Just read that tobacco contains haramine, anyone confirm this? Anyone know the percentage?

Not sure about harmine, I know tobacco contains harmane, norharmane, and some related alkaloids. Google & Google scholar searches for tobacco + harmane provides details.

I heard it mentioning that smoking can prevent altzheimer's. But i always figured that's simply because smokers die young .

Isn't it just certain types of tobacco that contain these alkaloids?

I can't think which ones do and which don't as there are so many varieties, but I'm fairly sure it's not across the board.

Nicotiana tabacum is the main commercially available tobacco right? I'm pretty sure that one doesn't contain Harmaloids, however I believe Rustica (mapacho) does. No clue about any other species.

That's pretty much the extent of my knowledge on tobacco

^^That's what I have heard/read too, although I'm not a tobacco expert. I think it is only the Amazonian mapacho tobacco Nicotiana rustica that is interesting from a harmaloids angle. Certainly this species contains a few different harmaloids, as well as much higher quantities of nicotine.

I am not familiar enough with chemistry, yet, to come to my own conclusions. So, will the other alkaloids in these tobaccos adhere to the chlorides from NaCl, using the rue salt extraction? Could you get just harmoliods from it?

Honestly, it's probably not worth it.

Although it's possible that the manske reaction will favour the alkaloids in question, for harmaloids you will definately get more bang for your buck with peganum harmala.