Plaxenone A and B: Cytotoxic halogenated monoterpenes from the South African red seaweed Plocamium maxillosum
- Authors: Knott, Michael G , de la Mare, Jo-Anne , Edkins, Adrienne L , Zhang, Angel , Stillman, Martin J , Bolton, John J , Antunes, Edith M , Beukes, Denzil R
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164446 , vital:41119 , https://doi.org/10.1016/j.phytol.2018.12.009
- Description: The endemic South African red seaweed Plocamium maxillosum (Poiret) Lamouroux produces two unusual isomeric dichlorinated cyclohexenone monoterpenes, plaxenone A and B (1 and 2). The structures of the isolated compounds were determined from spectroscopic data and their absolute configuration was determined by comparison of the experimental and calculated ECD spectra. Compounds 1 and 2 inhibit the growth of MDA-MB-231 breast cancer cells.
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- Date Issued: 2019
Isolation, characterization and antiproliferative activity of new metabolites from the South African endemic red algal species Laurencia alfredensis
- Authors: Dziwornu, Godwin A , Caira, Mino R , de la Mare, Jo-Anne , Edkins, Adrienne L , Bolton, John J , Beukes, Denzil R , Sunassee, Suthananda N
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59963 , vital:27715 , https://doi:10.3390/molecules22040513
- Description: The marine red algae of the genus Laurencia have been widely studied for their structurally diverse and biologically active secondary metabolites. We report here the natural product investigation of the organic extract of a newly identified South African endemic species, Laurencia alfredensis. A sequence of column chromatography, preparative TLC and normal phase HPLC resulted in the isolation of eleven compounds comprising three labdane-type diterpenes (1-3), four polyether triterpenes (4-7), three cholestane-type ecdysteroids (8-10) and a glycolipid (11). Compounds 1-3, 5-8 and 10 have not previously been reported, while compound 9 is reported here for the first time from a natural source and the known compound 11 isolated for the first time from the genus Laurencia. The structural elucidation and the relative configuration assignments of the compounds were accomplished by extensive use of ID- and 2D-NMR, HR-ESI-MS, UV and IR spectroscopic techniques, while the absolute configuration of compound 1 was determined by single-crystal X-ray diffraction analysis. All compounds were evaluated against the MDA-MB-231 breast and HeLa cervical cancer cell lines. Compound 2 exhibited low micromolar antiproliferative activity (IC50 = 9.3 gM) against the triple negative breast carcinoma and compound 7 was similarly active (IC50 = 8.8 gM) against the cervical cancer cell line.
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- Date Issued: 2017
AfrOBIS: a marine biogeographic information system for sub-Saharan Africa
- Authors: Grundlingh, M L , St Ange, U B , Bolton, John J
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:7137 , http://hdl.handle.net/10962/d1011813
- Description: AfrOBIS is one of 11 global nodes of the Ocean Biogeographic Information System (OBIS), a freely accessible network of databases collating marine data in support of the Census of Marine Life.Versatile graphic products, provided by OBIS, can be used to display the data. To date, AfrOBIS has loaded about 3.2 million records of more than 23 000 species located mainly in the seas around southern Africa. This forms part of the 13.2 million records of more than 80 000 species currently stored in OBIS. Scouting for South African data has been successful, whereas locating records in other African countries has been much less so.
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- Date Issued: 2007