Lupane Triterpenes with Antileukemia Activity from <i>Maytenus quadrangulata</i>.

Abstract

<i>Maytenus quadrangulata</i> occurs naturally in the Brazilian biomes Caatinga and Atlantic Forest, and previous studies have demonstrated its potential as a source of bioactive molecules. In light of this, a phytochemical study of the chloroform extract of <i>Maytenus quadrangulata</i> branches was carried out, yielding the new triterpene 30-oxo-2,3-<i>seco</i>-lup-20-(29)-ene-2,3-dioic acid (<b>1</b>) and a mixture containing the new semisynthetic triterpene 25-hydroxy-7-oxofriedelan-3α-yl acetate (<b>2</b>). In addition, seven known compounds were also obtained: friedelan-3-one (<b>3</b>), friedelan-3β-ol (<b>4</b>), friedelan-3α-ol (<b>5</b>), a mixture of long-chain fatty acids of β-sitosterol and lupeol-β-sitosterol alkanoate (<b>6</b>) and lupeol alkanoate (<b>7</b>), friedelane-3,7-dione (<b>8</b>) and 2,3-<i>seco</i>-lup-20-(29)-ene-2,3-dioic acid (<b>9</b>). Structural elucidation of the isolated metabolites was performed using ¹H and ¹³C nuclear magnetic resonance (NMR). The chemical structures of the new compounds, <b>1</b> and <b>2</b>, were confirmed by the analysis of two-dimensional NMR spectra (HSQC, HMBC, COSY, and NOESY). An <i>in vitro</i> cytotoxicity assay against the THP-1 and K-562 leukemia cell lines and an <i>in silico</i> analysis using ADMETLab 3.0 were performed for compounds <b>1</b> and <b>9</b>. The novel triterpene (<b>1</b>) exhibited the highest cytotoxicity and the most favorable drug-like profile, underscoring its potential as an anticancer therapeutic.