Synthesis of ferrocenyl conjugates of sulfa drugs and study as antimicrobial agents

Date
2023-03
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: As humans have spread across the globe so have infectious diseases. Malaria and tuberculosis are among the most widespread infectious diseases, after Covid-19, affecting millions of people annually. Despite the effectiveness of the currently used antimalarial and anti-TB drugs, the emergence of drug resistance in the malaria parasite, Plasmodium falciparum, as well as multidrug resistant and extremely drug resistant forms of Mycobacterium tuberculosis is a growing problem and calls for the urgent need of new antimicrobial agents. In efforts to decrease the morbidity/mortality rates related to these diseases, it is important for these new antimicrobial drugs to target the resistant strains. A unique strategy in drug discovery today is drug repositioning, which involves the modification of known clinical drugs to rapidly identity new ones to treat other diseases. Looking at the current economic situation, this strategy could speed up the process of drug development to save costs. This study investigated the synthesis, characterisation, electrochemical and biological properties of new ferrocenyl amido sulfonamide complexes prepared from known sulfa drugs. The new ferrocenyl organometallic complexes were prepared by the reaction of the primary amine functional group of sulfonamide compounds with ferrocenoyl chloride. All complexes were characterised using various spectroscopic and analytical techniques, such as 1H and 13C { 1H} nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, electrospray ionisation-mass spectrometry (ESI-MS), cyclic voltammetry (CV), and reversedphase high performance liquid chromatography (RP-HPLC). The new complexes were tested for antiplasmodial activity against the chloroquine-sensitive NF54 strain of Plasmodium falciparum. Upon the introduction of the ferrocenyl moiety, the activity of selected sulfonamides was significantly enhanced, with some of the complexes being more active than their respective sulfa drugs. Complex C2 displayed the best activity of all the complexes with an IC50 value of 3.714 µM followed by C5 (IC50 = 5.822 µM). Thereafter, the complexes and their respective sulfa drugs were tested for antimycobacterial activity against the non-pathogenic Mc2 155 and the pathogenic H37Rv strains of Mycobacterium tuberculosis. The complexes displayed better activities when tested against the strain H37Rv compared to results obtained for the Mc2 155 strain. The complexes also displayed to be more potent than isoniazid against both strains. Stellenbosch University https://scholar.sun.ac.za v In addition, the complexes were further screened for their cytotoxicity against the human embryonic kidney (HEK) and immortalised prostatic (PNT1A) cell lines and were found to be non-cytotoxic.
AFRIKAANS OPSOMMMING: Soos mense oor die hele wêreld versprei het, so het aansteeklike siektes ook. Malaria en tuberkulose is van die mees wydverspreide aansteeklike siektes, na Covid-19, wat jaarliks miljoene mense affekteer. Ten spyte van die doeltreffendheid van die tans gebruikte antimalaria- en anti-TB-middels, is die oorsprong van middel weerstandandigheid in die malariaparasiet, Plasmodium falciparum, sowel as multi-middel-weerstande en uiters middelweerstandige vorms van Mycobacterium tuberculosis 'n groeiende probleem en is daar ‘n dringende aanvraag na nuwe antimikrobiese middels. In pogings om die morbiditeit/sterftekoerse wat met hierdie siektes verband hou, te verlaag, is dit belangrik dat hierdie nuwe antimikrobiese middels die weerstandbiedende stamme teiken. 'n Unieke strategie in die ontdekking van geneesmiddels vandag is dwelmherposisionering, wat die wysiging van bekende kliniese middels behels om nuwes vinnig te identifiseer. As ons na die huidige ekonomiese situasie kyk, kan hierdie strategie die proses van geneesmiddelontwikkeling versnel om koste te spaar. Hierdie studie het die sintese, karakterisering, elektrochemiese en biologiese eienskappe van nuwe ferrosenielamido-sulfonamiedkomplekse wat van bekende sulfa middels berei is ondersoek. Hierdie nuwe ferroseniel-organometaalkomplekse is berei deur die reaksie van die primere amien funksionele groep van sulfonamide verbindings met ferrosenielchloried. Alle komplekse is gekarakteriseer deur gebruik te maak van verskeie spektroskopiese en analitiese tegnieke, soos 1H en 13C {1H} kernmagnetiese resonansie (KMR) spektroskopie, infrarooi (IR) spektroskopie, elektrosproei ionisasie-massaspektrometrie (ESI-MS), sikliese voltammetrie (CV), en omgekeerde-fase hoë werkverrigting vloeistofchromatografie (RP-HPLC). Die komplekse is getoets vir antiplasmodiese aktiwiteit teen die chlorokien-sensitiewe NF54- stam van Plasmodium falciparum. Met die inlywing van die ferroseniel-eenheid is die aktiwiteit van geselekteerde sulfonamiede aansienlik verhoog, met sommige van die komplekse wat meer aktief was as hul onderskeie sulfa-middels. Kompleks C2 het die beste aktiwiteit van al die komplekse vertoon met 'n IC50 waarde van 3.714 µM gevolg deur C5 (IC50 = 5.822 µM). Daarna is die komplekse en hul onderskeie sulfa-middels getoets vir antimikobakteriële aktiwiteit teen die nie-patogeniese Mc2 155 en die patogeniese H37Rvstamme van Mycobacterium tuberculosis. Die komplekse het beter aktiwiteite in die stam H37Rv vertoon in vergelyking met dié in die Mc2 155-stam. Die komplekse het ook getoon om sterker as isoniazied in beide stamme te wees. Stellenbosch University https://scholar.sun.ac.za vii Verder is die komplekse getoets vir hul sitotoksisiteit teen die menslike embrioniese nier (HEK) en geïmmobiliseerde prostaat (PNT1A) sellyne en is gevind dat dit nie-sitotoksies is nie.
Description
Thesis (MSc)--Stellenbosch University, 2023.
Keywords
Ferrocene, Sulfa drugs, microbial
Citation