Antimicrobial activities and formulations of the extracts of chewing sticks commonly used in Ethiopia for oral cleansing

Abstract

Chewing sticks are twigs, stems or roots of certain plants that are chewed until one end is frayed which is then used to clean the teeth. Studies have shown that chewing sticks can remove dental plaque. The hydroalcoholic extracts of different parts of three commonly used chewing sticks of Clausena anisata (Willd.) Benth. (Rutaceae), Sida schimperiana Hochst. ex. A. Rich (Malvaceae) and Stereospermum kunthianum Cham. (Bignoniaceae) were screened for antimicrobial activity against different strains of bacteria and fungi. All the plants investigated possessed antimicrobial activity against at least one strain of bacteria and/or fungi. The antimicrobial activity of the extract of S. schimperiana was prominent as compared to the other plant extracts. Hence, the powdered root of this plant was fractionated in different solvents and the resulting fractions were screened for antimicrobial activity against the same organisms. Potency of the fractions was in order of petroleum ether > chloroform > acetone > methanol > water, against the bacterial and fungal strains. Dilution of the extract was performed within a concentration range of 20 - 0.3125 mg/ml for the tested bacteria and fungi. The highest activity was observed against P. aeruginosa (MIC = 0.625 mg/ml) as compared to the least sensitive E. coli (MIC = 20 mg/ml). Toothpaste and mouthwash were formulated using the hydroalcoholic extract of S. schimperiana. The antimicrobial potentials of these formulations were assessed in vitro and the results indicate superior antimicrobial activity of the toothpaste as compared to the mouthwash.

Keywords: chewing sticks, antimicrobial activity, Clausena anisata, Stereospermum kunthianum, Sida schimper