Ex vivo relaxation effect of Cuscuta chinensis extract on rabbit corpus cavernosum

Asian J Androl. 2013 Jan;15(1):134-7. doi: 10.1038/aja.2012.124. Epub 2012 Nov 12.


The effect of Cuscuta chinensis extract on the rabbit penile corpus cavernosum (PCC) was evaluated in the present study. Penises obtained from healthy male New Zealand white rabbits (2.5-3.0 kg) were precontracted with phenylephrine (Phe, 10 µmol l(-1)) and then treated with various concentrations of Cuscuta chinensis extract (1, 2, 3, 4 and 5 mg ml(-1)). The change in penile tension was recorded, and cyclic nucleotides in the PCC were measured by radioimmunoassay (RIA). The interaction between Cuscuta chinensis and sildenafil was also evaluated. The result indicated that the PCC relaxation induced by Cuscuta chinensis extract was concentration-dependent. Pre-treatment with an nitric oxide synthase (NOS) inhibitor (Nω nitro-L-arginine-methyl ester, L-NAME), a guanylyl cyclase inhibitor (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, ODQ), or a protein kinase A inhibitor (KT 5720) did not completely inhibit the relaxation. Incubation of penile cavernous tissue with the Cuscuta chinensis extract significantly increased cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) in the PCC. Moreover, the Cuscuta chinensis extract significantly enhanced sildenafil-induced PCC relaxation. In conclusion, the Cuscuta chinensis extract exerts a relaxing effect on penile cavernous tissue in part by activating the NO-cGMP pathway, and it may improve erectile dysfunction (ED), which does not completely respond to sildenafil citrate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cuscuta / chemistry*
  • Cyclic GMP / physiology
  • Enzyme Inhibitors / pharmacology
  • Erectile Dysfunction / drug therapy*
  • Herb-Drug Interactions
  • Male
  • Muscle Relaxation / drug effects*
  • Muscle, Smooth / drug effects
  • NG-Nitroarginine Methyl Ester / pharmacology
  • Penile Erection / drug effects*
  • Penis / drug effects*
  • Penis / physiology*
  • Phytotherapy*
  • Piperazines / pharmacology
  • Plant Extracts / pharmacology*
  • Purines / pharmacology
  • Rabbits
  • Sildenafil Citrate
  • Sulfones / pharmacology


  • Enzyme Inhibitors
  • Piperazines
  • Plant Extracts
  • Purines
  • Sulfones
  • Sildenafil Citrate
  • Cyclic GMP
  • NG-Nitroarginine Methyl Ester