Browsing by Author "Namukobe, Jane"
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Item Anthocyanins from flowers of Hippeastrum cultivars(Elsevier, 2006) Byamukama, Robert; Jordheim, Monica; Kiremire, Bernard; Namukobe, Jane; Øyvind, M. AndersenThe anthocyanins, cyanidin 3-O-(6″-O-α-rhamnopyranosyl-β-glucopyranoside) (1) and pelargonidin 3-O-(6″-O-α-rhamnopyranosyl-β-glucopyranoside) (2), were isolated from the ornamental flowers of a Ugandan Hippeastrum cultivar by a combination of chromatographic techniques, and their structures were elucidated mainly by the use of homo- and heteronuclear nuclear magnetic resonance spectroscopy and electrospray mass spectrometry. The same anthocyanins were found in six different Hippeastrum cultivars purchased in Norway. However, the absolute amount of the anthocyanins (0.08–1.79 mg/g, fresh weight) and the relative proportions of the individual anthocyanins varied from cultivar to cultivar (13.2–96.5% of 1). The colours of the fresh petals of the three cultivars ‘Red Lion’, ‘Royal Velvet’ and ‘Liberty’ were described by the CIELab coordinates L* (lightness), C* (chroma) and hab (hue angles). All the cultivars showed hue angles corresponding to scarlet nuances (hab = 22–35°), with the highest value in ‘Red Lion’. The most reddish petals (in ‘Royal Velvet’) contained the highest relative proportion of 1. Thus, the in vivo colours of these cultivars seem to be correlated with the relative proportions of individual anthocyanin in the petals.Item Anthocyanins from leaf stalks of cassava (Manihot esculenta Crantz)(Byamukama, R., Namukobe, J., & Kiremire, B. (2009). Anthocyanins from leaf stalks of cassava (Manihot esculenta Crantz). African Journal of Pure and Applied Chemistry, 3(2), 020-025https://academicjournals.org/journal/AJPAC/article-abstract/1396EB61511., 2009) Byamukama, Robert; Namukobe, Jane; Kiremire, BernardThe anthocyanins, cyanidin 3-O-(6’’-O-a-rhamnopyranosyl-b-glucopyranoside) (1) and delphinidin 3-O-(6’’-O-a-rhamnopyranosyl-b-glucopyranoside) (2) isolated from the leaf stalks of cassava (Manihot esculenta Crantz) by a combination of chromatographic techniques, and their structures were elucidated mainly by the use of homo- and heteronuclear magnetic resonance spectroscopy. The relative amounts of 1 and 2 in the extracts were approximately 92 and 4%, respectively. The absolute amount was 124 mg/100 g.Item Anthocyanins from ornamental flowers of red frangipani, Plumeria rubra(Scientia Horticulturae, 2011) Byamukama, Robert; Namukobe, Jane; Jordheim, Monica; Andersen, Øyvind M.; Kiremire, Bernard T.Two anthocyanins were isolated from ornamental reddish flowers of Plumeria rubra L. (Apocynaceae) by a combination of chromatographic techniques. Their structures were elucidated mainly by the use of homo- and heteronuclear nuclear magnetic resonance spectroscopy and high-resolution electrospray mass spectrometry. The anthocyanin cyanidin 3-O- -(2 -glucopyranosyl-O- -galactopyranoside) (75%), has previously been isolated only from Cornus suecica (Cornaceae) fruits, while the other (20%) was identified as cyanidin-3-O- -galactopyranoside. This is the first report of the anthocyanins responsible for the attractive colours of the flowers of red frangipani.Item Antibacterial, antioxidant, and Sun Protection Potential of selected Ethno Medicinal Plants used for skin infections in Uganda(Tropical Medicine and Health, 2021) Namukobe, Jane; Sekandi, Peter; Byamukama, Robert; Murungi, Moses; Nambooze, Jennifer; Ekyibetenga, Yeremiah; Nagawa, Christine Betty; Asiimwe, SavinaBackground: Rural populations in Uganda rely heavily on medicinal plants for the treatment of bacterial skin infections. However, the efficacy of these medicinal plants for their pharmacological action is not known. The study aimed at evaluating the antibacterial, antioxidant, and sun protection potential of Spermacoce princeae, Psorospermum febrifugum, Plectranthus caespitosus, and Erlangea tomentosa extracts. Methods: The plant samples were extracted by maceration sequentially using hexane, dichloromethane, ethyl acetate, methanol, and distilled water. Antibacterial activity of each extract was carried out using an agar well diffusion assay against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Klebsiella pneumonie, Streptococcus pyogenes, and Salmonella typhi. Acute dermal toxicity of the aqueous extract of S. princeae and P. febrifugum, and E. tomentosa was assessed in young adult healthy Wistar albino rats at a dose of 8000 and 10,000 mg/kg body weight. The antioxidant activity of each extract was carried out using a 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay. The sun protection factor was determined using Shimadzu UltraViolet-Visible double beam spectrophotometer between 290 and 320 nm. Results: The plant extracts showed good antibacterial activity against the tested bacterial strains with minimum inhibitory concentration (MIC) ranging between 3.12 and 12.5 mg/ml. There was no significant change in the levels of creatinine, alanine aminotransferase, and aspartate aminotransferase in the rats even at a higher dose of 10,000 mg/kg, which was related to the results of biochemical analysis of the blood samples from the treated and control groups. The aqueous and methanol extracts of S. princeae showed potential antioxidant properties, with half maximal inhibitory concentration (IC50) values of 59.82 and 61.20 μg/ml respectively. The organic and aqueous extracts of P. caespitosus showed high levels of protection against Ultraviolet light with sun protection potential values ranging between 30.67 and 37.84. Conclusions: The study demonstrated that the selected medicinal plants possessed good antibacterial, antioxidant, and sun protection properties. Therefore, the plants are alternative sources of antibacterial, antioxidant, and sun protection agents in managing bacterial skin infections.Item Antimycobacterial Activity of the Extract and Isolated Compounds From the Stem Bark of Zanthoxylum leprieurii Guill. and Perr.(Natural Product Communications, 2021) Oloya, Benson; Namukobe, Jane; Heydenreich, Matthias; Ssengooba, Willy; Schmidt, Bernd; Byamukama, RobertZanthoxylum leprieurii Guill. and Perr. (Rutaceae) stem bark is used locally in Uganda for treating tuberculosis (TB) and cough-related infections. Lupeol (1), sesamin (2), trans-fagaramide (3), arnottianamide (4), (S)-marmesinin (5), and hesperidin (6) were isolated from the chloroform/methanol (1:1) extract of Z. leprieurii stem bark. Their structures were elucidated using spectroscopic techniques and by comparison with literature data. Furthermore, the extract and isolated compounds were subjected to antimycobacterial activity. The extract exhibited moderate activity against the susceptible (H37Rv) TB strain, but weak activity against the multidrug resistant (MDR)-TB strain with minimum inhibitory concentrations (MICs) of 586.0 and 1172.0 μg/mL, respectively. Compound 3 (trans-fagaramide) showed significant antimycobacterial activity against the susceptible (H37Rv) TB strain (MIC 6 μg/mL), but moderate activity against the MDR-TB strain (MIC 12.2 μg/mL). Compounds 2, 5, 6, and 1 showed moderate activitiesagainst the susceptible (H37Rv) strain (MIC 12.2-98.0 μg/mL) and moderate to weak activities against theMDR-TB strain (MIC24.4-195.0 μg/mL). This study reports for the first time the isolation of compounds 1 to 6 from the stem bark of Z leprieurii. trans-Fagaramide (3) may present a vital template in pursuit of novel and highly effective TB drugsItem Bioactive compounds in the stem bark of Albizia coriaria (Welw. ex Oliver)(International Journal of Biological and Chemical Sciences, 2015) Byamukama, Robert; Barbara, Ganza; Namukobe, Jane; Heydenreich, Matthias; Kiremire, Bernard T.Albizia coriaria was investigated for the bioactive compounds present in its stem bark. The plant was selected on the basis of its widespread use in traditional herbal medicine. Extraction of the plant material was done with ethyl acetate, methanol and water and the bioactivity of each extract was tested against Pseudomonas aeruginosa and Escherichia coli. Separation and purification of the compounds in the most active (ethyl acetate) extract was done using a combination of chromatographic techniques. The compounds were identified by 1D and 2D -1H and 13C NMR techniques as well as Mass spectrometry (MS). Six compounds, namely: Lupeol (1), Lupenone (2), Betulinic acid (3), Acacic acid lactone (4), (+) – Catechin (5) and Benzyl alcohol (6) were identified and characterized from the ethyl acetate extract. The results of the bioactivity tests carried out in this study indicated that A. coriaria has potential antimicrobial activity. Four of the characterized compounds (1, 2, 3 & 5) have a wide range of biological activity reported in literature. This justifies the use of this plant in traditional medicine and indicates a promising potential for the development of medicinal agents from A. coriaria stem bark.Item Bioactive secondary metabolites from the leaves of Secamone africana (Olive.) Bullock(International Journal of Biological and Chemical Sciences, 2020) Sekandi, Peter; Namukobe, Jane; Byamukama, Robert; Akala, Hoseah M.; Yeda, Redemptah A.; Heydenreich, MatthiasSecamone africana leaves are used in the treatment of malaria and other ailments in Uganda. The aim of the study was to characterize the antiplasmodial compounds from the leaves of Secamone africana. The leaves were extracted sequentially using dichloromethane (DCM) and methanol (MeOH). The crude extracts and isolated compounds were evaluated for their antiplasmodial activity against the chloroquine sensitive Sierraleone I (D6) and chloroquine-resistant Indochina I (W2) strains of Plasmodium falciparum. Isolation and purification were done using chromatographic techniques including column chromatography and high performance liquid chromatography. The isolated compounds were characterized using spectroscopic methods. The MeOH extract (IC50 = 5.45 μg/mL) was found to be more active than the DCM extract (IC50= 15.93 μg/mL) against the D6 malaria parasite. Chemical investigation of the MeOH extract yielded one new compound; 2-(2,4-dimethyloxetan-2-yl) acetic acid (3) in addition to the six known compounds; α-linolenic acid (1), conduritol B (4), β-sitosterol (5), 3,4-dihydroxybenzoic acid (6), 4-hydroxybenzoic acid (7) and coumaric acid (8). The DCM extract yielded one known compound: 1-methyl cyclobutene (2). The presence of these compounds with good anti-plasmodial activities and other bioactivities reported in literature, appears to argue for the therapeutic potential of Secamone africana.Item Cycloartane triterpenes from the leaves of Neoboutonia macrocalyx L.(Elsevier, 2014) Namukobe, Jane; Kiremire, Bernard T.; Byamukama, Robert; Kasenene, John M.; Dumontet, Vincent; Guéritte, Françoise; Krief, Sabrina; Florent, Isabelle; Kabasa, John DNeoboutonia macrocalyx is used by people in south western Uganda around Kibale National Park in the treatment of malaria. Phytochemical investigation on the leaves of this plant led to the isolation of nine cycloartane triterpenes (1–9) and one phenanthrene; 7-methoxy-2,8 dimethyl-9, 10-dihydrophenantherene-3,6 diol (10) along with three known compounds which included 22-de-Oacetyl- 26-deoxyneoboutomellerone (11), mellerin B (12) and 6-hydroxystigmast-4-en-3-one (13). The chemical structures of the compounds were established mainly through a combination of spectroscopic techniques. The isolated compounds were evaluated for antiplasmodial activity against the chloroquine-resistant FcB1/Colombia strain of Plasmodium falciparum and for cytotoxicity against the KB (nasopharyngeal epidermoid carcinoma) and MRC-5 (human diploid embryonic lung) cells. Seven out of 13 compounds exhibited good antiplasmodial activity with IC50 of 65 lg/ml with two compounds exhibiting low cytotoxicity and five compounds having significant cytotoxicity.Item An Ethnobotanical Study of Medicinal Plants used in the Management of Dermatological Disorders in Buyende and Kayunga Districts, Uganda(European Journal of Medicinal Plants, 2021) Namukobe, Jane; Lutaaya, Anthony; Asiimwe, Savina; Byamukama, RobertThis study was done to document medicinal plants used in the management of dermatologicaldisorders. Documentation of plants is important for conservation especially of rare and endangeredplant species. The study was done in Buyende and Kayunga districts in Uganda, between April andJuly 2017. Data was obtained using semi-structured questionnaires and group discussions,performed on 63 respondents (33 females; 30 males) who were purposively selected because oftheir expertise in plant use. The study recorded 111 plant species that belong to 46 plant familiesfor treatment of 30 skin disorders. The dominant life form was herb (41%), while leaves were themost used parts (59 %). Majority of plants (72%) were harvested from their natural habitats. Family Fabaceae contributed the highest number of species (20). Milicia excelsa was recorded to be threatened with extinction. The most cited diseases were skin rash (14%), wounds (12%), syphilis (9%), allergy (9%) and ring worm (7%). The plant species with high percent respondent knowledge were Hoslundia opposita, cited by 83% of the people; Bidens pilosa (76%) and Jatropha carcus (56%) all for treating wounds. Topical application (90%) was the common mode of administering herbal remedies, while decoction was least used to prepare remedies. Plants are important in the management of dermatological disorders by local communities in the study areas. The diversity of medicinal plant species used in these areas is based on the rich traditional knowledge of the local communities. There is need to domesticate the rare and threatened medicinal plant species to avoid extinction. Plant species with high percent respondent knowledge can be considered for further studies to identify key active compounds important to develop natural based skin care products.Item Hippeastrum hybridum anthocyanins as indicators of endpoint in acid – base titrations(International Journal of Biological and Chemical Sciences, 2016) Byamukama, Robert; Waninda, Eric Nicholas; Mukama, David; Namukobe, JaneAnthocyanins from Hippeastrum hybridum (Amaryllis) were investigated as indicators of endpoint in acid- base titrations. Extraction of the anthocyanins was done using distilled water, methanol and methanol containing 0.5% acetic acid. The extracts were used in determination of endpoint in titrations between strong acid/strong base, strong acid / weak base, weak acid / strong base and weak acid / weak base at concentration levels of 0.1 M, 0.5 M and 1.0 M. The titres were compared to those obtained using phenolphthalein, methyl orange and mixed indicator. The shelf life of anthocyanin extracts kept in amber bottles at room temperature (16.8 0C – 29.1 0C) was also investigated. The plant extracts gave accurate and precise results in titration of strong acids with strong bases and weak acids against strong bases at all concentrations investigated (0.1, 0.5 and 1.0 M) that were very comparable to the values obtained using phenolphthalein, methyl orange and mixed indicator. In titration of weak acids against weak bases, the plant extracts gave accurate results when concentration was 0.1 M but failed for 0.5 M and 1.0 M. On average the anthocyanins from Hippeastrumhybridum could be used in the titration of strong acid versus strong base, weak acid versus strong base andweak acid versus weak base. The anthocyanins from Hippeastrum hybridum had a good shelf life of 90 dayswhen kept at room temperature. The extracts can thus be used in any place including those that have no access to refrigeration facilities since they can be kept at room temperature for some time before they undergo degradation.Item Traditional Medicinal Uses, Phytoconstituents, Bioactivities, and Toxicities of Erythrina abyssinica Lam. ex DC. (Fabaceae): A Systematic Review(Evidence-Based Complementary and Alternative Medicine, 2021) Baker Obakiro, Samuel; Kiprop, Ambrose; Kigondu, Elizabeth; K’Owino, Isaac; Odero, Mark Peter; Manyim, Scolastica; Omara, Timothy; Namukobe, Jane; Oriko Owor, Richard; Gavamukulya, Yahaya; Bunalema, LydiaMany studies have been undertaken on the medicinal values of Erythrina abyssinica Lam. ex DC. (Fabaceae). )e details, however, are highly fragmented in different journals, libraries, and other publication media. )is study was therefore conducted to provide a comprehensive report on its ethnobotany, ethnomedicinal uses, phytochemicals, and the available pharmacological evidence supporting its efficacy and safety in traditional medicine. Method. We collected data using a PROSPERO registered systematic review protocol on the ethnobotany, phytochemistry, and ethnopharmacology of Erythrina abyssinica from 132 reports that were retrieved from electronic databases. Documented local names, morphology, growth habit and habitat, ethnomedicinal and nonmedicinal uses, diseases treated, parts used, method of preparation and administration, extraction and chemical identity of isolated compounds, and efficacy and toxicity of extracts and isolated compounds were captured. Numerical data were summarized into means, percentages, and frequencies and presented as graphs and tables. Results. Erythrina abyssinica is harvested by traditional herbal medicine practitioners in East, Central, and South African communities to prepare herbal remedies for various human and livestock ailments. )ese include bacterial and fungal infections, tuberculosis, malaria, HIV/AIDS, diarrhea, cancer, meningitis, inflammatory diseases, urinary tract infections, wounds, diabetes mellitus, and skin and soft tissue injuries. Different extracts and phytochemicals from parts of E. abyssinica have been scientifically proven to possess anti-inflammatory, antibacterial, antioxidant, antiplasmodial, antiproliferative, antifungal, antimycobacterial, antidiarrheal, anti-HIV 1, antidiabetic, and antiobesity activities. )is versatile pharmacological activity is due to the abundant flavonoids, alkaloids, and terpenoids present in its different parts. Conclusion. Erythrina abyssinica is an important ethnomedicinal plant in Africa harboring useful pharmacologically active phytochemicals against various diseases with significant efficacies and minimal toxicity to mammalian cells. )erefore, this plant should be conserved and its potential to provide novel molecules against diseases be explored further. Clinical trials that evaluate the efficacy and safety of extracts and isolated compounds from E. abyssinica are recommended.Item Traditional plants used for Medicinal purposes by local communities around the Northern sector of Kibale National Park, Uganda(Elsevier, 2011) Namukobe, Jane; Kasenene, John.M.; Kiremire, Bernard T.; Byamukama, Robert; Kamatenesi-Mugisha, Maud; Krief, Sabrina; Dumontet, Vincent; Kabasa, John D.Ethnopharmacological relevance: The study was done to establish medicinal plants used in the treatmentof various diseases by the people in the Northern sector of Kibale National Park in western Uganda. Itwas also aimed at establishing the plant parts used and the mode of preparation of remedies. Theseplants create a basis for phytochemical evaluation which can lead to the discovery of biologically activecompounds that can be used as starting materials in the development of new drugs targetingselected diseases such as malaria. Materials and methods: The required information was obtained using open interviews, semi-structured questionnaires, focus group discussions and transect walks. Results: Different medicinal plants (131 species) distributed over 55 families were observed to be used by the local communities around the Northern sector of Kibale National Park. The plants as reported in this paper are used to treat 43 physical illnesses/diseases. The most used parts of the plants are the leaves. Water is the main medium used for the preparation of the remedies which are mostly administered orally. Conclusion: The people in the study area have a rich heritage of traditional plants that are used in the health care system to treat diseases. These medicinal plants have contributed significantly to several disease therapies. The most common diseases treated are malaria and cough, which are mostly treated by Vernonia amygdalina Del. and Albizia coriaria Welw. respectively. The main sources of medicinal plants include bush land, home gardens, grasslands, and the forest.