VC Mbatchou, I Aggrey and EO Oyelude
Keywords: Extraction, polarity indices of solvents, secondary metabolites, optimal extractable ability, ciprofloxacin antibiotic drug and growth inhibitory activity.
Abstract: The roots of Burkea africana and Combretum adenogonium were separately subjected to extraction by macerating using n-hexane, chloroform, methanol and distilled water solvents in an increasing order of polarity indices. Extracts obtained in the extraction process were later screened for the presence of secondary metabolites by methods employed by Mbatchou et al. (2010) which revealed the presence of tannins, anthraquinones, glycosides, alkaloids, saponins, phenolics, amino acids, steroids, terpenoids and flavonoids in the root samples of both B. africana and C. adenogonium. This was an indication that roots of the two plants contained ingredients which have pharmacological effects. Of the four solvents used to extract ingredients from the roots of the two plants, methanol solvent yielded the highest weighed extracts. Methanol and distilled water extracts showed the presence of 80% and above of the tested classes of secondary metabolites. These results indicated the optimal extractable abilities of both methanol and distilled water solvents which were also evident in the antimicrobial test of the root extracts on Salmonella typhi. Methanol extracts of the roots of B. africana demonstrated growth inhibitory effects with mean values of 8.00±0.00mm, 10.33±1.33mm, 12.33±0.33mm and 13.66±0.00mm at concentrations of 500, 1,000, 1,500 and10, 000?g/ml respectively. Distilled water extracts of the same part of plant demonstrated growth inhibitory effects with mean values of 7.33±0.60mm, 9.66±0.33mm, 12.00±1.00mm and 13.00±0.33 at concentrations of 500, 1,000, 1,500 and10, 000?g/ml respectively. Methanol extracts of the roots of C. adenogonium demonstrated growth inhibitory effects with mean values of 5.66±0.37mm, 6.33±0.33mm, 7.33±0.32mm and 11.33±0.32mm at concentrations of 500, 1,000, 1,500 and10, 000?g/ml respectively. Distilled water extracts of the same part of plant demonstrated growth inhibitory effects with mean values of 5.00±1.00mm, 6.33±0.33mm, 8.00±0.32mm and 10.66±0.32mm at concentrations of 500, 1,000, 1,500 and10, 000 ?g/ml respectively. Ciprofloxacin antibiotic drug, used as positive control in the research also demonstrated growth inhibition on the bacterial isolate. The optimal extractable abilities demonstrated by the methanol and distilled water solvents supported their use to isolate antibacterial compounds from the roots of both plants by column chromatographic method. The presence of the fore mentioned classes of secondary metabolites in the root extracts, and the growth inhibitory effects shown on Salmonella typhi revealed that both B. africana and C. adenogonium contained antibacterial compounds which can treat typhoid fever in humans, and can also cure other diseases which affect elephants that feed on parts of the two plants.
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