Identification of phytotoxins produced by Drechslera portulacae, a pathogen of purslane (Portulaca oleracea). I. Isolation of methyldihydroxyzearalenone and its herbicidal activity.
A zearalenone derivative, methyldihydroxyzearalenone, was isolated from D. portulacae. It was characterized as 3,4,5,6,9,10-hexahydro-8,9,16-trihydroxy-14-methoxy-3-methyl-1H-2-benzoxacyclotetradecine-1,7(8H)-dione on the basis of spectral analysis. Treatment of Echinochloa crus-galli and Abutilon avicennae [A. theophrasti] with the phytotoxin at 3×10-5 smallcap˜M resulted in root length inhibition of 35.7 and 72.6%, resp.