Pharmaceuticals from the whole root of Nauclea latifolia (Rubiaceae)

Abstract

The fruit, leaf, stem and root of Nauclea latifolia have been found to posses antimicrobial properties. This work shows the characterization and antimicrobial studies of pharmaceuticals from the whole root of the plant. Soxhlet extraction of the whole root was done using HPLC grade n-hexane, ethylacetate and methanol in that order. Silica gel and sephadex column chromatography were used to isolate pure fractions. Three compounds were isolated. NMR spectroscopic analyses were used to elucidate the structures of the compounds as: strictosamide, quinovic acid and 3,4 dihydroxybenzoic acid. The compounds were found to have antibacterial and antifungal activities against eleven (11) human pathogenic bacteria namely: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Streptococcus mutans, Streptococcuss pyogenes, Klebsiella pneumonia, Salmonella typhii, Proteus vulgaris, Enterobacter aerogenes, Staphylococcus albus and Bacillus subtilis and three human pathogenic fungi namely: Candida albicans, Aspergillus flavus and Aspergillus niger . The average diameters of zones of inhibition of the isolated compounds were comparable with those of the standard antibiotics (gentamicin for bacteria and tioconazole for fungi). The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC) of the three compounds confirmed they were active even at low concentrations.