I have several ancestors who were Grand Prince or the like in my family tree. One has to remember, that there accounted kingdoms and Principalities during the course of Ukrainian history. I am no talking about small tow and three county sized states, either. Some of the ruling families were in the period just after the fall of Rome, and others were several centuries down the pike; some of which are Viking in origin. Just as other European Royal Families have loss power, they have NOT lost their status nor is their blood any less royal that it was.
There is a no difference between a reigning royal family and a non reigning royal family except the "reigning" part - the royal remains the same as does the rights, courtesies and status as a member of the "Royal Families Club". Thus, anyone with such ancestry from the Ukraine HAS royal blood in them.