Monocrotaline is a naturally occurring toxic pyrrolizidine alkaloid (PA) extracted from Crotalaria plant species. It acts as a defense mechanism against herbivores but can harm both humans and animals.
Where Monocrotaline is Found
Monocrotaline originates from Crotalaria plant species, such as Crotalaria spectabilis and Crotalaria retusa. These plants grow as weeds alongside agricultural crops. During harvest, parts of these toxic plants, including seeds, can mix with grains, contaminating the food supply.
Exposure also occurs through traditional herbal remedies or teas containing Crotalaria plants. Despite known toxicity, some Crotalaria species are still used in folk medicine in regions like Colombia. This highlights the need for careful identification and handling.
How Monocrotaline Damages the Body
Monocrotaline is not directly toxic; its harmful effects begin after liver metabolism. Liver enzymes convert it into reactive pyrrolic metabolites, the actual toxic agents. These metabolites damage cells by binding to DNA and proteins.
The liver is a primary target, where toxic metabolites cause hepatic veno-occlusive disease (HVOD). HVOD blocks small liver veins, impeding blood flow. The lungs are also affected, as reactive metabolites travel from the liver via the bloodstream, causing pulmonary hypertension. This condition involves high blood pressure in lung arteries, straining the heart.
Identifying Monocrotaline Poisoning
Monocrotaline poisoning symptoms primarily reflect liver and lung damage. Liver damage may present as abdominal pain, nausea, vomiting, and jaundice (yellowing of skin and eyes). Other indicators include an enlarged liver (hepatomegaly) and fluid accumulation in the abdomen (ascites).
When lungs are affected, individuals may experience shortness of breath, fatigue, and chest pain. Diagnosis involves a patient’s history, especially recent consumption of unknown herbal products or contaminated food. A physical examination, laboratory tests (like liver function tests), and imaging studies help confirm diagnosis and assess organ damage.
Addressing Monocrotaline Exposure
Currently, no specific antidote exists for monocrotaline poisoning. Treatment focuses on supportive care, managing symptoms and complications from organ damage. Diuretics may reduce fluid retention, and medications can help manage pulmonary hypertension.
Prevention is the most effective approach. Public education can raise awareness about risks of consuming unidentified herbal products or contaminated foods. Implementing agricultural practices, such as controlling Crotalaria plant growth in crop fields and animal feed, helps prevent contamination and protects health.