0000000001312035
AUTHOR
Michael Spiteller
Cytotoxic bufadienolides from the leaves of a medicinal plant Melianthus comosus collected in South Africa.
Abstract From the leaves of South African medicinal plant Melianthus comosus, four previously undescribed bufadienolides, 16β-formyloxymelianthugenin (1), 2β-acetoxymelianthusigenin (2), 2β-hydroxy-3β,5β-di-O-acetylhellebrigenin (3), and 2β-acetoxy-5β-O-acetylhellebrigenin (4) were isolated together with two known bufadienolides. The structural elucidation of the compounds was based on 1D and 2D NMR spectroscopy, high-resolution mass spectrometry, and other spectroscopic methods. The relative configurations were determined by single-crystal X-ray crystallography analysis and NOESY correlations. The isolated compounds displayed strong cytotoxicity against MCF-7 breast cancer cells, sensitive…
Cytotoxic alkaloids from the root of Zanthoxylum paracanthum (mildbr) Kokwaro
Chemical investigation of the root of Zanthoxylum paracanthum afforded 1 new alkamide derivative, (2E,4E)-6-oxo-N-isobutyldeca-2,4-dienamide (1) together with 10 known congeners including one phenolic amide (2), four benzophenanthridines (3 − 6), three indolonaphthyridines (7 − 9) and two lignans (10 and 11). Their structures were elucidated by a combination of spectroscopic and spectrometric data. Using resazurin reduction assay, the crude extract (10 µg/mL) and isolates (10 µM) were screened for their cytotoxic activities against the drug-sensitive (CCRF-CEM) leukemia cell line and its multidrug-resistant counterpart (CEM/ADR5000). Compounds 3, 4 and 6 showed cytotoxicity against CCRF-CEM…
Two new flavonoids from Dracaena usambarensis Engl.
Abstract Investigations of the root extract of Dracaena usambarensis Engl. for anticancer principles led to the characterization of one new homoisoflavonoid, (3S)-3,4ʹ,5,6-tetrahydroxy-7-methoxyhomoisoflavanone (1) and a new retrodihydrochalcone, 4ʹ,4-dihydroxy-2,3-dimethoxydihydrochalcone (2) along with six previously reported compounds, including two homoisoflavonoids, 7-O-methyl-8-demethoxy-3-hydroxy-3,9-dihydropunctatin (3) and loureiriol (4); a phenolic amide, 3-(4ʹʹʹ-hydroxyphenyl)-N-[2ʹ-(4ʹʹ-hydroxyphenyl)-2ʹ-methoxyethyl]acrylamide (5); a spirostane, 25S-spirosta-1,4-dien-3-one (6) and two steroids, stigmasterol (7) and stigmasterol 3-O-β-D-glucopyranoside (8). The structures of 1-8…
Cytotoxic alkaloids from the root of Zanthoxylum paracanthum (mildbr) Kokwaro
Chemical investigation of the root of Zanthoxylum paracanthum afforded 1 new alkamide derivative, (2E,4E)-6-oxo-N-isobutyldeca-2,4-dienamide (1) together with 10 known congeners including one pheno...
Cytotoxic Bufadienolides from the Leaves of Melianthus major
Melianthus major is a medicinal plant endemic to South Africa. Its leaf extract led to the isolation of five new bufadienolides, 2β-acetoxy-3,5-di-O-acetylhellebrigenin (1), 2β-acetoxy-3-O-acetylhellebrigenin (2), 2β-acetoxy-14-deoxy-15β,16β-epoxymelianthugenin (4), 2β-acetoxy-14-deoxy-15β,16β-epoxymelianthusigenin (5), and 2β-hydroxymelianthusigenin (6), and four known analogues. The structures of the compounds were elucidated using NMR and HRESIMS data analyses. The relative configurations were defined by single-crystal X-ray crystallography and NOESY correlations. The isolated compounds exhibited strong cytotoxicity against MCF-7 breast cancer cells and sensitive CCRF-CEM and multidrug-r…
CCDC 1981430: Experimental Crystal Structure Determination
Related Article: Kibrom Gebreheiwot Bedane, Lukas Brieger, Carsten Strohmann, Ean-Jeong Seo, Thomas Efferth, Michael Spiteller|2020|Bioorg.Chem.|102|104102|doi:10.1016/j.bioorg.2020.104102
CCDC 1961566: Experimental Crystal Structure Determination
Related Article: Kibrom Gebreheiwot Bedane, Lukas Brieger, Carsten Strohmann, Ean-Jeong Seo, Thomas Efferth, Michael Spiteller|2020|J.Nat.Prod.|83|2122|doi:10.1021/acs.jnatprod.0c00060
CCDC 1961567: Experimental Crystal Structure Determination
Related Article: Kibrom Gebreheiwot Bedane, Lukas Brieger, Carsten Strohmann, Ean-Jeong Seo, Thomas Efferth, Michael Spiteller|2020|J.Nat.Prod.|83|2122|doi:10.1021/acs.jnatprod.0c00060
CCDC 1981431: Experimental Crystal Structure Determination
Related Article: Kibrom Gebreheiwot Bedane, Lukas Brieger, Carsten Strohmann, Ean-Jeong Seo, Thomas Efferth, Michael Spiteller|2020|Bioorg.Chem.|102|104102|doi:10.1016/j.bioorg.2020.104102