Wits Research Outputs
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Browsing Wits Research Outputs by School "Chemistry"
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Item Antibacterial and Anticancer Activity and Untargeted Secondary Metabolite Profiling of Crude Bacterial Endophyte Extracts from Crinum macowanii Baker Leaves(Hindawi, 2020-12-10) T Sebola; N Uche-Okereafor; L Mekuto; Maya Makatini; E Green; Vuyo MavumengwanaThis study isolated and identified endophytic bacteria from the leaves of Crinum macowanii and investigated the potential of the bacterial endophyte extracts as antibacterial and anticancer agents and their subsequent secondary metabolites. Ethyl acetate extracts from the endophytes and the leaves (methanol: dichloromethane (1 : 1)) were used for antibacterial activity against selected pathogenic bacterial strains by using the broth microdilution method. The anticancer activity against the U87MG glioblastoma and A549 lung carcinoma cells was determined by the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. Bacterial endophytes that were successfully isolated from C. macowanii leaves include Raoultella ornithinolytica, Acinetobacter guillouiae, Pseudomonas sp., Pseudomonas palleroniana, Pseudomonas putida, Bacillus safensis, Enterobacter asburiae, Pseudomonas cichorii, and Arthrobacter pascens. Pseudomonas cichorii exhibited broad antibacterial activity against both Gram-negative and Gram-positive pathogenic bacteria while Arthrobacter pascens displayed the least MIC of 0.0625 mg/mL. Bacillus safensis crude extracts were the only sample that showed notable cell reduction of 50% against A549 lung carcinoma cells at a concentration of 100 mu g/mL. Metabolite profiling of Bacillus safensis, Pseudomonas cichorii, and Arthrobacter pascens crude extracts revealed the presence of known antibacterial and/or anticancer agents such as lycorine (1), angustine (2), crinamidine (3), vasicinol (4), and powelline. It can be concluded that the crude bacterial endophyte extracts obtained from C. macowanii leaves can biosynthesize bioactive compounds and can be bioprospected for medical application into antibacterial and anticancer agents.Item Carbon Encapsulated Ternary MnNiCo Oxide Nanoparticles as Electrode Materials for Energy Storage Applications(Wiley, 2020-12) Tarekegn Heliso Dolla; Isiaka A. Lawal; David Billing; K Pruessner; Patrick Ndungu; Dolla, TH; Lawal, IA; Billing, DG; Pruessner, k; Ndungu, PTernary transition metal oxides are promising advanced materials for use as electrode components in electrochemical energy storage systems. However, low electronic/ionic conductivity hinder practical applications. In this study, ternary Mn-Ni-Co oxide nanoparticles were encapsulated in carbon nanosheets, to improve the electrical conductivity and surface area. When tested as supercapacitor electrodes, the materials exhibited specific capacity of 91.2 mAh g(-1)at a current density of 1 A g(-1)in 2 M KOH. Moreover, after 3000 cycles the composite achieved a specific capacity of 74.6 mAh g(-1)at a current density of 6 A g(-1)and high capacitance retention of 96.4 %.Item Ivo Hummelgen(Springer, 2019-11-09) Neil Coville; Coville, N.