Characterization, phytochemical analysis and nematicidal activity of Daniella oliveri leaves against Meloidogyne incognita

This study was carried out to identify and evaluate the nematicidal potential of Daniella oliveri leaves. The leaves of D. oliveri were air dried and extracted with n-hexane, there after acetone. The concentrated extracts were subjected to chromatography on a silica gel packed column. The nematicidal activity of the fractions were evaluated in the laboratory using a 4x4x3 factorial experiment, while the crude extracts were tested on Meloidogyne incognita infecting Abelmoschus esculentus in the field. Three hundred juveniles were used for the assessment. Acetone extract coded DNLO/Me2CO caused a significant increase in plant height, number of leaves, number of fruits per plant and fruit weight per plant as compared with Carbofuran (p less than 0.05). In the laboratory, chromatographic fractions from acetone extract had the highest percentage juvenile mortality. The infrared analysis of the fractions revealed the presence of anhydride and carbonyl stretching frequencies at 3638, 1702, 1735 and 1771 cm-1. The Nuclear Magnetic Resonance (NMR) of the fractions showed signals that agreed with ozoic and daniellic acids. Preliminary phytochemical screening of the leaves revealed the presence of flavonoids, steroids, terpenoids, reducing sugars, phenols, alkaloids, glycosides and carbohydrates. Nematicidal activity of D. oliveri leaves is being reported for the first time. The crude extracts and chromatographic fractions are potent at very low concentrations compared with standard carbofuran. Therefore, the leaves of D. oliveri could be employed as a viable source of natural nematicide instead of synthetic toxic nematicides.