horses) with the milk of lactating animals (Olson, et al., 1984; Davis et al., 2016) and humans (Snively & Furbee, 1966), who they drink the milk of cows, goats, etc., grazing in places where the white nettle grows (Panter & James, 1990). Poisoning results in a rapid, irregular heart rate, signs of congestive heart failure, difficulty breathing due to myopathy affecting the respiratory muscles, muscle tremors, uncoordinated movements, and collapse (Hartmann et al., 1963).
In conclusion, A. altissima harbors a potent toxicity that can have severe consequences for both animals, and humans. Livestock, particularly cattle, sheep, and goats, are highly susceptible to white snakeroot toxicity. Consumption of the plant contaminated for age can lead to milk sickness in animals, posing economic and health risks for agricultural communities. Humans can be in directly affected by white snakeroot toxicity through the consumption of dairy products from animals that have ingested the plant. Symptoms of milk sickness include nausea, vomiting, and tremors, making it crucial for health care professionals to beware of the link between symptoms and plant exposure. The plant has some resistance to herbivory contributing to its ecological success. However, the potential for toxicity highlights the delicate balance required in managing ecosystems where the plant is present. Effective management strategies involve both preventive livestock exposure to the plant and rating awareness among communities about the risks associated with A. altissima. This includes proper identification, removal from grazing areas, and education on the historical and contemporary impacts of white snakeroot.
While our understanding of A. altissima and its toxicity has advanced, there is still much to learn. Ongoing research is essential to uncover the plant's interactions with different ecosystems, potential medicinal applications, and strategies for mitigating its impact on both animal and human health.
References
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