ISSN 2326-7267
International Journal of Pharmacy and Pharmacology ISSN: 2326-7267 Vol. 2 (6), pp. 001-008, June, 2011. © International Scholars Journals
Full Length Research Paper
Nitric oxide producing effect of six extracts from Harungana madagascariensis Lam. ex Poiret (Guttiferae) stem bark
E. O. Iwalewa1,2*, V. Naidoo3, V. Bagla2 and J. N. Eloff2
1Department of Pharmacology, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria.
2Phytomedicine Programme, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria.
3Section of Pharmacology and Toxicology, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa.
Accepted 12 April, 2011
Abstract
Preliminary pharmacological screening of the aqueous extract from the leaves, stem and root of Harungana madagascariensis Lam. ex Poiret (Guttiferae) are reported to have effect on some cardiovascular diseases like bleeding, cadiopathy, hematuria, and other complications. However, the mechanism underlying its therapeutic effect is not known. The effects of six extracts from the stem bark of H. madagascariensis on equine platelets and chicken hepatocyte cells were explored to examine the involvement of nitric oxide (NO) in platelet aggregation and cell viability capacity. Extracts exhibited concentration dependent platelet aggregation, and synergistically increased NO synthesis in platelets pre-treated with NO and prostaglandin (PG) inhibitors (L-NAME and ASA). The ED50 values observed in the extracts of H. madagascariensis extracts in this study were potentiated and the graphs were shifted to the left in the presence of both inhibitors. However, a contrary effect was observed in berberine, in which its ED 50 was shifted to the right non-competitively by the inhibitors. These results demonstrate that extracts from the stem of H. madagascariensis stimulates NO release and this may be a mechanism whereby the constituents of the plant elicit its therapeutic effects in herbal medicine. This study may have relevance in hemostasis, thrombosis and cancer chemotherapy.
Key words: Harungana madagascariensis; nitric oxide; equnine platelets, chicken hepatocyte cells, cytotoxicity