Antiangiogenic Pterocarpan and Flavonoid Constituents of Erythrina lysistemon.

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.

Cornigerin, a new sesqui-lignan from the hepatoprotective fractions of Cynara cornigera L.

The ethanol extract of Cynara cornigera L. was fractionated and the fractions were subjected to hepatoprotective assays using Wistar albino rats at a dose of 500 and 250mg/kg. The liver injury was induced in rats using carbon tetrachloride. Biochemical parameters such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and total bilirubin were estimated as reflections of the liver condition, with silymarin as a positive control. Phytochemical investigation and chromatographic separation of the hepatoprotective fractions led to the isolation of a new sesqui-lignan namely cornigerin (1), along with eight known compounds: apigenin (2), luteolin (3), ß-sitosterol glycoside (4), apigenin 7-O-ß-D-glucopyranoside (5), luteolin-7-O-ß-D-glucopyranoside (6), apigenin-7-O-rutinoside (7), cynarin 1,5-di-O-caffeoylquinic acid (8), and apigenin-7-O-ß-D-glucuronide (9). This is the first report for the isolation of 8 and 9 from this plant.

A new 3-arylcoumarin from the roots of an Egyptian collection of Lotus polyphyllos.

Further investigation of different fractions from Lotus polyphyllos Clarke roots resulted in the isolation of the new 3-arylcoumarin derivative; 4',6'-dihydroxy-7, 2'-dimethoxy-3-arylcoumarin (5). In addition, the known compounds beta-sitosterol, 1-hexacosanol (1), n-tetracosyl p-coumarate (2), 4'-O-methylderrone (4), and quercetin (6) were identified. The structures were determined from spectroscopic data including 1D- and 2D-NMR experiments.

Two new isoflavone derivatives from the roots of an Egyptian collection of Lotus polyphyllos.

Investigation of the roots of Lotus polyphyllos Clarke resulted in the isolation of two new isoflavone derivatives; 4'-O-methylerythrinin C (3) and 4'-O-methyl-2''-hydroxydihydroalpinumisoflavone (4). In addition, the three known isoflavone derivatives 4'-O-methylalpinumisoflavone (1) lupinalbin F (5), 4',7-dimethoxy-5-hydroxyisoflavone (6), and the phenylpropanoid ester tetracosyl p-coumarate (2) were also identified. The structures were determined from spectroscopic data.

Prenylated flavonoids of Erythrina lysistemon grown in Egypt.

Three prenylated flavonoid derivatives; 5,7,4'-trihydroxy-8-(3"'-methylbut-2"'-enyl)-6-(2"-hydroxy-3"-methylbut-3"enyl) isoflavone (isoerysenegalensein E), 5,7,2'-trihydroxy-4'-methoxy-5'-(3"-methylbut-2"-enyl) isoflavanone (lysisteisoflavanone), 5, 4'-dihydroxy-6-(3"'-methylbut-2"'-enyl)-2"-hydroxyisopropyl dihydrofurano [4",5":8,7] isoflavone (isosenegalensin), together with the four known flavonoids abyssinone V-4'-methylether, alpinumisoflavone, wighteone and burttinone were isolated from the stem bark of Erythrina lysistemon Hutch. (Leguminosae). Structures were elucidated by spectroscopic methods.

Two new alkaloids of the crinane series from Pancratium sickenbergeri.

Two new alkaloids; ent-6alpha/6beta-hydroxybuphanisine, (-)-8-demethylmaritidine and seven known alkaloids were isolated from Pancratium sickenbergeri grown in Egypt. Three of the known alkaloids were tested in the NCI cytotoxicity screen, but were found to be inactive.