Antiproliferative and antioxidant activities of Zephyranthes robusta (Herb. ex Sweet) Baker, a Brazilian Amaryllidaceae

Among medicinally significant botanical families, Amaryllidaceae ranks among the 20 most therapeutically relevant due to its unique alkaloids, which exhibit diverse biological activities, including antitumor and cytotoxic effects [ 1 ]. Zephyranthes robusta (Herb. ex Sweet) Baker is native to Brazil, although it is not endemic. This study aimed to investigate the biological activities of the secondary metabolites, particularly alkaloids, in the bulb and root of Z. robusta . Acid-base partitions were prepared from the crude methanolic extract from the plant’s bulb and root, resulting in five samples. Antioxidant activity was evaluated using ABTS, DPPH, and iron chelating assays. Although overall antioxidant activity was not optimal, the best results were observed in the basic ethyl acetate fraction (AB) for the ABTS assay (IC 50 122.8 μg/mL) and in the ethyl acetate with methanol in basic medium fraction (AM) for the iron chelation test (IC 50 121.3 μg/mL). Cytotoxicity assays using the MTT method on MCF-7 and MCF-10A cell lines revealed dose-dependent and time-dependent behavior. In the MCF-7 cell line, low IC 50 values were recorded for the AB (10.95 μg/mL, 72 h) and AM (9.93 μg/mL, 72 h) fractions, whereas cell viability in the MCF-10A cell line remained high [ 2 ]. Furthermore, selectivity index calculations indicated that the crude extract (EB), ethyl acetate with methanol in acid medium AA, AB, and AM samples exhibited selectivity, with the AB fraction at 72 h showing the highest index (SI 102.283). Funding FAPES – Fundação de Amparo à Pesquisa e Inovação do Espírito Santo/Brazil. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany