Mayapple (Podophyllum peltatum) is a herbaceous perennial which is native to North America. It colonizes by rhizomes and is often found in moist and dry woodland areas. The plant has glossy green, umbrella-like leaves and showy, apple blossom-like flowers which bloom early spring.
The leaves, roots, and unripe fruit from the mayapple plant contain podopyllotoxin, which is toxic to horses. The quantity of the toxin in the plant is increased at the time of flowering. The ripe fruit is not toxic. Podophyllotoxins are readily absorbed through intact skin and the digestive tract. The toxicity of podophyllotoxin is attributed to its binding to receptor sites on tubulin, thereby blocking cell division and cellular protein synthesis in a similar manner to colchicine found in the autumn crocus. Ingestion of large amounts of the mayapple can result in the onset of neurologic signs, liver degeneration, and bone marrow dysfunction.
- Neurological Signs