Isolation,purification and herbicidal activity of secondary metabolites from Curvularia lunata
[Aims]The aim of this study is to find novel lead compounds with herbicidal activity.[Methods]The secondary metabolites of mycelia and fermentation broth of Curvularia lunata were extracted by dichloromethane.The extracts and extraction residues were used as crude toxins to investigate their herbicidal activity by a seedling growth inhibition assay.The crude toxin with the highest activity was separated and purified using various chromatographic methods.All isolated compounds were evaluated for their herbicidal activities against 4 weeds.[Results]At the concentration of 200 mg/L,crude toxins from mycelia had a stronger inhibitory effect on the seedling growth of Echinochloa crus-galli and Amaranthus retroflexus than those from fermentation broth,and the toxicity of the dichloromethane extracts was higher than that of extraction residues.The dichloromethane extract of the mycelia was isolated and purified to obtain 3 compounds,which were identified as bis(2-ethylhexyl)phthalate(1),ergosterol(2)and(RS)-2-propylhexyl-2H-l,2,3-triazole-4-carboxylate(3).At the concentration of 200 mg/L,compound 2 decreased the root growth of Capsella bursa-pastoris by 44.26％,compound 3 inhibited the root growth of A.retroflexus and C.bursa-pastoris and the shoot growth of Digitaria sanguinalis,with inhibition rates of 30.64％,55.8％and 20.98％respectively.[Conclusions](RS)-2-Propylhexyl-2H-1,2,3-triazole-4-carboxylate(3)has the potential to be used as a lead compound for the development of new herbicides.
Curvularia lunatasecondary metaboliteseparation and purificationherbicidal activity
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