I know that this is true of (roasted) coffee but haven't been able to find any reliable information about mate in its smoked or steamed state. Thank you.
After a bit of research I can say that Yerba mate does not contain beta-carbolines. Now, I don't know if this makes you happy or sad but the tea has many antioxidant properties which makes it good for health. You can find a list of the components in Yerba mate in paper 1 and this article.