Identification and Biological Characteristics of an Antifungal Compound Extracted from Cocklebur (Xanthium strumarium) against Phytophthora drechsleri

Abstract

Crude extract of Xanthium strumarium inhibited mycelial growth and zoospore germination of Phytophthora drechsleri, the causal agent of Atractylis rot, in vitro. Fresh sap from X. strumarium at 50-fold dilution was highly effective in controlling the disease Incidence in pot and field trials. Purified extracts from cocklebur Inhibited mycelial growth and zoospore germination in vitro at a concentration of 12.5 <TEX>$\mu\textrm{g}$</TEX>/ml and 15.6 <TEX>$\mu\textrm{g}$</TEX>/ml, respectively. Hyphal tips affected by the compound showed malformation. The antifungal compound puri- fied fromX. strumarium was identified as 4-oxo-1 (5), 2,11, (13)-xanthatriene-12,8-olide, known as "deacetyl xanthumin".min".uot;.