Doctor of Philosophy (Ph.D.) Theses and Dissertations

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    Isolation And Characterization of some diterpenoids from Euphorbiaceae Family
    (Department Of Chemistry, Obafemi Awolowo University, 1992) Odunsi, Adepeju Olubanwo
    Plants of the Euphorbiaceous are used as sources of drugs. the biological activities of this family are attributed to their diterpenoid constituents. This study was therefore designed to isolate and characterise diterpenoids from some species of the Euphorbiaceans. Latex of Euphorbia Lateriflora Schum & Thonn. and root bark of Eupphorbia kaene
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    Open Access
    Synthesis, characterization, complexation and antimicrobial properties of guanidine derivatives and their mental complexes
    (Department of Chemistry, Obafemi Awolowo University, Ile-Ife., 2016) Jimoh, Ademola Aremu
    This study synthesized guanidines and their derivatives carried out complexation of the guanidines and derivatives with mentals, characterized it and its complexes and screened it and its complexes against hepatitis. This was with a view to investigating the antivirus properties of the compounds against hepatitis B and C diseases targeting liver virus organisms.
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    Phytochemical investigation of the anti-foodborne pathogens and antioxidant constituents of two combretum species leaf extracts
    (Department of Chemistry, Faculty of Science, Obafemi Awolowo University, Ile-Ife., 2025) Olusiji, Oyelekan Ajileye
    This study obtained the crude and solvent fractions of the leave extracts of C. platypterum and C. zenkeri and determined the yield and percentage yield of each extract,screened the anti-biofilm, anti-spores and anti-oxidant potentials of the plant extracts, isolated bioactive compounds from the active fractions of the plant extracts,characterized the isolated compounds using nuclear magnetic resonance spectroscopic techniques 1D and 2D; and evaluated the anti-biofilm, anti-spores of the most active compound and anti-oxidant potentials of each compound. These were with a view to establishing the constituents of the selected two Combretum species that are responsible for the anti-foodborne pathogens and antioxidant activities of the plants’ extracts. The leaves of Combretum platypterum and Combretum zenkeri were collected, identified, air dried, and powdered at room temperature. Powdered leaves (1.2 kg) each were extracted with 20 L of 80% v/v methanol/water. The crude extract obtained was partitioned using n-hexane, dichloromethane, ethyl acetate, and n-butanol in succession. The anti-bacterial and anti-oxidant activities screening of the extracts were carried out and the most active fraction was selected for fractionation. Isolated compounds were characterized using Nuclear Magnetic Resonance spectroscopy. The minimum inhibitory concentration (MIC), anti-biofilm and anti-spores activities of the most active isolated compound were evaluated against Bacillus cereus, Klebsiella pneumoniae, and Staphylococcus aureus. The anti-oxidant and anti cholinesterase activities of the extracts and isolated compounds were assessed.Combretum platypterum produced a lower extract yield (0.93%) compared to Combretum zenkeri (3.54%). The ethyl acetate fractions from both plants demonstrated the strongest anti-bacterial and antioxidant activities. The isolated bioactive compounds were characterized as kaempferol-3-O-glucoside (1), kaempferol-3-O-rutinoside (2) and 4hydroxybenzoic acid (3) from the Combretum platypterum, while catechin (4) and hydroxybenzoic acid were isolated from Combretum zenkeri. Antimicrobial sensitivity screening against Staphylococcus aureus, Bacillus cereus, and Klebsiella pneumoniae indicated resistance to kaempferol-3-O-rutinoside, kaempferol-3-O-glucoside and catechin and susceptibility to 4-hydroxybenzoic acid at 6 mg/mL. The MIC and MBC of 4-hydroxybenzoic acid were 1.5 and 3.0 mg/mL, respectively. At the MIC of 1.5 mg/mL, 4-hydroxybenzoic acid exhibited anti-biofilm activity of 93.03% (Staphylococcus aureus), 92.14% (Bacillus cereus), and 93.68% (Klebsiella pneumoniae). None of the compounds exhibited anti-spore activity. All the isolated compounds demonstrated significantly higher nitric oxide inhibition activity than the ascorbic acid standard (P ≤ 0.05); compounds 1-3 are not significantly different from the standard eserine in anti-cholinesterase activity. The 4-hydroxybenzoic acid isolated from the two plants recorded 727.45 AAE mg/g in the ferric reducing antioxidant power and 717.12 AAE mg/g in the total antioxidant capacity assay. The study concluded that 4-hydroxybenzoic acid is responsible for the plants' activity against foodborne pathogens and exhibited strong anti-biofilm properties. Additionally, every isolated compound demonstrated antioxidant activity in every model tested.
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    Open Access
    Evaluation of toxicological and biochemical activities of milicia excelsa (welw) C. C. Berg stem-bark extracts
    (Department of Biochemistry, Obafemi Awolowo University, Ile-Ife., 2014) Areola, Jacob Oladayo
    The study evaluated the toxicological and biochemical potentials of the ethanolic stem-bark extract of excelsa with a view to investigating its biochemical activities and the toxicity profile. The fresh stem-bark M. excelsa was air dried and milled to fine powder. The powdered stem bark (1 kg) was macerated in 3 litres of 70% (v/v) ethnol/water with regular shaking for12 h. The filtrate was concentrated, lyophilized and labelled ethanlic extract (EF). Twenty five grams (25 g) of EF was partitioned sequentially with hexane, ethyl acetate and n-butanol to give ethylacetate fraction (EAF), butanol fraction and aqueous fraction (AqF).
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    Some aspects of the population dynamics of sarotherodon galilaeus (artedi) in the opa reservoir of Obafemi Awolowo University, Ile-Ife, Nigeria.
    (Department of Zoology, Obafemi Awolowo University, Ile-Ife, Nigeria., 1996) Fawole, Olatunde Olubanjo.
    Field and laboratory investigations were carried out some aspects of the population dynamics of sarontherodon galilaeus in Opa reservoir between January 1989 and march 1994. These aspects include the mode of distribution, food and feeding habits reproduction, age and growth as well as the level of parasitic infestation of the fish species. The fishing employed were gill netting cast netting of the fish species.