Ugenyi, Assumpta Ugbonma2026-02-042026-02-042021-09Ugenyi, A.U(2021). Studies on antibacterial, antifungal and antioxidant activities of curcum longa, mimosa pudica, euphorbia serrata medicinally used in Nigeria [Unpublished Doctoral Thesis]. Federal University of Technology, Owerri, Nigeriahttps://repository.futo.edu.ng/handle/20.500.14562/2364This thesis is for the award of Doctor of Philosophy Degree (PhD.) in Environmental Health BiologyThree plants –Euphorbia serrata, Mimosa pudica L. and Curcum longa L. suggested from their ethno-medicinal uses to possess antimicrobial, and antioxidant activities were evaluated for their different biological activities. Phytochemical analyses were carried out using standard qualitative and quantative analytical methods. Antimicrobial activities were determined by well diffusion method for the isolates; Proteus mirabilis, Alcaligenes faecalis, Klebsiella pneumoniae, Wohlfahrtiimonas chitiniclastica, Candida tropicalis and Wickerharmoyces anomalus identified using DNA sequencing. The antioxidant potentials of the extracts were determined by their abilities to scavenge 2, 2-diphenyl-1- picrylhydrazyl radical, nitric oxide radical, hydrogen peroxide.The antioxidant potentials were further determined by the reducing power using standard methods. Acute and sub-chronic oral toxicity of the extracts were carried out with Lorke′s method using male albino rats. Pathology examinations of the organs (liver, kidney and heart) were also evaluated. Results of phytochemical analysis revealed the presence of Alkaloids (E. serrata 6.85%; M. pudica2.94%; C. longa 5.28%), Tannins (E. serrata, 35.2%; M. pudica, 24%; C. longa 24.2%), Saponnins (E. serrata 5.77%; M. pudica 6.20%%; C. longa 7.26%), Flavonoids (E. serrata 9.80%, M. pudica 53.8%, C. longa 13.18%), %) and Cardiac glycosides (E.serrata 5.31%, M. pudica 3.22%, C. longa 3.30%). All the extracts inhibited the growth of both bacteria(effective zone of inhibition 7 to 26 mm) and fungi (effective zone 5 to 17 mm) compared to chloramphenicol and griseofulvin respectively. Aqueous extracts of C.longa. had no inhibition for A. faecalis and the fungi at 25mg/ml. The magnitude of bacterial inhibition by the extracts followed order (M.pudica > C.longa > E.serrata) and (C.longa > E. serrata > M.pudica) for the fungi. Scavenging of DPPH, nitric oxide, H2O2 radicals and reducing power ability were concentration dependent. Ethanolic extracts had a significant (p < 0.05) antioxidant scavenging activities for H2O2 and reducing power. E. serrate, M. pudica, C. longa exhibited a strong reducing power (R.P 0.5AU = 15.01 µg/ml, 10.0 µg/ml, 9.38 µg/ml) (R.P 0.5AU = 34.09 µg/ml, 21.77 µg/ml and 21.63 µg/ml) for ethanol and methanol extracts respectively and effectively scavenged DPPH, nitric oxide and H2O2 radicals. Threshold inhibitory concentrations (IC50) of E. serrate, M. pudica, C. longa and ascorbic acid against DPPH radicals were (28.74 µg/ml,19.64 µg/ml,15.62 µg/ml and 15.62 µg/ml ) for ethanol extracts and (2.92 µg/ml, 16.10 µg/ml, 12.50 µg/ml and 15.62 µg/ml) for methanol extracts. IC50 of E. serrate, M. pudica, C. longa and ascorbic acid for nitric oxide radicals were (22.67µg/ml, 50.02µg/ml, 48.34µg/ml and 15.46 µg/ml) for ethanol extracts and (16.55µg/ml, 16.17 µg/ml, 15.36 µg/ml and 15.46 µg/ml) for methanol extracts. IC50 of E. serrata, M. pudica, C. longa and ascorbic acid against H2O2 radicals were (15.31 µg/ml, 15.26 µg/ml, 15.26 µg/ml and15.15 µg/ml) for ethanol extracts and (15.48 µg/ml, 24.17 µg/ml, 35.03 µg/ml and 15.15 µg/ml) for methanol extracts. Mortality from the extracts at a single dose of 5000 mg/kg body weight, were revealed. Sub-chronic oral toxicity of the extracts 200 mg/kg and 400 mg/kg body weight revealed non-significant difference (p ˃ 0.05) on the biochemical parameters (ALT, AST, ALP, LDH, SOD, GSH, TP, GPx, CAT, ALB, Urea and Creatinine). Haematology parameters (HB, WBC, RBC, PVC) values when compared with control, showed significant difference (p ˂ 0.05).Similar results were also revealed for body weight when compared with control. Examination of the liver, kidney and heart showed no significant morphological changes except with M. pudica, where observed pathological changes include fatty degeneration and inflammatory cells (lymphoctyes and macrophages) irrespective of extract dosage.enAttribution-NonCommercial-ShareAlike 4.0 InternationalPhytochemicalsantibacterialantifungalantioxidantstoxicityDepartment of BiotechnologyDoctoral Thesis