Not really. The whole thing with synthetic pesticides is that they are stable. They are literally the same as some natural molecule just modified to be persistant.Thing is if that organic soil your using has kelp-seaweed, Alfalfa, in it you are getting a good dose of PGRs.
Regarding paclobutrazol, there is not naturally occuring gibberilin inhibitor that is useful for horticulture. Natural compounds break down quickly so you would have to spray every day (assuming there's a shelf stable formulation).