Browsing by Author "Masalu, Rose"

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    Antimycobacterial and Cytotoxic Activities of Extracts from Fungal Isolates of Lake Magadi
    (International Formulae Group, 2017) Kowanga, Keno D; Munissi, Joan J.E; Masalu, Rose; Nyandoro, Stephen S.; Masimba, Pax; Gatebe, E.
    Antimycobacterial and cytotoxic activities of extracts from fungal isolates of Lake Magadi Keno David Kowanga, Joan John Eliona Munissi, Rose Masalu, Stephen Samwel Nyandoro, Pax Masimba, Erastus Gatebe Abstract In this study, antimycobacterial and cytotoxic activities of ethyl acetate extracts of fungal isolates from Lake Magadi were evaluated. The extracts were tested against Mycobacterium madagascariense (MM) and M. indicus pranii (MIP), and cytotoxicity against brine shrimp (Artemia salina) larvae. Fungal strains were identified using sequence comparison of the Internal Transcribed Spacer (ITS) region. Potent antimycobacterial activities against MM were exhibited by extracts from Volutella colletotrichoides, Helicoon richonis, Penicillium limosum, P. sacculum, Aspergillus parasiticus and A. nomius strains that exhibited minimum inhibition concentration (MIC) in the range of 0.19 – 12.5 mg/mL. On the other hand, significant antimycobacterial effects against MIP was shown by extracts from V. colletotrichoides, H. richonis, A. parasiticus, Fusarium merismoides, A. silvaticus and A. fumigatus strains in the same MIC range. Notable cytotoxic activities of the extracts were from A. versicolor, A. nomius, P. janthinellum and H. richonis strains with LC50 values ranging from 46.60 – 98.12 μg/mL. These results indicate that fungi inhabiting Lake Magadi have the ability to produce bioactive metabolites that could be further explored for potential medicinal agents
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    Free Radical Scavenging Activity of Some Fungi Indigenous to Tanzania
    (2012) Masalu, Rose; Hosea, Ken M.; Malendeja, Sylives
    The objective of this study was to evaluate free radical scavenging capacity of crude extracts from forest basidiomycetous fungi, domestic zygomycetous fungi and marine ascomycetous fungi. Lethal concentration values that kill 50% of the brine shrimps (LC50) were determined from 19 fungal extracts using brine shrimp test (BST). The LC50 values of fungal extract ranged between 0.28– 40µg/ml. The basidiomycetous (Lactarius volemoides) was the most toxic fungi with LC50 of 0.28µg/ml while ascomycete Pichia guilliermondii showed the least toxicity with LC50 of 40µg/ml. The concentrations of eleven fungal extracts were further evaluated on their ability to scavenge free radical using 1-diphenyl-2-picrylhydrazyl (α,α-diphenyl-β-picrylhydrazyl) (DPPH) as a dye reagent for spectrophotometric assay at 517nm. The extract concentrations that decreased the initial DPPH radical by 50% (EC50) were determined. The EC50 values ranged from 19–60.4µg/ml ascorbic acid equivalents. Extracts from an edible but undomesticated basidiomycetous fungus isolated from Miombo forest and identified as Termitomyces microcarpus showed the highest scavenging effect with EC50 at 19µg/ml while that from ascomycete Candida tropicalis showed the least EC50 at 60.4µg/ml. These results draw attention to wild undomesticated Miombo fungi as potential source of nutritional supplements worth further investigation.
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    Induction of Early Apoptosis and Reactive Oxygen Species (ROS) Production by Tanzanian Basidiomycete ( Cantharellus Miomboensis )
    (2010) Masalu, Rose; Hosea, Ken M.; Meyer, Mervin; Lyantagaye, Sylvester L.; Kanyande, Stonard
    Cantharellus miomboensis is a new basidiomycete fungus recently found in Miombo woodlands in Tanzania. In this study, crude extract was prepared from fruiting bodies of C. miomboensis and was in vitro screened for its cytotoxicity using Tetrazolium salt (3-(4,5-dimethlthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) in human cell lines namely; Hepatocellular carcinoma (HepG2), Human non-small cell lung carcinoma (H157) and Human colon adenocarcinoma (HT.29). Thereafter, pro-apoptotic effects were determined using biochemical changes in apoptotic cells. These included externalization of phospholipid phosphatidylserine (PS) using APO Percentage dye by flow cytometry and depolarization of mitochondrial membrane potential using Tetramethyl rhodamine ethyl ester perchlorate (TMRE) assay. The test extract was found to induce dose dependent PS externalization on human cell lines when treated with various concentrations (1 - 5 mg/ml) and completely depolarized the mitochondrial membrane potential after 6 hours on HepG2 cell line. When the extract was examined for ROS production using 2’,7’- dichlorofluorescin diacetate (DCFH-DA) staining, there was no ROS generation found in HepG2 cells. It is therefore concluded that C. miomboensis extract is able to induce apoptosis in HepG2 cells and PS externalization and loss of mitochondrial membrane potential in HepG2 cells appear to be independent of ROS production.