Accumulation of reactive
oxygen species in cells leads to oxidative
stress, with consequent damage for cellular components and activation
of cell-death mechanisms. Oxidative stress is often associated with
age-related conditions, as well as with several neurodegenerative
diseases. For this reason, antioxidant molecules have attracted a
lot of attention, especially those derived from natural sources—like
polyphenols and tannins. The main issue related to the use of antioxidants
is their inherent tendency to be oxidized, their quick enzymatic degradation
in biological fluids, and their poor bioavailability. Nanomedicine,
in this sense, has helped in finding new solutions to deliver and
protect antioxidants; however, the concentration of the encapsulated
molecule in conventional nanosystems could be very low and, therefore,
less effective. We propose to exploit the properties of tannic acid,
a known plant-derived antioxidant, to chelate iron ions, forming hydrophobic
complexes that can be coated with a biocompatible and biodegradable
phospholipid to improve stability in biological media. By combining
nanoprecipitation and hot sonication procedures, we obtained three-dimensional
networks composed of tannic acid–iron with a hydrodynamic diameter
of ≈200 nm. These nanostructures show antioxidant properties
and scavenging activity in cells after induction of an acute chemical
pro-oxidant insult; moreover, they also demonstrated to counteract
damage induced by oxidative stress both
in vitro
and
on an
in vivo
model organism (planarians).