It has been many years since I have read books on gensing, I have no clue if it possesses potasium iodine, my guess is it is not known for potassium iodine.
I am not sure if the Russians ever wrote "WHY" they believed this, we only know it was used in war time as a preventive and treatment for radiation diseases.
Much of what is written is handed down folk lore because ginseng was the most valuable herb on earth for the longest time, now I swear virgina snake rt is because no one hunts it anymore!