Leualacin, a novel calcium blocker from Hapsidospora irregularis. I. Taxonomy, fermentation, isolation, physico-chemical and biological properties.

Abstract

A new calcium blocker, designated leualacin, has been isolated from Hapsidospora irregularis. The compound inhibits the binding of 3H-nitrendipine, a well known synthetic calcium blocker, to cardiac Ca channel in a competitive manner, although its structure is completely different from dihydropyridines.