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Evidence-Based Complementary and Alternative Medicine
Volume 2012 (2012), Article ID 137386, 6 pages
Research Article

Erectogenic Effects of Clerodendron capitatum: Involvement of Phosphodiesterase Type-5 Inhibition

1Faculty of Medicine, University of Malaya, Petaling Jaya, Kuala Lumpur 50603, Malaysia
2Medicinal and Aromatic Plants Institute, National Centre for Research, Khartoum 1111, Sudan
3Department of Pharmacology, Faculty of Pharmacy, University of Khartoum, Khartoum 1111, Sudan
4UPM-MAKNA Cancer Research Laboratory, Institute of Biosciences, University of Putra Malaysia, Serdang, Selangor 43400, Malaysia
5Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia

Received 10 February 2011; Accepted 4 April 2011

Academic Editor: Pradeep Visen

Copyright © 2012 Siddig Ibrahim Abdelwahab et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Clerodendron capitatum (Willd) (family: verbenaceae) is locally named as Gung and used traditionally to treat erectile dysfunction. Therefore, the current study was designed to investigate the erectogenic properties of C. capitatum. The relaxation effect of this plant was tested on phenylephrine precontracted rabbit corpus cavernosum smooth muscle (CCSM). The effects of C. capitatum were also examined on isolated Guinea pig atria alone, in the presence of calcium chloride (Ca2+ channel blocker), atropine (cholinergic blocker), and glibenclamide (ATP-sensitive K+ channel blocker). These effects were confirmed on isolated rabbit aortic strips. The extract, when tested colorimetrically for its inhibitory activities on phosphordiesterase-5 (PDE-5) in vitro towards p-nitrophenyl phenyl phosphate (PNPPP), was observed to induce significant dose-dependent inhibition of PDE-5, with an ID50 of 0.161 mg/ml ( 𝑃 < . 0 5 ). In conclusion, our results suggest that C. capitatum possesses a relaxant effect on CCSM, which is attributable to the inhibition of PDE-5, but not mediated by the release calcium, activation of adrenergic or cholinergic receptors, or the activation of potassium channels.