The levels of serum NTBI were significantly reduced during the
first 6 months of treatment and slightly increased afterward,
whereas the levels of serum ferritin were nonsignificantly decreased
(Table 3). Curcumin is a bidentate chelator of Fe3+ where the
formation of Fe3+–curcumin complex occurred via the β-diketonate
group [50] with a constant of 1022 in the cell-free system [51]. Since
iron chelators remove NTBI transiently and incompletely [16], it is
possible that this is the reason why serum NTBI or MDA levels in RBC
decreased during the first 6 months, but remained unchanged or
gradually increased up to 12 months. Besides iron-binding, curcumin
modulated proteins involved in cellular iron metabolism [14]. In
response to curcumin, both transferrin receptor 1 and iron regulatory
proteins (IRPs) increased in cultured liver cells. Interestingly, conflict
between increased mRNA and decreased protein levels of ferritin
was also reported indicating another mode of action of curcumin.
This may explain the slight decrease of serum ferritin levels in our
patients.