Browsing by Author "Tukulula, Matshawandile"

Now showing 1 - 4 of 4
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    The application of the Multi-Component Reaction (MCR) strategy in the design and synthesis of new antiplasmodial and antimycobacterial agents
    (2012) Tukulula, Matshawandile; Chibale, Kelly
    Malaria and tuberculosis are ancient diseases that continue to have a profound impact on mankind, 5 millennia after their first documentation. Malaria is endemic in more than 100 countries and about 50% of the world's population is at risk of infection. Sub-Saharan Africa accounts for nearly 91% of malaria-related deaths annually. Tuberculosis on the other hand infects about one third of the word's population and is the second major cause of death in adults worldwide, with about 1.8 million deaths reported annually. The major challenge to the control of these diseases has been the rapid emergence of multi-drug resistant strains to the currently administered drugs, as such, these exert an enormous pressure on health care systems, especially in resource-limited areas. Alleviation of this pressure requires the development of highly efficacious new chemical entities (NCEs) to curb or manage these pathogens. The main aim of this study was to design NCEs based on quinoline-, PA-824-, and tetrazole-scaffolds, which exhibit in vitro antiplasmodial and antimycobacterial activity.
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    New Quinoline–Urea–Benzothiazole Hybrids as Promising Antitubercular Agents: Synthesis, In Vitro Antitubercular Activity, Cytotoxicity Studies, and In Silico ADME Profiling
    (2022-05-05) Moodley, Rashmika; Mashaba, Chakes; Rakodi, Goitsemodimo H; Ncube, Nomagugu B; Maphoru, Mabuatsela V; Balogun, Mohammed O; Jordan, Audrey; Warner, Digby F; Khan, Rene; Tukulula, Matshawandile
    A series of 25 new benzothiazole–urea–quinoline hybrid compounds were synthesized successfully via a three-step synthetic sequence involving an amidation coupling reaction as a critical step. The structures of the synthesized compounds were confirmed by routine spectroscopic tools (1H and 13C NMR and IR) and by mass spectrometry (HRMS). In vitro evaluation of these hybrid compounds for their antitubercular inhibitory activity against the Mycobacterium tuberculosis H37Rv pMSp12::GPF bioreporter strain was undertaken. Of the 25 tested compounds, 17 exhibited promising anti-TB activities of less than 62.5 µM (MIC90). Specifically, 13 compounds (6b, 6g, 6i–j, 6l, 6o–p, 6r–t, and 6x–y) showed promising activity with MIC90 values in the range of 1–10 µM, while compound 6u, being the most active, exhibited sub-micromolar activity (0.968 µM) in the CAS assay. In addition, minimal cytotoxicity against the HepG2 cell line (cell viability above 75%) in 11 of the 17 compounds, at their respective MIC90 concentrations, was observed, with 6u exhibiting 100% cell viability. The hybridization of the quinoline, urea, and benzothiazole scaffolds demonstrated a synergistic relationship because the activities of resultant hybrids were vastly improved compared to the individual entities. In silico ADME predictions showed that the majority of these compounds have drug-like properties and are less likely to potentially cause cardiotoxicity (QPlogHERG > −5). The results obtained in this study indicate that the majority of the synthesized compounds could serve as valuable starting points for future optimizations as new antimycobacterial agents
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    Synthesis and In Vitro Antiprotozoan Evaluation of 4-/8-Aminoquinoline-based Lactams and Tetrazoles
    (2020-12-15) Tukulula, Matshawandile; Louw, Stefan; Njoroge, Mathew; Chibale, Kelly
    A second generation of 4-aminoquinoline- and 8-aminoquinoline-based tetrazoles and lactams were synthesized via the Staudinger and Ugi multicomponent reactions. These compounds were subsequently evaluated in vitro for their potential antiplasmodium activity against a multidrug-resistant K1 strain and for their antitrypanosomal activity against a cultured T. b. rhodesiense STIB900 strain. Several of these compounds (4a–g) displayed good antiplasmodium activities (IC50 = 0.20–0.62 µM) that were comparable to the reference drugs, while their antitrypanosomal activity was moderate (200 µM) at pH 7.
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    The development and validation of an LC-MS/MS method for the determination of a new anti-malarial compound (TK900D) in human whole blood and its application to pharmacokinetic studies in mice
    (2014-01-31) Abay, Efrem T; van der Westhuizen, Jan H; Swart, Kenneth J; Gibhard, Liezl; Tukulula, Matshawandile; Chibale, Kelly; Wiesner, Lubbe
    Abstract Background Malaria is one of the most lethal and life-threatening killer infectious diseases in the world, and account for the deaths of more than half a million people annually. Despite the remarkable achievement made in preventing and eradicating malaria, it still remains a threat to the public health and a burden to the global economy due to the emergence of multiple-drug resistant malaria parasites. Therefore, the need to develop new anti-malarial drugs is crucial. The chemistry department at the University of Cape Town synthesized a number of new CQ-like derivatives (TK-series), and evaluated them for in vitro activity against both CQ-sensitive and -resistant Plasmodium falciparum strains, and for general cytotoxicity against a Chinese Hamster Ovarian (CHO) mammalian cell line. The lead compounds from the TK-series were selected for a comprehensive pharmacokinetic (PK) evaluation in a mouse model. Methods A sensitive LC-MS/MS assay was developed for the quantitative determination of TK900D. Multiple reaction monitoring (MRM) in the positive ionization mode was used for detection. The analyte and the internal standard (TK900E) were isolated from blood samples by liquid-liquid extraction with ethyl acetate. Chromatographic separation was achieved with a Phenomenex® Kinetex C18 (100 × 2.0 mm id, 2.6 μm) analytical column, using a mixture of 0.1% formic acid and acetonitrile (50:50; v/v) as the mobile phase. The method was fully validated over concentrations that ranged from 3.910 to 1000 ng/ml, and used to evaluate the PK properties of the lead compounds in a mouse model. Results The assay was robust, with deviation not exceeding 11% for the intra- and inter-run precision and accuracy. Extraction recovery was consistent and more than 60%. PK evaluation showed that TK900D and TK900E have moderate oral bioavailability of 30.8% and 25.9%, respectively. The apparent half-life ranged between 4 to 6 h for TK900D and 3.6 to 4 h for TK900E. Conclusion The assay was sensitive and able to measure accurately low drug levels from a small sample volume (20 μl). PK evaluation showed that the oral bioavailability was moderate. Therefore, from a PK perspective, the compounds look promising and can be taken further in the drug development process.