BIOASSAY- GUIDED ISOLATION AND CHARACTERIZATION OF A TRYPANOCIDEFROMMISTLETOE (VISCUM ALBUM) EXTRACTS

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dc.contributor.authorWASSAGWA, JOHN
dc.date.accessioned2024-09-24T13:42:05Z
dc.date.available2024-09-24T13:42:05Z
dc.date.issued2023-06
dc.descriptionA DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF DOCTOR OF PHILOSPHY IN BIOCHEMISTRY DEPARTMENT OF BIOCHEMISTRY, FACULTY OF LIFE SCIENCES, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
dc.description.abstractViscum album is a parasitic plant of immense medicinal significance and was evaluated for antitypanosomal potential. Fresh leaves and stemof V. albumwas obtainedfrom the following host plants;Azadirachta indica, Psidium guajava, Acacia albida, Khaya senegalensis and Moringa oleifera. The extracts were prepared by cold maceration using methanol. In vitro anti-trypanosomal screening of the extracts against T. b. brucei was carried out in 96 well microtiter plates at final concentrations of 0.8, 0.4, 0.2, 0.1 and 0.05 mg/mL. A bio-assay guided isolation of the active compound was carried out by repeated silica gel column chromatography, monitored by TLC. Structuralelucidation wasperformed by 1D and 2D NMR. The LD50 of HDN-one was evaluated in mice using OECD method. Body weights of mice were taken daily for two weeks and clinical signs of toxicity were observed. In vivo effect of the compound isolated was evaluated on Trypanosoma bruceibrucei infected mice. The results showed that leaves and stem of V. album harvested from A. albida and A. indica hadin vitro activity against Trypanosoma brucei brucei. Leaves and stem of V. album from A. albida had 75% and 57.50% inhibition respectively while leaves and stem of V. album from A. indica had 61.21% and 59% respectively. Viscum album leaves from A. albida had the highest anti-trypanosomal activity (IC50 = 0.30 mg/mL). Qualitative phytochemicalscreening of the methanol extract ofV. album leaves from A. albida showed the presence of alkaloids, tannins, saponins, anthraquinone, phenols, steroids, terpenes, courmarins, flavonoids, and glycosides. Quantitative phytochemistry of the phenolics, flavonoids, alkaloids, and saponins revealed 0.82, 0.04, 1.91, and 2.02% composition respectively.Sequenial extraction of the methanol extract of V. album leaves from A. albidawith n-hexane, ethyl acetate, and n-butanol showed thatn-butanolfraction had the highest yield of 45.26% and was themost active fraction against Trypanosoma brucei brucei (IC50 = 0.84 mg/mL). Bioassay- guided fractionation of n–butanol fraction and subsequentpurification of the resulting bioactive compound led to the isolation of [2-(4- hydroxyphenyl) ethyl]-2,6-dioxabicyclo [3.3.1] nonan-3-one (HDN-one)with in vitro antitrypanosomal activity against T. b. brucei (IC50 = 0.26 mg/ mL). The compound did not show toxicity in mice at a dose level of 2000 mg/kg bw. There was a significant decrease in parasitemia of the group treated with the compound compared to infected untreated group. The compound had no inhibitory effect on the activity of trypanosome alternative oxidase (TAO) and trypanosome glycerol kinase (TGK). In conclusion, the results of this study revealed that HDN-one isolated from V. album leavesdid not show signs of toxicity in mice at a dose level of 2000 mg/kg body weight and had in vivo anti-trypanosomal activity against T. b. brucei.
dc.identifier.urihttps://kubanni.abu.edu.ng/handle/123456789/13028
dc.language.isoen
dc.titleBIOASSAY- GUIDED ISOLATION AND CHARACTERIZATION OF A TRYPANOCIDEFROMMISTLETOE (VISCUM ALBUM) EXTRACTS
dc.typeThesis
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