Abstract

PHYTOCHEMICAL SCREENING AND ANTIMICROBIAL ACTIVITIES OF METHANOLIC EXTRACT OF NEWBOULDIA LAEVIS ROOTS

*Forghe B. N. and Nna P. J.

Abstract

The plant Newbouldia laevis belongs to the Bignoniaceae family and is commonly called Seem or boundary tree in English. Different parts of N. laevis are used by herbal practitioners to treat several diseases such as chest pain, sore feet, earache, epilepsy and children’s convulsion, malaria and others. Phytochemical screening of extract N. laevis root obtained from Bori metropolis was carried out. Antimicrobial activities of the plant extract were evaluated using agar well diffusion method. The phytochemical screening of N. laevis roots extract revealed presence of secondary metabolites such as steroids, alkaloids, flavonoids, triterpenoids, tannins, anthraquinone, glycosides, reducing sugars and saponins. Quantitation of phytochemicals by gas chromatography coupled with flame ionization detector (GC-FID) showed that the plant roots contained more of alkaloids like quinine, sparteine, ribalidine and lunamirine. Quinine (36.5481 μg/g)) and lunamarine (36.0202 μg/g)) were highest. The effective MIC of the plant extract was observed at 10 mg/mL against Proteus mirabilis, MRSA, E. coli, S. aureus, C. albicans and C. stellatoidea. The MIC 5 mg/mL was effective against A. nigre, Coniophora puteana, Estrophoria raclentii, Fusarium prokforatum, Scloratium rolfsii, Rhizopus sp. and Serpula lacrymans. The MBC and MFC were further carried out to ascertain whether certain concentrations of the plant extract would kill the test pathogens. The extract showed effective (MBC/MFC) (20 mg/mL) against all the test pathogens that were sensitive to the extract such as E. coli, MRSA, S. aureus, Candida albicans, and others. The presence of the detected secondary metabolites in the plant confirms the usefulness of the plant. The activity N. laevis against pathogenic strains makes the plant a potential drug development candidate for treatment of diseases caused by these pathogens.

Keywords: Newbouldia laevis, phytochemical, antimicrobial, GC-FID, pathogen.