Very good information in your publication. In my country Venezuela, Leonotis is a wild plant and can be seen near the roads, but I didn't know about its medicinal properties.
As it happens with most of the compounds of the metabolism of the plants, an excess can bring adverse effects like the ones you point out, when they are extracted. Quite different when parts of the plant are consumed.
Beautiful picturesHello @joanstewart.
Regards
One needs to know how to work with plants, ask local older folk if they have a use for it, or which plants they find useful. Thanks for visiting and sharing that the plant is in your country as well.