Discovery of anti-mycobacterial natural products from South African marine algae
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Date
2019
Authors
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Journal ISSN
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Publisher
University of the Western Cape
Abstract
Tuberculosis is a communicable disease which affects millions of people around the world.
Although the case reports are declining, the eradication rate of this disease is far too slow.
Natural products have played a key role in the treatment of the disease. However, tuberculosis
is developing resistance to current first-line therapy. In this study, a prefractionated marine
algal library was developed in order to identify and prioritise samples for isolation of their
active metabolites which exhibit anti-tuberculosis activity. Based on the results of the library
screening and chemical profiling, two seaweeds were selected for further investigation,
Laurencia glomerata and Plocamium cornutum. The extraction and fractionation of Laurencia
glomerata and Plocamium cornutum resulted in the isolation of three chamigrane
seqsuiterpenes (prepacifenol epoxide, johnstonol and one newly proposed structure) and two
monoterpenes (cartilagineal and 1,5,6-trichloro-2-(dichloromethyl)-6-methylocta-1,3,7-triene)
respectively. The structures of these compounds were elucidated by 1 and 2D NMR data and
were confirmed by literature comparisons. Although some of the initial library factions
screened showed rather good activity against Mycobacterium tuberculosis, the selected
seaweed fractions showed greater activity against M. aurum. The isolated monoterpenes
showed moderate cytotoxicity against the cancer cell line MCF-12a and the sesquiterpenes
however were more selective for MCF-7. The monoterpenes showed both activity and potential
selectivity towards Mycobacterium tuberculosis.
Description
>Magister Scientiae - MSc
Keywords
Tuberculosis, Communicable disease, Natural products, Mycobacterium tuberculosis, Marine algae