Cytotoxic and PTP1B inhibitory activities from Erythrina abyssinica

Bioassay-guided fractionation of the EtOAc extract of the stem bark of Erythrina abyssinica (Leguminosae) resulted in the isolation of three new (1-3), along with 12 known (4-15) pterocarpan derivatives. Their chemical structures were determined by physicochemical and spectroscopic data analysis (IR, UV, [α]D, CD, 1D and 2D NMR, and MS data). All the isolates were evaluated for their inhibitory effects on protein tyrosine phosphatase-1B (PTP1B), as well as their growth inhibition on MCF7, tamoxifen-resistant MCF7 (MCF7/TAMR), adriamycin-resistant MCF7 (MCF7/ADR) and MDA-MB-231 breast cancer cell lines. Compounds which exhibited PTP1B inhibitory activity (IC50 values ranging from 4.2 ± 0.2 to 19.3 ± 0.3 μM) showed strong cytotoxic activity (IC50 values from 5.6 ± 0.7 to 28.0 ± 0.2 μM). Our data suggested that pterocarpans could be considered as new anticancer materials by PTP1B inhibition. © 2009 Elsevier Ltd. All rights reserved.