Antibacterial activities of extracts from Nigerian chewing sticks.

Ten aqueous extracts from wooden chewing sticks widely used in Nigeria for teeth cleaning were studied for antibacterial activities against 25 different bacteria using an agar diffusion assay. The extracts from five sticks, namely Garcinia kola, Anogeissus leiocarpus, Terminalia glaucescens, Sorindeia warneckei and Vitex doniana, exhibited strong activities against a wide spectrum of bacteria including medically and dentally relevant bacteria. Notably, these five chewing stick extracts showed potent activities against methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and multidrug-resistant Burkholderia cepacia and Pseudomonas aeruginosa. Extracts from Vernonia amygdalina, Fagara zanthoxyloides and Massularia acuminata also showed activities against bacteria significant to periodontal disease. Methanol extracts prepared from G. kola, A. leiocarpus and V. doniana were further fractionated by solvent extraction. Results showed that the antibacterial activities were distributed into different fractions suggesting that the sticks contain different active antibacterial principles. In conclusion, the results showed that most of the Nigerian chewing sticks do contain antibacterial activities which may contribute to the reported anticaries effect of chewing sticks. These sticks may be sources for new lead antibacterial agents for therapeutic or preventive applications. Copyright 1999 John Wiley & Sons, Ltd.