In Vitro Biological Activities of Piper corcovadensis C.DC.: Antioxidant, Antineoplastic-Related and Antibacterial...

Oxidative stress, caused by excessive reactive oxygen (ROS) and nitrogen species (NOX), is linked to degenerative, inflammatory, and cancer-related conditions. Piper corcovadensis, a South American native plant, is recognized for its bioactive compounds. This study investigated the total phenolic content (TPC) by the Folin-Ciocalteu method, antioxidant activity (AA), cytotoxicity, and antimicrobial and anti-inflammatory effects of its extract. AA was determined by the ABTS, DPPH, and FRAP assays. Cytotoxicity was evaluated on SK-MEL-28 melanoma cells through the MTT assay. Oxidative stress biomarkers (ROS, NOX), protein thiols (PSH), and non-protein thiols (NPSH) and inflammatory mediators (NLRP3, IL-6, TNF) were analyzed by RT-qPCR at 50, 500, and 5000 μg mL^-1. Antibacterial activity against Bacillus subtilis, Escherichia coli, Listeria monocytogenes, and Salmonella Typhimurium was assessed using MIC and MBC. The extract showed 11.64 mg GAE g^-1 and AA of 33.15 mM Trolox g^-1 (ABTS), and 21.27 mM Trolox g^-1 (DPPH). At 500 and 5000 μg mL^-1, it reduced SK-MEL-28 viability and decreased ROS, NOX, and PSH. At 5000 μg mL^-1, it downregulated NLRP3 and IL-6 while upregulating TNF. MIC and MBC were > 5 mg mL^-1 for all strains and showed no antibacterial activity at the tested concentrations. However, the extract of Piper corcovadensis exhibits significant in vitro bioactivity, particularly in antioxidant capacity, modulation of oxidative stress markers, and effects on melanoma cell viability.