Cytotoxic isoquinoline alkaloids from the roots of <i>Thalictrum foliolosum</i>

Abstract

Phytochemical investigation on the 70% EtOH extract of the roots of <i>Thalictrum foliolosum</i> DC. resulted in the isolation of three new isoquinoline alkaloids, 5,6,7,12-tetramethoxy-2-methyl-13-hydroxy-11-(4'-methoxycarbonylphenoxy)benzylisoquinoline (<b>1</b>), 5,6,7,12-tetramethoxy-2-methyl-13-hydroxy-11-(4'-carbonylphenoxy) benzylisoquinoline (<b>2</b>), and 3-methoxy-10-<i>O</i>-acetylprodensiflorin B (<b>3</b>). The new structures were elucidated by using spectroscopic data (NMR, IR, UV, and MS). The isolated alkaloids were tested <i>in vitro</i> for cytotoxic potentials against six human lung cancer cell lines (H460, H23, HTB-58, A549, H441, and H2170). As a result, alkaloids <b>1</b> and <b>2</b> exhibited significant cytotoxic activities against all the tested tumor cell lines with IC₅₀ values less than 20 μM.