Hi all,
        All tea comes from camellia senensis and as  has been pointed out,
some is dried until dehydrated  and some is dried until slightly fermented.
Others are fired either in baskets or pans, though this doesn't mean cooking
them, just drying them further. The study that was done on the good pheynols
was done with green tea, but my understanding (from a local tea maven) is
that they all have the same properties, the study just didn't include black
tea.
From Mac who enjoys a cuppa.