Phytochemical Characterization and In Vitro Antioxidant Activity of the Extract and Fractions from Bidens subalternans Leaves

The species Bidens subalternans DC., belonging to the Asteraceae family, is a native plant of Brazil. The objective of this study was to perform preliminary phytochemical characterization and evaluate the antioxidant activity and acute toxicity of the ethanol extract (EE) and leaf fractions of B. subalternans. Phytochemical screening revealed the presence of steroids, saponins, alkaloids, coumarins, flavonoids and tannins. Analysis of the EE and the dichloromethane fraction (DCMF) by gas chromatography–mass spectrometry (GC-MS) suggested the presence of phytol, ethyl esters, fatty acids, terpenoid compounds, stigmasterol, untriacontane, ketones, and loliolide. The presence of chlorogenic acid, cinnamic acid derivatives, coumaric acid derivatives, caffeic acid derivatives, and flavonoids was putatively assigned using high-performance liquid chromatography coupled with a diode-array detector (HPLC-DAD). The ethyl acetate fraction (EAF) and DCMF showed higher levels of total phenolic compounds and flavonoids compared to the EE and hydroethanol fraction (HEF) (EAF > DCMF > EE > HEF). In antioxidant activity assays, the EAF exhibited the greatest potential, followed by the DCMF, EE, and HEF. The results showed no mortality of Artemia salina larvae, indicating an absence of acute toxicity under the tested conditions. This study contributes to the preliminary chemical characterization of B. subalternans, toxicity and antioxidant activity in vitro, highlighting it as a potential source of natural antioxidants.