Tagetolone and tagetenolone: two phytotoxic polyketides from Alternaria tagetica

Two new phytotoxic polyketides, tagetolone (1) and tagetenolone (2), in addition to tyrosol and p-hydroxybenzoic acid, have been isolated from the organic crude extract of culture filtrates from the fungal pathogen Alternaria tagetica. Complete characterization of all structures was carried out following a careful analysis of their spectroscopic data (IR, MS, (1)H and (13)C NMR, and 2D NMR experiments).     

Insect deterrent activity of ethanolic leaf extracts of landrace maize and determination of active compounds against Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae)

Journal of Plant Diseases and Protection - The present work was carried out to gain insight into the chemical defense of maize against phytophagous insects. Leaves of sixteen landrace populations...     

Natural zinniol derivatives from Alternaria tagetica. Isolation, synthesis, and structure-activity correlation

Two novel phytotoxins, 8-zinniol methyl ether (5) and 8-zinniol acetate (6), in addition to 6-(3',3'-dimethylallyloxy)-4-methoxy-5-methylphthalide (2), 5-(3',3'-dimethylallyloxy)-7-methoxy-6-methylphthalide (3), and the novel metabolites 8-zinniol 2-(phenyl)ethyl ether (4) and 7-zinniol acetate (7) have been identified as natural zinniol derivatives from the organic crude extract of Alternaria tagetica culture filtrates. Using zinniol as the starting material, phytotoxin 5 was synthesized, together with a number of synthetic intermediates (8-13). Both natural and synthetic zinniol derivatives were evaluated in the leaf-spot bioassay against marigold leaves (Tagetes erecta).