Preliminary Antibacterial Screening of the Whole Stem of Rothmannia whitfieldii

Aim: To assess the antibacterial activity of the crude ethanolic and water extracts of the stem of Rothmannia whitfieldii on clinically isolated and typed pathogenic bacterial strains.

Study Design: This experiment was performed in duplicates under aseptic condition.

Place and Duration of Study: Department of Microbiology, University of Nigeria, Nsukka, Enugu State, Nigeria between April 2005 to August, 2005.

Methodology: Whole dried stem specimen of Rothmannia whitfieldii was extracted by maceration and screened for antibacterial activity using agar well-diffusion technique. Five typed bacterial strains namely, Staphylococcus aureus (ATCC 12600), Pseudomonas aeruginosa (ATCC 10145), Escherichia coli (ATCC 11775), Salmonella kintambo (SSRL 113) and Bacillus subtilis (ATCC 6051), and six locally isolated clinical strains (Escherichia coli, Salmonella typhi, P. aeruginosa, S. aureus and two Proteus species designated as Proteus I and Proteus II), were tested for susceptibility to the plant extract.

Results: Phytochemical analysis revealed the presence of flavonoids, saponnins, tannins, carbohydrates and steroidal aglycone. Alkaloid was present in trace amount only in the ethanolic extract. The ethanolic extract exhibited a wider spectrum of activity, being effective against 81.8% of the test organisms compared with the cold-water extract (54.5%) or hot water extracts (27.3%). The minimum inhibitory concentrations (MICs) varied not only with the test organisms but also with the various extracts of the plant.

Conclusion: All the extracts had bacteriostatic activity on the susceptible organisms and none was bactericidal. The screening test results authenticate the folkloric claims that Rothmannia whitfieldii is medicinal against gastrointestinal diseases and aid in wound healing.