..i was reminded by new member 
caracas in their intro. essay of the US species 
Peganum mexicana..
it seems that this paper has info. on it's contents..
"Upper motor neurone effects in sheep of some beta‐carboline alkaloids identified in zygophyllaceous plants" CA Bourke, MJ Carrigan… - Australian veterinary …, 1990..
Quote:... At least 5 of these contain mixtures of the following beta-carboline alkaloids: harmane,
tetrahydroharmine, harmine, harmaline, harmol, harmalol ... Peganum harmala
or African rue (Moran et al 1940; Kingsbury 1964; Bailey 1979), Peganum mexicanum or Mex ...
  ..does anyone have the full text..?