Articles, Conference and Workshop Papers Collection

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Browsing Articles, Conference and Workshop Papers Collection by Author "Alinanuswe Mwakalesi"

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    Commiphora swynnertonii-derived silver nanoparticles significantly enhance the selectivity of the medium for isolating fungal species
    (Springer, 2026-02) Celina Ntibigwahake; Alinanuswe Mwakalesi; Eliapenda Elisante Mariki; Douglas Mushi
    Silver nanoparticles (Ag-NPs) were synthesized using an eco-friendly and economically feasible procedure from the root bark of the medicinal plant Commiphora swynnertonii, with optimized physicochemical variables in the reaction medium. The formation of Ag-NPs was visually monitored by a color change in the reaction mixture and confirmed by various analyses, including UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The synthesized Ag-NPs were tested for their antimicrobial properties and applied to enhance the detection and selective isolation of fungal species on potato dextrose agar (PDA). The optimal synthesis conditions for Ag-NPs were found to be at 60 °C, pH 9, 0.004 M AgNO₃, 40 mL of C. swynnertonii root bark extract, and a reaction time of 10 min. Under these conditions, the Ag-NPs exhibited a maximum absorption peak at 413 nm, spherical shapes, and an average size of 40 ± 15 nm. EDX analysis confirmed the presence of a substantial amount of silver in the synthesized nanoparticles, while FT-IR analysis identified functional groups on their surfaces derived from the root bark of C. swynnertonii. The Ag-NPs demonstrated enhanced antimicrobial activity against Gram-positive and Gram-negative bacteria (MIC, 0.058 mg/mL) compared to filamentous and non-filamentous fungi (MIC, 0.116 mg/mL). PDA without Ag-NPs supported bacterial and fungal growth, whereas PDA with Ag-NPs completely inhibited bacterial outgrowth while permitting fungal outgrowth. This study underscores the potential of C. swynnertonii root bark extract for synthesizing antimicrobial Ag-NPs with applications in controlling pathogenic bacteria and improving the detection sensitivity and selectivity of fungal growth media, particularly PDA.
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    In vitro evaluation of antiproliferative and cytotoxic effects of Annona stenophylla (Engl. & Diels), Strophanthus petersianus (Klotzsch), and Synadenium glaucescens (Pax) extracts against MCF-7 breast cancer and Vero cell lines
    (Elsevier, 2026-06) Roberto Nhamussua; Mohammed Ibrahim; Alinanuswe Mwakalesi; Faith Mabiki; Lyndy McGaw
    Breast cancer remains a major global health burden, underscoring the development of safer and more effective anticancer agents. Medicinal plants represent an important source of bioactive metabolites with potential se- lective cytotoxicity. This study evaluated the antiproliferative activity and selectivity of extracts from Annona stenophylla, Strophanthus petersianus, and Synadenium glaucescens against the MCF-7 breast cancer and the Vero cell lines, with doxorubicin used as a positive control. Root, stem and leaf extracts were obtained through sequential solvent extraction, and cytotoxic activity was assessed using the MTT assay. IC50 values were deter- mined to quantify cytotoxicity. Statistical differences among treatments were determined using Tukey’s HSD post hoc test, and the selectivity index was determined to compare the relative cytotoxicity between cancerous and non-cancerous cell lines. The RSPE (root ethyl acetate extract of S. petersianus) exhibited the highest anti- proliferative activity against MCF-7 cells (IC50 = 0.12 μg/mL; p < 0.05), while other extracts from the same plant produced IC50 values of up to 12.61 μg/mL. In contrast, substantially higher IC50 values were observed in Vero cells (1.73 to 265.81 μg/mL; p < 0.05), resulting in a high selectivity index of 31.33, 28.40 and 21.08 for SSPM, SSPE and LSPE (stem methanol, stem ethyl acetate and leaf ethyl acetate extracts S. petersianus), respectively. A. stenophylla extracts exhibited variable cytotoxicity against MCF-7 (IC50: 3.14 to 37.96 μg/mL; p < 0.05) and Vero (5.36 to 42.33 μg/mL), yielding moderate selectivity (1 70 μg/mL), with only SWSGE (stem wood ethyl acetate of S. glaucescens) exhibiting a statistically signicant effect at tested concentrations of 3.90, 31.30, 15.60 and 125 μg/mL (p < 0.05), but not at 1.90, 31.30 and 62.50 μg/mL. In contrast, the other extracts showed no signicant difference relative to the control group (p > 0.05) and poor selectivity. Doxorubicin (positive control) exhibited an IC50 value of 0.30 μg/mL in MCF-7 and 53.69 μg/mL in Vero cells, corresponding to an SI of 178.97. S. petersianus demonstrated potent and selective antiproliferative activity against MCF-7 cells, highlighting it as a source for anticancer agents. Further mechanistic and phytochemical investigations are warranted.