Plumbagin as a new natural herbicide candidate for Sicyon angulatus control agent with the target 8-amino-7-oxononanoate synthase

A natural compound plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) was isolated from the leaves of Plumbago auriculata and found to inhibit the enzyme, 8-amino-7-oxononanoate synthase (AONS, also known as 7-keto-8-aminopelargonate synthase, KAPAS) an IC50 of 2.1 μM in vitro. Biotin supplement significantly rescued the plant injury caused by the plumbagin treatment, and this result confirmed the target site, AONS. Foliar application of 1000 ∼ 2000 μg/mL plumbagin in a greenhouse condition showed lethal activity against eight species of weeds, containing three grass species of Sorghum bicolor, Echinochloa crus-galli, Digitaria sanguinalis and five broad leaf species of Solanum nigrum, Aeschynomene indica, Abutilon avicennae, Xanthium strumarium, Calystegia japonica. Field trial of foliar application with plumbagin 2000 μg/mL have successfully controlled 10 ∼ 15 leaf-stages and 2 ∼ 3 m vine lengths of Sicyos angulatus at the natural habitats around riparian zone in the Nam-Han River in Korea. Visual symptom of desiccation might be induced by the physiological cellular leakage which was significantly dose dependent on the plumbagin treatment regardless of light.

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► We developed a natural product plumbagin from Plumbago auriculata.
► We discovered the plumbagin having 8-amino-7-oxononanoate synthase inhibition.
► Field trial with plumbagin has successfully controlled Sicyos angulatus.
► Natural product plumbagin might be used for LOHAS herbicide candidate.