Isoflavonoids from Erythrina poeppigiana: Evaluation of Their Binding Affinity for the Estrogen Receptor

• Published in: Journal of natural products (Washington, D.C.) D.C.), 2009-09, Vol.72 (9), p.1603-1607
• Main Authors: Djiogue, Sefirin, Halabalaki, Maria, Alexi, Xanthippi, Njamen, Dieudonne, Fomum, Zacharias Tanee, Alexis, Michael N, Skaltsounis, Alexios-Leandros
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Bolivia; Erythrina - chemistry; Estrogen Receptor alpha - drug effects; Estrogen Receptor beta - drug effects; General pharmacology; Genistein - pharmacology; Humans; Isoflavones - chemistry; Isoflavones - isolation & purification; Isoflavones - pharmacology; Medical sciences; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Plant Bark - chemistry; Plant Stems - chemistry; Structure-Activity Relationship
• ISSN: 0163-3864; 1520-6025
• DOI: 10.1021/np900271m

Five new isoflavones, named 5,4′-dihydroxy-7-methoxy-3′-(3-methylbuten-2-yl)isoflavone (1), 5,2′,4′-trihydroxy-7-methoxy-5′-(3-methylbuten-2-yl)isoflavone (2), 5,4′-dihydroxy-7-methoxy-3′-(3-methyl-2-hydroxybuten-3-yl)isoflavone (3), 3′-formyl-5,4′-dihydroxy-7-methoxyisoflavone (4), and 5-hydroxy-3′′-hydroxy-2′′,2′′-dimethyldihydropyrano[5′′,6′′:3′,4′]isoflavone (5), as well as six known compounds, wighteone (6), 3′-isoprenylgenistein (7), isolupabigenin (8), alpinumisoflavone (9), erypoegin D (10), and crystacarpin (11), were isolated from Erythrina poeppigiana. The structures of the isolated compounds were elucidated on the basis of chemical and spectroscopic analysis. The affinity of these compounds for the estrogen receptors ERα and ERβ was evaluated using a receptor binding assay. While isoprenyl and dimethylpyrano substituents in ring A reduced the affinity of binding to ERβ ca. 100-fold compared to genistein, the isoprenyl substituent in ring B was better accommodated, allowing 7 to bind with ca. 10-fold lower affinity than genistein.