What is bromelain?

I was in the checkout lane at Publix yesterday and saw a headline on one of the magazines.  The cover page teaser and the article said that you could reduce your sinus symptoms with pineapples, because they contain bromelain.  This is a group of enzymes that digest proteins.  The idea is that bromelain will digest and reduce the mucus present in the sinuses from infections as well as act as an anti-inflammatory medicine.  I am interested in safe, effective and inexpensive treatments for allergic diseases.  However, I can't vouch for bromelain.  Some questions: how does bromelain get from your mouth and stomach into the sinuses? Wouldn't it get digested itself in the gut?  Are there any studies that measure how well bromelain digests nasal or sinus mucus?  Are there any studies the measure the benefit of bromelain in sinus infections?  I couldn't find any.  How would a proteolytic enzyme benefit inside our body cells?  If bromelain is not specific, then would it digest the cells and other structures?

That's it from your Allergy Dude.  Nix on products containing bromelain.  Yix, I mean yes, on fresh fruits without preservatives and additives.  Go back to my nutrition and allergy pyramid please.