Chemical constituents from the heartwood of Haematoxylon campechianum as protein tyrosine kinase inhibitors

Abstract

In a previous study, we showed that a series of homoisoflavonoids from the stems of Haematoxylon campechianum possess potent protein tyrosine kinase inhibitory activity. In a further chemical investigation of the heartwood of H. campechianum, three new homoisoflavonoids, epihematoxylol B (2), 10-O-methylhematoxylol B (3), and 10-O-methylepihematoxylol B (4), were isolated and identified, together with 15 known compounds, including three homoisoflavonoids, three flavonoids, six lignans, and three unsaturated fatty acids. The structures of the new compounds were established on the basis of 1D- and 2D-NMR and other spectroscopic analyses. Using ELISA method, the new compounds and selected known compounds were tested for protein tyrosine kinase inhibitory activity targeting kinase insert domain receptor. Epihematoxylol B (2) and the known compounds, hematoxylol B (1) and hematoxylin (5), exhibited inhibitory rates of 92.22.3, 71.31.1, and 94.81.6, respectively, at 10 μM concentration.

Keywords: Epihematoxylol B; Haematoxylon campechianum; Hematoxylol B, 10-O-methyl-; Homoisoflavonoids; Kinase insert domain receptor (KDR); Protein tyrosine kinases (PTKs).