Antioxidant and antiangiogenic activity of Astronium graveolens Jacq. leaves.

Angiogenesis is involved in many physiological and pathological conditions. Natural compounds with antioxidant activity have also been reported to possess potent antiangiogenic properties by regulating angiogenesis modulators such as vascular endothelial growth factor (VEGF). Based on this, we screened the antioxidant and antiangiogenic activities of Astronium graveolens leaf extracts by a DPPH test and a competitive enzyme-linked immunosorbent assay, respectively.

Bioassay-guided isolation of proanthocyanidins with antiangiogenic activities.

The proangiogenic members of the vascular endothelial growth factor (VEGF) family and related receptors play a central role in the modulation of pathological angiogenesis. In order to identify plant compounds able to interfere in the VEGFs/VEGFR-1 (Flt-1) recognition by VEGF family members, the extracts of the aerial parts of Campsiandra guayanensis and Feretia apodanthera were screened by a competitive ELISA-based assay. By using this bioassay-oriented approach five proanthocyanindins, including the new natural compounds (2S)-4',5,7-trihydroxyflavan-(4β→8)-afzelechin (1) and (2S)-4',5,7-trihydroxyflavan-(4β→8)-epiafzelechin (2) and the known geranin B (3), proanthocyanidin A2 (4), and proanthocyanidin A1 (5), were isolated.

New flavonoid glycosides from Vernonia ferruginea.

Four new flavonoid glycosides, quercetin 3-O-beta-D-xylopyranosyl-(1-4)-beta-D-glucopyranoside, quercetin 3-O-beta-D-apiofuranosyl-(1-4)-beta-D-glucopyranoside, kaempferol 3-O-beta-D-apiofuranosyl-(1-4)-beta-D-glucopyranoside, and kaempferol 4'-methyl ether 3-O-beta-D-xylopyranoside, along with other known flavonoids and phenolic derivatives, were isolated from the leaves of Vernonia ferruginea Less. Their structures were established on the basis of detailed spectral analysis.