Browsing by Author "Rissanen, Kari"

Now showing 1 - 3 of 3
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    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).
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    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.
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    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.