Insights on Possible Mechanism of Action of Vasorelaxant Activity Exhibited by Fungal Malbrancheamides

Abstract

The alkaloids 1 – 3 biosynthesized by the coprophilous fungus Malbranchea aurantiaca displayed a significant vasorelaxant effect on endothelium-intact rat aortic rings pre-contracted with norepinephrine. This effect was not reduced when indomethacin, atropine or tetraethylamonium were added to the organ bath. Nevertheless, it was reduced in the presence of L-NAME, an inhibitor of the enzyme Nitric Oxide Synthase (NOS), suggesting that the pharmacological action was mediated by a nitrergic mechanism, as predicted by docking studies, were 1 showed a strong affinity by NOS.