The aimof this studywas to assess the phytotoxic potential of Cleome arabica L, as well as to isolate the main bioactive\ud compounds. Phytotoxicity was evaluated on germination and seedling growth of Lactuca sativa, Raphanus\ud sativus, Peganum harmala and Silybum marianum, through testing aqueous and organic extracts of different C.\ud arabica organs (roots, shoots, siliquae and seeds). Results showed that siliquae methanol extract caused the\ud greatest negative effect on lettuce germination and growth. For the bioactive subfractions (petroleum ether,\ud ethyl acetate andmethanol–water), the ethyl acetate induced highly significant reduction, showing 100% inhibition\ud of lettuce growth at 6 g/L. The bioactive ethyl acetate subfraction was chromatographed and subjected to\ud NMR techniques. Based on bio-guided chromatographic fractionation, five bioactive allelochemical compounds\ud were isolated from ethyl acetate extract of siliquae of C. arabica. The most inhibitory compound on lettuce seedling\ud growth was elucidated as 11-α-acetylbrachy-carpone-22(23)-ene

Aqueous and organic (hexane, chloroform, and methanol) extracts of siliquae, stems and leaves, and seeds of Cleome arabica L. (Brassicales: Capparidaceae) were evaluated in the laboratory for their antifeeding and insecticidal effect on larvae of the cotton leafworm, Spodoptera littoralis (Boisduval) (Lepidoptera, Noctuidae), using a leaf dipping bioassay with castor bean, Ricinus communis L. (Malpighiales: Euphorbiaceae), leaf discs. The polar extracts caused significant mortality. At the highest dose, C. arabica extracts exhibited significant antifeeding and phagostimulating activities against S. littoralis larvae. Under no-choice conditions, the methanol extract of siliquae was the most active, and the antifeedant index calculated over 24 hr for 3rd instar larvae varied significantly from 16 to 37%. Using nutritional indices, it was established that there was a significant decrease in growth rate concomitant with a reduction in consumption. These results suggest the presence of anti-feeding and/or toxic substances in the extracts that may be useful in developing bio-insecticides based on C. arabica extracts for use in integrated pest management of leafworm and other agricultural pests.

No abstract

No abstract

No abstract