ANTIFUNGAL MELAMPOLIDES FROM LEAF EXTRACTS OF SMALLANTHUS-SONCHIFOLIUS

A new antifungal melampolide, oyl-1(10),4,11(13)-germacuratrien-12,6-o lid-14-oic acid methyl ester, named sonchifolin, as well as three know n melampolides, polymatin B, uvedalin and enhydrin, were isolated from leaf extracts of Yacon [Smallanthus sonchifolius (Poepp. and Endl.) H . Robinson]. Sonchifolin exhibited the highest fungicidal activity aga inst Pyricularia oryzae, a fungus causing rice blast disease and the E D(50) value for the spore germination was 22 ppm. This is the first re port of these melampolides as fungicidal compounds.