Browsing by Author "Gumula, Ivan"

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    Antibacterial properties of phytochemicals isolated from leaves of alstonia boonei and aerial parts of ipomoea cairica
    (Natural Product Communications, 2024-09-26) Gumula, Ivan; Kyarimpa, Christine; Nanyonga, Sarah Kiwanuka; Kwesiga, George; Busulwa, George; Opio, Boniface; Heydenreich, Mathias; Omara, Timothy
    Objective: The leaves of Alstonia boonei and aerial parts of Ipomoea cairica are used for treatment of microbial infections among other ailments in African traditional medicine. The aim of this study was to investigate the antimicrobial phytochemicals in A. boonei leaves and Ipomoea cairica aerial parts to validate their traditional use in Ugandan herbal medicine. Methods: The plant materials were separately extracted using a dichloromethane/methanol (1:1) solvent system and subjected to repeated chromatographic separation to isolate pure compounds. The chemical structures of the isolated compounds were determined through 1H NMR, 13C NMR and 2D NMR(COSY, HSQC and HMBC). The antibacterial activity of the extracts and pure compounds were assessed using the agar well diffusion method. Results: Chromatographic fractionation of the extracts yielded trans-fagaramide and a pentacyclic lupane-type triterpenoid, lupeol, from A. boonei, and friedelin from I. cairica. Trans-fagaramide was identified for the first time in the Alstonia genus while friedelin was identified for the first time in I. cairica. The isolated compounds demonstrated antibacterial activity, with trans-fagaramide showing a minimum inhibitory concentration (MIC) of 125 μg/mL against Pseudomonas aeruginosa and 250 μg/mL against Staphylococcus aureus, Salmonella typhi and Escherichia coli. Friedelin exhibited a MIC of 125 μg/mL against Escherichia coli and 250 μg/mL against Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhi. Conclusion: The antibacterial activities observed in this study support the traditional use of A. boonei and I. cairica by indigenous communities in Uganda for treating microbial infections.
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    Fruits and vegetables used in treating respiratory and other troubles in Africa: ethnopharmacology and phytochemistry
    (Springer Nature Link, 2025-08-01) Gumula, Ivan; Buyinza Daniel; Onen Patrick; Kyarimpa Christine
    This book provides a comprehensive overview of bioactive compounds derived from African traditional medicinal plants, shedding light on their potential applications in modern medicine. It compiles crucial information on compounds with proven in vitro and in vivo activity against various diseases, providing a foundation for further research in drug discovery. The book also introduces the use of these bioactive secondary metabolites in cosmetics, nutrition, and pest control, with detailed description of medicinal plant species, including their botanical names, ethnomedicinal uses, and pharmacological activities, making it an invaluable resource for researchers and pharmaceutical companies. Key concepts include the exploration of secondary metabolites from plants in Ethiopia, Egypt, Kenya, Uganda, Zimbabwe, Cameroon, Tanzania, Madagascar, and Nigeria, and their industrial applications. The chapters cover ethnobotanical knowledge, bioactivities, and chemical profiling of these plants, including the ethnobotanical and phytochemical studies of Ethiopian flora, the role of rose-scented geranium in the perfume industry, and the use of fruits and vegetables in treating respiratory ailments. Readers will also discover insights into the use of secondary metabolites for pest control, the conservation strategies for endangered African plants, and the synthesis of bio-nanoparticles for therapeutic applications. The book presents a detailed analysis of medicinal plants with anti-malarial, antileishmanial, improve sexual desire and antimicrobial properties, highlighting their significance in traditional and modern medicine. This volume is an essential resource for researchers, graduate students, and professionals in the fields of natural products, phytochemistry, and pharmaceuticals. It provides a unique perspective on the integration of traditional African medicine with contemporary scientific research, offering valuable insights into the potential of these bioactive compounds in drug development.