College of Natural Sciences (CoNAS)

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    A 3d basin modelling approach to the assessment of hydrocarbon potential of Lake Edward basin, western Uganda
    (Makerere University., 2023-09-06) Atwebembeire, Conscent
    Lake Edward basin is a rift basin located in the extreme south of the Ugandan portion of the western arm of the East African Rift System (EARS), popularly known as the Albertine Graben. 3D basin modelling approach was applied to Lake Edward basin with the objective of gaining an understanding of its hydrocarbon potential. The approach utilized 2D Seismic data, well data, geochemical data and well completion reports from Lake Edward basin. 2D seismic data were integrated with well log data to define stratigraphic framework of the basin, onto which heat flow and geochemical characterization was undertaken to establish the possible potential source rocks of the basin. The integrated 3D basin modelling revealed the burial history, including the development of potential entrapment and source rock maturation. The major structures responsible for the hydrocarbon migration and entrapment in the field as interpreted are fault structures especially tilted faults blocks and normal faults. PetroMod software (version 2018.2) produced hydrocarbon maturation and generation model of the Lake Edward basin. The model shows that the source rock, Lower Ngaji Formation is currently at temperatures between 50oC-80oC. According to the model, the source rock, Lower Ngaji with typical characteristics of a mixture of Type II and III kerogen is immature with respect to petroleum generation. The research has provided a better understanding of key controls on hydrocarbon potential of Lake Edward basin and has enhanced the understanding of the timing and extent of hydrocarbon generation in Lake Edward basin and so the petroleum exploration risk can be potentially reduced This is useful for the oil and gas industry in the country as the findings are helpful in setting the next drilling phase of future exploration activities.
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    Abundance and some aspects of breeding biology of African Catfish (Clariasgariepinus) in Kafu Riverine wetland
    (Kikonyogo, F.E. (2017). Abundance and some aspects of breeding biology of African Catfish (Clariasgariepinus) in Kafu Riverine wetland. Unpublished masters dissertation. Makerere University, Kampala, Uganda., 2017) Kikonyogo, Francis Exavier
    Various studies on the ecology and biology of Clarias gariepinus have been carried out elsewhere by different scholars but not specific to Kafu Riverine wetland, because of its intraspecific ecological variations, fisheries resource management decisions that have been taken have not helped to address the environmental and human induced problems in the river catchment areas, therefore information generated from this study will help to address the above problems. This riverine wetland has two habitat types (open pools of water and closed wetland) this support a variety of fish species including Clarias gariepinus which account for 82% of the fishery of river Kafu. In this study, fish samples were caught using various fishing gears such as basket traps gillnets and hooks. This was done once every fortnight and average catch per unit effort derived. The relations of fecundity to standard length (cm), total weight (g) and gonadal weight (g) were determined by regressionPearson‟s statistics.Results of this study revealed that, the abundance of Clarias gariepinusper day was significantly higher in the open than in the closed wetland type, the abundance was6.19±0.65and 3.0±0.65 fish in the open and closed wetlands respectively (P< 0.008). Within seasons, a significant difference in abundance of this species per day was 6.75±0.612and 2.43±0.612in the wet and dry seasons, respectively(P<0.042).Clarias gariepinus exhibited a weak positive linear relationship with total length and somatic weight. However, a strong positive linear relationship was found between fecundity and gonadal weight: y = 366.3x + 7982, (r2=0.721, N = 157, p< 0.01). Therefore, gonadal weight was the best indicator of fecundity accounting for 72% of the variation in fecundity of Clarias gariepinus in Kafu riverine wetland. Gonadal somatic index (GSI) values of both females and males were at their highest during the months of October and November respectively and eventually started declining in mid-November which indicated the spawning activity. Therefore, November was presumed to represent the spawning period of Clarias gariepinus in Kafu riverine wetland. Males matured earlier (L50=33.7cm) than females (50= 33.7cm). Despite of C.gariepinus enormous contribution to the livelihood of the people especially in its catchment area, it is being threatened by human activities such as over fishing and environmental fluctuations which have caused changes in the abundance and reproduction of this specie Therefore information from this study will help to update managers especially in the affected districts on the key aspects of ecology and reproduction that needs attention for sustainable management of the fisheries resources.
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    Adsorption behavior of acid-leached clays in bleaching of oil
    (Scientific Research Publishing, 2015) Mukasa-Tebandeke, I. Z. ; Ssebuwufu, P. J. M. ; Nyanzi, S. A. ; Nyakairu, G. W. ; Ntale, M. ; Lugolobi, F. ; Schumann, Andreas
    The available data have shown that acid-leached clays had sites for adsorption of impurities in oils. Data obtained on residual impurities in cotton and sunflower-seed oils bleached with the same clay materials produced linear Langmuir and Freundlich isotherms. The increase in constant, k with increase in both temperature of thermal activation and concentration of acid used to leach the clay, suggests that bleaching efficiency increased. The value of n decreased with increase in temperature of activation and concentration of acid used to leach the clay suggesting that bleaching capacity increased. The mineral compositions of the clays influenced their surface, structural and bleaching properties.
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    Advances in carbon dioxide and propylene oxide copolymerization to form poly(propylene carbonate) over heterogeneous catalysts
    (Elsevier, 2022) Mbabazi, Ruth ; Wendt, Ola F. ; Nyanzi, Steven Allan ; Naziriwo, Betty ; Tebandeke, Emmanuel
    Chemical conversion of carbon dioxide (CO2) into value-added products is an attractive industrial process because it offers several economic and environmental advantages. This review presents advances and challenges in the CO2 and propylene oxide (PO) co-polymerization using heterogeneous catalysts to form poly (propylene carbonate) (PPC), an environmentally friendly polymer with several applications. In the co-polymerization process, CO2 is employed as a green carbon source, an alternative to the toxic phosgene which has numerous negative environmental impacts. However, this route of polycarbonate production, is hindered by the chemical inertness of CO2, and to overcome this, various catalysts have been developed. A number of heterogeneous catalysts including carboxylates, double metal cyanides and composites, have achieved varying success in activating CO2 in the production of polycarbonates. The effect of different reaction conditions including pressure, temperature and solvent has been explored. The limitations faced by various heterogeneous catalysts and im- provements made over the past decades have been highlighted. Mechanistic insights for the production of PPC from CO2 and PO have been presented and the differences in both the regioselectivity and stereochemistry of the resultant polymers discussed.
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    Aflatoxin exposure in Southwestern Uganda and the ameliorative effects of selected medicinal plants on induced aflatoxicosis in wistar rats
    (Makerere University, 2023-11) Murokore, Biryomumaisho Justus
    Introduction: Over 5.5 billion people, worldwide are chronically exposed to aflatoxins. This contributes to 40% of the African disease burden. Aflatoxins are mycotoxins produced by Aspergillus flavus and A. parasiticus, A. nomius, and A. tamarii, which are fungal species. Aflatoxin B1 (AFB1) is the most prevalent and carcinogenic among them. Since prevention of their production is not practical, we ingest them making toxicity control the easiest option. Consumption of high phenolic medicinal plant ameliorates the toxicological effects of aflatoxins. Objectives: The goal of the study was to assess dietary aflatoxin exposure in selected foodstuffs in Southwestern Uganda and the ameliorative effects of selected medicinal plants on aflatoxicosis in wistar rats. Specifically, the study set out to: (i) determine the aflatoxin susceptible food consumption frequency, prevalence and levels of aflatoxins in household foodstuffs in Southwestern Uganda; (ii) determine the phenolic, and flavonoid contents and antioxidant capacity of different selected medicinal plants (iii) assess the ameliorative effects of the selected medicinal plants on aflatoxin induced changes in liver, kidney and immune functions. Methods: Flours of Arachis hypogaea (groundnuts), Zea mays (maize), Eleusine coracana (millet), and Sorghum bicolor (sorghum), the most commonly aflatoxin contaminated foods, were systematically sampled, following a consumption frequency questionnaire. Samples were analysed for aflatoxin content using competitive ELISA. Ocimum gratissimum, Allium sativum, Cymbopogon citratus, Zingiber officinale, and primary grades and green tea, Camellia sinensis, were analysed for phenolics and flavonoids, following Folin-ciocalteu and Aluminium chloride methods respectively. Their antioxidant capacity was determined following DPPH and FRAP methods. Ninety-six male wistar rats were grouped into 16 groups of 6 and treated for 30 days as follows; 1. Control, 2. Olive oil. 3. AFB1 Low-dose (100µg/kg), 10. AFB1 High-dose (300µg/kgAFB1). 4-9. AFB1 Low-dose + 2% extracts, 11-16. AFB1 High-dose + 2% extract. Liver and kidney functions, histopathology, and immune function indicators were evaluated using standard methods. Results: The highest aflatoxin prevalence, levels and consumption frequency were observed in maize and groundnuts (Tables 4.1.2 and 4.1.1, respectively). Indoor dried/processed medicinal plants yielded higher total phenolic content (TPC) than fresh ones. In addition, 40 minutes extracts of medicinal plants yielded higher TPC. Green tea yielded the highest DPPH (93.82%) and FRAP (39.04µg AAE/mL), and tea harvested from Buganda (4,371 µgQE/g) the highest total flavonoid content (TFC). Green and black tea, C. sinensis, O. gratissimum, and C. citratus reduced the damaging effects of aflatoxin toxicity in liver functions, histopathology and blood and immunity parameters. Conclusion: Groundnut and maize were the main foods through which aflatoxin exposure occurs. For maximum TPC, it is better to use processed medicinal plants and longer extraction periods. Green and black tea, C. sinensis, O. gratissimum, and C. citratus have ameliorative effects in aflatoxicosis. Community awareness in aflatoxin contamination avenues and health effects, and encouragement to regularly consume high phenolic medicinal plants is urgently needed.
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    Amphibian diversity patterns in the Namulonge agricultural landscape
    (Makerere University, 2017) Akoth, Sisiria
    Uganda’s agricultural landscapes are patterns of cultivated areas and semi-natural elements. Although comprising only a small fraction of the total area, semi-natural elements provide habitats for most of the landscape biodiversity. Agricultural intensification has increasingly destroyed or fragmented semi-natural elements resulting into species decline. Insights into the effects of landscape structure on species’ distributions within and among semi-natural habitats are needed to effectively conserve biodiversity in agricultural landscapes. The influence of land use practices on amphibian species diversity was investigated in areas of intensive and subsistence agriculture in Namulonge for 12 weeks. Amphibians were sampled using Visual Encounter Surveys while environmental parameters were measured using digital multimetre. Altogether, 19 amphibian species were recorded in the Namulonge agricultural landscape. The Mann-Whitney U test showed no significant difference in species diversity between the land use areas. Characteristics of the landscape were used to predict patterns of amphibian species distribution in canonical correspondence analysis (CCA). The model identified plant materials, water and ambient temperature as the most important variables in predicting species distribution. Areas with relatively intact natural vegetation cover supported a few more species than completely converted areas. Such pockets of vegetation provide microhabitat conditions suitable for amphibian species occurrence. The foregoing observation suggests that there is value at landscape-level to preserve natural/semi-natural pockets of vegetation to enhance biodiversity in any agricultural environment.
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    Analgesic, anti-inflammatory and oxytocic activities of Dracaena steudneri Engl. stem bark aqueous extract in Wistar rats
    (Academic journals, 2022) Katuura, Esther ; Tenywa, Mercy Gladys ; Agaba, Amon Ganafa ; Ajayi, Clement Olusoji ; Tolo, Casim Umba
    Dracaena steudneri Engl. (Dracaenaceae) is a medicinal plant that is used in labour by traditional birth attendants to induce labour, relieve pain and treat various diseases; albeit no documentation. This study determined the analgesic, anti-inflammatory and oxytocic effects of the D. steudneri stem bark aqueous extract. D. steudneri stem bark was collected, authenticated, oven-dried at 45ºC for 48 h, pulverized and extracted using the decoction method. The analgesic effect of the aqueous extract was determined using the acetic acid writhing test, anti-inflammatory activity was determined using paw oedema method while oxytocic activity was determined using abortion and other standard test procedures and were tested at 12.1 24.1 and 48.2 mg/kg. The results of the analgesic study showed that the extract reduced the number of abdominal writhing between 53.51 and 92.40% at 6.02 and 48.2 mg/kg dose, respectively while the standard drug showed a reduction of 36.58% at 10 mg/kg. The anti-inflammatory results showed percentage inhibition of 18.6% (2 h), 22% (2 h) and 18.9% (6 h) at 12.1, 24.1 and 48.2 mg/kg, respectively. The in vivo oxytocic activity showed average time taken for the rats to deliver was between 20.63 h at lowest dose (12.1 mg/kg) and 8.25 h at highest dose (48.0 mg/kg) while Oxytocin the reference drug exhibited, 22 h as the average time taken for delivery.
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    Analysis of microbial quality of common bean (Phaseolus vulgaris l.) seeds from five bean producing districts in Uganda
    (Makerere University, 2022-04-25) Isout, Sylas
    Being a basic and an affordable source of protein, common bean (Phaseolus vulgaris L.) is grown widely in Uganda and the world at large. The quality of bean seeds has gained little attention yet remains a significant aspect of the value chain of production and consumption in Uganda. The aim of this study was to assess the microbial quality of common beans from five bean producing districts of Uganda. One hundred bean samples were collected from farmers and traders purposively selected from five bean producing districts of Uganda (Arua, Oyam, Hoima, Nakaseke, and Sironko districts). Three replicates of twenty samples of bean seeds randomly obtained from each district were subjected to microbial quality analysis using whole seed and agar plate standard protocols under laboratory conditions. The modified blotter method was used to test germinability and health of bean seeds in the laboratory. Standard seedling symptom tests were conducted in screen house experiments using a completely randomized design to assess germination and health of bean seedlings. Seed health tests revealed that 85% of the bean samples were contaminated with seed borne fungi. Five seed borne fungal genera were isolated from the seed samples, with Aspergillus (42.8 %) and Fusarium (37.1 %) being the most common fungi followed by Penicillium (18.9 %) while Colletotrichum (12.2 %) and Rhizopus (6.2%) were the least occurring fungi. Xanthomonas sp. was the only bacteria isolated from 15% of the samples tested. In the laboratory, bean seeds exhibited relatively poor germination (58.2%), with 30.9% of seeds having fungal outgrowths. While in the screen house, only 63.2% of seeds germinated, with 23.9% of ungerminated seeds being rotten. Disease assessment in the screen house revealed that, 25.1% of seedlings were diseased with various symptoms. Six seed borne diseases were recorded including; Fusarium wilt, Angular leaf spot (ALS), Ascochyta blight, Anthracnose, Common Bacterial Blight (CBB) and Bean common mosaic virus (BCMV). Determinately, the beans available in Uganda are of low/poor quality. Poor quality seeds contaminated with seed borne pathogens may result in poor germination rates, poor health of seedlings and reduced crop stand and yield. Therefore, improving access to clean and healthy seed for farmers is inevitable. Farmers are urged to embrace good bean production practices especially disease management in the field and post-harvest handling practices in order to improve production of safe and quality beans.
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    Analysis of x-ray characteristics of narrow line Seyfert 1 Galaxies from nuclear spectroscopic telescope array data
    (Makerere University, 2022) Kamulali, Juma
    Narrow line Seyfert 1 (NLS1) galaxies are among the most variable active galactic nuclei (AGN) in the sky. Hard X-ray spectral and timing analysis of two of these galaxies, NGC 4051 and ARK 564, using NuSTAR data is presented. The data was processed using nupipeline task in HEASoft and spectral, light curve and response files were generated using nuproducts module. X-ray spectra of the two sources were fitted in XSPEC with a reflection model (Pexrav) plus a Gaussian component (Gauss), corrected for line-of-sight galactic absorption using photo-electric absorption component (Phabs). The intrinsic powerlaw continuum is of slope Γ > 1.59, which is slightly steeper than the typical Seyfert 1 galaxies. Strong emission lines (EW > 100 eV) were detected at ∼ 6.4 keV in the two X-ray sources. The X-ray spectra of these sources above 10 keV exhibit a Compton hump, produced by Compton backscattering of hard X-ray photons by reprocessing optically- thick accretion disc, and is prominent at high energies. The deduced 3-79 keV luminosity of the two studied X-ray sources differ by 2 orders of magnitude (∼ 6.12×1041 ergs-1 for NGC 4051 and ∼ 2.47×1043 erg s-1 for ARK 564), thus ARK 564 is brighter than NGC 4051 in hard X-ray energies. High-amplitude X-ray variability of NLS1 galaxies was analysed by means of cross power spectral density (CPSD) in this study since multiple instrument simultaneous observations were made by NuSTAR. The average CPSD for each of the two sources was generated using High Energy Data Reduction Interface from Command Shell and the fitting performed in XSPEC. The spectra were fitted quite well in the frequency range ∼ 10-3 to ∼ 0.2 Hz, using four broad Lorentzian models with ARK 564 revealing more variability power estimates (total rms = 63.59%) than NGC 4051 (total rms = 37.3%). The coherence of variablity (Q < 2) of the X-ray sources shows no evidence of quasi-periodic oscillations (QPOs) possibly owing to the short period NuSTAR observations. Only two NLS1 galaxies have been considered. Further analysis of a large sample of these objects and the typical Seyfert 1 galaxies needs to be done in order to draw meaningful deductions about evolution of their hard X-ray spectra and timing properties and to distinguish between the two classes.
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    Anti-bacterial activity and characterisation of compounds of leaf extracts of Erlangea tomentosa S. Moore
    (Makerere University, 2022-12-05) Ekyibetenga, Yeremiah
    Bacterial infections such as pneumonia, lower respiratory tract infections, gastrointestinal disorders and skin infections are health burden to mankind. In Uganda, several medicinal plants are locally used to treat various bacterial infections because of affordability and accessibility of herbal medicine. Erlangea tomentosa (ET) is one of the plants used to treat various bacterial infections such as gastrointestinal disorders, skin infections, diarrhea, syphilis and cough. However, compounds responsible for its activity are not known and this limits its wider use and development into drugs. Therefore, the purpose of the study was to characterise the compounds from leaf extract of ET that could be responsible for its antibacterial properties. The leaves were collected, ground into a course powder and extracted sequentially using n-hexane, dichloromethane, ethyl acetate and methanol. Antibacterial activity of the extracts against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Klebsiella pneumoniae (K. pneumoniae) and Salmonella typhi (S. typhi) was done to identify the more active extract. Isolation of compounds from ethyl acetate extract (ETE) and dichloromethane extract (ETD) was done by column chromatography and compounds characterised by spectroscopic techniques. ETE showed a highest zone of inhibition (17.3 ±0.6, 16±1.0, 11.7±0.6 and 13.7±0.6 mm) followed by methanol extract (ETM) (10.3±0.6, 15±1.0, 14.7±0.6 and 10±0.0 mm) for E. coli, S. aureus, K. pneumoniae and S. typhi, respectively and ETD (17.3±0.6 and 10±0.0 mm) for E. coli and S. typhi, respectively. Hexane extract showed no zone of inhibition. Eriodictyol-7-O-β-glucoside (1) and 5, 7, 3’, 4’-tetrahydroxy-7-O-[6"-O-(acetyl)-β-D-glucopyranosyloxy]-flavanone (2) were isolated from ETE while di-(2-ethylhexyl) phthalate (3) was isolated from ETD. This was the first time to identify these compounds from the plant species of genus Erlangea. Compound 3 has been reported to have a moderate activity against Bacillus subtilis, Staphylococcus aureus, Streptococcus equosemens, Escherichia coli and Pseudomonas aeruginosa. Therefore, the bioactivity of the leaf extracts and the presence of compound 3 that is reported to be very active against various bacterial strains support the use of the plant. Compounds from ETM should be isolated and characterised to obtain more bioactive compounds from ET.
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    Anti-bacterial activity and characterization of compounds from the leaf extract of Solenostemon Latifolius Hochst.ex benth.
    (Makerere University, 2021-03) Imalingat, Betty
    Infectious diseases have continuously been reported among the leading causes of death in the world. These include bacterial infections like tuberculosis and pneumonia. Several antibiotics have been used against these infections. However, bacteria are becoming resistant to a number of antibiotics, leading to increased mortality, morbidity and treatment costs. Therefore, there is need to discover more effective antibacterial drugs and plants have been sought as sources of antibiotics. The aim of this study was to isolate and identify antibacterial compounds from Solenostemon latifolius, a plant that is locally used to treat bacterial infections in Uganda. The plant sample was collected, dried and ground into a fine powder. The powder was extracted using distilled water and 1:1 DCM -methanol mixture. Phytochemical screening was done and both extracts and isolated compounds were subjected to antibacterial test using the agar well diffusion method. The organic extract was then partitioned and subjected to isolation using a column packed with silica gel. Structural elucidation of the isolated compounds was done using NMR, MS and UV spectroscopy. Phytochemical screening revealed presence of flavonoids, terpenoids and steroids among others. The zone of inhibition (ZOI) for the organic extract was 14 mm and 18 mm against Staphylococcus aureus and Escherichia coli. The aqueous extract had ZOI as 13 mm for E. coli. S. aureus was not susceptible to the aqueous extract. Isolated compounds were identified as Coleone U, β-sitosterol, stigmasterol and 3,4-dihydroxyphenyl caffeate. Coleone U (ZOI between 10-12 mm at a concentration of 40 mg/ml) had activity comparable to that of gentamicin standard used. Therefore, Solenostemon latifolius is a medicinal plant with several classes of phytochemicals responsible for its antibacterial activity. This supports its use as a medicinal plant against bacterial infections
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    Anti-infective activity, phytochemistry and cytotoxicity of Dalbergia Melanoxylon Guill. & Perr and Ormocarpum Sennoides ssp. Zanzibaricum Brenan & J.B. Gillett
    (Makerere University, 2025-03-26) Chalo, Duncan Mutiso
    Infectious diseases account for 90% of the disease burden worldwide with a significant rampage being felt in developing countries. This is coupled by the widespread antibiotic resistance to available conventional drugs. Infectious agents have been reported to raise the risk of human cancer which is a major cause of mortality worldwide. The aim of this study was to investigate Dalbergia melanoxylon Guill. & Perr and Ormocarpum sennoides subsp. zanzibaricum Brenan & J.B. Gillett as potential anti-infective and anticancer agents. Extraction of root bark of D. melanoxylon was done using CH2Cl2/MeOH (1:1) while O. sennoides subsp. zanzibaricum was extracted using 80% methanol and partionioned to obtain n-hexane, ethylacetate, n-butanol and water extracts. The structures and absolute configuration of the isolated compounds were elucidated by Mass spectrometry, Nuclear magnetic resonance and Electronic circular dichroism spectroscopy. The antibacterial activity of the crude extract and the isolated compounds against Bacillus subtilis and Aliivibrio fischeri was determined in a turbidimetric assay. The pure compounds were subjected to a panel of human pathogenic bacteria (Enterococcus faecalis, Escherichia coli, Mycobacterium vaccae, Staphylococcus aureus, methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa using agar diffusion assay. The crude extracts were tested for antifungal activity against Phytophthora infestans, Botrytis cinerea, and Septoria tritici using turbidimetric assay. The pure compounds were subjected to further antifungal testing against human pathogenic fungi (Sporoidiobolus salmonicolor, Candida albicans and Penicillium chrysogenum) using agar diffusion assay. The crude extracts of O. sennoides subsp. zanzibaricum and D. melanoxylon (500 μg/ml) were tested for anthelmintic activity using Caenorhabditis elegans. The cytotoxicity (CC50) of the crude extracts against the human prostate cancer (PC-3) and colon adenocarcinoma (HT-29) was performed using colorimetric cell viability assays. The cytotoxicity assay against HeLa cells was performed on the most promising active pure compound using the methylene blue assay.Phytochemical investigation of root and root bark of O. sennoides subsp. zanzibaricum and D. melanoxylon resulted in the isolation of twenty compounds (1-20), of which seven are new. The root bark of D. melanoxylon yielded six previously undescribed prenylated isoflavanones (1-6), alongside isoflavanoids (7-10), neoflavones (11-13) and alkyl hydroxycinnamates (14). A new biflavonoid, trime-chamaejasmin (15) alongside two known biflavonoids (16-17), bi-4-phenyldihydrocoumarin (18), isoflavan (19), triterpenoid (20) were also isolated from the roots of O. sennoides subsp. zanzibaricum. The crude extracts at 50 and 500 μg/mL exhibited promising antibacterial activity against Bacillus subtilis. Sophoraisoflavanone A (10) caused inhibition against both B. subtilis and Aliivibrio fischeri assays at 99% at 100 µM. Kenusanone H (7) and (3R)-tomentosanol B (9) exhibited promising antibacterial activity against MRSA and M. vaccae showing minimum inhibitory concentrations between 0.8 and 6.2 µg/mL. Both crude extracts showed promising antifungal activity against all phytopathogens at 125 µg/mL. Kenusanone H (7) at 42 µg/mL showed very promising activity against S. tritici (74%) and B. cinerea (99%). At low 0.05 μg/mL, both crude extracts showed no cytotoxic effect against PC-3 and HT-29 cells. Kenusanone H (7) was highly cytotoxic against HeLa cells with CC50 of 1.8 ± 1.4 µg/mL (4.2 µM). The crude extracts of both O. sennoides subsp. zanzibaricum and D. melanoxylon are not toxic in general but show selective antibacterial and antifungal activities. Kenusanone H (7) proved to be a lead drug candidate as an antibacterial, antifungal and cytotoxic compound.
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    The Anti-mycobacterial activity and safety profile of selected Crinum species in Northwestern Uganda
    (Global Scientific Journals, 2021) Katuura, Esther ; Waako, Paul ; Chandia, Milton
    Crinum species is a source of many bioactive molecules with both antimicrobial and anti-tumor properties. Chloroform, methanol and aqueous extracts of Crinum scabrum and Crinum macowanii bulbs and leaves were investigated for their anti-mycobacterial activity against Mycobacteria tuberculosis using agar well diffusion, and broth dilution methods. Rifampicin streptomycin resistant (R.S), pan African sensitive (H37Rv) and wild type (Sou 14827) strains of the bacteria were used. The investigation aimed to determine the anti-mycobacterial activity and safety profile of the crude extracts of Crinum scabrum and Crinum macowanii. The extracts had antimycobacterial activity that ranged between 1-5µg/ml. Their patterns of inhibition varied with the plant extract, solvent used for extraction and the organisms tested. Different concentrations of methanol extract were compared with similar concentrations of chloroform and aqueous extracts for their maximum zones of inhibition. All the extracts of Crinum macowanii were found inactive against Mycobacteria tuberculosis. Methanol leaf extract of Crinum scabrum was the most active, with minimum inhibitory concentration (MIC) less than1µg/ml and minimum bactericidal concentration (MBC) of 1µg/ml. acute toxicity test in mice for Crinum scabrum leaf was found to have LD50 greater than 2000mg/kg. In conclusion, the leaf of Crinum scabrum is a natural source of new anti-mycobacterial compound that is tolerable and effective in treatment of tuberculosis. The study recommends herbalists to use the leaves instead of bulb of C. scabrum Alani Davis for treating TB patients. In future, a comparative study should be done on activity of crude methanol leaf extract of C. scabrum and combination of the drugs used to treat multidrug resistant MTB. The active principles in the leaves of C. scabrum Alani Davis should also be isolated, identified and tested on strains of Mycobacteria tuberculosis resistant to at least two or three drugs
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    Anti-plasmodial activity and phytochemical analysis of leaf extract of Chenopodium Opulifolium Schrad. EX W.D.J. Koch and Ziz used in Uganda
    (Makerere University, 2022-04-28) Juma, Saidi,
    Malaria is a life-threatening disease caused by Plasmodium species. It had one of the highest motality and morbidity rates globally. with 229 million cases and 409,000 malaria death in 2019. In Uganda. Malaria has an incidence rate of 26% and it kills 34 people per day. Malaria control has been more effective with antimalarial drugs commonly developed from natural products but are toxic and plasmodium species has evolved, developed resistance where control will greatly require new alternative effective, tolerable, and affordable antimalarial medicines. In this study, Chenopodium opulifolium was investigated for its antiplasmodial activity, phytochemical and antiplasmodial compounds present in its leaves. The plant was selected based on its widespread use in traditional herbal medicine. The plant leaves were collected from Mbirizi, Masaka District, Uganda in June 2019. Extraction was done seqentially with n-hexane, DCM, EtOAc, MeOH and water by means of maceration. The antiplasmodial activity of each extract and compound was tested against P. falciparum 3D7 strain and clinical field isolates KOM_234 and KDH_204 using a fluorescence based SYBR Green 1 assay technique. Separation and purification of the compounds in the most active methanol and DCM extracts was done using column and thin layer chromatography. The compounds were identified by one dimensional and two dimensional (1D and 2D) 1H and 13C NMR, FTIR, Mpt and GC-MS techniques. The antiplasmodial activity test against P. falciparum 3D7 strain, it showed that DCM extract obtained the highest activity with IC50 value of 0.1177 µg/mL followed by methanol extract (1.189 µg/mL), hexane extract (4.850 µg/mL), EtOAc extract (4.856 µg/mL) and aqueous extract (10.24 µg/mL). Methanol extract also demonstrated a promising antiplasmodial activity against P. falciparum clinical field isolate KOM_234 and KDH_204 with IC50 of 5.30 µg/mL ±1.10 and 5.06 µg/mL ±2.23 respectively. Isolation and purification resulted in the identification of two known compounds which are allantoin and decan-2-one. In addition, 19 compounds were identified in the volatile components of the plant using GC-MS analysis which were reported to have numerous bioactivities. Allantoin demonstrated a high antiplasmodial activity against the clinical field isolate KOM_234 with IC50 of 2.29 µg/mL ± 0.98 and a promising activity against clinical field isolate (KDH_204) with IC50 of 10.94 µg/mL ± 1.51. The findings show that the crude extracts, isolated pure and characterised compounds of C. opulifolium leaves have got antiplasmodial activity. This justifies the use of this plant in traditional medicine and indicates a promising potential for the development of medicinal agents.
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    Antiplasmodial activities of extracts and pure compounds from Securidaca Longipedunclata Fresen (Polygalaceae)
    (Makerere University, 2023-01-30) Ochora, Douglas Ongeri
    Introduction: Malaria is the most significant parasitic disease globally especially in Sub-Saharan Africa. The disease kills a child every two minutes. This is coupled with increased malaria parasites resistance to the available drugs. The challenges of parasites resistance call for search of novel antimalarial compounds from plants. This led to the determination of antiplasmodial activities of extracts and pure compounds from Securidaca longipedunculata Fresen (Polygalaceae). Cytotoxicity activities of extracts and pure compounds was also determined. Methodology: The roots extracts were subjected to a combination of chromatographic separations. Structures of isolated compounds were elucidated by mass spectrometry and Nuclear Magnetic Resonance spectroscopy. Crude roots, stems and leaves extracts, pure compounds and drug-extract combinations were each tested for immediate ex vivo and in vitro antiplasmodial activities using SYBR Green I method against W2, D6, 3D7 and DD2 reference strains of Plasmodium falciparum. Cytotoxicity assays were also done using the antiproliferative assay using drug-sensitive and multidrug-resistant cancer cell lines. Results: Roots extracts yielded a novel benzophenone 2,3,4,5-tetramethoxybenzophenone (37), alongside seven known compounds. Both methanol (MeOH) and ethyl acetate (EtOAc) roots extracts were active with IC50 values of less than 5 ng/mL against the D6 and 3D7 strains of P. falciparum. The MeOH extract showed good antiplasmodial activity against field isolates with IC50 value of 9.8±1.3 ng/mL and IC50 value of 1.4±0.07 ng/mL against W2 strain. Compounds 41 and 44 exhibited in vitro activity with IC50 value of 19.7 μM and 14.5 μM respectively and compounds 37 and 38 displayed ex vivo antiplasmodial activities with IC50 value of 28.8 μM and 18.6 μM, respectively all against D6 strain. Synergism was displayed across all fixed doses of artemether-roots extract, lumefantrine-stems extract, and lumefantrine-leaves extract combinations against D6, DD2, and W2 strains of P. falciparum, respectively. The artemether-roots extract combinations displayed the highest synergism across all fixed doses with an average FIC50 value of 0.403±0.068 against D6 strain. For cytotoxicity assay, all the extracts (apart from MeOH leaves extract) and pure compounds were not toxic to the normal BEAS and LO2 cell-lines. Conclusion: The observed synergism and high antiplasmodial activities of the species indicates its potential use as an alternative antimalarial drug in controlling the occurrence of malaria resistance.
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    Antiplasmodial activity, Toxicity and Phytochemistry of Selected Plant Species used by Rukararwe and Prometra Herbalists in Treatment of Malaria in Uganda
    (Makerere University, 2021-03-30) Adia, Madina Mohamed
    Resistance of malaria parasites to known antimalarial drugs necessitated to finding new drugs from natural products which are readily available to treat malaria. The study documented; medicinal plants used in malaria treatment by Traditional Herbalists of Prometra and Rukararwe, determined antiplasmodial activity and toxicity, and characterised isolated chemical structures of the compounds. The selected plant species were identified from ethnobotanical surveys. Micro Mark III test was used for in vitro antiplasmodial analysis of the extracts and some pure compounds. Acute and sub-chronic toxicity was done on Wister mice and Albino rats. A combination of chromatographic techniques were used to isolate pure compounds and their chemical structures were determined using spectroscopic techniques. 86 and 54 plant species were used in malaria treatment by Prometra and Rukararwe Herbalists respectively. Clerodendrum rotundifolium (leaves) and Zanthoxylum chalybeum (stem bark) were selected for further investigation. The most active extracts against Plasmodium falciparum from Z. chalybeum and C. rotundifolium had IC50 values of ≤ 0.03 µg/mL and the water extracts had very low toxicity values (LD50 20,216 mg/kg and 8,300mg/kg) respectively. A dose of 200 mg/kg of the water extract of C. rotundifolium was found to be safe for use. Fagaramide from Z. chalybeum, Verbascoside and Quercetin from C. rotundifolium were isolated and elucidated with IC50 values of 2.85 µg/ml, IC50 17.0 µg/ml and IC50 27.0 µg/ml respectively against P. falciparum. The findings indicate that the selected plants are efficacious and non-toxic which justifies their use in malaria treatment. The isolated compounds are potential antiplasmodial agents for the discovery of new natural antimalarial compounds. The compounds can also be used as markers in the formulation of antimalarial herbal remedies from these plants.
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    Aspects of bats ecology in Kaptum cave in Mt. Elgon, Eastern Uganda
    (Makerere university, 2019-10-14) Matovu, Benard
    Few studies have addressed the ecology of cave bats in Uganda. This study aimed at assessing the diversity; roosting and feeding ecology of micro chiropterans as well as aspects of human disturbance in Kaptum cave of Mt Elgon Eastern Uganda. Data collection was conducted during two field visits in July/August 2016 and October/November 2016 survey periods. Mist nets and a harp trap were used to capture bats for examination and identification of species present. Infrared trail trap cameras were used to augment the monitoring of roosting habits and activity patterns of the bats in the cave; as well as record instances of human disturbance in the cave. A portable weather station (Novalyx WS-18) was used to record the microclimatic conditions in the different sections of the cave to evaluate their influence on choice of roost. Kaptum cave contains three main chambers each dominated by different genera or species of insectivorous bats. These chambers vary in structural complexity and size. The cave contained six species of insectivorous bats namely; Nycteris thebaica, Rhinolophus landeri, R. hildebrandtii, Hipposideros caffer, H. ruber, and Myotis bocagii. These generally roosted and segregated themselves in the three different cave chambers and hence referred to as: “Nycteris”, “Rhinolophus” and “Hipposideros” chambers. The bats exhibited similar and slight variations activity and roosting patterns. From evidence of insect remains in the roost, the diet of the bats in Kaptum Cave consisted of eight insect orders (Lepidoptera, Coleoptera, Orthoptera, Dictyoptera, Hymenoptera, Isopteran, Hemiptera, and Odonata) with the order Lepidoptera constituting the bulk of insects preyed upon. The specific prey items of each bat species could not be established since most insect remains were recovered from a section the cave we referred to as the “Nycteris corner” dominated Nycteris thebaica, where most of the bats fed from. The Nycteris corner was however, frequented by the other species (Rhinolophids and Hipposiderids) at any time in a 24-hr period. Temperature and relative humidity varied significantly in all the cave chambers, and these had a big influence on segregation of bats in the cave. There were several encounters and signs of human disturbance and use of the cave such as: cave mass tourism, extraction of volcanic crystal stones, making fireplaces, and collection bat guano. Continued human presence in the cave could have serious implications for roost stability; but also, it could predispose humans to potentially harmful aerosols and pathogens associated with bats and bat guano
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    Assemblages of Hawkmoths (Sphingidae: Lepidoptera) in Kalinzu Forest South-western Uganda
    (Makerere University., 2023-02-01) Kasangaki, Dismas
    Intensification in anthropogenic activities has significantly lowered habitat quality, accelerated habitat loss and habitat isolation within forest ecosystems. However, there is less documentation on recovery of communities against reference landscapes in afrotropical forests. This study investigated the diversity and faunal composition of sphingid moths (Lepidoptera: Sphingidae) in old-growth and regenerating forest in Kalinzu Central Forest Reserve, South-western Uganda. The goal of the study was to generate information on how habitat recovery impacts insect fauna. The study was guided by the following questions: 1) how do sphingidae moth diversity patterns in regenerating forest compare with those in old-growth forest? 2) How does hawkmoth species diversity correlate with habitat vegetation variables? and 3) what phylogenetic relationships exist among hawkmoths in Kalinzu Forest? Sphingid moths were sampled between July 2019 and February 2020, using a combination of two 20W Ultraviolet light traps (FL20S-BLB and FL20-BL), operated on a battery. Habitat vegetation variables measured or estimated included: basal area of trees, understorey cover, tree density, understorey density and understorey complexity. Phylogenetic relationships among hawkmoths based on mt(CO1) gene were inferred using Maximum Likelihood method and General Time Reversible model in MEGA X. A total of 378 hawkmoth individuals belonging to 22 species were collected. Individual-based extrapolation curves did not reach asymptote implying that more species would be recorded with additional sampling effort. The overlap of curves at 95% CI indicated that richness between forest types did not differ significantly. Fisher’s α diversity was not significantly different between forest types (t(2.2) = 1.786, p > 0.05), also agreeing with very low beta diversity (βChao-Jaccard = 0.0499). Species dominance did not differ significantly between old-growth and regenerating forest (t(3.438) = -0.96). The highest proportion of species in both forest types were closed forest species. Analysis of similarity revealed no significant difference in hawkmoth community composition between forest types (R = -0.241, p > 0.05). Negative value of ANOSIM statistic signifies greater variability within a particular forest portion, than between forests. The genetic distances based on mt(CO1) between any two species of Hawkmoths ranged between 10% and 22%. The findings of this study add to the evidence that species richness does not always decrease with habitat modification. As a way of conserving biodiversity, natural regeneration of formerly degraded habitats should be considered.
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    Assessing Enrofloxacin use practices and residue levels of Enrofloxacin/Ciprofloxacin in breast and liver tissues of broiler chicken sold in selected markets in Kampala Capital City-Uganda
    (Makerere University, 2022) Munanura, Edson Ireeta
    Human exposure to veterinary drugs like fluoroquinolones occurs due to the presence of their residues in foods from animal sources in varying concentrations. The existence of antibiotics residues in foodstuff can pose great public health problems to consumers. To limit the risks from such exposure, Maximum Residue Levels (MRLs) for specific drugs have been set by various continental regulatory bodies. Withdrawal time (WDT) allows tissue concentrations of the drugs to reduce to levels below the drug’s MRL but these are largely not adhered to by farmers. The purpose of this study was to assess enrofloxacin use patterns and assess residue levels of enrofloxacin/ciprofloxacin in breast muscle and liver tissues of broiler chickens sold for consumption in Kampala capital city. A total of 68 chicken breast tissues and liver tissues samples were collected from main markets over one month. Analysis was performed using HPLC coupled with a UV detector. For the enrofloxacin use patterns sub-study, 34 broiler farmers and 10 veterinary drug vendors were interviewed using a questionnaire. From the field survey, the most used antibiotics for the management of poultry diseases were enrofloxacin (100%), oxytetracycline (80%), and amprolium (30%). Enrofloxacin was prescribed majorly for the management of respiratory diseases (100%), and salmonella infections (40%), but also for disease prevention (60%). On average every week, over 15 farmers procured or got prescriptions of enrofloxacin to treat their chicken. The most used brands of enrofloxacin were Enrosol-s® (61.8%), Enrovet® (17.6%), and Enroveto-20® (14.7%). Most of the farmers interviewed had completed secondary and tertiary levels of education (76.5%). The veterinary drugs vendors included; one veterinary extension officer, 5 veterinary assistants, and 4 veterinary surgeons. Enrofloxacin/ciprofloxacin residues were identified in 35.3% (12/34) of the muscle and 38.2% (13/34) of the liver tissues analyzed. Furthermore, of those samples of muscle and liver that tested positive for enrofloxacin/ciprofloxacin, 25% (3/12) and 38.5% (5/13) respectively had drug concentrations higher than the recommended MRLs. The overall mean concentration of enrofloxacin/ciprofloxacin in the broiler chicken muscle and liver tissues was found to be 83.6 (±34.5) µg/kg and 171.5 (±75.9) µg/kg. More so, although over 76% of the farmers knew the WDT for enrofloxacin, none of them adhered to this. This could be attributed to the fact that the veterinary drug vendors do not always emphasize the importance of WDT. In this study, over 70% of the farmers reported that the veterinary drug vendors were not giving them WDT information.
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    Assessing the impact of biological control in the Rivers Kagera, Mara, Pangani and Sigi.
    (Makerere University, 2007-07) Katagira, F.
    Water hyacinth Eichhornia crassipes (Martius) Solms-Laubach, is considered to be the worst aquatic weed worldwide. Biological control using Neochetina weevils was initiated in Tanzania in1995; however this control mechanism was successful in Lake Victoria where water hyacinth was reduced by 80%, but failed in some water bodies (Rajabu et al., 2000; LVEMP, 2001). Studies were conducted during 2003 to 2005 to assess the impact of biological control in the rivers Kagera, Mara, Pangani and Sigi and to evaluate potential effect of nitrogen, phosphorus and silt on weevil establishment in greenhouse conditions at Kyaka near Kagera river in Kagera region, Tanzania. The objectives were achieved by studying the following aspects: (i) The status of water hyacinth and Neochetina weevils in fresh water rivers (Kagera, Mara, Pangani and Sigi rivers) of Tanzania; (ii) Effect of nitrogen and phosphorus on weevil establishment and damage on water hyacinth; (iii) Effect of silt on establishment and performance of Neochetina weevils on water hyacinth; and (iv) Effect of water quality on weevil establishment and damage on water hyacinth. The study on rivers involved sampling of water hyacinth and determination of population densities and growth. Weevil densities, stages of development and feeding scars were also determined. Results showed that Kagera river had the highest water hyacinth densities (44.2 plants m-2) followed by Mara (32.8 plants m-2), Pangani (27.2 plants m-2 ) and least in Sigi (22.8 plants m-2). Plant height was highest in Mara (51.04 cm), followed by Kagera, Pangani and the least height in Sigi (28.6 cm). Other plant parameters namely, leaf length and width and root length followed the same trend. Kagera river had the highest number of ramets per plant (1.13) followed by Mara, Sigi and Pangani (0.69). The number of adult weevils per plant was highest in Sigi (1.93) and Pangani (1.78) and lowest in Kagera and Mara (0). The number of weevil feeding scars per plant was highest in Pangani (22.1) and Sigi (17.81). Overall Mara (1.4) and Kagera (0.21) had the lowest. Water hyacinth growth suppression and population reduction was only evident in Pangani and Sigi rivers and was associated with abundance and feeding by weevils. On the other hand, the weed continued to proliferate in Kagera and Mara rivers in Lake Victoria basin despite monthly weevil releases. The effect of N and P on water hyacinth growth and Neochetina weevil establishment and efficacy was conducted under greenhouse conditions. It consisted of 0 (control), 50 mg N L-l , 100 mg N L-l, 42.5 mg P L-l and 85 mg P L-l and their combinations. Weevil damage was suppressed at higher N (100 mg N L-l) but not high P application rates. Plants fed with high levels of N had low counts of adult weevils and pupae. On the other hand, growth of water hyacinth was limited in low N by 40%, yet weevil numbers, eggs, larvae and pupae per plant as well as weevil damage, increased at low N. Similarly, the number of adult weevil feeding scars per plant was higher (P<0.01) in lower N than at high levels. However, P concentration had no significant effect on number of weevil feeding scars per plant. Total plant N and P varied among nutrient application rates and N uptake depended on P availability; and plant N content increased with increase in P application rate. There was a significant positive correlation (P<0.001) between number of eggs and larvae per plant. The number and length of roots per plant increased with P application while application of N resulted to significant reduction in number and length of roots per plant. Water quality in the Kagera, Mara, Pangani and Sigi rivers differed. The highest total nitrogen was found in Kagera (0.99 mg N L-l) while the lowest was in Sigi (0.12 mg N L-l). Similary, total phosphorus was highest in Kagera (0.36 mg P L-l), while the lowest was in Sigi (0.12 mg P L-l). Likewise, electrical conductivity was highest in Kagera (969.8 µscm-l) follwed by Mara while Pangani and Sigi had the lowest indicating pollution loads in Kagera and Mara rivers. Water temperature was high in Pangani (30.39 oC) and Sigi (29.4 oC), while Mara had (26.2 oC) and Kagera had the lowest (26.23 oC). Air temperatures and relative humidity followed the same trend. It was concluded that high N and P levels might be partly responsible for poor weevil damage on water hyacinth in eutrophic habitat such as in Kagera and Mara rivers. On addition, the low temperatures and relative humidity may have contributed by limiting the weevil activities. The study on the effect of silt on the water hyacinth and weevil development and efficacy consisted of control (no silt applied) and silt at levels 17 kg, 51 kg and 85 kg in 50 litres of water applied in order to achieve distances of 20, 10 and 0 cm between the root tips and silt topmost level/surface. Silt and water for the experiments was from Lake Victoria and Kagera river. There was reduced weevil reproduction in treatments with silt as evidenced by low numbers of eggs, larvae, pupae and adult weevils. In contrast water hyacinth plant populations, leaf length and number of ramets were significantly enhanced (P<0.05) by silt application. Water hyacinth grown in water and silt from Kagera river, had higher weevil feeding scars per plant were 32.2 at low silt (17 kg) and 8.7 at 85 kg silt level indicating reduced weevil damage at high silt. A significant and positive relationship (r = 0.881, P < 0.01) was obtained between water hyacinth leaf length and lamina width. Silt levels appear to directly affect different life stages of the weevil, thereby reducing the ability of the insects to multiply to populations that can suppress growth of water hyacinth. Sediment loads in Kagera and Mara rivers may have contributed to poor establishment of Neochetina weevils and favoured water hyacinth proliferation.