Phytochemical screening and investigation on the antibacterial activity of fermented noni (Morinda citrifolia) fruit juice extracts on selected microorganisms in Makurdi Metropolis

Abstract

Plant products are generally useful for medicinal purposes, one of which is the noni plant. Noni or pace (Morinda citrifolia L.) fruit juice was extracted using aqueous and methanol solvents, then fermented and screened for the presence or absence of bioactive constituents (phytochemicals) using the modified standard procedures. The major phytochemical constituents revealed were alkaloids, anthraquinones, cardiac glycosides, and flavonoids, phenolic compounds, saponins, tannins, reducing sugar, saponnins, carbohydrate and terpenoids. Bacterial cell viability and MIC values were also determined by turbidity test. The lowest concentration of the extract with clear suspension was considered the MIC values. The lowest concentration of the extract in the post-incubation suspensions which did not harbour any bacterial growth upon spotting on MHA after overnight incubation at 37° C was considered the MBC values. The test was performed in triplicates alongside antibiotics ciprofloxacin (5μg) as a positive control at a concentration of 0.1mg/ml. Antibacterial activity was perfumed against three bacteria (Salmonella typhi, Escherichia coli, and Staphylococcus aureus) by agar-well diffusion method. Activity was observed for both methanolic and aqueous extracts of Morinda citrifolia L. fruit juice against the organisms tested. The extracts had both bacteriostatic and bactericidal activity against the test microorganisms. The Minimum Inhibitory Concentration (MIC) test revealed that the bacterial isolates were inhibited between concentrations of 50mg/ml and 25mg/ml for the methanolic extract, and between 100mg/ml and 50mg/ml for the aqueous extract of the fermented fruit juice. The extract was bactericidal from the range of 100mg/ml to 200mg/ml for both extracts, though with the exception of S. aureus which was bactericidal at 50mg/ml for methanolic extract.