Despite the antioxidant potential of vitamin A, recent studies reported that chronic retinol ester supplementation can also exert pro-oxidant effects and neurotoxicity in vivo and raises the mortality rates among healthy subjects. Our aim was to find evidence for a safer (i.e., less toxic) molecule with provitamin A activity. Therefore, we investigated whether chronic supplementation of healthy Wistar rats with β-carotene (0.6, 3, and 6 mg/kg/day) would demonstrate antioxidant characteristics without leading to pro-oxidant side effects in the brain. Total reactive antioxidant potential (TRAP), thiobarbituric reactive species level (TBARS), and total reduced thiol content (SH) were evaluated in plasma. TBARS and SH were additionally evaluated in selected brain regions together with superoxide dismutase (SOD) and catalase (CAT) activity. In the present study, we show that β-carotene is able to exert antioxidant activity in plasma without triggering pro-oxidant events in the brain, providing evidence that may justify its further evaluation as a safer nutritional supplement with provitamin A activity.

Remirea maritima is a tropical plant with a reticulated root system belonging to the family Cyperaceae, also known to have biologically active secondary metabolites. However, very few data on R. maritima’s biological actions are available and there are no reports regarding the redox-active profile of this plant. In this study, we examined the total phenolic content of Remirea maritima hydroalcoholic (RMHA) extracts, redox properties against different reactive species generated in vitro and their cytotoxic effect against fibroblasts (L929) and melanoma (B16F10) cells. Total reactive antioxidant potential index (TRAP) and total antioxidant reactivity (TAR) results revealed that RMHA at all concentrations tested showed significant antioxidant capacity. RMHA was also effective against hydroxyl radical formation, reduction of Fe³⁺ to Fe²⁺ and in scavenging nitric oxide (NO) radicals. In vitro, the level of lipid peroxidation was reduced by RMHA extract and the data showed significant oxidative damage protection. The RMHA cytotoxicity was evaluated by a neutral red assay in fibroblast (L929) and melanome (B16F10) cells. The obtained results showed that the RMHA (40 and 80 µg/mL, respectively) reduced 70% of the viable cells. In conclusion, this study represents the first report regarding the antioxidant and anti-proliferative potential of R. maritima against B16F10 melanoma cells.