Browsing by Author "Mmongoyo, Juma A."

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Aflatoxin levels in sunflower seeds and cakes collected from micro- and small-scale sunflower oil processors in Tanzania
    (2017-04-18) Mmongoyo, Juma A.; Wu, Felicia; Linz, John E.; Nair, Muraleedharan G.; Mugula, Jovin K.; Tempelman, Robert J.; Strasburg, Gale M.
    Aflatoxin, a mycotoxin found commonly in maize and peanuts worldwide, is associated with liver cancer, acute toxicosis, and growth impairment in humans and animals. In Tanzania, sunflower seeds are a source of snacks, cooking oil, and animal feed. These seeds are a potential source of aflatoxin contamination. However, reports on aflatoxin contamination in sunflower seeds and cakes are scarce. The objective of the current study was to determine total aflatoxin concentrations in sunflower seeds and cakes from small-scale oil processors across Tanzania. Samples of sunflower seeds (n = 90) and cakes (n = 92) were collected across two years, and analyzed for total aflatoxin concentrations using a direct competitive enzyme-linked immunosorbent assay (ELISA). For seed samples collected June-August 2014, the highest aflatoxin concentrations were from Dodoma (1.7–280.6 ng/g), Singida (1.4–261.8 ng/g), and Babati-Manyara (1.8–162.0 ng/g). The highest concentrations for cakes were from Mbeya (2.8–97.7 ng/g), Dodoma (1.9–88.2 ng/g), and Singida (2.0–34.3 ng/g). For seed samples collected August-October 2015, the highest concentrations were from Morogoro (2.8–662.7 ng/g), Singida (1.6–217.6 ng/g) and Mbeya (1.4–174.2 ng/g). The highest concentrations for cakes were from Morogoro (2.7–536.0 ng/g), Dodoma (1.4– 598.4 ng/g) and Singida (3.2–52.8 ng/g). In summary, humans and animals are potentially at high risk of exposure to aflatoxins through sunflower seeds and cakes from micro-scale millers in Tanzania; and location influences risk.
  • Thumbnail Image
    Item
    Antimicrobial activities of Tephrosia vogelii against selected pathogenic fungi and bacteria strains
    (2019-12-19) Mlozi, Stephano H.; Mmongoyo, Juma A.; Chacha, Musa
    Candida albicans and Cryptococcus neoformans are dangerous pathogens causing fungal dis eases. C. albicans and C. neoformans developed resistance to fungicides such as fluconazole. Similarly, pathogenic bacteria Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Salmonella typhi have become resistant to antibiotcs such as methicillin. Thus, searching for alternative antimicrobial agents is inevitable. Tephrosia vogelii used traditionally for manage ment 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 T. vogelii were evaluated against C. albicans (ATCC 90028), C. neoformans (clinical isolate), S. aureus (ATCC25923), E. coli (ATCC29953), K. pneumoniae (ATCC 700603) and S. typhi (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 T. vogelii revealed potentiality of bioactives against fungal and bacterial diseases.
  • Thumbnail Image
    Item
    COMPOUNDS FOR INHIBITION OF FUNGAL MYCOTOXIN AND SPORULATION
    (United States Patent No .: US 10,531,662 B2, 2020-01-14) Strasburg, Gale M.; Mmongoyo, Juma A.; Linz, John E.; Wu, Felicia; Mugula, Jovin K.; Dissanayake, Amila A.; Zhang, Chuan-Rui; Wee, Josephine M.; Nair, Muraleedharan G.; Day, Devin M.
    Compounds and compositions are described herein that inhibit the biosynthesis of mycotoxins and fungal sporula tion . Such compounds and compositions are useful for inhibiting mold . Methods of using such compounds and compositions are also described herein that involve applying the compositions to plants , plant parts , structures , contain ers , and other surfaces
  • Thumbnail Image
    Item
    The in vivo toxicity evaluation of leaf and root methanolic extracts of Tephrosia vogelii Hook.f using animal model
    (2020-11-10) Mlozi, Stephano H.; Mmongoyo, Juma A.; 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 sub acute 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. Keywords: Herbal medicines, Tephrosia vogelii Hook.f, Methanolic extracts, Lethality, Sub-acute toxicity
  • Thumbnail Image
    Item
    Synthesis of A Kairomone and Other Chemicals From Cardanol, A Renewable Resource
    (Wiley, 2012-09) Mmongoyo, Juma A.; Mgani, Quintino A.; Mdachi, Stephen J. M.; Pogorzelec, Peter J.; Cole‐Hamilton, David J.
  • Thumbnail Image
    Item
    Synthesis of a kairomone and other chemicals from cardanol, a renewable resource
    (2012-06-05) Mmongoyo, Juma A.; Mgani, Quintino A.; Mdachi, Stephen J. M.; Pogorzelec, Peter J.; Cole‐Hamilton, David J.
    Synthesis of a tsetse fly kairomone component (3-propylphenol), a detergent [sodium 2-(dec-8-enyl)-6hydroxybenzenesulfonate], a polymer additive (1-octene), and a detergent precursor [3-(non-8enyl)phenol] using cardanol [3-(pentadec-8-enyl)phenol], has been accomplished. Both carbon– carbon double bond isomerization and metathesis methodologies were employed in the syntheses of these target molecules. The kairomone component was obtained, albeit in low yield, in three steps starting with cardanol. Synthesis of a new detergent, sodium 2-(dec-8-enyl)-6-hydroxybenzenesulfonate, was achieved by direct metathesis of cardanol with cis-2-butene followed by sulfonation and basification. Finally, synthesis of 1-octene and 3-(non-8-enyl)phenol was accomplished in one pot by direct metathesis of cardanol with ethylene. These products have been characterized spectroscopically, especially using 1H and 13C NMR.