@alunsfor,
The Reset Course endpoint is the simplest for removing all content from a course. A nice bonus for this is when someone accidentally resets a course and you need the content restored, you can recover it from the deleted version of the course. Is there a particular reason you don't want to have the course deleted and a new one made?
Unfortunately, to "reset" a course without deleting it, you would need to go through all the different possibilities for course content (i.e. assignments, quizzes, discussions, pages, files, announcements, modules, etc.) and delete them manually or with API calls.