Potent Nematicidal Activity of Phthalaldehyde, Salicylaldehyde, and Cinnamic Aldehyde against Meloidogyne incognita

Abstract

The nematicidal activity of selected aromatic aldehydes was tested against the root knot nematode Meloidogyne incognita. The most active aldehyde was phthalaldehyde (1) with an EC(50) value of 11 ± 6 mg/L followed by salicylaldehyde (2) and cinnamic aldehyde (3) with EC(50) values of 11 ± 1 and 12 ± 5 mg/L, respectively. On the other hand, structurally related aldehydes such as 2-methoxybenzaldehyde (21), 3,4-dimethoxybenzaldehyde, and vanillin (23) were not active at the concentration of 1000 mg/L. By liquid chromatography-mass spectrometry the reactivity of tested aldehydes against a synthetic peptide resembling the nematode cuticle was characterized. At the test concentration of 1 mM, the main adduct formation was observed for 3,4-dihydroxybenzaldehyde (22), 2-methoxybenzaldehyde (21), and 3,4-dimethoxybenzaldehyde. Considering that 2-methoxybenzaldehyde (21) and 3,4-dimethoxybenzaldehyde were not active against M. incognita in in vitro experiments led us to hypothesize a different mechanism of action rather than an effect on the external cuticle modification of nematodes. When the toxicity of the V-ATPase inhibitor pyocyanin (10) was tested against M. incognita J2 nematodes, an EC(50) at 24 h of 72 ± 25 mg/L was found. The redox-active compounds such as phthalaldehyde (1) and salicylaldehyde (2) may share a common mode of action inhibiting nematode V-ATPase enzyme. The results of this investigation reveal that aromatic redox-active aldehydes can be considered as potent nematicides, and further investigation is needed to completely clarify their mode of action.

Nematicidal activity of furanocoumarins from parsley againstMeloidogynespp.

“…Investigating the molecular structural basis for activity, we previously reported that salicylaldehyde bearing an hydroxyl group in the ortho position to the formyl group showed high nematicidal activity . Similarly, in the present study, xanthotoxol was the most active furanocoumarin (Table ), followed by psoralen, which lacks the hydroxyl group, and xanthotoxin, which has a methoxy group and was 3 times less active than xanthotoxol.…”

Larvicidal, molluscicidal and nematicidal activities of essential oils and compounds from Foeniculum vulgare

“…Generally, oxygenated compounds, namely ketones (L-carvone and pulegone), alcohols (geraniol and terpinen-4-ol) and phenols (eugenol, carvacrol and thymol), have revealed good nematotoxic properties (LC 50 from 115 to 754 mg l -1 after 24 h) (Ntalli et al 2010;Caboni et al 2013a). Volatile aromatic aldehydes, including benzaldehyde derivatives, have been recognized for their outstanding nematotoxicity against J 2 of M. javanica (50 % paralysis for concentrations between 13 and 33 ll l -1 after 48 h) (Oka 2001) and M. incognita (LC 50 between 11 and 167 mg l -1 after 24 h) (Caboni et al 2013b). …”

Nematicidal activity of acetophenones and chalcones against Meloidogyne incognita and structure–activity considerations

“…Notwithstanding the fact that plant secondary metabolites have not managed to reach the market yet, they have gained much scientific interest in recent years for their ability to control soil nematodes sustainably . On the basis of our recent research results, plant secondary metabolites belonging to the chemical groups of the α , β ‐unsaturated aldehydes, ketones, lactones and isothiocyanates show significant activity against Meloidogyne species . Among the various types of chemically mediated plant resistance to nematodes, the most important is the production of toxins, followed by the lack of necessary compounds for nematode development in the host, lack of attraction and hypersensitivity .…”