Ethanol extract of seeds of Oenothera odorata induces vasorelaxation via endothelium-dependent NO-cGMP signaling through activation of Akt-eNOS-sGC pathway

J Ethnopharmacol. 2011 Jan 27;133(2):315-23. doi: 10.1016/j.jep.2010.09.024. Epub 2010 Oct 27.

Abstract

Aim of study: The vasorelaxant effect of ethanol extract of seeds of Oenothera odorata (Onagraceae) (one species of evening primroses) (ESOO) and its mechanisms involved were defined.

Materials and methods: Changes in vascular tension, guanosine 3',5'-cyclic monophosphate (cGMP) levels, and Akt expression were measured in carotid arterial rings from rats. Seeds of Oenothera odorata were extracted with ethanol (94%) and the extract was filtered, concentrated and stored at -70°C.

Results: ESOO relaxed endothelium-intact, but not endothelium-denuded, carotid arterial rings in a concentration-dependent manner. Similarly, ESOO increased cGMP levels of the carotid arterial rings. Pretreatment of endothelium-intact arterial rings with L-NAME, an inhibitor of nitric oxide synthase (NOS), or ODQ, an inhibitor of soluble guanylyl cyclase (sGC), blocked the ESOO-induced vasorelaxation and increase in cGMP levels. Nominally Ca(2+)-free but not L-typed Ca(2+) channel inhibition attenuated the ESOO-induced vasorelaxation. Thapsigargin, Gd(3+), and 2-aminoethyl diphenylborinate, modulators of store-operated Ca(2+) entry (SOCE), significantly attenuated the ESOO-induced vasorelaxation and increase in cGMP levels. Further, wortmannin, an inhibitor of Akt, attenuated the ESOO-induced vasorelaxation and increases in cGMP levels and phosphorylated Akt2 expression. K(+) channel blockade with TEA, 4-aminopyridine, and glibenclamide attenuated the ESOO-induced vascular relaxation.

Conclusion: Taken together, the present study demonstrates that ESOO relaxes vascular smooth muscle via endothelium-dependent NO-cGMP signaling through activation of the Akt-eNOS-sGC pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism
  • Calcium Channel Blockers / pharmacology
  • Carotid Arteries / drug effects
  • Carotid Arteries / physiology
  • Cyclic GMP / metabolism
  • Ethnopharmacology
  • Guanylate Cyclase / metabolism
  • Hypertension / drug therapy
  • In Vitro Techniques
  • Male
  • Medicine, Korean Traditional
  • Models, Biological
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / physiology
  • Nitric Oxide / metabolism
  • Nitric Oxide Synthase Type III / metabolism
  • Oenothera* / chemistry
  • Phytotherapy
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology
  • Plants, Medicinal / chemistry
  • Potassium Channel Blockers / pharmacology
  • Proto-Oncogene Proteins c-akt / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Seeds / chemistry
  • Signal Transduction / drug effects
  • Vasodilation / drug effects*

Substances

  • Calcium Channel Blockers
  • Plant Extracts
  • Potassium Channel Blockers
  • Nitric Oxide
  • Nitric Oxide Synthase Type III
  • Nos3 protein, rat
  • Proto-Oncogene Proteins c-akt
  • Guanylate Cyclase
  • Cyclic GMP
  • Calcium