Small-molecule inhibitors of the cancer target, isoprenylcysteine carboxyl methyltransferase, from Hovea parvicalyx

The roots of Hovea parvicalyx yielded 2′-methoxy-3′-prenyl-licodione ( 1) and 2′-methoxy-3′,3′′-diprenyl-licodione ( 2), two prenylated β-hydroxychalcone compounds, together with the known flavanone ( S)-glabrol ( 3). These compounds showed Icmt inhibitory activity. Isoprenylcysteine carboxyl methyltransferase (Icmt) is enzyme target in anticancer drug discovery. An Icmt natural product high-throughput screening campaign was conducted and a hit extract from the roots of Hovea parvicalyx was identified. 2′-Methoxy-3′-prenyl-licodione and 2′-methoxy-3′,3′′-diprenyl-licodione, two prenylated β-hydroxychalcone compounds, together with the known flavanone ( S)-glabrol, were isolated and identified as bioactive constituents. Their structures were determined largely by 1D and 2D NMR spectroscopy.