A hunter's toxic toolkit
In the forests surrounding Dambana, the indigenous Vedda people of Sri Lanka traditionally hunted game using arrows tipped with potent, fast-acting poisons. This ethnobotanical knowledge, passed down through generations, allowed them to create complex paralytic substances from local plants. The primary ingredients for this potent mixture came from two specific trees: the Upas tree (Antiaris toxicaria) and the Goda Kaduru, or strychnine tree (Strychnos nux-vomica).
The preparation involved extracting a thick, milky latex from the bark of the Upas tree. This sap contains cardiac glycosides, particularly the compound antiarin. From the strychnine tree, they sourced seeds that contain powerful indole alkaloids, chiefly strychnine and brucine. These components were combined to create a poison that, upon entering an animal's bloodstream, induced rapid paralysis and convulsions. This effect was critical for hunting, as it immobilized the animal quickly, preventing it from escaping deep into the forest after being struck.
The pharmacology of paralysis
The effectiveness of the Vedda arrow poison lies in the distinct biochemical actions of its two main components. The cardiac glycosides from Antiaris toxicaria, like antiarin, are myocardial poisons. They disrupt the normal function of the heart muscle, leading to cardiac arrest in large enough doses. The poison works only when it enters the bloodstream and is surprisingly harmless if ingested, allowing the hunters to safely consume the meat of their quarry.
The alkaloids from Strychnos nux-vomica operate on the central nervous system. Strychnine is a potent neurotoxin that blocks glycine receptors in the spinal cord. This inhibition of an important neurotransmitter leads to uncontrolled, convulsive muscle contractions. Brucine, a related alkaloid also present in the seeds, is less toxic than strychnine but contributes to the paralytic effect on peripheral motor nerves. The combination of a heart-stopping cardiotoxin and a seizure-inducing neurotoxin made the arrow poison exceptionally effective for hunting. Researchers documented this traditional knowledge before it faded due to changes in the Vedda way of life.