A Brazilian snake's venom led to a blood pressure pill

In 1965, a Brazilian pharmacologist described a venom factor that boosted bradykinin; later work in London showed it blocked an enzyme the body uses to keep vessels constricted. That discovery set off a search for a drug that could do the same thing on command.

Researchers tested the venom factor against isolated guinea pig ileum and perfused animal lungs, then purified it down to its active peptide fragments. Chemists at a pharmaceutical company used those fragments as a template to design a small synthetic molecule that blocked the same enzyme without requiring snake venom at all.

That molecule became captopril, approved in 1981 as the first in a class of blood pressure drugs now taken by hundreds of millions of people. It also became the template for how a defensive venom peptide could be reverse-engineered into a pill, a strategy since repeated with venoms from cone snails and other animals.

A predator's weapon, turned into a daily pill.