Comparative Study of the Antibacterial Effect of Mouth Washes and Vernonia amygdalina (del.) on Some Tooth Decay Causing Bacteria

Aims: To determine the antibacterial effect of the ethanol stem extract of Vernonia amygdalina (bitter-leaf) and some mouth washes against some bacteria that have been implicated in causing tooth decay so as to establish the role of herbal medicine and chemical compounds in oral hygiene.

Study Design: In vitro assay of antibacterial activities

Place and Duration of Study: Dental Department of the State Specialist Hospital, Akure, Ondo State, Nigeria and Department of Microbiology, Federal University of Technology, Akure, Nigeria, between October, 2012 and January, 2013.

Methodology: Bacterial isolates were collected, identified, standardized and the stem extract was prepared. Phytochemical screening of the extracts was carried out as well as the in vitro antibacterial assay using agar well diffusion technique. Minimum Inhibitory Concentration and antibiotics sensitivity test (disc diffusion assay) were also determined.

Results: The stem extract showed the presence of anthraquinone, alkaloid, saponin, steroid and cardiac glycoside. The ethanolic stem extract of Vernonia amygdalina inhibited all the test isolates at a concentration of 50 mg/ml with the highest zone of inhibition observed against Staphylococcus aureus (26.0 mm) while the least zone of inhibition of 14.0 mm was observed against Streptococcus mutans. Colgate mouthwash exhibited the highest zone of inhibition against Staphylococcus aureus while the least was recorded by Brett against Staphylococcus epidermidis. The antibacterial assay compared well with Ciprofloxacin, and in most cases higher zones of inhibition were recorded than the commercial antibiotics. The Minimum Inhibitory Concentration of the mouth washes ranged from 30 to 70% while it was 12.5 mg/ml for the stem extract.

Conclusion: Bioactive components of Vernonia amygdalina can be incorporated as ingredients in manufacturing mouthwashes and the plants’ stem can be used in the form of chewing stick. Further purification of the extract is necessary to further enhance greater antibacterial activity.