Fractions and isolated compounds from oxyanthus speciosus subsp. stenocarpus (Rubiaceae) have promising antimycobacterial and intracellular activity

Show simple item record Aro, A.O. (Abimbola) Dzoyem, Jean Paul Awouafack, Maurice D. Selepe, Mamoalosi A. Eloff, Jacobus Nicolaas McGaw, Lyndy Joy 2019-09-04T11:00:09Z 2019-09-04T11:00:09Z 2019-05-22
dc.description.abstract BACKGROUND : Tuberculosis is a deadly disease caused by Mycobacterium species. The use of medicinal plants is an ancient global practice for the treatment and prevention of diverse ailments including tuberculosis. The aim of this study was to isolate and characterize antimycobacterial compounds by bioassay-guided fractionation of the acetone leaf extract of Oxyanthus speciosus. METHODS: A two-fold serial microdilution method was used to determine the minimum inhibitory concentration (MIC) against mycobacteria. Cytotoxicity and nitric oxide inhibitory activity of the isolated compounds was determined to evaluate in vitro safety and potential anti-inflammatory activity. Intracellular efficacy of the crude extract against Mycobacterium-infected macrophages was also determined. RESULTS : Two compounds were isolated and identified as lutein (1) and rotundic acid (2). These had good antimycobacterial activity against the four mycobacteria tested with MIC values ranging from 0.013 to 0.1 mg/mL. Rotundic acid had some cytotoxicity against C3A human liver cells. Lutein was not cytotoxic at the highest tested concentration (200 μg/mL) and inhibited nitric oxide production in RAW 264.7 macrophages by 94% at a concentration of 25 μg/mL. The acetone crude extract (120 μg/mL) of O. speciosus had intracellular antimycobacterial activity, reducing colony forming units by more than 90%, displaying bactericidal efficacy in a dose and time-dependent manner. CONCLUSION : This study provides good proof of the presence of synergism between different compounds in extracts and fractions. It is also the first report of the antimycobacterial activity of lutein and rotundic acid isolated from Oxyanthus speciosus. The promising activity of the crude extract of O. speciosus both in vitro and intracellularly in an in vitro macrophage model suggests its potential for development as an anti- tuberculosis (TB) herbal medicine. en_ZA
dc.description.department Chemistry en_ZA
dc.description.department Paraclinical Sciences en_ZA
dc.description.librarian am2019 en_ZA
dc.description.sponsorship The South African Medical Research Council (SIR funding to LJM) and the National Research Foundation (NRF), South Africa. Funding was supplied by the National Research Foundation to LJ McGaw and JN Eloff (Grant No 81010). en_ZA
dc.description.uri en_ZA
dc.identifier.citation Aro, A.O., Dzoyem, J.P., Awouafack, M.D. et al. 2019, 'Fractions and isolated compounds from Oxyanthus speciosus subsp. stenocarpus (Rubiaceae) have promising antimycobacterial and intracellular activity', BMC Complementary and Alternative Medicine, vol. 19, art. 108, pp. 1-11. en_ZA
dc.identifier.issn 1472-6882 (online)
dc.identifier.other 10.1186/s12906-019-2520-x
dc.language.iso en en_ZA
dc.publisher BioMed Central en_ZA
dc.rights © The Author(s). 2019 Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License. en_ZA
dc.subject Oxyanthus speciosus en_ZA
dc.subject Mycobacterium tuberculosis en_ZA
dc.subject Rotundic acid en_ZA
dc.subject Lutein en_ZA
dc.subject Intracellular en_ZA
dc.subject Nitric oxide inhibition en_ZA
dc.subject Tuberculosis (TB) en_ZA
dc.title Fractions and isolated compounds from oxyanthus speciosus subsp. stenocarpus (Rubiaceae) have promising antimycobacterial and intracellular activity en_ZA
dc.type Article en_ZA

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