The effect of crude extracts of nine African chewing sticks on oral anaerobes

This study evaluated the antimicrobial effects of crude extracts from nine Nigerian chewing sticks against oral anaerobic bacteria, specifically four Bacteroides species. Researchers tested extracts from bark, pulp, and whole stick components at various concentrations (1-80%) against reference strains and clinical isolates of B. gingivalis, B. asaccharolyticus, B. melaninogenicus, and B. oralis. Serindeia warneckei demonstrated the strongest and most consistent bactericidal activity, killing all four species at concentrations as low as 1%. The other eight sticks showed variable effectiveness, with bactericidal concentrations ranging from 2-30%. Notably, all three black-pigmented Bacteroides species displayed high susceptibility to eight of nine extracts, while the non-pigmented B. oralis showed variable resistance patterns. Fagara zanthoxyloides was completely ineffective against all tested anaerobes. The researchers attribute the antimicrobial activity to heat-stable, methanol-soluble tannin-like polyphenolic compounds present in the plant tissues. These findings support the traditional use of chewing sticks for oral hygiene in Nigeria and suggest potential applications in commercial oral health products.

Key findings

• Serindeia warneckei extracts showed the most potent and consistent bactericidal activity against all four Bacteroides species at concentrations of 1-11%
• Black-pigmented oral anaerobes were highly susceptible to eight of nine chewing stick extracts, while non-pigmented B. oralis showed variable susceptibilities
• Eight chewing sticks demonstrated bactericidal activity at concentrations below 10%, with Fagara zanthoxyloides being completely inactive
• Antimicrobial activity is attributed to heat-stable tannin-like polyphenolic compounds that form complexes with bacterial cell wall proteins
• Bark and pulp extracts showed varying potencies, suggesting differences in tannin concentration across plant tissues and species