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Item A preliminary study on the chemical characteristics of Kei apple (Dovyalis caffra), an undervalued South African fruit.(Elsevier B.V., 2018-05-30) Augustyn, W.A.; Regnier, T.; De Jager, K.; Hajari, E.; Du Preez, R.; Nonyane, D.Although a profusion of indigenous fruits occurs in South Africa, knowledge of their uses lies mainly with the local people. This study was aimed at filling the void in scientific literature by investigating the nutritional value and characteristics of a lesser-known wild fruit, the Kei apple (Dovyalis caffra). The colour was assessed, in addition to the chemical characteristics (total soluble phenolics, protein, volatiles, antioxidants) of the fruits. The results indicate that the fruit is a rich source of amino acids with good antioxidant properties. Although, the protein content was found to be lower than those of commercial fruits, it was similar to values reported for the wild plum. Chemometric analysis of chromatographic data on secondary metabolites produced by the fruit was used to determine if the collection of Kei apple trees established at the Agricultural Research Council's experimental farm in Mbombela is representative of the wild population of South Africa.Item Development of EVA and LLDPE polymer-based carvone and spearmint essential oil release systems for citrus postharvest diseases applications.(Elsevier B.V., 2022-11-21) Phala, Katlego; Mapossa, Antonio B.; Augustyn, Wilma A.; Combrinck, Sandra; Botha, BenCarvone and spearmint essential oil vapours are suitable candidates for the control of citrus postharvest pathogens due to their strong antifungal activity. However, the high volatility of essential oils remains a hurdle that needs to be overcome before it can be applied as an alternative fungicide. This work investigates the antifungal activity of 20 and 30 wt-% spearmint essential oil or carvone, incorporated into ethylene–vinyl acetate (EVA) and linear low-density polyethylene (LLDPE) strands postharvest pathogens affecting kumquats. Following the melt-extrusion process, an average yield of 16–29 % and 15–28 % of the total carvone and spearmint essential oil, respectively, was determined in the polymer strands. Morphological studies using scanning electron microscopy (SEM) revealed the presence of microporous structures in the internal structure of the strands. The membrane-like skin that covers the polymer strand was also confirmed by SEM. Variations in the release rates were observed between carvone and spearmint essential oils, which was attributed to the difference in the vapour pressure of the neat essential oils. Furthermore, in this study, the results demonstrated that the diffusion exponent ‘n’ of the Korsmeyer–Peppas, Weibull and Log-logistic models exceeded 1.0. In most cases, the Super Case II mechanism was observed. In the case of the Mapossa model, as k2 was ˃>1, it implies that the outer skin-like membrane covering the polymer strand fully controlled the carvone release. The application of the essential oil-loaded polymer strands resulted in a significant reduction in deterioration, caused by citrus postharvest pathogens, of kumquats kept at room temperature for 21 days. This study indicates that the incorporation of spearmint essential oil or carvone into LLDPE or EVA polymer strands promoted the preservation of kumquat over a 21-day period.Item Chemical variations, trichome structure and antifungal activities of essential oils of Helichrysum splendidum from South Africa.(Elsevier B.V., 2014-12-05) Mashigo, M.; Combrinck, S.; Regnier, T.; Du Plooy, W.; Augustyn, W.; Mokgalaka, N.The chemical profiles of essential oils isolated from nine populations of Helichrysum splendidum were obtained by gas chromatography. Plants were harvested in both summer and winter seasons in two provinces of South Africa. Essential oils originating from Limpopo Province were characterized by high levels of β-phellandrene, 1,8-cineole, δ-cadinene, α-cadinol, τ-cadinol, and β-pinene. These could be clearly distinguished through multivariate analysis from those collected in Mpumalanga Province. The Mpumalanga oils contained germacrene D, spathulenol and bicyclogermacrene as major constituents. Seasonal variations in the volatile compositions and yields were observed. A prediction model obtained through orthogonal projection to latent structures discriminant analysis was used to compare the essential oil profiles to that of a commercial H. splendidum sample, in addition to those reported for Zimbabwean specimens. One of the specimens from Zimbabwe differed substantially from all the others, indicating the existence of more chemotypes. The structures of the oil-bearing trichomes, as observed on the leaf surfaces using scanning electron microscopy, were investigated and are described for the first time. Since this investigation forms part of an ongoing screening of plants to identify natural alternatives to synthetic fungicides, the essential oils were tested in vitro against several economically important pathogens of fruit. Essential oils from Mpumalanga specimens totally inhibited the growth of Alternaria alternata from avocado and Colletotrichum gloeosporioides isolated from mango at a concentration of 500 μL/L in a toxic medium assay. The presence of high concentrations of germacrene D, spathulenol and bicyclogermacrene probably contributed to the antifungal properties of these essential oils.Item The crystal structure of factricarbonyl(4,4-dimethyl-2,2-dipyridyl-κ2 N,N′)- (pyrazole-κN)rhenium(I) nitrate, C18H16O3N4Re(De Gruyter, 2020-11-12) Moremi, Mamolatelo J.; Alexander, Orbett T.; Vatsha, Banele; Makgopa, Katlego; Manicum, Amanda-Lee E.C18H16O3N4Re, monoclinic, P21/c (no. 14), a = 9.8409(6) Å,b = 14.0933(9) Å, c = 13.9153(9) Å, β = 90.558(2)°,V = 1929.8(2) Å3, Z = 4, Rgt(F) = 0.0266, wRref(F2) = 0.0584,T = 100(2) K.Item Acetylacetone and imidazole coordinated Re(I) tricarbonyl complexes: Experimental, DFT studies, and molecular docking approach.(Elsevier, 2023-01-18) Manicum, Amanda-Lee E.; Louis, Hitler; Agwamba, Ernest C.; Chima, Chioma M.; Nzondomyo, Wakopo J.; Sithole, Sibusiso A.The research work presents the synthesis, spectral characterization (UV, FT-IR, and NMR), and modelling of tricarbonyl rhenium complexes (R1, R2, R3, R4, and R5) bearing the β-diketone ligand and acetylacetone (Acac) for potential application as cancer drugs. The theoretical investigation was carried out within the framework of density functional theory (DFT) computation at the ωB97XD/Gen/6–311++G (d,p)/LanL2DZ level of theory. The studied rhenium complexes: fac-[Re(Acac)(CO)3(H2O)] (R1), fac-[Re(Acac)(CO)3(Py)] (R2), fac-[Re(Acac)(CO)3(Im)] (R3), fac-[Re(Acac)(CO)3(1-CH3Im)] (R4), fac-[Re(Acac)(CO)3(Pz)] (R5) follows an increasing pattern of stability: R5 < R4 < R2 < R3 < R1, with energy gap values of 6.4487, 6.6281, 7.6758, 7.7487 and 8.0608 eV respectively. The MolDock score ranges from -65.769 to -42.141 kcal/mol compared to the much smaller value of -13.191 kcal/mol for Cisplatin (Cispt) interaction with 2ES3, indicating that the rhenium complex ligands exhibit higher inhibitory activities against TNC to promote apoptosis and regulate cell cycle associated with breast cancer compared to Cispt. The highest score is R4 at -115.954 with H-Bond energy of -2.923 kcal/mol, then followed by R2 with a score of -103.773 and H-Bond energy bond of -0.392 kcal/mol due to only Steric interaction and R3 with a score of -102.885 and H-bond of -0.2259 kcal/mol due to steric interaction with Phe16(I), Val17(I), Cys53(B) amino acid similar to R2. Due to their stability and MolDock score, R2 and R3 complexes exhibit the potency to be used as potential anti-breast cancer drug participants.Item The crystal structure of [μ-hydroxido-bis [(5,5′-dimethyl-2,2′-bipyridine-κ2 N,N′)- tricarbonylrhenium(I)] bromide hemihydrate, C30H26N4O9Re2Br(De Gruyter, 2021-06-14) Moherane, Lehlohonolo; Alexander, Orbett T.; Visser, Hendrik G.; Manicum, Amanda-Lee E.C30H26N4O9Re2Br, triclinic, P1 (no. 2), a = 9.407(6) Å,b = 11.769(8) Å, c = 15.055(11) Å, α = 82.70(2)°, β = 76.68(3)°,γ = 77.364(2)°, V = 1577.5(19) Å3, Z = 2, Rgt(F) = 0.0291,wRref(F2) = 0.0868, T = 100 K.Item Characterisation of sclerocarya birrea (marula) seed oil and investigation of the geographical origin by applying similarity calculations, differential NMR and hierarchical cluster analysis.(Wiley, 2023-06-29) Schripsema, Jan; Augustyn, Wilma; Viljoen, AlvaroIntroduction: The marula fruit is an important indigenous African fruit since various commercial products are produced from the pulp and the seed oil. The increased demand requires methods for authentication, quality control and determination of geographical origin. Objective: The study aimed to establish a fast and reliable method for characterisation and authentication of marula seed oil. Furthermore, to identify marker compounds that can distinguish marula seed oils from other commercial oils and indicate regional differences. Materials and Methods: Metabolic profiling of 44 commercial marula seed oils was performed using proton nuclear magnetic resonance (1H NMR). For rapid classification similarity calculations were compared with principal component analysis. Differential NMR was used to determine marker compounds. Results: Marula seed oil was found to be similar to macadamia and olive oils and was distinguished from these oils by the detection of minor components. Marula seed oil is differentiated from the other two oils by the absence of α-linolenic acid, relatively high levels of monoglycerides and diglycerides, and an approximately 1:1 ratio of 1,2- and 1,3-diglycerides. When comparing marula seed oils from various regions using hierarchical cluster analysis, clustering of the marula seed oils from Namibia and Zimbabwe was observed and was related to the quantities of linoleic acid and monoglycerides and diglycerides. Some samples displayed deviations in their composition which might indicate adulteration or contamination during the production process. Conclusion: The study demonstrates the potential of NMR as a tool in the quality control of marula seed oil. This technique requires very little sample preparation, circumvents derivatisation of the oil components with fast run-times. In addition, samples with chemical profiles that differ from the general signature profile can easily be identified.Item Application of coal fly ash for trace metal adsorption from wastewater: A review.(Elsevier Ltd., 2024-05-16) Munyengabe, Alexis; Banda, Maria; Augustyn, Wilma; Netshiongolwe, Khathutshelo; Ramutshatsha-Makhwedzha, DengaEnvironmental pollution has become a global issue due to continuing anthropogenic activities that result in the production of enormous amounts of waste and the subsequent release of hazardous trace metals. The increasing levels of trace metals in the environment must be monitored regularly and reduced to prevent contamination of food chain. Numerous conventional technologies that are widely used for the removal of trace metals from environmental matrices have many drawbacks. Currently, the preferred method to remove trace metal ions is the adsorption process, which normally uses adsorbents. This review investigated the applications of coal fly ash (CFA) as a cost-effective adsorbent and the role it plays in the improved properties of nanomaterials that are used for treatment of trace metals in water. The use of CFA and its role in chemical modification processes results to high removal efficiency of trace metals. CFA is a byproduct of coal combustion which is available in abundance and therefore its use is not only beneficial in water treatment processes, but also reduce the burden of solid waste disposalItem Adsorption mechanism of AsH3 pollutant on metal-functionalized coronene C24H12-X (X = Mg, Al, K) quantum dots(Elservier, 2023-05-06) Angwamba, Enerst C.; Udoikono, Akaninyene D.; Louis, Hitler; Mathias, Gideon E.; Benjamin, Innocent; Ikenyirimba, Onyinye J.; Etiese, Daniel; Ahuekwe, Eze F; Manicum, Amanda-Lee E.Inorganic arsenic compounds are frequently found to occur naturally or as a result of mining in soils, sediments, and groundwater. Organic arsenic exists mainly in fish, shellfish, and other aquatic life and as a result of this, it may be contaminated in edible consumables such as rice and poorly purified drinking water. Exposure to this toxic gas can cause severe lung and skin cancer as well as other related cancer cases. Therefore, the need to develop more efficient sensing/monitoring devices to signal or detect the presence of excessive accumulation of this gas in our atmosphere is highly demanding. This study has effectively employed quantum mechanical approach, utilizing density functional theory (DFT) to investigate the nanosensing efficacy of metal-decorated coronene quantum dot (QD); (CadecQD, AldecQD, KdecQD, and MgdecQD) surface towards the efficient trapping of AsH3 gas molecule in an attempt to effectively detect the presence of the gas molecule which would help in reducing the health risk imposed by the AsH3. The result obtained from the electronic studies reveals that the engineered molecules interacted more favorably at the gas and water phase than other solvents, owing to their varying calculated adsorption energies (Eads). It was observed that the decoration of potassium and aluminum into the QD surface enhanced the adsorption process of AsH3 gas onto KdecQD and AldecQD surfaces with a comparably moderate level of stability exhibited by the said systems, which is evidently shown by the excellent energy gap (Eg) of 6.9599 eV and 7.3313 eV respectively for the aforementioned surfaces.Item The crystal structure of fac-tricarbonyl(2-pyridin 2-yl-quinoline-κ2 N,N′)-(pyrazole-κN)rhenium(I) nitrate, C20H14N4O3ReNO3(De Gruyter, 2023-04-26) Sithole, Sibusiso; Malan, Federick P.; Katerere, David R.; Manicum, Amanda-Lee E.C20H14N4O3ReNO3, monoclinic, P21/c (no. 14), a = 12.9572 (2), b = 9.1568 (2), c = 17.3658 (3) Å, β = 97.267(2)°, V = 2043.84(7) Å3, Z = 4, Rgt(F) = 0.0231, wRref (F2) = 0.0514, T = 154 K.Item The crystal structure of fac-tricarbonyl((pyridin 2-yl)methanamino-κ2 N,N′)-((pyridin-2-yl) methanamino-κN)rhenium(I) nitrate, C15H16O3N4Re(De Gruyter, 2023-04-23) Ramoba, Lesetja V.; Alexander, Orbett T.; Malan, Frederick P.; Manicum, Amanda-Lee E.C15H16O3N4Re, triclinic, P1̄ (no. 2), a = 7.4939(2) Å, b = 10.1316(2) Å, c = 13.8351(3) Å, α = 103.453(2)°, β = 101.992(2)°, γ = 107.880(2)°, V = 926.98(4) Å3 , Z = 2, Rgt(F) = 0.0341, wRref(F2) = 0.0861, T = 150 K..Item The crystal structure of fac-tricarbonyl(N-benzoyl N,N-cyclohexylmethylcarbamimidothioato-κ2 S,O)- (pyridine-κN)rhenium(I), C23H24N3O4ReS(De Gruyter, 2023-04-26) Makhakhanyi, Luleka; Malan, Frederick P.; Tembu, Vuyelwa J.; Nkambule, Comfort M.; Manicum, Amanda-Lee E.C23H24N3O4ReS, orthorhombic, Pbca (no. 61), a = 15.1264(4) Å,b = 15.1167(5) Å, c = 20.1500 Å, V = 4607.5(2) Å3, Z = 8,T = 150(2) K, Rgt(F) = 0.0416, wRref (F2) = 0.0691.Item 6,8-Dichloro-3-(pyridin-2-yl)-2-[1-(pyridin-2-yl)eth yl]-1,2-dihydroquinoxaline(International Union of Crystallography/Society Publisher, 2023-07-31) Malan, Frederick P.; Mansour, Ahmed M.; Manicum, Amanda-Lee E.Item Two-dimensional materials for bone-tissue engineering(Willey, 2023-04-14) Khodabandehloo, Amir Hossein; Pourmadidi, Mehrab; Shamsabadipour, Amin; Langari, Hadis; Manicum, Amanda-Lee; Rahdar, Abbas; Baino, FrancescoThere are diverse diseases such as some infections, trauma, and tumor resections during cancer surgery that can cause bone damage or skeletal defects in persons. Most of the time, these defects cannot heal spontaneously due to several medical conditions that patients encounter, like diabetes, hormone-related problems, and autoimmune disorders. This issue is even worse for older people and some special treatments should be provided for them. Bone-tissue engineering has emerged to tackle these challenges. By investigating bone repair strategies, studying bone structures and biomechanics, and employing appropriate growth factors, suitable scaffolds, and biomaterial-centered regenerative approaches can be employed to treat bone defects more effectively. This study reviews some recent bone-tissue-engineering strategies relying on two-dimensional (2D) materials, including graphene and its derivatives, black phosphorus, and MXenes that are exhibiting a great potential in regenerative medicine.Item Nano-scale drug delivery systems for carboplatin: A comprehensive review(Elsevier, 2023-07-23) Pourmadidi, Mehrab; Eshaghi, Mohammad Mahdi; Shaghaghi, Meysam; Das, Sabya Sachi; Arshad, Rabia; Ghotekar, Suresh; Rahdar, Abbas; Manicum, Amanda-Lee; Pandey, SadanandHepatocellular carcinoma (HCC) is recognized as a global health issue accounting for millions of deaths every year. Surgery, liver ablation, and embolization therapy are amongst the conventional methods for treatment of HCC. Chemotherapy plays a major role in HCC therapy, however, owing to its conventional pharmacotherapy limitations, it necessitates the development of novel therapeutic strategies. In contrast, nanomedicines for HCC have shown remarkable prospects for solving these complications in HCC owing to their high stability, controlled release, and high drug loading capacity. This review gives an insight into the nano-constructs used for HCC treatment and its active and passive targeting strategies. This review also inculcates the various approaches for targeting the liver cells, its targeting moieties and the conjugation chemistries involved in surface functionalization. A brief description of various therapeutic approaches in the treatment of HCC has also been discussed.Item The crystal structure of (bromido, chlorido)- tricarbonyl-(5,5′-dimethyl-2,2′-bipyridine)- rhenium(I), C15H12Br0.2Cl0.8N2O3Re1(De Gruyter, 2023-07-19) Moherane, Lehlohonolo; Makhatshwa, Marcus; Malan, Frederick P.; Visser, Hendrik G.; Manicum, Amanda-LeeC15H12Br0.2Cl0.8N2O3Re1, monoclinic, P21/c (no. 14),a = 14.6713(4) Å, b = 11.4724(3) Å, c = 9.6206(3) Å, β = 106.592(3), V = 1551.87(8) Å3, Z = 4, Rgt(F) = 0.0452, wRref(F2) = 0.1110,T = 149.99(10) K.Item Quantum chemical studies, spectroscopic NMR and FT-IR analysis, and molecular docking investigation of 3,30.625pt′0.625pt-di-O-methyl ellagic acid (DMA) as a potent Mycobacterium tuberculosis agent(Elsevier, 2023-06-10) Runde, Musa; Shagal, Mohammed H.; Imojara, Anna; Mbim, Elizabeth N.; Edeghor, Uwamere O.; Edim, Moses M.; Okoro, Bernaed C; Louis, Hitler; Manicum, Amanda-LeeTuberculosis which is mainly caused by Mycobacterium tuberculosis remains of public health importance due to the resistance of the causative pathogen to the present antibiotics used as treatment options. This resistance has led to the need for the discovery of new treatment options. Herein, the isolation, geometrical optimization, spectroscopic NMR and FT-IR analysis, a study of weak interactions, electronic properties, and the in-silico biological activity of 3,3′-di-O-methyl ellagic acid (DMA) were determined. In addition, the effect of solvent on the kinetic stability, reactivity, and other electronic properties of DMA was determined in three solvents; DMSO, methanol, and water. Also, the biological activity potential and the drug-likeness of DMA were determined using molecular docking protocol and ADMET studies. The studied compound was isolated using column and thin-layer chromatography techniques while characterization was done using spectroscopic techniques. Key vibrations in the compound are C = O vibrations, C = C vibrations, C-H vibrations, –CH3 vibrations, and O-H vibrations. A study of quantum descriptors revealed that DMA is more reactive in water with an energy gap of − 3.162 eV and those in three solvents are − 3.163, − 3.944, and − 4.3022 eV in methane, gas, and water respectively. The compound shows great optical potentials with dipole moments of 3.2415D, 5.221D, 5.2015D, and 4.469D in water, DMSO, methanol, and Gas-phase respectively which are greater than that of urea used in the comparison. The QTAIM analysis based on the bond ellipticity < 0.5 suggests the presence of covalent bonds within the atoms of the studied compound. The MESP result shows the presence of π- H bond interaction within the OCH3 and oxygen atom. Molecular docking studies of the studied compound were carried out employing proteins 1W2G, 1YWF, and 1F0N proteins for mycobacterial tuberculosis and the standard drug isoniazid. The result was compared with that of a standard drug. The binding affinities of − 7.1, − 6.9, and − 7.1 kcal/mol for 1W2G, 1YWF, and 1F0N were obtained, and − 5.9, − 5.9 and − 6.0 kcal/mol for the standard drug with 1W2G, 1YWF and 1F0N. These results show that the studied compound has greater biological activity against these proteins as compared to the standard drug. ADMET studies show that the studied compound has great drug-likeness and bioavailability since it did not violate any of Lipinski’s rule of five.Item Review on the applications of selected metal-based complexes on infectious diseases(MDPI, 2024-01-10) Dube, Nondumiso P.; Thatyana, Maxwell; Mokgalaka-Fleischmann, Ntebogeng S.; Mansour, Ahmed M.; Tembu, Vuyelwa J.; Manicum, Amanda-Lee E.Fatalities caused by infectious diseases (i.e., diseases caused by parasite, bacteria, and viruses) have become reinstated as a major public health threat globally. Factors such as antimicrobial resistance and viral complications are the key contributors to the death numbers. As a result, new compounds with structural diversity classes are critical for controlling the virulence of pathogens that are multi-drug resistant. Derivatization of bio-active organic molecules with organometallic synthons is a promising strategy for modifying the inherent and enhanced properties of biomolecules. Due to their redox chemistry, bioactivity, and structural diversity, organometallic moieties make excellent candidates for lead structures in drug development. Furthermore, organometallic compounds open an array of potential in therapy that existing organic molecules lack, i.e., their ability to fulfill drug availability and resolve the frequent succumbing of organic molecules to drug resistance. Additionally, metal complexes have the potential towards metal-specific modes of action, preventing bacteria from developing resistance mechanisms. This review’s main contribution is to provide a thorough account of the biological efficacy (in vitro and in vitro) of metal-based complexes against infectious diseases. This resource can also be utilized in conjunction with corresponding journals on metal-based complexes investigated against infectious diseases.Item Advances in phytonanotechnology: A plant-Mediated green synthesis of metal nanoparticles using phyllanthus plant extracts and their antimicrobial and anticancer applications(MDPI, 2024-09-14) Thatyana, Maxwell; Dube, Nondumiso P; Kemboi, Douglas; Manicum, Amanda-Lee E; Mokgalaka-Fleischmann, Ntebogeng S; Tembu, Jacqueline VNanoparticles and nanotechnology developments continue to advance the livelihood of humankind. However, health challenges due to microorganisms and cancerous cells continue to threaten many people’s lives globally. Therefore, new technological interventions are of great importance. The phytochemicals present in medicinal plants are suggested as biocompatible, cost effective, and regenerative sources that can be utilized for the green synthesis of nanoparticles. Different plant extracts with various phytochemical constituents can form nanoparticles with specific shapes, sizes, and optical properties. This review focuses on advances in green nanotechnology and provides details on reliable synthetic routes toward medically and biocompatible relevant metallic nanoparticles. We cover a wide range of applications that use Phyto nanoparticles with an in-depth look at what makes these materials interesting. The study also provides details of the literature on the interventions made in phytonanotechnology for the production of plant-mediated synthesis and capped metallic nanoparticles and their applications in various industries. It was observed that a variety of plants have been well studied, and detailed findings have been reported; however, the study of Phyllanthus is still in its early stages, and more needs to be uncovered.Item Identification of biomarkers associated with phyllosticta citricarpa tolerance.(MDPI, 2024-07-29) Tswaai, Puseletso O. J.; Augustyn, Wilma A.; Regnier, Thierry; Du Plooy, WilmaCitrus black spot (CBS) is a fungal disease caused by Phyllosticta citricarpa Kiely, (McAlpine Van der Aa), with most cultivars being susceptible to infection. Currently, disease control is based on the application of protective fungicides, which is restricted due to resistance, health and environmental concerns. Although using natural products for disease management is gaining momentum, more advances are required. This study obtained the metabolic profiles of the essential oil and cuticular waxes of two citrus cultivars with a varying susceptibility to CBS infection using gas chromatography–mass spectrometry. A multivariate data analysis identified possible biomarker compounds that contributed to the difference in susceptibility between the two cultivars. Several identified biomarkers were tested in vitro for their antifungal properties against P. citricarpa. Two biomarkers, propanoic acid and linalool, were able to completely inhibit pathogen growth at 750 mg/L and 2000 mg/L, respectively