Alkaloids and flavone acyl glycosides from Acanthus arboreus

Phytochemical study of Acanthus arboreus resulted in the isolation of three novel alkaloids: 6-hydroxy-benzoxazolinone, 4-hydroxyacanthamine and acanthaminoside. In addition, a new acyl flavonoid apigenin-7-O-beta-D-(6"-trans-p -coumaroyl)-3"-O-acetyl glucopyranoside was also isolated. The known compounds were identified as apigenin, apigenin-7- O-beta-D-(6"-trans-p-coumaroyl) -glucoside, vanillic acid, lupeol, stigmasterol and sitosterol glucoside. The structures were determined by physical, chemical and spectral techniques

Antiangiogenic Pterocarpan and Flavonoid Constituents of <i>Erythrina lysistemon</i>

The roots of Erythrina lysistemon, growing in Egypt, yielded 24 flavonoid compounds, including 17 pterocarpans, two isoflavanones, one flavanone, two isoflavans, one 2-arylbenzofuran, and an isoflava-3-ene. Nine pterocarpans have not been reported previously (7–9, 11–14, 19, and 20), and 11 are reported here for the first time from this species. Structures were established using HRESIMS, NMR, and circular dichroism techniques. Selected compounds were tested for their ability to block the growth of human retinal endothelial cells and antiangiogenic activity in vitro. The isoflavonoids 5 and 6, and the pterocarpans 1, 2, 4, 20, and 22 demonstrated selective antiproliferative activities on endothelial cells compared to a nonendothelial cell type, with concentration-dependent antiangiogenic effects in vitro against HRECs, a cell type relevant to neovascular eye diseases