Browsing by Author "Mlozi, Stephano"

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Antimicrobial activities of against selected pathogenic fungi and bacteria strains.
(Taylor & Francis Online, 2019-12-19) Chacha, Musa; Mlozi, Stephano; Mmongoyo, Juma
and are dangerous pathogens causing fungal diseases. and developed resistance to fungicides such as fluconazole. Similarly, pathogenic bacteria have become resistant to antibiotcs such as methicillin. Thus, searching for alternative antimicrobial agents is inevitable. used traditionally for management of fungal and bacterial diseases is potential source of antimicrobial agents. It is in this vein that, antimicrobial activities of leaf and root extracts of were evaluated against (ATCC 90028), (clinical isolate), (ATCC25923), (ATCC29953), (ATCC 700603) and (NCTC 8385). A two-fold serial dilution method using the sterilised 96 wells of polystyrene microlitre plates used to determine the minimum inhibitory concentration (MIC) of extracts. Hexane and dichloromethane extracts exhibited the lowest activity against fungi strains with MICs >10 mg/mL. Root and leaf methanolic extracts exhibited activity at MICs of 5 and 1.25 mg/mL, respectively, against both tested fungi. Dichloromethane and methanolic extracts exhibited antibacterial activity with MICs ranging from 2.5 - 10 mg/mL and 0.625 - 5 mg/mL, respectively. Antimicrobial activities of the extracts of revealed potentiality of bioactives against fungal and bacterial diseases.
The in vivo toxicity evaluation of leaf and root methanolic extracts of Tephrosia vogelii Hook.f using animal model
(Springer Nature, 2020-11-10) Mlozi, Stephano; Mmongoyo, Juma; Chacha, Musa
Background: Traditionally, herbal medicines are commonly used to cure several diseases since immemorial of human life. Nevertheless, the safety of some traditionally used medicinal plants is uncertain. Since Tephrosia vogelii Hook.f is a traditionally used medicinal plant, the effects of its extracts were evaluated on lethality (LD50) and subacute toxicity in this study. Methods: Phytochemistry screening and an in vivo toxicity evaluation of leaf and root methanolic extracts of T. vogelii using laboratory albino rats were conducted. Methanolic extracts of doses 600, 1200, 2000 and 5000 mg/kg body weights were administered single dose in rats to observe deaths within 72 h in order to determine the LD50. Methanolic extracts doses of 600, 1200 and 2000 mg/kg body weights were consecutively administered for 14 days in order to evaluate sub-acute toxicity. Results: Tannins, steroids, terpenoids, flavonoids and saponins were identified in the phytochemical screening. The LD50 experiments revealed zero deaths of rats for the administered doses, 600 to 5000 mg/kg body weight. Histopathological examination of liver and kidney for sub-acute toxicity test showed safety at all doses except root methanolic extracts dose of 2000 mg/kg which exhibited necrosis and vacuolation of liver cells on the 14th day. Nonetheless, hepatic necrosis and hepatic vacuolation disappeared upon time elongation without dose administration to 28th day. Conclusion: The conducted toxicity evaluation of methanolic leaf and root extracts in albino rats revealed no deleterious effects, henceforth, suggesting that T. vogelii could be safe to users using it as a medicinal plant.
Seasons and bee foraging plant species strongly influence honey antimicrobial activity
(Elsevier, 2023-06) Rikohe, Isack; Mlozi, Stephano; Ngondya, Issakwisa
Honey has been used in human medicine since ancient times due to its antimicrobial properties. However, honey antimicrobial potential varies due to floral sources, geographical origins, and seasonality. The current study assessed the antimicrobial activity of honey and honeybees’ preferred plants namely, Acacia mellifera, Ocimum basilicum, Hoslundia opposita, Combretum schumannii, Grewia bicolor, Terminalia brownii, Cordia monoica from Same district in Northern Tanzania, during the short and long rain seasons of 2021/2022. The agar well diffusion method was employed for the antimicrobial assay, and the antimicrobial activity was evaluated by measuring inhibition zones. Significant differences were observed in antimicrobial activities among honey of different seasons (F = 28.5, p = <0.001) and plant extracts (F = 15.9, p < 0.001). Honey A and D that were harvested at the end of the short rain season were found with higher antimicrobial activities (10–19 mm inhibition) than that harvested at the end of the long rain season (10–15 mm inhibition), and the most susceptible microorganisms were Escherichia coli and Staphylococcus aureus. For the tested plant extracts, T. brownii, C. schumannii, and H. opposita showed higher antimicrobial activities (11.3–19 mm inhibition) against pathogenic microorganisms than other tested plants. There was a strong positive correlation in antimicrobial activities (r = 0.836, p = 0.078, r = 0.756, p = 0.139, and r = 0.732 p = 0.159) between honey harvested at the end of the short rain season with some plant extracts from plants blooming during the same season. The study highlighted the variation in antimicrobial activities among honey harvested in different rain seasons and that there is antimicrobial relation between honey and plants that are foraged by honeybees. Thus, the antimicrobial ability of the honey depends much on the plant species foraged by honeybees.