Endothelium-independent and endothelium-dependent vasorelaxation by a dichloromethane fraction from &lt;i&gt;Anogeissus leiocarpus&lt;/i&gt; (dc) &lt;i&gt;guill&lt;/i&gt;. Et &lt;i&gt;Perr. (combretaceae)&lt;/i&gt;: possible involvement of cyclic nucleotide phosphodiesterase inhibition
African Journal of Traditional Complementary and Alternative Medicines