The first ACE inhibitor added to western pharmacology for hypertension was the molecule captopril. This was isolated as the active ingredient in pit viper venom

The first ACE inhibitor added to western pharmacology for hypertension was the molecule captopril. This was isolated as the active ingredient in pit viper venom which causes the snake's victim to calm down, and was used as a traditional medicine by some Brazilian indian tribes. It also functions as an anxiolytic, though is not prescribed for that in western medicine. The drug doesn't use the paralysis agent or toxin from the snake, which the raw venom still contains and thus has certain notable side effects. Remaining side effects of captopril were removed by testing alterations to the molecule and the altered result, called lisinopril, is now the primary treatment for hypertension. It's not clear if the venom from east indian snakes used medically contains the same ACE inhibitor captopril as west indian snakes, but it may be a related molecule. In any case articles and some discussions of east indian snake treatments seem to often position venom as some sort of illicit narcotic that is being used and abused, and candidates for criminalization/regulation, as opposed to what it likely really is: a natural medicine which not only works to treat anxiety, hypertension, and addiction, but best practice modern pharmacological solutions were inspired by and directly developed from these natural medicines. People don't call captopril a narcotic or heroin substitute, which is interesting.