Chemical constituents and cytotoxic activity of Miconia burchellii Triana (Melastomataceae) leaves

Miconia is the largest genus of the flowering plant family Melastomataceae and is widely distributed in the American continent. However, despite its size and widespread distribution, there are few studies on its phytochemical composition and biological activities. Therefore, the aims of this study were to isolate and identify the constituents of Miconia burchellii Triana (Melastomataceae) leaves, and assess their in vitro antiproliferative activity. Phytochemical study allowed the characterization of eight compounds: pheophorbide A ethyl ester (1), kaempferol (2), kaempferol-3-O-β-glucopyranoside (3), kaempferol-3-O-β-galactopyranoside (4), oleanolic acid (5), ursolic acid (6), lupeol (7) and β-sitosterol (8). The ethyl acetate fraction showed potent cytotoxic activity against four of five tumor cell lines tested and compound (1) was cytotoxic against leukemia cell lines (IC50 4.74 μg mL−1), although neither the fraction nor the compound (1) showed selectivity between tumor and non-tumor lines. To the best of our knowledge this is the first study to report on the chemical composition and biological activity of M. burchellii and this is the first case in which cytotoxic activity is attributed to pheophorbide A ethyl ester.