Some researchers of this family have claimed that the wife Diana mentioned only once by first name in a 1746 Orange County, VA deed record was "Diana Corntassel" the daughter of Chief Corntassel of the Cherokees.
I know of no real documentation for this claim. Although there appear to be claims of Indian and Cherokee blood in many branches of this family, I first saw two problems with this claim - date and location. The famous Chief Corntassel or Old Tassel was commonly said to be born about 1730 (although sometimes earlier) and therfore not old enough to produce an adult daughter living in 1746. Also, although John Bradley later lived in Rutherford County, NC near Cherokee lands, he lived prior to the 1770's in the tidewater areas of Virginia and NC, very distant from contact with Cherokee families. The deed in Orange County Virginia was for a more western county but I believe the land in question was for speculation and they may have never lived in Orange County.
I did find that Chief Corntassel may have been the son of another man named Corntassel and if so, Diana Corntassel, if she existed at all could have been the daughter of the first Corntassel and the sister to Chief Corntassel (Old Corntassel). Even so, the proplem of location still exists.
Cherokee genealogy is difficult because of the lack of written records for the early period. There was a strong verbal tradition just as we find in early Irish or Scottish genealogy. Correlating as many sources as I could I tried to generate a "feasible" genealogy for Diana Corntassel and anyone who wants it can e-mail me and I will send. Keep in mind that this is a highly speculative genealogy. If we are related to this family, they were the Who's Who of Cherokee individuals for that period, including mant leading chiefs and Sequoyah who invented the Cherokee alphabet who I show on my genealogy as the nephew of Diana.