Ujowundu, Favour Ntite2026-04-082026-04-082016-04Ujowundu, F. N. (2016). Isolation, characterization and radical-scavenging potentials of bioactive components of combretum dolichopentalum leaves [Unpublished Doctoral Thesis]. Federal University of Technology, Owerri, Nigeriahttps://repository.futo.edu.ng/handle/20.500.14562/2610This thesis is for the award of Doctor of Philosphy (PhD.) in Medical BiochemistryThe present study isolated, identified and characterized the bioactive components of Combretum dolichopentalum leaves and determined the antioxidant potentials of the extracts of the leaves on some biochemical and physiological parameters. Biochemical methods such as ion exchange chromatography, column chromatography, thin layer chromatography, gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), spectrophotometric analyses, atomic absorption spectrometry and Fourier transform infra red (IR) were used. Preliminary phytochemical analyses showed the presence of flavonoids, alkaloids, saponins, tannins, oxalate and phytate. Further screening show the presence of flavonoids: kaempferol, luteolin, isorhamnetin and apigenin; alkaloids: akuamidine, undulantine, powelline and their hydroxylated compounds, voacangine and buphranidine; saponins: hicogenin, sapogenin, tribuloin and tannic acids. The use of GC-MS aided the identification of organic acids: (heptedecanoic acid), organic esters (ethyl octadecanoate), ketones (6,10-dimethyl-2- undecanone), alcohols (3,7,11,15-tetramethyl-2-hexadecen-1-ol) and phenol derivatives (Phenol-2,6-bis (1,1-dimethyl)-4 -methyl, methyl carbamate). Also, the eluates obtained from column and thin layer chromatography were analysed with IR and phenol-2,6-bis (1,1- dimethyl)-4-methyl, methyl carbamate, nitrocyclohexane, fluorodecane and others were identified. Proximate analysis showed the presence of carbohydrates, proteins, lipids, sodium, potassium, phosphorus, vitamins A, E and B-vitamins. Amino acid profile using the technicon sequential multi-sample amino acid analyser (TSM) showed the presence of essential and non essential amino acids. The effects of isolates such as flavonoids, saponins, alkaloids and tannins were determined for in vitro hydrogen peroxide scavenging ability. The effects of the extract in comparison with a standard drug (silymarin) on animal organ/tissue functions and on serum concentrations of electrolytes, beneficial transition minerals, lipids, antioxidants and markers of lipid peroxidation were determined. The effects of the crude extract in comparison with standard plant antioxidant (quercetin) and butylated hydroxyl toluene (BHT), for in vitro scavenging potentials showed dose dependent scavenging potentials on nitric oxide, hydroxyl radical, H2O2 induced lipid peroxidation and reducing power. Intoxication with CCl4 after pre-treatment with the ethanol extract and crude flavonoid, saponin, alkaloid and tannin fractions indicated hepatoprotective and antinephrotoxic potentials except saponins isolate which showed a significant (P˂0.05) adverse effect as indicated by some biochemical and physiological parameters. Flavonoid and alkaloid extracts are the major fractions that elicited biochemical and physiological benefits in CCl4 intoxication. The in vitro and in vivo radical scavenging properties of extracts of C. dolichopentalum make a promising drug with strong antioxidant potentials and inhibitory against Escherichia coli and Salmonella typhi.The present study isolated and characterized the phytochemicals in C. dolichopentalum leaves which could be further exploited for the treatment of oxidative stress and microbial induced disorders and diseases especially in lightenAttribution-NonCommercial-ShareAlike 4.0 InternationalCombretum dolichopentalumgas chromatographyGC-mass spectrometryinfra red spectrometryatomic absorption spectrometryphytochemicalsradical-scavengingantimicrobialscarbon tetrachlorideoxidative stressantioxidantsDepartment of BiochemistryDoctoral Thesis