Browsing by Author "Usman, A."

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    ALLELOPATHY OF VELVET BEAN (Mucuna cochinchinensis (Wight) Burck) EXUDATES AND ITS INHIBITORY EFFECTS ON WEEDY RICE (Oryza sativa L.)
    (Department of Agronomy, Nasarawa State University Keffi, 2021-01-01) Ibrahim, Abdullahi Jaji; Usman, A.; Jatto, I.M.
    The experiment was conducted at the Toxicology laboratory, Faculty of Agriculture, University Putra Malaysia, Serdang, Malaysia in 2013. Allelopathic potential of aqueous methanol and water extracts of Mucuna. cochinchinensis leaves, seeds and roots were investigated on seed germination and seedlings growth of weedy rice (Oryza sativa); and biotest crop specie: lettuce (Lactuca sativa). The treatments consisted of five concentrations (100, 75, 50, 25, 0 %); plant parts (leaves, seed, root) and extraction solvents (methanol, water) were replicated three times and arranged as a completely randomized block (CRD) design. Germination, hypocotyl and radicle growth of all test plant species were inhibited at concentrations (100, 75, 50 and 25%). Inhibitory activity was dependent on the extraction solvents and extract concentrations as reported that methanol at higher extract concentration had the stronger inhibitory activity. The mean EC50 values of M. cochinchinensis leaves, seed and root of methanol extracts in relation to the germination inhibition of O. sativa, 86.06%, 416.32% and 72% respectively, and 30.66% 55.84% and 18.24%, respectively, in Lactuca sativa. Similar trend was observed with the varying concentration of the water extracts. The methanol extract of root showed a greater inhibitory effect on the hypocotyl and radicle growth of weedy rice than its water extract, and more effective on total germination.
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    Phytochemical Screening and Antioxidant Activity of Balanites Aegyptiaca Root Bark Extracts: Influence of solvent
    (Department of Chemistry, Nasarawa State University Keffi, 2020-05-05) Usman, A.; Mohammed, Y.; Muhammed, N.L.; Usman, N/A; Zakari, A.H.
    Balanites aegyptiaca (L) Del is a medic- inal plant used in Africa’s folk medicines to treat wide range of diseases. Phytochemical screening of aqueous and ethanolic extracts of Balanites ae- gyptiaca (L) Del root indicated the presence of flavonoids, saponins, tannins and phenols.The ethanolic extract of the plant root had in addition carbohydrate, cardiac glycoside and steroids while n-hexane extract indicated the presence of anthraquinone, carbohydrates, cardiac glycoside, terpenoids and resins. The extracts were also eval- uated for their free radical scavenging potential, total phenolic and total flavonoid contents. The antioxidant activity was determined using 1,1-di- phenyl-2-picrylhydrazyl (DPPH) assay, the total phenolic content was evaluated using Folin-Cio- calteau assay, while the total flavonoid content was assessed by the aluminium chloride colori- metric assay. The results obtained revealed that the ethanolic extract exhibited higher total antiox- idant capacity in the range of 55.23±0.4 to 81.04±0.9% while concentrations in the aqueous extract ranged from 20.15±0.2 to 35.11±0.2% compared to 80 % of standard ascorbic acids. Es- timated total phenolic content in aqueous and eth- anolic extracts were 179.48±1.99 and 260.07±2.31 mg/gallic acid equivalent (GAE)/g respectively. However, the total flavonoid content for aquoues and ethanolic extracts were 69.17±0.32 and 95.52±0.41 mg/ quercetin equiva- lent (QE)/g respectively. Total phenol and flavo- noid were absent in normal hexane extract. The results obtained from the study indicated that the choice of solvent can influence the components that can be extracted from Balanites aegyptiaca (L) Del root and that for optimum extracts to be obtained, the best solvent is ethanol.
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    PHYTOCHEMICAL, ANTIOXIDANT AND CYTOTOXIC SCREENING OF THE LEAVES OF Calotropis procera EXTRACTS
    (Department of Agronomy, Nasarawa State University Keffi, 2020-05-12) Usman, A.; Onore, R.O.; Opaluwa, O.D.; Ibrahim, Abdullahi Jaji
    The bioactive components of the leaves of Calotropis procera was extracted using aqueous, methanol, and n- hexane and investigated for the presence of secondary metabolites. All the extracts revealed the presence of steroid and saponins while flavonoids are present in aqueous and methanol extracts. The antimicrobial activities of the extracts were tested against fungi, gram positive and gram negative bacteria’s such as Candida albicans, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Salmonela typhi using the agar disk diffusion method. The n-hexane extract demonstrated a significant broad-spectrum antimicrobial activity against S. typhi and S. aureus with the zone of inhibition of 7 and 11 mm. The methanol extract was only active against Gram negative P. aeruginosa with the zone of inhibition of 6, while the aqueous extract was inactive against all the organisms tested. The result of the antioxidant property showed that methanol extract has the highest activity of about 88% while aqueous extract is 37%. The flavonoid content of the extracts was also quantified to be 96.90 and 39.90 mg/g for methanol and aqueous extracts. The crude extracts were also subjected to brine shrimp lethality bioassay and hexane extract showed significant cytotoxicity having LC50 of 2.01 μg/ml.
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    Phytochemicals, Antibacterial, Antioxidant and Cytotoxic Analyses of Balanites Aegyptiaca Stem Bark Extracts
    (Department of Chemistry, Nasarawa State University Keffi, 2020-03-03) Usman, A.; Mohammed, Y.; Opulawo, O.D.
    Powdered stem bark of B. aegyptiaca was extracted using ethanol, aqueous and n-hexane. Test for the secondary metabolites showed the presence of flavonoids, saponins, tannins, phenols and carbohydrates in aqueous and ethanol extracts, while ethanol extract has in addition cardiac glycoside and steroids. Anthraquinone was the only metabolite detected in n-hexane extract. The antibacterial activity of the plant extracts showed ethanol extract to have a broad spectrum of activity against the test isolates with varying zones of inhibition, as shown by the results of the minimum inhibitory concentration (MIC) which for hexane extract was obtained at 50 mg/ml for S. aureus, while that of ethanol extract was obtained at25mg/ml for S. typhi, 50 mg/ml for E.coli and 100 mg/ml for S. aureus. However, the test organisms were not susceptible to the aqueous extract. DPPH (1,1- diphenyl-2 picrylhydrazyl) free radical scavenging assay was used to determine the antioxidant property of the extracts. The result showed that DPPH% inhibition varied between extracts with ethanol extract having a maximum of 80% while aqueous extract had 32% inhibition. The crude extracts of the plant sample were also subjected to brine shrimp lethality bioassay. The results obtained were 0.46, 3.13, 9.70 and13.35μg/ml for vincristine sulphate, hexane, ethanol and aqueous extracts respectively. Comparing this result with the standard vincristine sulphate, hexane extract showed significant cytotoxicity having LC50 of 3.13μg/ml.