ANTIMICROBIAL ACTIVITIES OF CLAY

ABSTRACT

Clay minerals are formed by weathering of other silicate minerals on and in the earth’s crust. Clays have been used in traditional medicine for the production of clay gels or pastes that can be applied externally for cosmetic or skin protective purposes. Clay has been found to contain chemicals which are antimicrobial in nature. This study was carried out to determine the extent to which different types of clay exhibit antimicrobial properties. Samples of clay were collected from different locations around the Benin Metropolis and the hydrogen ion concentration, electrical conductivity, mineral composition and total organic carbon was evaluated. The clay samples were observed to have varying quantities of sulphur, aluminum, iron, Iolite and calcium oxide. The antimicrobial assay of the clay samples was carried out against some selected microorganisms. The isolates used were Aspergillus sp., Multi-drug resistant Pseudomonas, Susceptible Pseudomonas, Methicillin resistant Staphylococcus aureus and Susceptible Staphylococcus aureus. The agar disk diffusion method was employed for the test. Ketoconazole and Ciprofloxacin were used as positive control. The determination of the minimum inhibitory concentration values for the different clay samples was carried out using the broth dilution method. The zones of inhibition produced were measured using a millimeter rule and represented in millimeters. The zones of inhibition ranged from 11.00 mm (for clay soil from Imegba area) to 16.00 mm (for clay soil from Okpekpe area). And percentage minimum inhibitory concentration values ranged from 17 to 20 mg/ml. The findings of this study revealed clay indeed has potent antimicrobial properties. Clay has the potential to be used as an alternative to synthetic antibiotics to combat the growth in multidrug resistant bacterial strains.