It's interesting but I just learnt that bracken ferns cause stomach cancer. Even milk from bracken fed cows cause cancer. So I don't think it is as simple as boiling the plant.
Bracken is everywhere and there is a temptation to try cooking it for food because of its abundance but now you know that it is one of the few plants known to be a carcinogen.
Quite scary when you think about it but so there are plants out there that can trigger cells to divide uncontrollably. Now if only there was a plant that reverses or nullifies the process