Nematicidal, larvicidal and antimicrobial activities of some new mannich base imidazole derivatives

X Chen,A Manilal,Rs Kumar,Sw Lee,A Idhayadhulla

doi:10.4314/tjpr.v14i8.16

Abstract

Purpose: To synthesize Mannich base imidazole derivatives, and evaluate their antimicrobial, nematicidal and larvicidal properties .Methods: Compounds 1a-g and 2a-g were prepared using a Mannich condensation method. The chemical structures of compounds 2a-g were confirmed by Fourier transform infrared spectroscopy (IR), proton nuclear magnetic resonance (1H-NMR), carbon nuclear magnetic resonance (13C-NMR), and mass spectrometry (MS) and elemental analyses. Compounds 1a-f and 2a-f were screened for antimicrobial properties using an agar diffusion method. The nematicidal activity of the compounds was evaluated against juvenile Meloidogyne javanica as test organism while larvicidal activity was assessed against the urban mosquito, Culex. Quinquefasciatus, using a standard bioassay protocol.Results: Compounds 1b, 1g, 2e and 2g were highly active against a few bacterial organisms compared with the reference antibacterial, ciprofloxacin while the antifungal activity of compound 2d was high compared with the reference, clotrimazole. Compounds 1c, 1e, 1g, and 2e showed high toxicity levels of larvicidal activity based their half maximal lethal dose (LD50) values. Compounds 1d, 1e, 1f, 1g, 2d and 2e were highly toxic to nematodes.Conclusion: Compounds 1b, 1g, 2e and 2g may be useful as lead molecules for the development of new classes of larvicidal, nematicidal and antimicrobial agents.

Highlights

Culex is an important genus of mosquito that acts as a vector for several serious diseases, including filariasis, west Nile virus, dangue fever, yellow fever, chikungunya and other diseases caused by encephalitides
Compounds 1a-1g and 2a-2g were evaluated for their in vitro antifungal activity Aspergillus niger, Candia albicans, Aspergillus fumigatus, Cryptococcus neoformans and Microsporum audouinii using an agar diffusion method [17,18] with Sabouraud’s dextrose agar (Hi-Media)
The assessment of larvicidal activity of synthesized test compounds 1a-1g and 2a-2g was tested against the urban mosquitoes Culex

Summary

INTRODUCTION

Culex is an important genus of mosquito that acts as a vector for several serious diseases, including filariasis, west Nile virus, dangue fever, yellow fever, chikungunya and other diseases caused by encephalitides. The optimum methods of controlling mosquito larvae and nematodes involve the use of insecticides such as various organophosphates, and natural and synthetic heterocyclic products. Occurring and synthetic imidazole derivatives are an important class of heterocycles that are known to exhibit various biological activities [1]. Many substituted imidazoles are used as fungicides and herbicides, plant growth regulators and therapeutic agents [4]. The Mannich reaction is commonly employed to develop agricultural chemicals such as plant growth regulators [9] and is an important tool in the synthesis and modification of biologically active compounds [10]. Compounds 1a-1g and 2a-2g were evaluated for their in vitro antifungal activity Aspergillus niger, Candia albicans, Aspergillus fumigatus, Cryptococcus neoformans and Microsporum audouinii (recultured) using an agar diffusion method [17,18] with Sabouraud’s dextrose agar (Hi-Media). The zone of inhibition was measured incubated at 37 °C for 24 h and MICs were determined

Evaluation of larvicidal activity

RESULTS

DISCUSSION

CONCLUSION