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Bioassay-guided fractionation of the EtOAc extract of the root of Erythrina addisoniae (Leguminosae) resulted in the isolation of four new (1-4), along with 2 known prenylated isoflavonoids (5-6). The structures of the isolates were assigned on the basis of spectroscopic data analysis, focusing on interpretation of 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, adriamycin-resistant MCF7 (MCF7/ADR), and MDA-MB-231 breast cancer cell lines. Compounds which exhibited PTP1B inhibitory activity (IC(50) values ranging from 4.6 ± 0.3 to 24.2 ± 2.1 μM) showed potential cytotoxic activity (IC(50) values ranging from 3.97 ± 0.17 to 11.4 ± 1.9 μM). Taken together, our data suggest that prenylated isoflavonoids, especially the isoflavone-type skeleton could be considered as new lead compounds against breast cancer via PTP1B inhibition., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Influenza occurs with seasonal variations and reaches the peak prevalence in winter causing the death of many people worldwide. A few inhibitors of viral neuraminidase, including amantadine, rimantadine, zanamivir, and oseltamivir, have been used as influenza therapy. However, as drug-resistant influenza viruses are generated rapidly, there is a need to identify new agents for chemotherapy against influenza. Therefore, research on more effective drugs has been given high priority. During the course of an anti-influenza screening program on natural products, two new compounds (1 and 2) along with seven known flavonoid derivatives (3-9) were isolated as active principles from an EtOAc-soluble extract of the root bark of Erythrina addisoniae. The stilbenoid (2) and chalcone (3, 4, and 6) compounds of the isolates exhibited stronger activity than the isoflavone ones. Compound 2, which is a formylated stilbenoid derivative, exhibited strong inhibition of both influenza H1N1 and H9N2 neuraminidases with IC(50) values of 8.80±0.34 μg/mL and 7.19±0.40 μg/mL, respectively., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

AMP-activated protein kinase (AMPK) has been proposed as a therapeutic target for the treatment of metabolic syndrome including obesity and type-2 diabetes. The bioassay-guided fractionation of an EtOAc-soluble extract of the stem bark of Erythrina abyssinica led to the isolation of a new coumestan, erythribyssin N (1), and two new benzofurans, erythribyssin F (2) and erythribyssin H (3), along with five known compounds (4-8). When tested for their stimulatory effects on AMPK activity at a concentration of 10 muM, compounds 4 and 5 showed potent activation, while compounds 1, 2, and 7 had moderate effects. These results suggest that benzofurans and coumestans may be new lead compounds for regulating the AMPK enzyme.

Bioassay-guided fractionation of the MeOH extract of the stem bark of Erythrina lysistemon Hutch. resulted in isolation of pterocarpans (1-3), named erylysins A-C, along with nine known pterocarpans (4-12). Their structures were determined to be 3''-hydroxy-2',2'-dimethylpyrano[6',5':3,4]-2'',2''-dimethyldihydropyrano[6'',5'':9,10]pterocarpan (1), furano[5',4':3,4]-9-hydroxy-10-prenylpterocarpan (2), and 8-formyl-3,9-dihydroxy-4,10-diprenylpterocarpan (3), based on spectroscopic analyses. All the isolates, with the exception of 3, 6, and 11, strongly inhibited protein tyrosine phosphatase 1B (PTP1B) activity in an in vitro assay, with IC(50) values ranging from 1.01+/-0.3 to 18.1+/-0.9 microg/mL. This is the first report showing the potential of prenylated pterocarpans as a class of natural PTP1B inhibitors.

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, [alpha](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 (IC(50) values ranging from 4.2+/-0.2 to 19.3+/-0.3 microM) showed strong cytotoxic activity (IC(50) values from 5.6+/-0.7 to 28.0+/-0.2 microM). Our data suggested that pterocarpans could be considered as new anticancer materials by PTP1B inhibition.

Abstract: In the course of our program to search for protein tyrosine phosphatase 1B (PTPB) inhibitors, five new 5-deoxyflavonoids along with eight known derivatives were isolated from EtOAc layer of the root bark of Erythrina abyssinica. Their structures were elucidated on the basis of spectroscopic (IR, UV, MS, CD, 1D- and 2D-NMR) and physicochemical analyses. All isolates exhibited moderate inhibitory effects on the enzyme assay with IC50 values ranging from 14.9±1.6 to 98.1±11.3μM. Compounds with prenyl and methoxy groups in the B ring (1, 2, 4, 8, and 13) possessed strong activity (IC50 14.9±1.6 to 19.2±1.1μM), while compounds (3, 5, and 9) with 2,2-dimethylpyrano ring showed less inhibitory effect (IC50 22.6±2.3 to 72.9±9.7μM). These results suggest that prenyl and methoxy groups may be responsible for the increase on the activity of 5-deoxyflavonoids against PTP1B, but the presence of 2,2-dimethylpyrano ring on the B ring may be induced the decrease of PTP1B inhibitory activity. [Copyright &y& Elsevier]