Toxicological safety, antioxidant effect, and chemoprotection determination of an extract from the babassu mesocarp ( <i>Orbignya phalerata</i> Mart.) in preclinical studies

Reactive nitrogen species (RNS) and reactive oxygen species (ROS) play a key role in chronic diseases and aging by initiating protein oxidation, impaired cellular membrane damage and functions, and induction of DNA mutations. When endogenous antioxidants are insufficient to counteract oxidant stress, bioactive compounds might serve as physiological therapeutic agents attributed to their ability to neutralize ROS. The aim of this study was to examine the antioxidant, chemoprotective and toxicological aspects of the hydroethanolic extract from <i>Orbignya phalerata</i> Mart. mesocarp using <i>in vitro</i> and <i>in vivo</i> bioassays. The extract presented 9.9 mg/g of total flavonoids, primarily catechin and epicatechin. This extract exhibited no apparent toxicity upon <i>Artemia salina</i> (LC₅₀ > 1000 μg/ml) or <i>Zophobas morio</i> larvae (LD₅₀ > 3000 mg/kg), low hemolysis, genotoxicity, or mutagenicity utilizing <i>Allium cepa</i> cells. Cytotoxicity effects were observed on in L-929 murine fibroblast only at concentrations above 130 μg/ml. This extract effectively neutralized free radicals [DPPH^• (EC₅₀ 25.3 μg/ml) and ABTS^•+ (EC₅₀ 52.6 μg/ml)] and reduced H₂O_2-initiated effects on <i>Saccharomyces cerevisiae</i>. The chemoprotective activity of this extract was also noted in <i>A. salina</i>, L-929 cells, and <i>S. cerevisiae</i> as evidenced from oxidative damage and toxicity tests results. This constitutes the first report describing the toxicological safety profile of a babassu mesocarp extract a rich source of flavonoids (catechin and epicatechin) with antioxidant and chemoprotective activities.