Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Structure and fungicidal activity of four pseudoguaianolides isolated from Helenium quadridentatum Labill.

Abstract

The leaves and stems have been widely used in Mexican folk medicine for the treatment of colds, stomach-aches and swelling, and as a diuretic and an insecticide. A new pseudoguaianolide, quadridenin, and three known pseudoguaianolides, thurberilin, tenulin, and 6-O-angeloylplenolin, were isolated from the foliage. Of these, quadridenin exhibited the most potent fungicidal activity against Pseudoperonospora cubensis, a causative fungus of cucumber downy mildew.