Planta Med 2006; 72(5): 468-470
DOI: 10.1055/s-2005-916236
Letter
© Georg Thieme Verlag KG Stuttgart · New York

Inhibition of cGMP-Phosphodiesterase-5 By Biflavones of Ginkgo biloba

Mario Dell’Agli1 , Germana V. Galli1 , Enrica Bosisio1
  • 1Department of Pharmacological Sciences, Faculty of Pharmacy, Milan, Italy
Further Information

Publication History

Received: June 15, 2005

Accepted: September 26, 2005

Publication Date:
20 January 2006 (online)

Preview

Abstract

Ginkgo biloba dimeric flavonoids (GBDF) were shown to inhibit cAMP phosphodiesterase activity and to promote vasorelaxation. In particular, amentoflavone exhibited endothelium-dependent relaxation of rat aorta rings via enhanced generation and/or increased biological activity of nitric oxide, leading to elevated cGMP levels. The aim of this study was to investigate whether GBDF were able to inhibit cGMP-specific phosphodiesterase-5 (PDE5) as well. Human recombinant PDE5A1 was prepared by expression of the full-length cDNA of PDE5A1 in COS-7 cells. The PDE activity was determined in the presence of biflavones at 0.1 - 100 μM. All biflavones inhibited PDE5A1 in a concentration-dependent fashion, ginkgetin being the most potent (IC50 = 0.59 μM). The ability to inhibit the enzyme followed this order: ginkgetin > bilobetin > sciadopitysin > amentoflavone > sequoiaflavone. These data suggest that GBDF could exert a vasodilating effect through a mechanism independent of NO release.

References

Mario Dell’Agli

Department of Pharmacological Sciences

Faculty of Pharmacy

Via Balzaretti 9

20133 Milan

Italy

Phone: +39-(0)2-5031-8345

Fax: +39-(0)2-5031-8391

Email: mario.dellagli@unimi.it