Browsing by Author "Fitzpatrick, Paul A."

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Flavonoids from Erythrina Schliebenii
    (American Chemical Society, 2017-01-23) Nyandoro, Stephen S.; Munissi, Joan J.E; Kombo, Msim; Mgina, Clarence A; Pan, FangFang; Gruhonjic, Amra; Fitzpatrick, Paul A.; Lu, Yu; Wang, Bin; Rissanen, Kari; Erdelyi, Mate
    Prenylated and O-methylflavonoids including one new pterocarpan (1), three new isoflavones (2–4), and nineteen known natural products (5–23) were isolated and identified from the root, stem bark, and leaf extracts of Erythrina schliebenii. The crude extracts and their constituents were evaluated for antitubercular activity against Mycobacterium tuberculosis (H37Rv strain), showing MICs of 32–64 μg mL–1 and 36.9–101.8 μM, respectively. Evaluation of their toxicity against the aggressive human breast cancer cell line MDA-MB-231 indicated EC50 values of 13.0–290.6 μM (pure compounds) and 38.3 to >100 μg mL–1 (crude extracts).
  • Thumbnail Image
    Item
    N -Cinnamoyltetraketide Derivatives from the Leaves of Toussaintia orientalis
    (PubMed, 2015-07) Nyandoro, Stephen S.; Ndanu, Joseph; Munissi, Joan J. E.; Gruhonjic, Amra; Fitzpatrick, Paul A.; Landberg, Göran; Lu, Yu; Wang, Bin; Pan, Fangfang; Rissanen, Kari; Erdélyi, Máté
    Seven N-cinnamoyltetraketides (1-7), including the new Z-toussaintine E (2), toussaintine F (6), and toussaintine G (7), were isolated from the methanol extract of the leaves of Toussaintia orientalis using column chromatography and HPLC. The configurations of E-toussaintine E (1) and toussaintines A (3) and D (5) are revised based on single-crystal X-ray diffraction data from racemic crystals. Both the crude methanol extract and the isolated constituents exhibit antimycobacterial activities (MIC 83.3-107.7 μM) against the H37Rv strain of Mycobacterium tuberculosis. Compounds 1, 3, 4, and 5 are cytotoxic (ED50 15.3-105.7 μM) against the MDA-MB-231 triple negative aggressive breast cancer cell line.
  • Thumbnail Image
    Item
    Phytoconstituents with Radical Scavenging and Cytotoxic Activities from Diospyros shimbaensis
    (MDPI, 2016-01-15) Aronsson, Per; Munissi, Joan J. E.; Gruhonjic, Amra; Fitzpatrick, Paul A.; Landberg, Göran; Nyandoro, Stephen S.; Erdélyi, Máté
    As part of our search for natural products having antioxidant and anticancer properties, the phytochemical investigation of Diospyros shimbaensis (Ebenaceae), a plant belonging to a genus widely used in East African traditional medicine, was carried out. From its stem and root barks the new naphthoquinone 8,8′-oxo-biplumbagin (1) was isolated along with the known tetralones trans-isoshinanolone (2) and cis-isoshinanolone (3), and the naphthoquinones plumbagin (4) and 3,3′-biplumbagin (5). Compounds 2, 4, and 5 showed cytotoxicity (IC50 520–82.1 μM) against MDA-MB-231 breast cancer cells. Moderate to low cytotoxicity was observed for the hexane, dichloromethane, and methanol extracts of the root bark (IC50 16.1, 29.7 and > 100 μg/mL, respectively), and for the methanol extract of the stem bark (IC50 59.6 μg/mL). The radical scavenging activity of the isolated constituents (1–5) was evaluated on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The applicability of the crude extracts and of the isolated constituents for controlling degenerative diseases is discussed.
  • Thumbnail Image
    Item
    Polyoxygenated Cyclohexenes and Other Constituents of Cleistochlamys kirkii Leaves
    (American Chemical Society, 2016-12-21) Nyandoro, Stephen S.; Munissi, Joan J.E; Gruhonjic, Amra; Duffy, Sandra; Pan, FangFang; Puttreddy, Rakesh; Holleran, John P.; Fitzpatrick, Paul A.; Pelletier, Jerry; Avery, Vicky M.; Rissanen, Kari; Erdelyi, Mate
    Thirteen new metabolites, including the polyoxygenated cyclohexene derivatives cleistodiendiol (1), cleistodienol B (3), cleistenechlorohydrins A (4) and B (5), cleistenediols A–F (6–11), cleistenonal (12), and the butenolide cleistanolate (13), 2,5-dihydroxybenzyl benzoate (cleistophenolide, 14), and eight known compounds (2, 15–21) were isolated from a MeOH extract of the leaves of Cleistochlamys kirkii. The purified metabolites were identified by NMR spectroscopic and mass spectrometric analyses, whereas the absolute configurations of compounds 1, 17, and 19 were established by single-crystal X-ray diffraction. The configuration of the exocyclic double bond of compound 2 was revised based on comparison of its NMR spectroscopic features and optical rotation to those of 1, for which the configuration was determined by X-ray diffraction. Observation of the co-occurrence of cyclohexenoids and heptenolides in C. kirkii is of biogenetic and chemotaxonomic significance. Some of the isolated compounds showed activity against Plasmodium falciparum (3D7, Dd2), with IC50 values of 0.2–40 μM, and against HEK293 mammalian cells (IC50 2.7–3.6 μM). While the crude extract was inactive at 100 μg/mL against the MDA-MB-231 triple-negative breast cancer cell line, some of its isolated constituents demonstrated cytotoxic activity with IC50 values ranging from 0.03–8.2 μM. Compound 1 showed the most potent antiplasmodial (IC50 0.2 μM) and cytotoxic (IC50 0.03 μM, MDA-MB-231 cell line) activities. None of the compounds investigated exhibited translational inhibitory activity in vitro at 20 μM.
  • Thumbnail Image
    Item
    Selenium Accumulating Leafy Vegetables Are a Potential Source of Functional Foods
    (Hindawi Publishing Cooperation, 2015) Mabeyo, Petro E.; Manoko, Mkabwa L.K.; Gruhonjic, Amra; Fitzpatrick, Paul A.; Landberg, Göran; Erdélyi, Máté; Nyandoro, Stephen S.
    Selenium deficiency in humans has been associated with various diseases, the risks of which can be reduced through dietary supplementation. Selenium accumulating plants may provide a beneficial nutrient for avoiding such illnesses. Thus, leafy vegetables such as Amaranthus hybridus, Amaranthus sp., Cucurbita maxima, Ipomoea batatas, Solanum villosum, Solanum scabrum, and Vigna unguiculata were explored for their capabilities to accumulate selenium when grown on selenium enriched soil and for use as a potential source of selenium enriched functional foods. Their selenium contents were determined by spectrophotometry using the complex of 3,3󸀠-diaminobenzidine hydrochloride (DABH) as a chromogen. The mean concentrations in the leaves were found to range from 7.90 ± 0.40 to 1.95 ± 0.12 𝜇g/g dry weight (DW), with C. maxima accumulating the most selenium. In stems, the accumulated selenium content ranged from 1.12 ± 0.10 𝜇g/g in Amaranthus sp. to 5.35 ± 0.78 𝜇g/g DW in C. maxima and was hence significantly different (𝑃 < 0.01). The cancer cell line MDA-MB-231 was used in cytotoxicity assays to determine the anticancer potential of these extracts. With exception of S. scabrum and S. villosum, no cytotoxicity was detected for the selenium enriched vegetable extracts up to 100 𝜇g/mL concentration. Hence, following careful evaluation the studied vegetables may be considered as selenium enriched functional foods.
  • Thumbnail Image
    Item
    Selenium Accumulating Leafy Vegetables Are a Potential Source of Functional Foods
    (Hindawi Publishing Corporation, 2015-11-12) Mabeyo, Petro E.; Manoko, Mkabwa L. K.; Gruhonjic, Amra; Fitzpatrick, Paul A.; Landberg, Göran; Erdélyi, Máté; Nyandoro, Stephen S.
    Selenium deficiency in humans has been associated with various diseases, the risks of which can be reduced through dietary supplementation. Selenium accumulating plants may provide a beneficial nutrient for avoiding such illnesses. Thus, leafy vegetables such as Amaranthus hybridus, Amaranthus sp., Cucurbita maxima, Ipomoea batatas, Solanum villosum, Solanum scabrum, and Vigna unguiculata were explored for their capabilities to accumulate selenium when grown on selenium enriched soil and for use as a potential source of selenium enriched functional foods. Their selenium contents were determined by spectrophotometry using the complex of 3,3′-diaminobenzidine hydrochloride (DABH) as a chromogen. The mean concentrations in the leaves were found to range from to  μg/g dry weight (DW), with C. maxima accumulating the most selenium. In stems, the accumulated selenium content ranged from  μg/g in Amaranthus sp. to  μg/g DW in C. maxima and was hence significantly different (). The cancer cell line MDA-MB-231 was used in cytotoxicity assays to determine the anticancer potential of these extracts. With exception of S. scabrum and S. villosum, no cytotoxicity was detected for the selenium enriched vegetable extracts up to 100 μg/mL concentration. Hence, following careful evaluation the studied vegetables may be considered as selenium enriched functional foods.