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Ndlovu M, Serem JC, Selepe MA, Opoku AR, Bester MJ, Apostolides Z, Mosa RA. Triterpenoids from Protorhus longifolia Exhibit Hypocholesterolemic Potential via Regulation of Cholesterol Biosynthesis and Stimulation of Low-Density Lipoprotein Uptake in HepG2 Cells. ACS Omega 2023; 8:30906-30916. [PMID: 37663489 PMCID: PMC10468762 DOI: 10.1021/acsomega.3c01995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/16/2023] [Indexed: 09/05/2023]
Abstract
The increasing incidence of hypercholesterolemia-related diseases even in the presence of the currently available cholesterol-lowering drugs indicates a need to discover new therapeutic drugs. This study aimed to investigate the hypocholesterolemic potential of two triterpenoids isolated from Protorhus longifolia stem bark. In silico techniques and in vitro enzyme assays were used to evaluate the potential inhibition of cholesterol esterase and HMG-CoA reductase by the triterpenoids (ARM-2 and RA-5). The toxicity, modulation of low-density lipoprotein (LDL) uptake, and associated gene expression were determined in HepG2 hepatocytes. In silico molecular docking revealed that ARM-2 compared with RA-5 has a relatively stronger binding affinity for both enzymes. Both triterpenoids further demonstrated promising in silico drug-likeness properties and favorable ADMET profiles characterized by high intestinal absorption and lack of CYP450 enzyme inhibition. The compounds further showed, to varying degrees of efficacy, inhibition of cholesterol micellization as well as both cholesterol esterase and HMG-CoA reductase activities with IC50 values ranging from 16.4 to 41.1 μM. Moreover, enhanced hepatic cellular LDL uptake and the associated upregulation of the LDL-R and SREBP-2 gene expression were observed in the triterpenoid-treated HepG2 cells. It is evident that the triterpenoids, especially ARM-2, possess hypocholesterolemic properties, and these molecules can serve as leads or structural templates for the development of new hypocholesterolemic drugs.
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Affiliation(s)
- Musawenkosi Ndlovu
- Department
of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield 0028, South Africa
| | - June C. Serem
- Department
of Anatomy, University of Pretoria, Pretoria 0007, South Africa
| | - Mamoalosi A. Selepe
- Department
of Chemistry, University of Pretoria, Hatfield 0028, South Africa
| | - Andrew R. Opoku
- Department
of Biochemistry and Microbiology, University
of Zululand, KwaDlangezwa 3886, South Africa
| | - Megan J. Bester
- Department
of Anatomy, University of Pretoria, Pretoria 0007, South Africa
| | - Zeno Apostolides
- Department
of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield 0028, South Africa
| | - Rebamang A. Mosa
- Department
of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield 0028, South Africa
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Adewole AH, Famuyide IM, McGaw LJ, Selepe MA, October N. Antifungal Compounds from the Leaves of Rhynchosia minima. Chem Biodivers 2022; 19:e202200837. [PMID: 36305375 DOI: 10.1002/cbdv.202200837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/26/2022] [Indexed: 12/27/2022]
Abstract
Rhynchosia minima, commonly known as jumby bean, is used as a remedy for respiratory ailments in various parts of the world. It is also used by South African traditional healers to treat heart or chest pain. This study aimed to investigate the bioactive constituents of the leaf extracts of R. minima against selected fungal isolates that have been identified as risk factors in respiratory illness. Rhynchosia minima leaves were extracted sequentially using hexane, dichloromethane, ethyl acetate and methanol in increasing order of polarity. The extracts were subjected to repeated chromatographic techniques, for phytochemical isolation. The extracts and isolated compounds were screened against Candida albicans and Cryptococcus neoformans by determining the minimum concentration that inhibited fungal growth. Six flavonoids, one norisoprenoid and one cyclitol were isolated and characterized by 1D and 2D NMR and HR-ESI-MS. The extracts obtained in the study had moderate to weak antifungal activities, with MICs ranging from 312.5 to 1250.0 μg/mL against both fungi. Four isolated compounds were also screened, with two of them exhibiting activity against C. albicans (MIC=6.25 μg/mL) that was comparable to amphotericin B, the positive control. These two compounds also had better antifungal potential against C. neoformans with an MIC=6.25 μg/mL, compared to the MIC of 12.5 μg/mL of amphotericin B. Seven of the eight isolated compounds were obtained from the extracts of Rhynchosia minima for the first time. Two of the isolated compounds demonstrated activity comparable or superior to amphotericin B activity. The notable potency displayed by these compounds warrants further investigation on their development as antifungal agents.
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Affiliation(s)
- Adetola H Adewole
- Department of Chemistry, University of Pretoria, Hatfield, Pretoria, 0002, South Africa
| | - Ibukun M Famuyide
- Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa
| | - Lyndy J McGaw
- Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa
| | - Mamoalosi A Selepe
- Department of Chemistry, University of Pretoria, Hatfield, Pretoria, 0002, South Africa
| | - Natasha October
- Department of Chemistry, University of Pretoria, Hatfield, Pretoria, 0002, South Africa
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Selepe MA, Kunyane P, Seboletswe P, Nair S, Cele N, Engelbrecht M, Joubert DF, Vandevoorde C, Singh P, Sonopo MS. Synthesis and evaluation of benzoylbenzofurans and isoflavone derivatives as sirtuin 1 inhibitors with antiproliferative effects on cancer cells. Bioorg Chem 2022; 128:106101. [PMID: 35998518 DOI: 10.1016/j.bioorg.2022.106101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/01/2022] [Accepted: 08/12/2022] [Indexed: 11/17/2022]
Abstract
Isoflavone derivatives were prepared from benzoylbenzofuran precursors. The synthesized compounds were analyzed by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, as well as high-resolution mass spectrometry (HRMS) to confirm their structures. The benzoylbenzofuran and isoflavone analogues were evaluated for inhibition of sirtuin 1 (SIRT1) and cell proliferation in MDA-MB-231 triple-negative breast cancer (TNBC) cells. Several isoflavone and benzoylbenzofuran derivatives exhibited potent antiproliferative effects against the MDA-MB-231 cancer cell line. Most of the isoflavone derivatives attenuated SIRT1 activity to below 50%. The most active compounds were the isoflavone quinones 38, 39, and 40, at IC50 values of 5.58 ± 0.373, 1.62 ± 0.0720, and 7.24 ± 0.823 μM, respectively. Importantly, the most active compound, 6-methoxy-4',6'-dimethylisoflavone-2',5'-quinone (39) displayed SIRT1 inhibitory activity comparable to that of the reference compound, suramin. The in silico docking simulations in the active site of SIRT1 further substantiated the experimental results and explored the binding orientations of potent compounds in the active site of the target.
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Affiliation(s)
- Mamoalosi A Selepe
- Department of Chemistry, University of Pretoria, Lynnwood Rd, Hatfield, Pretoria 0002, South Africa.
| | - Phaladi Kunyane
- Department of Chemistry, University of Pretoria, Lynnwood Rd, Hatfield, Pretoria 0002, South Africa
| | - Pule Seboletswe
- School of Chemistry and Physics, University of KwaZulu-Natal, P/Bag X54001, Westville, Durban 4000, South Africa
| | - Shankari Nair
- Radiation Biophysics Division, Separated Sector Cyclotron Laboratory, NRF-iThemba LABS, Cape Town 7131, South Africa
| | - Nosipho Cele
- School of Chemistry and Physics, University of KwaZulu-Natal, P/Bag X54001, Westville, Durban 4000, South Africa
| | - Monique Engelbrecht
- Radiation Biophysics Division, Separated Sector Cyclotron Laboratory, NRF-iThemba LABS, Cape Town 7131, South Africa
| | - Daniël F Joubert
- Department of Physiology, University of Pretoria, Lynnwood Rd, Hatfield, Pretoria 0002, South Africa
| | - Charlot Vandevoorde
- Radiation Biophysics Division, Separated Sector Cyclotron Laboratory, NRF-iThemba LABS, Cape Town 7131, South Africa
| | - Parvesh Singh
- School of Chemistry and Physics, University of KwaZulu-Natal, P/Bag X54001, Westville, Durban 4000, South Africa.
| | - Molahlehi S Sonopo
- Radiochemistry, South African Nuclear Energy Corporation Ltd, Pelindaba, Brits 0240, South Africa.
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Ramabulana T, Ndlovu M, Mosa RA, Sonopo MS, Selepe MA. Phytochemical Profiling and Isolation of Bioactive Compounds from Leucosidea sericea (Rosaceae). ACS Omega 2022; 7:11964-11972. [PMID: 35449904 PMCID: PMC9016878 DOI: 10.1021/acsomega.2c00096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
In the study, ultraperformance liquid chromatography-quadrupole time-of-flight-mass spectrometry analysis of Leucosidea sericea leaf and stem extracts led to the identification of various classes of compounds. Further chromatographic purifications resulted in the isolation of 22 compounds that consisted of a new triterpenoid named leucosidic acid A (1), an acetophenone derivative 2, a phloroglucinol derivative 3, three chromones 4-6, seven pentacyclic triterpenoids 7-13, a phytosterol glucoside 14, a flavonoid 15, and seven flavonoid glycosides 16-22. Nineteen of these compounds including the previously undescribed triterpenoid 1 are isolated for the first time from L. sericea. The structures of the isolated compounds were assigned based on their high-resolution mass spectrometry and nuclear magnetic resonance data. Some of the isolated triterpenoids were evaluated for inhibitory activity against α-amylase, α-glucosidase, and pancreatic lipase. Of the tested compounds, 1-hydroxy-2-oxopomolic acid (7) and pomolic acid (13) showed higher potency on α-glucosidase than acarbose, which is used as a positive control in this study. The two compounds inhibited α-glucosidase with IC50 values of 192.1 ± 13.81 and 85.5 ± 6.87 μM, respectively.
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Affiliation(s)
- Tshifhiwa Ramabulana
- Department
of Chemistry, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
| | - Musawenkosi Ndlovu
- Department
of Biochemistry, Genetics and Microbiology, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
| | - Rebamang A. Mosa
- Department
of Biochemistry, Genetics and Microbiology, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
| | - Molahlehi S. Sonopo
- Radiochemistry, South African Nuclear Energy Corporation Limited, Pelindaba, Brits 0240, South Africa
| | - Mamoalosi A. Selepe
- Department
of Chemistry, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
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Malefo MS, Ramadwa TE, Famuyide IM, McGaw LJ, Eloff JN, Sonopo MS, Selepe MA. Synthesis and Antifungal Activity of Chromones and Benzoxepines from the Leaves of Ptaeroxylon obliquum. J Nat Prod 2020; 83:2508-2517. [PMID: 32790311 DOI: 10.1021/acs.jnatprod.0c00587] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This study reports the first total synthesis of the bioactive oxepinochromones 12-O-acetyleranthin (8) (angular isomer) and 12-O-acetylptaeroxylinol (9) (linear isomer). The antifungal activity of these compounds and their derivatives was determined against Candida albicans and Cryptococcus neoformans. Most compounds had good selectivity between the two fungi and showed moderate to good activity. 12-O-Acetyleranthin (8) had the highest activity against C. albicans, with an MIC value of 9.9 μM, while 12-O-acetylptaeroxylinol (9), the compound present in Ptaeroxylon obliquum, had the highest activity against C. neoformans, with an MIC value of 4.9 μM.
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Affiliation(s)
- Modibo S Malefo
- Department of Chemistry, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
| | - Thanyani E Ramadwa
- Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, Pretoria 0110, South Africa
| | - Ibukun M Famuyide
- Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, Pretoria 0110, South Africa
| | - Lyndy J McGaw
- Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, Pretoria 0110, South Africa
| | - Jacobus N Eloff
- Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, Pretoria 0110, South Africa
| | - Molahlehi S Sonopo
- Radiochemistry, South African Nuclear Energy Corporation (Necsa), Pelindaba, Brits R104, South Africa
| | - Mamoalosi A Selepe
- Department of Chemistry, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
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Ramabulana T, Scheepers LM, Moodley T, Maharaj VJ, Stander A, Gama N, Ferreira D, Sonopo MS, Selepe MA. Bioactive Lignans from Hypoestes aristata. J Nat Prod 2020; 83:2483-2489. [PMID: 32786879 DOI: 10.1021/acs.jnatprod.0c00443] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Phytochemical investigation of extracts of the stems of Hypoestes aristata led to the isolation of nine lignans that included four known compounds, namely, hinokinin (1), savinin (2), medioresinol (3), and two cubebins (8a,b), three new butyrolactone lignans (4-6), and butyrolactol lignans 7a-c. The structures of the new compounds were established using 1D and 2D NMR and HRESIMS data. The absolute configurations of the new lignans were determined from their ECD data and the Mosher's ester method. This is the first unequivocal assignment of the absolute configuration at C-7 and C-7' of 7- and 7'-hydroxybutyrolactone lignans. The compounds were screened for inhibition of an HIV-1 protease enzyme, and compounds 1 and 6 exhibited moderate activity in this regard.
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Affiliation(s)
- Tshifhiwa Ramabulana
- Department of Chemistry, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
| | - Luki-Marié Scheepers
- Department of Chemistry, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
| | - Thirshen Moodley
- Department of Chemistry, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
| | - Vinesh J Maharaj
- Department of Chemistry, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
| | - André Stander
- Department of Physiology, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
| | - Ntombenhle Gama
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
| | - Daneel Ferreira
- Department of Biomolecular Sciences, Division of Pharmacognosy, School of Pharmacy, The University of Mississippi, University, Mississippi 38677, United States
| | - Molahlehi S Sonopo
- Radiochemistry, South African Nuclear Energy Corporation (Necsa), Pelindaba, Brits, South Africa
| | - Mamoalosi A Selepe
- Department of Chemistry, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
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Kunyane P, Sonopo MS, Selepe MA. Synthesis of Isoflavones by Tandem Demethylation and Ring-Opening/Cyclization of Methoxybenzoylbenzofurans. J Nat Prod 2019; 82:3074-3082. [PMID: 31702151 DOI: 10.1021/acs.jnatprod.9b00681] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The unexpected conversion of benzoylbenzofurans into isoflavones through an intramolecular cascade that involves deprotection and ring-opening/cyclization is described. This was discovered in an investigation of the possible transformation of benzoylbenzofurans into coumaronochromones. This route affords isoflavones in two major steps from acetophenones and benzoquinones. The transformation was validated by synthesizing differently substituted isoflavone derivatives and further applied to a concise synthesis of a potential anticancer lead compound, glaziovianin A (1).
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Affiliation(s)
- Phaladi Kunyane
- Department of Chemistry , University of Pretoria , Lynnwood Road , Hatfield , Pretoria 0002 , South Africa
| | - Molahlehi S Sonopo
- Radiochemistry , South African Nuclear Energy Corporation (Necsa) , Pelindaba , Brits 0240 , South Africa
| | - Mamoalosi A Selepe
- Department of Chemistry , University of Pretoria , Lynnwood Road , Hatfield , Pretoria 0002 , South Africa
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Aro AO, Dzoyem JP, Awouafack MD, Selepe MA, Eloff JN, McGaw LJ. Fractions and isolated compounds from Oxyanthus speciosus subsp. stenocarpus (Rubiaceae) have promising antimycobacterial and intracellular activity. BMC Complement Altern Med 2019; 19:108. [PMID: 31117999 PMCID: PMC6532187 DOI: 10.1186/s12906-019-2520-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 05/09/2019] [Indexed: 02/06/2023]
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.
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Affiliation(s)
- Abimbola O. Aro
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa
| | - Jean P. Dzoyem
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa
- Department of Biochemistry, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon
| | - Maurice D. Awouafack
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa
- Laboratory of Natural Products Chemistry, Department of Chemistry, Faculty of Science, University of Dschang, P.OBox 67, Dschang, Cameroon
| | | | - Jacobus N. Eloff
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa
| | - Lyndy J. McGaw
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa
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Moyo P, Kunyane P, Selepe MA, Eloff JN, Niemand J, Louw AI, Maharaj VJ, Birkholtz LM. Bioassay-guided isolation and identification of gametocytocidal compounds from Artemisia afra (Asteraceae). Malar J 2019; 18:65. [PMID: 30849984 PMCID: PMC6408838 DOI: 10.1186/s12936-019-2694-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 03/01/2019] [Indexed: 12/31/2022] Open
Abstract
Background Optimal adoption of the malaria transmission-blocking strategy is currently limited by lack of safe and efficacious drugs. This has sparked the exploration of different sources of drugs in search of transmission-blocking agents. While plant species have been extensively investigated in search of malaria chemotherapeutic agents, comparatively less effort has been channelled towards exploring them in search of transmission-blocking drugs. Artemisia afra (Asteraceae), a prominent feature of South African folk medicine, is used for the treatment of a number of diseases, including malaria. In search of transmission-blocking compounds aimed against Plasmodium parasites, the current study endeavoured to isolate and identify gametocytocidal compounds from A. afra. Methods A bioassay-guided isolation approach was adopted wherein a combination of solvent–solvent partitioning and gravity column chromatography was used. Collected fractions were continuously screened in vitro for their ability to inhibit the viability of primarily late-stage gametocytes of Plasmodium falciparum (NF54 strain), using a parasite lactate dehydrogenase assay. Chemical structures of isolated compounds were elucidated using UPLC-MS/MS and NMR data analysis. Results Two guaianolide sesquiterpene lactones, 1α,4α-dihydroxybishopsolicepolide and yomogiartemin, were isolated and shown to be active (IC50 < 10 μg/ml; ~ 10 μM) against both gametocytes and intra-erythrocytic asexual P. falciparum parasites. Interestingly, 1α,4α-dihydroxybishopsolicepolide was significantly more potent against late-stage gametocytes than to early-stage gametocytes and intra-erythrocytic asexual P. falciparum parasites. Additionally, both isolated compounds were not overly cytotoxic against HepG2 cells in vitro. Conclusion This study provides the first instance of isolated compounds from A. afra against P. falciparum gametocytes as a starting point for further investigations on more plant species in search of transmission-blocking compounds. Electronic supplementary material The online version of this article (10.1186/s12936-019-2694-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Phanankosi Moyo
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Phaladi Kunyane
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Mamoalosi A Selepe
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Jacobus N Eloff
- Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag x04, Onderstepoort, Pretoria, 0110, South Africa
| | - Jandeli Niemand
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Abraham I Louw
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Vinesh J Maharaj
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Lyn-Marie Birkholtz
- Malaria Parasite Molecular Laboratory, Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa.
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Selepe MA, Van Heerden FR. Application of the Suzuki-Miyaura reaction in the synthesis of flavonoids. Molecules 2013; 18:4739-65. [PMID: 23609624 PMCID: PMC6269869 DOI: 10.3390/molecules18044739] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 04/10/2013] [Accepted: 04/19/2013] [Indexed: 11/16/2022] Open
Abstract
The application of the Suzuki-Miyaura reaction in the synthesis of flavonoids, an important class of natural products, is reviewed. This reaction has not only been employed to provide access to flavonoid nuclei, but has also been applied to the synthesis of dimeric flavonoids and in the synthesis of libraries of flavonoid derivatives for biological activity studies. The classes of flavonoids that are discussed are the chalcones, flavones, isoflavones, neoflavones, biflavones and derivatives of flavonoids obtained by C-C bond formation via the Suzuki-Miyaura reaction.
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Affiliation(s)
| | - Fanie R. Van Heerden
- School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, South Africa; E-Mail:
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Abstract
The first total synthesis of the pyranoisoflavone kraussianone 1 (1) is described. The key steps involved the Suzuki-Miyaura reaction for the construction of the isoflavone core and the regioselective formation of the dimethylpyran scaffolds to the phloroglucinol (ring A) and resorcinol (ring B) moieties of kraussianone 1 (1). This route also provided access to the related isoflavones eriosemaone D (2) and genistein (3) via simple structural modifications.
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Affiliation(s)
- Mamoalosi A Selepe
- School of Chemistry, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, Pietermaritzburg, South Africa
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