Authors: E.I.O. Ajayi, A.O. Adeola, O.B. Ajayi
Journal: UNIOSUN Journal of Sciences
Objective: The extracts of N. latifolia Sm, a shrub of dry forest and savanna were studied for proximate, mineral, antinutritional and phytochemical compositions. The root and stem are known to be used in folklore medicine for treatment of several infections, and record has it that all the parts of the plants are medicinally useful. Methods: Cold extraction method was employed using methanol and chloroform. Proximate, antinutrient, mineral analyses and phytochemical screening of plant parts were carried out according standard methods. Using the disc diffusion method, the antimicrobial activities of the methanol and choloroform extracts were ascertained against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Shigella somnei. Results: Results show that the stem has the highest moisture content (7.83±0.04%), while the root sample shows the least (5.93± 0.05%). The highest ash content was observed in the fruit skin (5.42±0.04%) and lowest in the stem (2.71±0.05%). The crude fibre was shown to be highest in the stem (59.38±0.11%) and lowest in the fruit skin (11.24±0.004%). Lipid was highest in the fruit (11.53±0.11%) and lowest in fruit skin. Also protein was highest in fruit (12.76±0.05%) and lowest in fruit skin (8.31±0.01%). The results for antinutritional factors confirmed the presence of cyanide and phytic acid. Cyanide was highest in stem (11.58±0.001mg/kg) and lowest in fruit (3.35±0.003mg/kg). Phytic acid content ranged between 6.28±0.005% and 7.37% among the samples, lowest in the root and highest in fruit. Minerals present show sodium has the highest value (908.67±0.01ppm, root) and phosphorus, the lowest (10.75±0.01ppm, fruit). The extracts were also screened and found to contain important bioactive components including tannins, phlobatannins and saponins. The methanol and chloroform extracts of the root and stem of N. latifolia Sm were studied for their antimicrobial activities on some pathogens. These are Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Shigella somnei. The methanol extracts of both root and stem had more inhibitory effect on the test organisms than the chloroform extracts, which inhibited best at concentration of 50mg/ml and 100mg/ml, respectively. Conclusion: The data produced in this study have confirmed that N. latifolia has a broad spectrum of antimicrobial activities depending on the method of extraction. The antimicrobial property exhibited by the various samples of this plant as reported here may be attributed to the presence of phytochemicals, while the edibility of the fruit may be due to the moderately high nutritive values and low cyanide content.