Chemical composition and biological activity of ethanolic leaf extract from Tillandsia usneoides in a murine model of acute myeloid leukemia

Medicinal plants constitute a valuable reservoir for discovering novel therapeutic compounds that target leukemia and various other forms of cancer. Plants of the genus Tillandsia, such as T. recurvata, have different ethnobotanical uses, including the treatment of hemorrhoids, gastritis, arthritis, ulcers, sore throats, cancer, and diabetes. Specifically, T. usneoides has been used by the indigenous Zenúes in the Urabá region for diabetes management. However, few studies have been published on T. usneoides. The aim of this work was to determine the chemical composition of T. usneoides extracts and evaluate their biological activity in vitro and in vivo in a murine model of acute myeloid leukemia. The chemical composition of the extracts and fractions were analyzed by chromatographic techniques revealed the presence of cycloartane-type triterpenes and methoxylated flavonoids. The in vitro cytotoxic effects on the breast cancer (4T1 and MCF-7), melanoma (B16-F10), and leukemia (K562 and DA-3/ER-GM) cell lines of the ethanolic extract and fractions were evaluated. Furthermore, T. usneoides extract decreased the proliferation rate of DA-3/ER-GM cells, as well as their glucose consumption, and exerted a pro-oxidant effect. Despite the in vitro cytotoxic effects exerted on the murine leukemia cell line, the ethanolic extract of T. usneoides did not exhibit antitumor activity in a murine model of acute myeloid leukemia, which suggests that ex vivo analysis has no direct correlation with the in vivo effect. This observation also highlights the role of the microenvironment in regulating the activity of antitumor molecules, particularly the extract studied here. Therefore, for the development of phytomedicines, as for other antitumor molecules, extensive in vitro and in vivo analyzes are warranted to demonstrate the various interactions necessary to control tumor growth.