Bioactivity of three plant species native to the Brazilian Atlantic Forest front of microcrustacean Artemia salina. This study aimed to carry out phytochemical and antioxidant properties, and assess, in vitro, the lethality of a leaf extract Trigynaea Schltdl oblongifolia Schltdl (Annonaceae), Ottonia frutescens Trel (Piperaceae), Bathysa australis (St Hill) Hooz (Rubiaceae) front of the microcrustaceans Artemia salina Leach. Extracts were prepared by soaking in 10% methanol (w/v) for seven days at room temperature. The antioxidant activity of extracts was determined by the stable radical DPPH method. The toxicity of the extracts was evaluated against the microcrustaceans A. saline. Extracts of O. frutescens and B. australis showed the following classes of secondary metabolites: Alkaloid, Anthraquinones, Coumarins, polyphenols (tannins), Saponin. The extracts from T. oblongifolia, besides the aforementioned metabolites the presence of flavonoids was detected. The antioxidant activity was observed in 30 minutes, the concentration 24 mg/mL of extract was: O. frutescens -38.3%, T oblongifolia -32.3%, and B. australis -32.1%. The lethal concentration, LC 50 , extracts of A. salina was: O. frutescens -149.75 ± 1.02 mg/mL, T. oblongifolia -148.8 ± 1.74 mg/mL, and B. australis -684 ± 9.04 mg/mL. In this context, we highlight the species, native to the Atlantic Forest, O. frutescens and T. oblongifolia great potential in bioprospecting of biologically active molecules.