Background: The functional potential of the phenolic extract of apple peel in protecting
insulin-producing RINm5F cells under conditions of stress induced by glucose is sparse.
Objective: This study evaluated the in vitro protective effect of the phenolic extracts from apple
peel (Gala and Fuji).
Method: Insulin-producing RINm5F cells were induced by oxidative stress with glucose and hydrogen
peroxide, which simulated cellular damage.
Results: The Gala peel extract had the highest content of phenolic compounds (1299 mg CAE/kg)
and in vitro antioxidant activity (14263 µmol TE/kg). At concentrations above 10 µg/mL the Fuji
peel extract was cytotoxic, whereas the Gala peel extract (10 µg/mL) increased cell viability. The
Gala peel extract showed the potential to protect cells under conditions of stress induced by glucose,
with low intracellular production of superoxide. Under hydrogen peroxide, both extracts did
not have a cytoprotective effect.
Conclusion: The high antioxidant and cytoprotective activities of the apple peels indicated that
they may convey health benefits and should be considered as a valuable source of antioxidants.