Antibacterial Activity of Anacardium occidentale Leaf Extracts on Some Microorganisms Associated with Dental Plaque

Dental plaque has become a major problem in Africa and the world and current antibiotics has almost become ineffective for its treatment. Hence there is a need to find alternative ways of treatment for dental plaque. Anacardium occidentale is used for this purpose in many parts of Africa. Bacteria were isolated from dental plaque and identified using morphological and biochemical characteristics of the isolates. The study of the activity of Anacardium occidentale leaf extracts dissolved in four solvents (Ethanol, Ethyl acetate, Dichloromethane, Hexane) on some bacteria isolated from patients with dental plaque were investigated using the agar well diffusion and the broth dilution method. The bacteria isolated were Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Serratia marcescens, Neisseria sicca, Staphylococcus epidermidis, Corynebacterium matruchotii. The results obtained showed that the ethanolic extracts had the highest antibacterial activity on the test bacteria with zones of inhibition ranging from 2.0mm to 13.0mm, and a minimum inhibitory concentration ranging from 5mg/ml to 10mg/ml. The dichloromethane extracts had the lowest activity with a zone of inhibition ranging from 1.0mm to 4.0mm and a minimum inhibitory concentration ranging from 10mg/ml-20mg/ml while they had no activity on some of the test bacteria. Anacardium occidentale leaf can act as a good alternative to standard drugs as a treatment for dental plaque and other infections caused by these bacteria.