I'm not sure we know. There are some species of Salvia that are actively poisonous, even to the point of being used as drugs.

Thanks for the interesting question.

There are hundreds of types of mint that grow all around the world. Some mints gain their strong flavor because they produce menthol. Mint plants that produce the most menthol have the strongest mint flavor, including wild mint.

Mint oil since ancient times has been used to treat upset stomachs and to help with aches and pains on the skin. Today, the strongest mint flavor is found by taking the menthol put of mint plants and concentrating it. This is how strong minty flavors like in toothpaste and gum are made.