Exploring the potential of imines as antiprotozoan agents with focus on t. Brucei and p. Falciparum
- Authors: Oluwafemi, Kola Augustus
- Date: 2018
- Subjects: Protozoa , Parasites , Imines , Nuclear magnetic resonance , HeLa cells , Plasmodium falciparum , Trypanosoma brucei , Isomerism
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/62235 , vital:28145 , DOI 10.21504/10962/62235
- Description: This work focuses on the design, synthesis and evaluation of imine-containing heterocyclic and acyclic compounds with special focus on their bioactivity against parasitic protozoans (P. falciparum and T. brucei) - given the context of drug resistance in the treatment of malaria and Human African sleeping sickness and the fact that several bioactive organic compounds have been reported to possess the imino group. Starting from 2-aminopyridine, novel #-alkylated-5-bromo-7-azabenzimidazoles and substituted 5-bromo-1-(carbamoylmethy)-7-azabenzimidazole derivatives were prepared, and their bioactivity against parasitic protozoans was assessed. NMR spectra of the substituted 5- bromo-1-(carbamoylmethy)-7-azabenzimidazole derivatives exhibited rotational isomerism, and a dynamic NMR study was used in the estimation of the rate constants and the free- energies of activation for rotation. The free-energy differences between the two rotamers were determined and the more stable conformations were predicted. Novel 2-phenyl-7-azabenzimidazoles were also synthesised from 2-aminopyridine. A convenient method for the regioselective formylation of 2,3-diaminopyridines into 2-amino- 7-(benzylimino)pyridine analogues of 2-phenyl-7-azabenzimidazole was developed, and some of the resulting imino derivatives were hydrogenated to verify the importance of the imino moiety for bioactivity. The 2-phenyl-7-azabenzimidazoles and the 2-amino-7- (benzylimino)pyridine analogues were screened for their anti-protozoal activity and their cytotoxicity level was determined against the HeLa cell line. In order to validate the importance of the pyridine moiety, novel #-(phenyl)-2- hydroxybenzylimines, #-(benzyl)-2-hydroxybenzylimines and (±)-trans-1,2-bis[2- hydroxybenzylimino]cyclohexanes were also synthesized and screened for activity against the parasitic protozoans and for cytotoxicity against the HeLa cell line. The biological assay results indicated that these compounds are not significantly cytotoxic and a good number of them show potential as lead compounds for the development of new malaria and trypanosomiasis drugs. , Thesis (PhD) -- Faculty of Science, Chemistry, 2018
- Full Text:
- Date Issued: 2018
- Authors: Oluwafemi, Kola Augustus
- Date: 2018
- Subjects: Protozoa , Parasites , Imines , Nuclear magnetic resonance , HeLa cells , Plasmodium falciparum , Trypanosoma brucei , Isomerism
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/62235 , vital:28145 , DOI 10.21504/10962/62235
- Description: This work focuses on the design, synthesis and evaluation of imine-containing heterocyclic and acyclic compounds with special focus on their bioactivity against parasitic protozoans (P. falciparum and T. brucei) - given the context of drug resistance in the treatment of malaria and Human African sleeping sickness and the fact that several bioactive organic compounds have been reported to possess the imino group. Starting from 2-aminopyridine, novel #-alkylated-5-bromo-7-azabenzimidazoles and substituted 5-bromo-1-(carbamoylmethy)-7-azabenzimidazole derivatives were prepared, and their bioactivity against parasitic protozoans was assessed. NMR spectra of the substituted 5- bromo-1-(carbamoylmethy)-7-azabenzimidazole derivatives exhibited rotational isomerism, and a dynamic NMR study was used in the estimation of the rate constants and the free- energies of activation for rotation. The free-energy differences between the two rotamers were determined and the more stable conformations were predicted. Novel 2-phenyl-7-azabenzimidazoles were also synthesised from 2-aminopyridine. A convenient method for the regioselective formylation of 2,3-diaminopyridines into 2-amino- 7-(benzylimino)pyridine analogues of 2-phenyl-7-azabenzimidazole was developed, and some of the resulting imino derivatives were hydrogenated to verify the importance of the imino moiety for bioactivity. The 2-phenyl-7-azabenzimidazoles and the 2-amino-7- (benzylimino)pyridine analogues were screened for their anti-protozoal activity and their cytotoxicity level was determined against the HeLa cell line. In order to validate the importance of the pyridine moiety, novel #-(phenyl)-2- hydroxybenzylimines, #-(benzyl)-2-hydroxybenzylimines and (±)-trans-1,2-bis[2- hydroxybenzylimino]cyclohexanes were also synthesized and screened for activity against the parasitic protozoans and for cytotoxicity against the HeLa cell line. The biological assay results indicated that these compounds are not significantly cytotoxic and a good number of them show potential as lead compounds for the development of new malaria and trypanosomiasis drugs. , Thesis (PhD) -- Faculty of Science, Chemistry, 2018
- Full Text:
- Date Issued: 2018
Prevalence and seasonal changes of gastro-intestinal parasites of ovine on three different veld types in communal farming areas of the Eastern Cape Province, South Africa
- Jansen, Mlungisi Selby https://orcid.org/0000-0002-6735-1054
- Authors: Jansen, Mlungisi Selby https://orcid.org/0000-0002-6735-1054
- Date: 2023
- Subjects: Gastrointestinal system , Parasites , Traditional farming
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28233 , vital:73956
- Description: The current study aimed to investigate the prevalence and seasonal changes of gastro-intestinal parasites GIP of ovine grazed don three different veld types in the communal farming areas of the Eastern Cape Province. A total of 1242 sheep faecal samples were collected monthly between January 2012 and December 2015 to investigate the prevalence and season occurrence of internal parasites. From September to November 2018, a semi-structured questionnaire survey was conducted in three agro-ecological zones, humid Wartburg, semi-humid Allen waters, and arid region Cradock commonages to investigate farmers’ knowledge of the prevalence and occurrence of GIP in sheep. The prevalence of gastro-intestinal parasites was significantly higher in the humid zone roundworms 81 percent and coccidia 37 percent, followed by the semi-humid zone roundworms 75 percent and coccidia 22 percent and the arid zone was the lowest roundworms 71 percent and coccidia 14 percent. Roundworms had significantly higher counts P 0.05 mostly in hot-wet seasons of the year spring and summer and low during dry cold months of the year autumn and winter across all veld types. The humid zone had significantly higher counts P 0.05 in the seasonal occurrence of roundworms and coccidia, followed by humid zone, and very low counts were encountered in the arid zone during the study period. Seasonal occurrence of roundworm species was significant across all veld types, 64 percent of farmers were males and 36 percent were females. The study reveals that helminths and coccidia are major causative agents causing parasitic infections in livestock production, and therefore, good animal health practices management practices including proper hygiene should be followed to prevent parasitic infection in small ruminants. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
- Authors: Jansen, Mlungisi Selby https://orcid.org/0000-0002-6735-1054
- Date: 2023
- Subjects: Gastrointestinal system , Parasites , Traditional farming
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28233 , vital:73956
- Description: The current study aimed to investigate the prevalence and seasonal changes of gastro-intestinal parasites GIP of ovine grazed don three different veld types in the communal farming areas of the Eastern Cape Province. A total of 1242 sheep faecal samples were collected monthly between January 2012 and December 2015 to investigate the prevalence and season occurrence of internal parasites. From September to November 2018, a semi-structured questionnaire survey was conducted in three agro-ecological zones, humid Wartburg, semi-humid Allen waters, and arid region Cradock commonages to investigate farmers’ knowledge of the prevalence and occurrence of GIP in sheep. The prevalence of gastro-intestinal parasites was significantly higher in the humid zone roundworms 81 percent and coccidia 37 percent, followed by the semi-humid zone roundworms 75 percent and coccidia 22 percent and the arid zone was the lowest roundworms 71 percent and coccidia 14 percent. Roundworms had significantly higher counts P 0.05 mostly in hot-wet seasons of the year spring and summer and low during dry cold months of the year autumn and winter across all veld types. The humid zone had significantly higher counts P 0.05 in the seasonal occurrence of roundworms and coccidia, followed by humid zone, and very low counts were encountered in the arid zone during the study period. Seasonal occurrence of roundworm species was significant across all veld types, 64 percent of farmers were males and 36 percent were females. The study reveals that helminths and coccidia are major causative agents causing parasitic infections in livestock production, and therefore, good animal health practices management practices including proper hygiene should be followed to prevent parasitic infection in small ruminants. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
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