Browsing by Author "Kisula, Lydia"

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Comparative evaluation of antimicrobial activity and synergistic effects of selected Tanzanian medicinal plants against urinary tract infection pathogens
(Elsevier, 2025-10) Mwalongo, Optatus; Kisula, Lydia; Credo, David; Sauli, Elingarami
The emergence of microbial resistance towards existing drugs for treating UTIs seriously threatens public health worldwide, thus necessitating the search for alternative antimicrobial agents, particularly from medicinal plants. This study determined the standalone in vitro antimicrobial activity of ethanolic extracts from Ocimum gratissimum, Sida acuta, Lantana camara, Plectranthus barbatus, Tridax procumbens, and Euphorbia hirta against selected non-antimicrobial-resistant (AMR) and AMR uropathogens (bacterial strains and Candida albicans). Among these, Plectranthus barbatus, Euphorbia hirta, and Lantana camara exhibited the highest antimicrobial efficacy. Subsequently, their synergistic interactions were determined against the same test microbes. Plant materials were extracted using 80% ethanol via a maceration technique. The antimicrobial efficacy of the individual and combined extracts was evaluated by broth microdilution against standard and clinical isolate microbial strains, namely Escherichia coli ATCC25922, Klebsiella pneumoniae K6 ATCC700603, Staphylococcus aureus ATCC25923, Methicillin-resistant Staphylococcus aureus (MRSA, WHO control), Enterococcus faecalis ATCC29212, Candida albicans NR29341 and clinical isolate Klebsiella pneumoniae, while a checkerboard microdilution assay was employed to assess the combined extracts’ interaction. Results revealed that all the individual plant extracts significantly inhibited the growth of the test microorganisms with varying efficacy [F (5, 36) = 2.48, η² = 0.8, p = 0.002]. The minimum inhibitory concentration (MIC) values ranged from 0.31 to 6.67 mg/mL. Of the six tested plant extracts, P. barbatus and E. hirta were highly effective against all tested microbes. The combined extracts exhibited significantly higher antimicrobial activity than individual extracts against all tested microbes [t (46.74) = -6.49, Cohen’s d = 1.4, p < 0.001]. Furthermore, the analysis of interaction types among combined extracts demonstrated that double and triple crude extract combinations exhibited partial synergy, additive and indifferent effects. Thus, this study demonstrates the significance of herb therapies of selected medicinal plants in treating UTIs.
Development of a banana stem native cellulose and pine resin-based nanocomposite film for wound dressing applications
(Elsevier Ltd., 2025-10-25) Livifile, Silla; Tarus, Bethwel; Kisula, Lydia; Kivevele, Thomas; Jande, Yusufu
Bio-based polymer films offer sustainable wound care materials with absorbance capability, alongside biocompatibility, antimicrobial action, moisture retention, and low toxicity. In this study, a sustainable composite, biopolymer was fabricated through the electrospinning of native cellulose obtained from banana pseudo-stems and with Pinus patula resin. The composite film was evaluated for antibacterial activity on four bacterial species and characterized as well as for its water absorption and retention, vapor transmission, tensile strength, thermal stability, morphology, wettability, biocompatibility and surface area analysis. Antimicrobial tests showed a zone of inhibition measuring 8 mm for E. coli, 11 mm for S. aureus, 11 mm for K. pneumoniae and none for P. aeruginosa. Scanning electron microscopy images revealed that adjusting the cellulose-to-resin blending ratio produced fibers with distinct diameter ranges: 67–96 nm at a 9.5:0.5 ratio, 52–123 nm at an 8.4:1.6 ratio, and 100–137 nm at a 7.6:2.4 ratio, with the latter displaying a porous rough-surfaced network. The fibers had a water vapor transmission rate of 284.93 g/(m2.24 h) and an absorption capacity of 126.23 %. They attained a tensile strength of 7.28 MPa which is comparable to that of natural human skin (2.5–16 MPa), while their hydrophilic nature was proven by water contact angle of 54.13°. Thermal stability results indicated that thermal degradation started at approximately 160 °C. Porosity tests showed the films to be micro porous and appropriate for gaseous exchange and bacteria capture. Collectively, these results highlight the potential of banana cellulose-pine resin films as effective, natural wound dressing materials.
Electro-spun transparent film from banana pseudo-stem native cellulose using N-methylmorpholine-N-oxide solvent system
(Elservier, 2025-06) Livifile, Silla; Tarus, Bethwel; Kisula, Lydia; Kivevele, Thomas; Jande, Yusufu
The study-utilized electrospinning to prepare a transparent film from native cellulose extracted from banana pseudo stems. The process of electrospinning was performed at room temperature conditions, after which the cellulose film was obtained through water coagulation. Dimethyl sulfoxide and dimethylformamide were added to the electrospinning solution to adjust the surface tension, viscosity, and conductivity of the prepared solutions. The formed thin film was characterized using Infrared spectroscopy (IR) and X-ray crystallography tests to confirm the elimination of non-cellulosic materials during extraction. It was revealed that the banana fibers were dominated by crystallinity and converted from cellulose-I to cellulose-II after dissolution in N-methyl morpholine N-oxide (NMMO). Scanning electron microscopy images revealed that fiber and electro-spun film morphologies could be achieved by varying sodium hydroxide solution concentration and solution parameters during fiber treatment and electrospinning. Concentration of 17.5 % (wt./v)of the alkaline solution showed to be more effective in changing the surface morphology of the fiber. The structure and mechanical characteristics of the films were influenced most by the concentration of banana native cellulose, process stability, and the solidification of the electro-spun fibers. The film exhibited an initial degradation temperature of 165°C, a light transmittance of 83.3 % in the visible UV range, and a tensile strength ranged from 5.83 MPa to 8.13 MPa. This performance highlights its potential applications in various fields, including packaging and biomedical engineering.
Electro-spun transparent film from banana pseudo-stem native cellulose using N-methylmorpholine-N-oxide solvent system
(Elsevier, 2025-04-21) Livifile, Silla; Tarus, Bethwel; Kisula, Lydia; Kivevele, Thomas; Thomas, Yusufu
The study-utilized electrospinning to prepare a transparent film from native cellulose extracted from banana pseudo stems. The process of electrospinning was performed at room temperature conditions, after which the cellulose film was obtained through water coagulation. Dimethyl sulfoxide and dimethylformamide were added to the electrospinning solution to adjust the surface tension, viscosity, and conductivity of the prepared solutions. The formed thin film was characterized using Infrared spectroscopy (IR) and X-ray crystallography tests to confirm the elimination of non-cellulosic materials during extraction. It was revealed that the banana fibers were dominated by crystallinity and converted from cellulose-I to cellulose-II after dissolution in N-methyl morpholine N-oxide (NMMO). Scanning electron microscopy images revealed that fiber and electro-spun film morphologies could be achieved by varying sodium hydroxide solution concentration and solution parameters during fiber treatment and electrospinning. Concentration of 17.5 % (wt./v)of the alkaline solution showed to be more effective in changing the surface morphology of the fiber. The structure and mechanical characteristics of the films were influenced most by the concentration of banana native cellulose, process stability, and the solidification of the electro-spun fibers. The film exhibited an initial degradation temperature of 165°C, a light transmittance of 83.3 % in the visible UV range, and a tensile strength ranged from 5.83 MPa to 8.13 MPa. This performance highlights its potential applications in various fields, including packaging and biomedical engineering.
Unlocking nature’s pharmacy: Euphorbia hirta (L.) as a potent defense against Escherichia coli and Klebsiella pneumoniae infections in Tanzania
(Elsevier, 2024) Mbwale, Issaya; Giliba, Richard; Kisula, Lydia; Kemboi, Douglas
Background Urinary tract infections (UTIs) are among the most common bacterial infections, primarily caused by Escherichia coli and Klebsiella pneumoniae, both of which have mostly developed resistance to various antibiotics. The Maasai and Meru communities in Tanzania have traditionally used Euphorbia hirta to combat resistant pathogens, particularly those causing UTIs. Purpose This study aimed to evaluate the antimicrobial compounds of aqueous extracts and the antibacterial compounds in methanolic extracts of E. hirta. We specifically focused on the antibacterial activity of aqueous and methanolic extracts against E. coli and K. pneumoniae strains, which are significant contributors to UTIs. Study design In March 2024, we randomly collected E. hirta plant parts from the Kikwe and Kisongo wards in the Arusha region of Tanzania. The samples were washed with distilled water and shade-dried for three weeks to prevent the degradation of bioactive compounds. After drying, the samples were powdered using a laboratory grinder and stored in sterile nylon bags. Methods We conducted qualitative and quantitative analyses to assess the presence of various phytochemicals, including alkaloids, saponins, coumarins, terpenoids, quinones, flavonoids, and glycosides, in the aqueous and methanolic extracts of E. hirta. To identify specific phytochemical compounds in these extracts, we used gas chromatography-mass spectrometry (GC–MS) and disc diffusion assays to test their antibacterial activity against E. coli and K. pneumoniae. Results The GC–MS analysis identified sixteen potential bioactive compounds with antibiotic properties, including dodecanal, trans-Farnesol, phytol, 13-tetradecynoic acid, methyl ester, cis-5,8,11,14,17-Eicosapentaenoic acid, 2(4H)-Benzofuranone, 5,6,7,7a-tetrahydro-4,4,7a-trimethyl-, (R)-, paromomycin, decanoic acid, methyl ester, azelaic acid, undecanoic acid, 10-methyl-, methyl ester, palmitoleic acid, 9,12,15-Octadecatrienoic acid (Z,Z,Z), 7-Hydroxy-3-(1,1-dimethylprop-2-enyl) coumarins, linoleyl methyl ketone, and 8,11,14-Eicosatrienoic acid, methyl ester (Z,Z,Z). When tested at a concentration of 1 g/mL, all extracts demonstrated significant antibacterial activity. The methanolic extract exhibited the highest performance, with a minimum inhibition zone of 12.0 ± 2.35 mm, followed by the aqueous cold extract at 9.25 ± 1.75 mm, and the aqueous boiled extract at 8.0 ± 1.35 mm. Conclusion The traditional methods employed by the Maasai and Meru communities for preparing herbal medicine from E. hirta, such as boiling and soaking in cold water, seemed to be effective in treating UTIs. Organic solvent extraction using methanol generally showed superior antibacterial activity compared to aqueous extraction. However, soaking in cold water produced extracts with higher inhibitory activity against E. coli, while boiling was more effective against K. pneumoniae. This study validates the local practices of E. hirta preparation, suggesting that water-based extracts could be both effective and safe for treating certain bacterial strains responsible for UTIs in the Arusha region