Sizwe Zamisa

Mr. Sizwe Zamisa

orcid

Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 February 2021 in Molecules
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Adesola AdelekeAdesola Adeleke
Adesola Adeleke
SZSizwe Zamisa
Sizwe Zamisa
Shahidul IslamShahidul Islam
Shahidul Islam
KOKolawole Ayodapo Olofinsan
Kolawole Ayodapo Olofinsan
VSVeronica Salau
Veronica Salau
Bernard OwagaBernard Owaga
Bernard Owaga
A series of fifteen silver (I) quinoline complexes Q1–Q15 have been synthesized and studied for their biological activities. Q1–Q15 were synthesized from the reactions of quinolinyl Schiff base derivatives L1–L5 (obtained by condensing 2-quinolinecarboxaldehyde with various aniline derivatives) with AgNO3, AgClO4 and AgCF3SO3. Q1–Q15 were characterized by various spectroscopic techniques and the structures of [Ag(L1)2]NO3Q1, [Ag(L1)2]ClO4Q6, [Ag(L2)2]ClO4Q7, [Ag(L2)2]CF3SO3Q12 and [Ag(L4)2]CF3SO3Q14 were unequivocally determined by single crystal X-ray diffraction analysis. In vitro antimicrobial tests against Gram-positive and Gram-negative bacteria revealed the influence of structure and anion on the complexes′ moderate to excellent antibacterial activity. In vitro antioxidant activities of the complexes showed their good radical scavenging activity in ferric reducing antioxidant power (FRAP). Complexes with the fluorine substituent or the thiophene or benzothiazole moieties are more potent with IC50 between 0.95 and 2.22 mg/mL than the standard used, ascorbic acid (2.68 mg/mL). The compounds showed a strong binding affinity with calf thymus-DNA via an intercalation mode and protein through a static quenching mechanism. Cytotoxicity activity was examined against three carcinoma cell lines (HELA, MDA-MB231, and SHSY5Y). [Ag(L2)2]ClO4Q7 with a benzothiazole moiety and [Ag(L4)2]ClO4Q9 with a methyl substituent had excellent cytotoxicity against HELA cells.

2 January 2023 in Green Chemistry Letters and Reviews
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MKMoses Kigozi
Moses Kigozi
GKGabriel N. Kasozi
Gabriel N. Kasozi
SMSachin Balaso Mohite
Sachin Balaso Mohite
SZSizwe Zamisa
Sizwe Zamisa
RKRajshekhar Karpoormath
Rajshekhar Karpoormath
ETEmmanuel Tebandeke
Emmanuel Tebandeke
Poly(ethylene terephthalate) (PET) has a wide range of applications that generate a lot of waste globally; thus, upcycling PET is important because it offers several industrial and economic advantages. This study describes a sustainable, emissions-free process for converting PET plastics into carbon nanomaterials (CNMs) named PT-nano powder. The thermal-hydrothermal method has employed the production of PT-nano powder above the glass transition temperature (Tg) of PET plastics. Under optimal conditions, PET plastics were efficiently converted into PT-nano powder with 86.6% crystallinity and an average particle size of 6.5 nm. The PT-nano powder was characterized for physical and chemical properties using different techniques, including UV-Vis, FTIR, Raman spectroscopy, XRD, FESEM, TEM, and proton NMR analysis. The characterization confirms the complete conversion of PET to solid fractions of carbon nanomaterial. The PT-nano powder was tested in supercapacitor performance application with electrochemical characterization. The symmetric fabrication showed a specific capacitance of 250.8 F/g, energy density of 34.83Wh/kg, and power density of 999.9W/kg with a current density of 0.5A/g. The device fabrication exhibited high cycle stability and high capacitance retention of 96.8% with a current density of 1.5A/g after 10000 cycles. GRAPHICAL ABSTRACT

30 June 2021 in European Journal of Chemistry
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SOSegun Daniel Oladipo
Segun Daniel Oladipo
TYTUNDE LEWIS YUSUF
TUNDE LEWIS YUSUF
SZSizwe Zamisa
Sizwe Zamisa
GTGideon Femi Tolufashe
Gideon Femi Tolufashe
KOKolawole Ayodapo Olofinsan
Kolawole Ayodapo Olofinsan
Nonhlangabezo MABUBANonhlangabezo MABUBA
Nonhlangabezo MABUBA
Three Schiff bases 1-(4-chlorophenyl)-N-(naphthalen-1-yl)methanimine (1), 1-(4-methoxy phenyl)-N-(naphthalen-1-yl)methanimine (2), and 1-(4-chlorophenyl)-N-(2,6-diisopropyl phenyl)methanimine (3) were synthesized and characterized by elemental analysis, 1H and 13C NMR, FT-IR and UV-Visible spectroscopic techniques. The crystal structure of compound 3 was obtained and it revealed that the compound crystallized in a monoclinic space group P21/n and there exists an intermolecular hydrogen bond in a phenyl-imine form with C-H⋯N. Crystal data for C19H22ClN: a = 7.28280(10) Å, b = 9.94270(10) Å, c = 24.0413(2) Å, β = 97.0120(10)°, V = 1727.83(3) Å3, Z = 4, μ(Mo Kα) = 0.215 mm-1, Dcalc = 1.1526 g/cm3, 14038 reflections measured (12.42° ≤ 2Θ ≤ 52.74°), 3448 unique (Rint = 0.0223, Rsigma = 0.0182) which were used in all calculations. The final R1 was 0.0337 (I≥2u(I)) and wR2 was 0.0927 (all data). The free radical scavenging activities of all three compounds were assayed using DPPH, FRAP, and OH assays. According to results obtained, compound 2 shows effective DPPH- (IC50 = 22.69±0.14 μg/mL), FRAP+ (IC50 = 28.44±0.12 μg/mL), and OH- (IC50 = 27.97±0.16 μg/mL) scavenging activities compared with compounds 1 and 3 but less than standard antioxidant compound Trolox (TRO). Additionally, theoretical calculations for the three complexes were performed by using density functional theory (DFT) calculations at the B3LYP/6-31++G(2d,2p) level in the ground state to obtain an optimized geometrical structure and to perform an electronic, molecular electronic potential surface and natural bond orbital (NBO) analysis. The geometrical calculation obtained was found to be consistent with the experimental geometry. Further analysis was conducted using the in silico technique to predict the drug likeness, molecular and ADME properties of these molecules.

2 June 2022 in Crystal Growth & Design
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Journal Article
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SZSizwe Zamisa
Sizwe Zamisa
NNNtombizonke Precious Ngubane
Ntombizonke Precious Ngubane
Adesola AdelekeAdesola Adeleke
Adesola Adeleke
Sreekantha Babu JonnalagaddaSreekantha Babu Jonnalagadda
Sreekantha Babu Jonnalagadda
Bernard OwagaBernard Owaga
Bernard Owaga

13 August 2018 in ChemMedChem
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Anamika SharmaAnamika Sharma
Anamika Sharma
SNSikabwe Noki
Sikabwe Noki
SZSizwe Zamisa
Sizwe Zamisa
HHHeba A. Hazzah
Heba A. Hazzah
ZAZainab M. Almarhoon
Zainab M. Almarhoon
Fernando AlbericioFernando Albericio
Fernando Albericio

19 July 2023 in RSC Advances
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SZSizwe Zamisa
Sizwe Zamisa
AAAdesola A. Adeleke
Adesola A. Adeleke
NDNikita Devnarain
Nikita Devnarain
MRMahasin Abdel Rhman
Mahasin Abdel Rhman
POPeter M. O. Owira
Peter M. O. Owira
Bernard OwagaBernard Owaga
Bernard Owaga
In this study, we synthesized and characterized ten chromenopyrimidine derivatives using analytical and spectroscopic methods. Studies on DNA and albumin binding affinity, as well as cytotoxicity tests on human breast cancer (MCF-7) cells, of the chromenopyrimidines, were conducted. The natural logarithm of the relative stability constant of DNA- and BSA-chromenopyrimidine complexes [ln(KDNA/KBSA)] was used as a criterion for selecting compounds for cytotoxicity studies. We found that ln(KDNA/KBSA) was inversely related to IC50 values of the compounds in MCF-7 cells. The antiproliferative effects of the compounds were found to induce apoptosis in MCF-7 cells, which is a desired mechanism of cell death. Correlations between the DNA and albumin binding affinities of chromenopyrimidines were established. We propose that this relationship approach can, for a given set of compounds, assist in predicting the cytotoxicity of potential drug candidates towards MCF-7 cells based on their experimentally determined CT-DNA and BSA binding affinities.