Potentiation of the Fungicidal Activity 1-(2, 4-Dihydroxyphenyl) Ethanone Ligand and Its Divalent Metal Complexes

 

I.E. Otuokere1, G.U. Okafor2 and A.J. Chinweuba3

1Department of Chemistry, Michael Okpara University of Agriculture, Umudike.

2Department of Pharmacy, Nnamdi Azikiwe University, Awka. Department of Chemistry, Anambra State University, Uli.

 

 

ABSTRACT:

Newly synthesized 1-(2, 4-Dihydroxyphenyl) Ethanone ligand and its Co(II), Ni(II), Zn(II) and Pd(II) metal complexes were tested for their fungicidal potentials against Gibberela, Cercospora arachidicola, Physolopora piricola and Fusarium oxysporium.

Preliminary in vitro test for fungicidal activity of the ligand and complexes were carried out by the fungi growth inhibition method. In general, the ligand and the complexes displayed certain activity against the fungi species at 25ppm, 50ppm and 100ppm. The complexes are more toxic to the fungi species than the uncomplexed ligand at different concentrations. The inhibition percentage of the ligand and complexes increases as the concentration increases. The metal complexes show more increased activity than the corresponding ligands.

 

KEYWORDS: 1-(2, 4-Dihydroxyphenyl) Ethanone, Fungi, inhibition, complexes.

 

 

INTRODUCTION:

The role played by metal ions in living system is well established. Many enzymes depend on metal ions. This dependence is well exemplified by the observation that one third of all enzymes have metal ions as an essential component1. The discovery that some metal complexes were antiviral2, anticonvulsant3, antitumour4, anticancer5, antibacterial6, antiamoebic7, anti- HIV8, antimicrobial9 and fungicidal10 stimulated renewed interest in coordination compounds and their role in chemotherapy. A large number of chelating agents have been synthesized to develop effective and cheap therapy for diseases. Metal complexes may inactivate fungi by occupying sites on its host surface which would be normally utilized in the initiation of the initiation of the infection or the cell. The first step in the infection would be an adsorption reaction involving electrostatic attraction. In the second step, the complex  cations may  penetrate the cell wall and thus prevent viral reproduction11. In this paper, we present the potentiation of the fungicidal activity 1-(2, 4-Dihydroxyphenyl) Ethanone ligand and its divalent metal complexes.

 

MATERIALS AND METHOD:

The synthesis and characterization of the ligand have been reported elsewhere14. All chemicals used in the syntheses were analytical grade and purchased from Aldrich Chemical Company.

 

Biological Activity:

Preliminary in vitro tests for fungicidal activity of ligand and complexes have been carried out by the fungi growth inhibition method12. These compounds are dissolved in DMF at a concentration of 25ppm, 50 ppm and 100ppm. The ligand and complexes were screened against Gibberela, Cercospora arachidicola, Physolopora piricola and Fusarium oxysporium.

 

RESULTS AND DISCUSSION:

The chemical structure of the ligand and complexes are shown in Figure 1 and 2 respectively.

 

The inhibition ratio of the ligands and complexes in Gibberela, Cercospora arachidicola, Physolopora piricola and Fusarium oxysporium are shown in Figure 3, 4, 5 and 6 respectively.

 

In general, the ligand and the complexes displayed certain activity against the fungi species at 25ppm, 50ppm and 100ppm. The complexes are more toxic to the fungi species than the uncomplexed ligand at different concentrations. The inhibition percentage of the ligand and complexes increases as the concentration increases. The metal complexes show more increased activity than the corresponding ligands. It is known that chelation reduces the polarity of the metal ion because of partial sharing of its positive charge with the donor groups of the ligand. Such chelation increases the lipophilic character of the metal complex which is necessary to cross the permeability barrier of cells resulting in interference with normal process of fungi.

The general trend of inhibition percentage against the fungi species is found to be in the order ligand < Co < Ni < Zn > Pd. This is in agreement with the Irving-Williams series13 .

 

CONCLUSION:

Newly synthesized 1-(2, 4-Dihydroxyphenyl) Ethanone ligand and its Co(II), Ni(II), Zn(II) and Pd(II) metal complexes have been tested for their fungicidal potentials against Gibberela, Cercospora arachidicola, Physolopora piricola and Fusarium oxysporium.

 

Preliminary in vitro test for fungicidal activity of the ligand and complexes were carried out by the fungi growth inhibition method. In general, the ligand and the complexes displayed certain activity against the fungi species at 25ppm, 50ppm and 100ppm. The complexes were more toxic to the fungi species than the uncomplexed ligand at different concentrations. The inhibition percentage of the ligand and complexes increases as the concentration increases. The metal complexes show more increased activity than the corresponding ligands.

 

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14.     Otuokere IE, Orjiako EN, Okafor GU and Chinweuba AJ. Complexation behavior of 1-(2,4-dihydroxyphenyl)Ethanone ligand  towards Co(II), Ni(II), Zn(II) and Pd(II) metal ions. Asian J. Research Chem. 2010: 695-697.

 

Received on 13.03.2011

Modified on 20.04.2011

Accepted on 19.05.2011           

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Research J. Science and Tech.  3(5): Sept.-Oct. 2011: 273-275