Faculty of Applied Sciences

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2-(4-Bromoanilino)-6-(4-chlorophenyl)-5-methoxycarbonyl-4- methyl-3,6-dihydropyrimidin-1-ium chloride
(International Union of Crystallography, 2013-03-09) Venugopala, Katharigatta Narayanaswamy; Nayak, Susanta K.; Odhav, Bharti
In the title molecular salt, C19H18BrClN3O2+·Cl-, the dihedral angles between the pyrimidine ring and the chlorobenzene and bromobenzene rings are 72.4 (2) and 45.5 (2)°, respectively. The dihedral angle between the chlorobenzene and bromobenzene rings is 27.5 (2)°. The conformation of the molecule is stabilized by an intramolecular C-H...O interaction. In the crystal, the anion and cation are linked by an N-H...Cl hydrogen bond. Pairs of weak C-H...O and C-H...Cl hydrogen bonds form inversion dimers. Further N-H...Cl hydrogen bonds form R21(6) motifs and link the dimers into chains along [101]. Br...Cl short contacts [3.482 (2) Å] interlink the hydrogen-bonded chains along the b-axis direction.
{2-[(1,3-Benzothiazol-2-yl)methoxy]-5- bromophenyl}(phenyl)methanone
(International Union of Crystallography, 2013) Venugopala, Katharigatta Narayanaswamy; Nayak, Susanta K.; Odhav, Bharti
In the title compound, C21H14BrNO2S, the dihedral angle between the planes of the benzothiazole and phenylmethanone groups is 63.4 (2)°. In the crystal, pairs of C-H...N hydrogen bonds link the molecules to form inversion dimers, which are further linked by C-H...O interactions into chains along the c axis. C-H...[pi] and [pi]-[pi] interactions [centroid-centroid distance = 3.863 (1) Å] further stabilize the molecular assembly.
{2-[(1,3-Benzothiazol-2-yl)methoxy]-5-bromophenyl}(phenyl)methanone
(International Union of Crystallography, 2014-05-21) Venugopala, Katharigatta Narayanaswamy; Nayak, Susanta K.; Odhav, Bharti
In the title compound, C21H14BrNO2S, the dihedral angle between the planes of the benzothiazole and phenylmethanone groups is 63.4 (2)°. In the crystal, pairs of C-H...N hydrogen bonds link the molecules to form inversion dimers, which are further linked by C-H...O interactions into chains along the c axis. C-H...[pi] and [pi]-[pi] interactions [centroid-centroid distance = 3.863 (1) Å] further stabilize the molecular assembly.
4-Dihydroxy-3-(indol-2-)-yl-quinoline via substantial methodology-fisher indole synthesis
(Heterocyclic Letters, 2016) Pitchai, P.; Nepolraj, A.; Sathiyaseelan, M.; Gengan, Robert Moonsamy
Fisher indole methodology, a simple application was used to generate indole as a substitution on the quinoline ring. Conventional heating and microwave irradiation was compared. The ease of work up procedure, reduced time and moreover the high yield is exceptional however microwave irradiation presented more advantages.
57Fe Emission Mossbauer study on Gd3Ga5O12 implanted with dilute 57Mn
(Springer International Publishing Switzerland, 2016) Krastev, P. B.; Gunnlaugsson, H. P.; Nomura, K.; Adoons, V.; Gerami, A. M.; Johnston, K.; Ncube, M.; Mantovan, R.; Masenda, Hilary; Matveyev, Y. A.; Mølholt, Torben Esmann; Unzueta, I.; Bharuth-Ram, Krish; Gíslason, H.; Langouche, G.; Naidoo, D.; Ólafsson, S.
57Fe emission M¨ossbauer spectroscopy has been applied to study the lattice location and properties of Fe in gadolinium gallium garnet Gd3Ga5O12 (GGG) single crystals in the temperature interval 300 – 563 K within the extremely dilute (<10−4 at.%) regime following the implantation of 57Mn (T1/2 = 1.5 min.) at ISOLDE/CERN. These results are compared with earlier M¨ossbauer spectroscopy study of Fe-doped gadolinium gallium garnet Gd3Ga5O12(GGG), with implantation fluences between 8×1015 and 6×1016 atoms cm−2. Three Fe components are observed in the emission M¨ossbauer spectra: (i) high spin Fe2+ located at damage sites due to the implantation process, (ii) high spin Fe3+ at substitu-tional tetrahedral Ga sites, and (iii) interstitial Fe, probably due to the recoil imparted on the daughter 57∗Fe nucleus in the β− decay of 57Mn. In contrast to high fluence 57Fe implanta-tion studies the Fe3+ ions are found to prefer the tetrahedral Ga site over the octahedral Ga site. No annealing stages are evident in the temperature range investigated. Despite the very low concentration, high-spin Fe3+ shows fast spin relaxation, presumably due to an indirect interaction between nearby gadolinium atoms.
Acceptance of a ready-to-use supplementary food by stable HIV-treated and HIV and tuberculosis (co-infected)-treated patients
(NISC (Pty) Ltd and Taylor & Francis, 2014) Pillay, K.; Siwela, M.; Feldman, F.J.; Amonsou, Eric Oscar; Mabaso, B.P.
Objectives: The objective of the study was to determine consumer acceptance and perceptions of a ready-to-use supplementary food (RUSF) by subjects treated for human immunodeficiency virus (HIV) and HIV and tuberculosis (co-infected subjects). Design: A cross-sectional study was conducted. Subjects: One hundred and thirty-nine stable HIV-treated and HIV and tuberculosis (co-infected)-treated patients participated in the study. Sixty-eight healthy subjects served as the control group. Setting: The setting was Northdale Hospital and Grey’s Hospital in Pietermaritzburg, KwaZulu-Natal. Outcome measures: Acceptance of the RUSF was assessed using a five-point facial hedonic scale by stable HIV-treated and HIV and tuberculosis (co-infected)-treated patients (n = 139) from Northdale Hospital and Grey’s Hospital in Pietermaritzburg, KwaZulu-Natal. Perceptions of the RUSF were determined through focus group discussions in which HIV-treated and HIV and tuberculosis (co-infected)-treated patients (n = 43) participated. Results: The overall acceptance of the RUSF was significantly associated with the health status of the subjects (p-value < 0.05). Overall, the product was liked by more than 90% of the HIV-treated and HIV and tuberculosis (co-infected)-treated individuals compared to 85% of the control group. More than 90% of the HIV-treated and HIV and tuberculosis (co-infected)-treated individuals liked the taste, compared to 87% of the control group. The colour and mouth feel were rated to be “good” by more than 80% of the HIV-treated and HIV and tuberculosis (co-infected)-treated group, compared to approximately 70% of the healthy group. Focus group discussions revealed that the subjects perceived the mouth feel of the RUSF to be “rough”, and that as a health supplement, the RUSF should be provided free of charge, or at a reasonable cost, at public health centres. Conclusion: The RUSF was found to be highly acceptable to stable HIV-treated and HIV and tuberculosis (co-infected)-treated subjects, although concern was raised about the mouth feel.
Advances in synthesis of biodiesel via enzyme catalysis : Novel and sustainable approaches
(Elsevier, 2015-01) Singh, Bhaskar; Mutanda, Taurai; Permaul, Kugen; Bux, Faizal; Guldhe, Abhishek
Biodiesel, a renewable fuel has a great potential in fulﬁlling an ever-increasing transport fuel demand. The enzymatic conversion process of feedstock oil to biodiesel is greener when compared to the conventional approach of chemical conversion due to mild reaction conditions and less wastewater generation. Lipases obtained from various microbial sources have been widely applied as catalysts for the conversion of oil to biodiesel. Biodiesel and glycerol obtained by enzymatic conversion have shown a higher purity as compared to that obtained by other conversion techniques. Enzymatic conversion of oil to biodiesel is less energy intensive because of milder reaction conditions and fewer puriﬁcation steps involved in processing. Lipases, due to their catalytic efﬁciency and speciﬁcity, have emerged as a great tool for converting a wide range of feedstock oils to biodiesel. This manuscript presents an overview of the use of enzymatic conversion for making biodiesel production sustainable and environmentally-friendly. The constraints of enzymatic conversion are the high cost of the enzyme and its inhibition by alcohol and glycerol. The possible solutions to overcome these constraints are discussed. Recent advances to develop an effective process for enzymatic conversion of feedstock oils into biodiesel are critically evaluated. Prospective and challenges in scaling up of this technology are also discussed.
Algebraic and singularity properties of a class of generalisations of the Kummer–Schwarz equation
(Springerlink, 2016-09-28) Sinuvasan, R.; Tamizhmani, K. M.; Leach, P. G. L.
The Kummer–Schwarz Equation, 2y′y′′′−3y′′2=0, (the prime denotes differentiation with respect to the independent variable x) is well known from its connection to the Schwartzian Derivative and in its own right for its interesting properties in terms of symmetry and singularity. We examine a class of equations which are a natural generalisation of the Kummer–Schwarz Equation and find that the algebraic and singularity properties of this class of equations display an attractive set of patterns. We demonstrate that all members of this class are readily integrable.
The algebraic properties of the space- and time-dependent one-factor model of commodities
(Taylor and Fancis, 2016-06-06) Paliathanasis, Andronikos; Morris, Richard M.; Leach, P. G. L.
We consider the one-factor model of commodities for which the parameters of the model depend upon the stock price or on the time. For that model we study the existence of group-invariant transformations. When the parameters are constant, the one-factor model is maximally symmetric. That also holds for the time-dependent problem. However, in the case for which the parameters depend upon the stock price (space) the one-factor model looses the group invariants. For speciﬁc functional forms of the parameters the model admits other possible Lie algebras. In each case we determine the conditions which the parameters should satisfy in order for the equation to admit Lie point symmetries. Some applications are given and we show which should be the precise relation amongst the parameters of the model in order for the equation to be maximally symmetric. Finally we discuss some modiﬁcations of the initial conditions in the case of the space-dependent model. We do that by using geometric techniques.
Algebraic structures of generalised symmetries of n th-order scalar ordinary differential equations of maximal lie point symmetry
(Natural Sciences Publishing, 2015-05-01) Charalambous, K.; Leach, P. G. L.
We compute for the representative scalar ordinary differential equation of maximal point symmetry the generalised symmetries of order-one and two. We examine the Lie Brackets for the generalised symmetries and see that closure does not occur for generalised symmetries of order-two. Consequently all generalised symmetries up to the maximum order possible must be admitted.
Analysis of lubricating grease by ICP-OES : a case study on preparation methodology
(Asian Publication Corporation, 2016-01-30) Marume, Cathrine; Kumar, Bhajanthri Natesh; Redhi, Gan G.
The aim of this study was to develop simple, cost effective and reliable sample preparation methods for the analysis of lubricating grease samples. Direct dilution, microwave digestion and emulsification methods were designed and compared for the analysis of Ca, B, Al, Na, Mo, Zn and Ba with inductively coupled plasma optical emission spectroscopy (ICP-OES). The direct dilution method gave most inconsistent results in terms of percentage recovery. The optimized microwave digestion and emulsification methods compared well and showed good reliability in terms of sensitivity and selectivity. The calibration curves resulting from oil emulsion has no significant difference with that of aqueous emulsions, but the stability of the emulsified samples was very low. The limit of detection and limit of quantification values obtained from the microwave digestion method were very low and therefore it is superior amongst the three methods for the analysis of various lubricating grease samples.
Analytical evaluation of steviol glycosides by capillary electrophoresis supported with molecular docking studies
(Iranian Chemical Society, 2014-05-05) Ayyappa, Bathinapatla; Kanchi, Suvardhan; Singh, Parvesh; Dovey, Martin; Sabela, Myalowenkosi Innocent; Bisetty, Krishna
This paper reports on a newly developed elec-trokinetic chromatographic method for the simultaneous separation and determination of steviol glycosides in real stevia samples by capillary electrophoresis and supported by molecular docking studies. Our results obtained using 30-mM heptakis-(2,3,6-tri-o-methyl betacyclodextrin) as a separating agent, suggest that at optimum experimental conditions the detection limits of 2.017 9 10-5 and 7.386 9 10-5 M and relative standard deviations (n = 5) of 1.10 and 1.17 were obtained for rebaudioside-A and stevioside, respectively. In addition, the molecular docking studies explained to a certain extent why the separation was successful. The calculated binding free energy results for the rebaudioside-A and stevioside complexes formed with the separating agent showed that although both ligands penetrated deeply into the hydrophobic cavity of the sep-arating agent, the presence of additional hydrogen bonding in the case of stevioside is probably responsible for its stronger binding afﬁnity than that of rebaudioside-A.
Analytical solutions in R + qRn cosmology from singularity analysis
(American Physical Society, 2016) Paliathanasis, Andronikos; Leach, P. G. L.
The integrability of higher-order theories of gravity is of importance in the determining the proper-ties of these models and so their viability as models of reality. An important tool in the establishment of integrability is the singularity analysis. We apply this analysis to the case of fourth-order the-ory of gravity f(R) = R + qRn to establish those values of the free parameters q and n for which integrability in this sense exists. As a prelininary we examine the well-known case of n = 4/3.
Antibacterial properties of organosulfur compounds of garlic (Allium sativum)
(Frontiers Media SA, 2021-07-27) Bhatwalkar, Sushma Bagde; Mondal, Rajesh; Krishna, Suresh Babu Naidu; Adam, Jamila Khatoon; Govender, Patrick; Anupam, Rajaneesh
A popular food spice and flavoring agent, has also been used traditionally to treat various ailments especially bacterial infections for centuries in various cultures around the world. The principal phytochemicals that exhibit antibacterial activity are oil-soluble organosulfur compounds that include allicin, ajoenes, and allyl sulfides. The organosulfur compounds of garlic exhibit a range of antibacterial properties such as bactericidal, antibiofilm, antitoxin, and anti-quorum sensing activity against a wide range of bacteria including multi-drug resistant (MDR) strains. The reactive organosulfur compounds form disulfide bonds with free sulfhydryl groups of enzymes and compromise the integrity of the bacterial membrane. The World Health Organization (WHO) has recognized the development of antibiotic resistance as a global health concern and emphasizes antibiotic stewardship along with the urgent need to develop novel antibiotics. Multiple antibacterial effects of organosulfur compounds provide an excellent framework to develop them into novel antibiotics. The review provides a focused and comprehensive portrait of the status of garlic and its compounds as antibacterial agents. In addition, the emerging role of new technologies to harness the potential of garlic as a novel antibacterial agent is discussed.
Antibacterial screening of gunnera perpensa-Mediated silver nanoparticles
(Hindawi Limited, 2020-05-21) Patel, Naazlene; Kasumbwe, Kabange; Mohanlall, Viresh
The biosynthesis of nanoparticles has become quite popular and has been proposed as an alternative over the tedious, expensive, and toxic physical and chemical methods of synthesis due to its cost-effectiveness and ecofriendliness. This study involved the biosynthesis, characterization, and evaluation of the antibacterial activity of Gunnera perpensa-mediated AgNPs. Biosynthesized AgNPs were characterized using TEM, UV, and FTIR spectroscopy. The antimicrobial activity was evaluated in six bacterial strains, using the disc diffusion assay, and MIC was determined using the broth dilution assay. All NPs generally presented as spherical clusters, with sizes ranging from 13 to 24 nm, as determined by TEM. The absorption peaks ranging between 421 and 425 nm and the presence of the C=O bond with amine groups, as indicated by UV and FTIR spectra, confirmed the synthesis and stabilization of G. perpensa extract-mediated AgNPs. Good antimicrobial activity ranging from 7.0 to 9.0 mm was exhibited by both preparations of G. perpensa extract-mediated AgNPs against both Gram-positive and Gram-negative studied bacteria, at MIC ranging from 3.2 to 12.5 μg/ml. Overall, good antibacterial activity was achieved at lower doses with both preparations of the G. perpensa-mediated AgNPs against all tested bacterial strains, suggesting G. perpensa-mediated AgNPs as good antimicrobial agents.
Antibacterial, anti-inflammatory and antioxidant activities of anthraquinones from Ceratotheca triloba (Bernh) Hook F
(Academic Journals, 2013-04-10) Mohanlall, Viresh; Odhav, Bharti
9, 10-Anthracenedione and 1-hydroxy-4-methylanthraquinone showed antibacterial activity against Staphylococcus aureus, Micrococcus luteus, Bacillus cereus and Escherichia coli. Due to the synergistic effect of the individual compounds, the crude extract from leaves and roots of Ceratotheca triloba exhibited good potency (>500) against S. aureus and M. luteus, medium potency against E. coli and S. typhimurium (<100) and very low potency against B. cereus (<10). Although a similar trend was observed for 9, 10 anthracenedione and 1-hydroxy -4-methyl anthraquinone unlike the crude extract. A very low potency against S. aureus was observed for 9, 10 anthracenedione and a high potency for 1-hydroxy-4-methylanthraquinone. Thus 9, 10 anthracenedione is an effective drug against E. coli and S. typhimurium and 1-hydroxy-4-methylanthraquinone is effective against S. aureus and M. luteus. The crude root extract and 9, 10 anthacenedione, 1-hydroxy-4-methylanthraquinone and 5, 8-dimethoxy-2, 3, 10, 10a-tetrahydro-1H-phenanthrene-4, 9-dione showed a ± 50% reduction of the free radicals. No anti-inflammatory activity was observed. The purified extracts showed moderate toxicity against HepG2 cells at high concentrations and no toxicity was observed against brine shrimp larvae. No mutagenicity was observed with the crude extracts using the Ames test. All purified and crude extracts showed potent inhibition of the human topoisomerase II enzyme.
Antibodies to erythropoietin are associated with erythropoietin resistance in hemodialysis patients in KwaZulu-Natal (South Africa)
(Medknow, 2020) Benjamin, Sherilene; Adam, Jamila; Krishna, Suresh Babu Naidu; Assounga, Alain G.
Recombinant human erythropoietin (rHuEPO) is a glycoprotein and biological equivalent to the endogenous compound administered to treat anemia of end-stage renal disease patients. Resistance to rHuEPO has been reported, whereby patients require higher and higher doses of rHuEPO to maintain an adequate hemoglobin level. In this study, assessment of native and administered erythropoietin (EPO), antibody and hemoglobin levels was carried out on a sample of patients with renal failure on hemodialysis (HD). This is a randomized controlled trial where consecutive subjects attending HD units at Addington Hospital and King Edward Hospital, Durban (South Africa) were included until the target number was reached. Forty patients with renal failure on HD and receiving recombinant EPO Beta (Recormon) for treatment of anemia via the subcutaneous route in weekly doses of 2000 IU, 4000 IU, 6000 IU, 8000 IU, 12,000 IU, or 18,000 IU according to the severity of the anemia were included after obtaining informed consent. Also included in the study were 10 HD patients not on rHuEPO therapy and 10 healthy individuals from the Durban University of Technology, recruited as described above to form the control group. ELISA was used to measure serum levels of EPO as well as antibodies to EPO. Results were analyzed by descriptive, inferential methods and by logistic regression analysis using IBM SPSS Statistics for Windows version 22.0. Antibodies to EPO were found in almost all patients who were receiving EPO. The highest levels of antibody to EPO were found to be associated with patients receiving the highest weekly dose of EPO (18,000 IU). Logistic regression analysis also revealed that serum levels of EPO, gender or age were not associated with any significant variation of serum antibody level. High levels of serum antibodies to EPO are a risk factor for EPO resistance.
Antimicrobial activity of plant phenols from Chlorophora excelsa and Virgilia oroboides
(Academic Journals, 2013-04-24) Padayachee, Thiriloshani; Odhav, Bharti
The anti-bacterial and anti-fungal activity of four aqueous plant extracts (1 x 104 µg/ml) of 2,3'4,5'-tetra hydroxy-4'-geranylstilbene (chlorophorin) and 3',4, 5' - trihydroxy - 4' - geranylstilbene (Iroko) from the tree Chlorophora excelsa and (6aR,11aR)-3-hydroxy-8,9-methylenedioxypterocarpan (Maackiain) and 7-hydroxy-4'-methoxyisoflavone (formononetin) from Virgilia oroboides were evaluated by the seeded agar overlay well diffusion method. The test organisms and bioautography used included: Bacillus coagulans, Streptococcus pneumoniae, Klebsiella pneumoniae, Escherichia coli, Mycobacteria tuberculosis, Aspergillus flavus and Fusarium verticilloides. Vancomycin, the drug of choice for these organisms was used as the control at 30 µg/ml. The extracts showed that chlorophorin at 1.95 µg/ml and Iroko at 3.125 and 6.25 µg/ml respectively were active in inhibiting the growth of S. pneumoniae and B. coagulans and not active against K. pneumoniae and E. coli. Maackiain; formononetin and formononetin acetate showed little activity against S. pneumonia, B. coagulans, K. pneumoniae and E. coli. None of the extracts showed activity against M. tuberculosis. Maackiain, formononetin, chlorophorin and Iroko inhibited F. vertiicilloides, maackiain being the most active compound. Formononetin, chlorophorin and Iroko inhibited A. flavus. A. flavus was most sensitive to chlorophorin and Iroko. The bioautography method confirmed these results and was attributed to the phenolic nature of the compounds.
Antimosquito properties of 2-substituted phenyl/benzylamino-6-(4-chlorophenyl)-5-methoxycarbonyl-4-methyl-3,6-dihydropyrimidin-1-ium chlorides against anopheles arabiensis
(Bentham Science Publishers, 2014) Gleiser, Raquel M.; Chalannavar, Raju K.; Odhav, Bharti; Odhav, Bharti; Venugopala, Katharigatta Narayanaswamy
Eight novel dihydropyrimidine analogs named DHPM1-DHPM8 was synthesized in their hydrochloride salt form using one pot synthesis between methyl 2-chloro-4-(4-chlorophenyl)-6-methyl-1,4-dihydropyrimidine-5-carboxylate and substituted arylamines in isopropanol. The antimosquito effect of the test compounds were assessed against the adult mosquito Anopheles arabiensis. For adulticidal properties the test compounds were sprayed onto ceramic tiles and screened using the cone bio-assay method. The larvicidal activity was tested by monitoring larval mortality daily and up to 3 days of exposure. Repellency properties were tested in a feeding-probe assay using unfed female Anopheles arabien-sis. Compounds DHPM1, DHPM4, DHPM5 and DHPM6 exerted larval mortality equivalent to temephos (trade name Abate, a commercial larvicidal compound). Compounds DHPM1 to DHPM5 repelled or knocked down 92 to 98% of mosquitoes exposed to rodent skin treated with the compounds. None of the compounds showed any significant activity against the adult mosquito Anopheles arabiensis.
The antimosquito properties of extracts from flowering plants in South Africa
(NCBI, 2013) Chalannavar, Raju K.; Hurinanthan, Vashka; Singh, Alveera; Venugopala, Katharigatta Narayanaswamy; Gleiser, Raquel M.; Baijnath, Himansu; Odhav, Bharti
Extracts of selected flowering plants, which are considered eco-friendly, are used for the treatment of numerous ailments and vector control worldwide. This has resulted in approximately 25 per cent of currently used drugs being derived from herbal sources. The aqueous and methanolic extracts of twelve plant species, Psidium guajava (pink fruit), Psidium guajava (white fruit), Psidium cattleianum var. cattleianum, Psidium guineense and Psidium X durbanensis, Achyranthes aspera, Alternanthera sessilis, Guilleminea densa, Capparis tomentosa, Leonotis leonurus, Dichrostachys cinerea and Carpobrotus dimidiatus, were tested for insecticidal activity, including larvicidal, adulticidal and repellent activities against the adult female mosquito, Anopheles arabiensis. The extracts of P. guajava (white fruit), C. tomentosa, L. leonurus,D. cinerea, and C. dimidiatus exerted a pronounced inhibitory effect on adult insects, while those of P. guajava (pink fruit), P. X durbanensis, P. cattleianum var. cattleianum, P. guineense, A. aspera, A. sessilis, and G. densa were ineffective and failed to satisfy the criteria set by the World Health Organization. In the tests for repellency against An. arabiensis, all the tested aqueous and methanolic plant extracts except those of A. sessilis repelled 80-100% of mosquitoes. The most effective mosquito repellents were the methanol and aqueous extracts of P. guajava (pink fruit), P. X durbanensis, P. cattleianum var. cattleianum, P. guineense, G. densa,L. leonurus and D. cinerea, which are potential sources of cost effective mosquito repellents to be utilized in malarial endemic areas.