Not necessarily even if they had a low bp, eg you can heat up MeI (bp <40) in ethanol to the high 70's and the MeI won't boil off, I'm not sure of the exact term (something to do with vapor pressure?) but i just know it doesn't happen. The melting point of harmine is 321C, and 232C for harmaline, so they won't boil in a double boiler (at 100C) and definitely won't boil off in solution. Steam distillation involves steam being generated outside the vessel and piped through the plant material then condensed, so its different to boiling aya which generates a small amount of steam in situ but is very inefficient and wouldn't be expected to carry steam volatile species anywhere.