If we treat NHDF cells with ascobic acid for 1 hour at 33ug/mL and then irradiate the cells with a low dose of UVA we see a good antioxidant response and cell viability does not change compared to non-irradiated NHDF cells. However, if we followed this procedure but with a incubation of ascorbic acid for 24 hours, after irradiation we were unable to detect an antioxidant effect and we also observed an increase in cell viability.

We know that ascorbic acid can reduce our cell viability reagent, but we do not know why its antioxidant effect and viability depend on its incubation time. Do you have any idea?