Friedelane-Type Triterpenoids from Maytenus quadrangulata as Potential Anticancer Agents

Maytenus quadrangulata is a species endemic to the Atlantic Forest in Brazil. While the pharmacological potential of the Maytenus genus is well-documented, specific phytochemical studies on M. quadrangulata remain limited, although previous investigations have identified triterpenes with significant cytotoxic effects. In this study, five new acetylated triterpenoid derivatives, namely, friedelane-3α,29-diyl diacetate (1), friedelane-3α,11β-diyl diacetate (2), friedelane-3α,25-diyl diacetate (3), 3β-hydroxyfriedelane-24-yl acetate (4), and 11β-hydroxyfriedelane-3α-yl acetate (5), were obtained by acetylation of a triterpenoid mixture from the chloroform extract of M. quadrangulata leaves. Additionally, 12 known compounds were identified from this extract. The structural elucidation was performed using spectroscopic (IR, NMR) and spectrometric (MS) techniques. The cytotoxic activity of the isolated triterpenes was assessed on leukemia (K-562, THP-1), breast cancer (MDA-MB-231), and epithelial lung carcinoma (A549) cell lines. Among the tested compounds, compound 5 showed a more pronounced effect against the K-562 chronic myeloid leukemia cell line . Furthermore, all tested compounds exhibited moderate cytotoxic activity against the A549 epithelial lung carcinoma cell line. The antiviral potential of the isolated compounds was also evaluated against Zika virus (ZIKV), along with the activity against phytopathogenic fungi Alternaria alternata, Botrytis cinerea, and Fusarium oxysporum; however, no significant inhibitory effects were observed. Collectively, this study provides a detailed characterization of the bioactive triterpenoids from M. quadrangulata, reinforcing its relevance as a potential source of cytotoxic natural products.