Faculty of Applied Sciences
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Item Biocatalytic and biological activities of cassia occidentalis mediated silver nanoparticles(College of Graduate Studies, Walailak University, 2022-01-01) Singh, Shashika; Mohanlall, VireshSilver nanoparticles (AgNPs) were synthesized using the leaf extracts from Cassia occidentalis. The reactions were marked by a distinct colour change and the formation of AgNPs was monitored by measuring the UV-Vis spectra. The morphology and crystalline phase of the metal nanoparticles were determined using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray analysis (EDX) and Fourier-Transform-Infrared Spectroscopy (FTIR). The biocatalytic activity of the AgNPs against nitrifying compounds was determined using 4-nitrophenol and 4-nitroalanine. The biological screening involved analyzing the AgNPs effectiveness against gram-negative and gram-positive bacteria (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus cereus and Enterococcus faecalis). The AgNPs displayed minimal inhibition at low concentrations ranging from 25 to 50 μg/mL. The toxicity of the AgNPs was tested using the brine shrimp assay and was observed as non-toxic with a nearly zero mortality rate. The AgNPs exhibited an antioxidant potential of 70.90 % inhibition at 1000 µg/mL. C. occidentalis is noted as a potential bioresource for synthesizing AgNPs with applications as antibacterial, antioxidant and biocatalytic agents. HIGHLIGHTS The addition of Ag nanoparticles to C. occidentalis plant extracts resulted in the formation of AgNPs-C. occidentalis complexes The AgNPs-C. occidentalis complexes were characterized using Transmission Electron Microscopy, Scanning Electron Microscopy with EDX, UV-Vis spectrophotometry and IR spectroscopy These AgNPs-C. occidentalis complexes were very stable and showed antibacterial activity against a range of tested gram-positive and gram-negative bacteria at low doses, thus proving to be good antimicrobial agents The AgNPs-C. occidentalis complexes showed higher scavenging activity than leaf extracts of C. occidentalis. The AgNPs have increased catalytic ability for the reduction of 4-nitrophenol and 4-nitroalanine after a 30 min time interval GRAPHICAL ABSTRACTItem Biocatalytic and biological activities of Kigelia africana mediated silver monometallic and copper-silver bimetallic nanoparticles(NISCAIR, 2022-01-08) Biyela, Buyani; Mohanlall, VireshAqueous extract of Kigelia africana leaves have been utilized for the synthesis of silver (AgNPs) and copper-silver bimetallic nanoparticles (Ag-CuNPs) that were generally found to be spherical and oval in shape. The synthesized nanoparticles were characterized using UV-Vis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX), and transmission electron microscopy (TEM). The antimicrobial activities were evaluated against both gram-negative and gram-positive strains of bacteria. The UV-Vis and FTIR techniques revealed the formation of nanoparticles and the active components were adsorbed on the surface of the particles thereby stabilizing the nanoparticles. The SEM reveals uniform microspheres of AgNPs and anisotropic particles for Ag-CuNPs. TEM shows the size of synthesized particles. The nanoparticles inhibited the growth of both gram-negative and gram-positive bacteria. The bimetallic nanoparticles synthesized from aqueous extract of K. africana leaves showed greater inhibition against Escherichia coli as compared to the monometallic nanoparticles. The AgNPs was more effective for the reduction of 4-nitrophenol and 4-nitroaniline as compared to Ag-CuNPs. The results of this study confirmed that Kigelia africana leaf and fruit aqueous extract can successfully reduce metallic ions to synthesize metallic nanoparticles that have antimicrobial and biocatalytic properties.Item Coumarin containing hybrids and their pharmacological activities(Phytochemistry & Organic Synthesis Laboratory, 2021-08-09) Kasumbwe, Kabange; Saheed, Sabiu; Makhanya, Talent R.; Venugopala, Katharigatta Narayanaswamy; Mohanlall, VireshCoumarin moiety is of great interest to both chemists and biologists as it is present in a wide variety of naturally occurring bioactive compounds. Studies have lent scientific credence to the biological activities of several coumarin derivatives. The broad spectrum of biological activities linked with coumarin includes antibacterial, antimycobacterial, antioxidant, anticancer, antifungal, anti-inflammatory, anticoagulant and antiviral properties. The electron releasing and withdrawing substituent of coumarin affects the pharmacological properties of its resulting derivatives. Thus, identifying key structural features within the coumarin family is vital to the design and development of new analogues with enhanced pharmacological activity due to the variability in the structural complexity of coumarin. This article presents an up-to-date synopsis on the synthesis of coumarin derivatives and their pharmacological properties.Item Crystallography, molecular modeling, and COX-2 inhibition studies on indolizine derivatives(MDPI AG, 2021-06) Venugopala, Katharigatta N.; Chandrashekharappa, Sandeep; Tratrat, Christophe; Deb, Pran Kishore; Nagdeve, Rahul D.; Nayak, Susanta K.; Morsy, Mohamed A.; Borah, Pobitra; Mahomoodally, Fawzi M.; Mailavaram, Raghu Prasad; Attimarad, Mahesh; Aldhubiab, Bandar E.; Sreeharsha, Nagaraja; Nair, Anroop B.; Alwassil, Osama I.; Haroun, Michelyne; Mohanlall, Viresh; Shinu, Pottathil; Venugopala, Rashmi; Kandeel, Mahmoud; Nandeshwarappa, Belakatte P.; Ibrahim, Yasmine F.The cyclooxygenase-2 (COX-2) enzyme is an important target for drug discovery and development of novel anti-inflammatory agents. Selective COX-2 inhibitors have the advantage of reduced side-effects, which result from COX-1 inhibition that is usually observed with nonselective COX inhibitors. In this study, the design and synthesis of a new series of 7-methoxy indolizines as bioisostere indomethacin analogues (5a–e) were carried out and evaluated for COX-2 enzyme inhibition. All the compounds showed activity in micromolar ranges, and the compound diethyl 3-(4-cyanobenzoyl)-7-methoxyindolizine-1,2-dicarboxylate (5a) emerged as a promising COX-2 inhibitor with an IC50 of 5.84 µM, as compared to indomethacin (IC50 = 6.84 µM). The molecular modeling study of indolizines indicated that hydrophobic interactions were the major contribution to COX-2 inhibition. The title compound diethyl 3-(4-bromobenzoyl)-7-methoxyindolizine-1,2-dicarboxylate (5c) was subjected for single-crystal X-ray studies, Hirshfeld surface analysis, and energy framework calculations. The X-ray diffraction analysis showed that the molecule (5c) crystallizes in the monoclinic crystal system with space group P 21/n with a = 12.0497(6)Å, b = 17.8324(10)Å, c = 19.6052(11)Å, α = 90.000°, β = 100.372(1)°, γ = 90.000°, and V = 4143.8(4)Å3. In addition, with the help of Crystal Explorer software program using the B3LYP/6-31G(d, p) basis set, the theoretical calculation of the interaction and graphical representation of energy value was measured in the form of the energy framework in terms of coulombic, dispersion, and total energy.Item Larvicidal Activities of 2-Aryl-2,3-Dihydroquinazolin-4-ones against Malaria Vector Anopheles arabiensis, in Silico ADMET prediction and molecular target investigation(MDPI, 2020-03-02) Venugopala, Katharigatta Narayanaswamy; Ramachandra, Pushpalatha; Tratrat, Christophe; Gleiser, Raquel M.; Bhandary, Subhrajyoti; Chopra, Deepak; Morsy, Mohamed A.; Aldhubiab, Bandar E.; Attimarad, Mahesh; Nair, Anroop B.; Sreeharsha, Nagaraja; Venugopala, Rashmi; Deb, Pran Kishore; Chandrashekharappa, Sandeep; Khalil, Hany Ezzat; Alwassil, Osama I.; Abed, Sara Nidal; Bataineh, Yazan A.; Palenge, Ramachandra; Haroun, Michelyne; Pottathil, Shinu; Girish, Meravanige B.; Akrawi, Sabah H.; Mohanlall, VireshMalaria, affecting all continents, remains one of the life-threatening diseases introduced by parasites that are transmitted to humans through the bites of infected Anopheles mosquitoes. Although insecticides are currently used to reduce malaria transmission, their safety concern for living systems, as well as the environment, is a growing problem. Therefore, the discovery of novel, less toxic, and environmentally safe molecules to effectively combat the control of these vectors is in high demand. In order to identify new potential larvicidal agents, a series of 2-aryl-1,2-dihydroquinazolin-4-one derivatives were synthesized and evaluated for their larvicidal activity against Anopheles arabiensis. The in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of the compounds were also investigated and most of the derivatives possessed a favorable ADMET profile. Computational modeling studies of the title compounds demonstrated a favorable binding interaction against the acetylcholinesterase enzyme molecular target. Thus, 2-aryl-1,2-dihydroquinazolin-4-ones were identified as a novel class of Anopheles arabiensis insecticides which can be used as lead molecules for the further development of more potent and safer larvicidal agents for treating malaria.Item A brief review of secondary plant metabolites as anticancer agents(COJ Reviews & Research, 2020-05-18) Mohanlall, Viresh; Naicker, LeeannPlants have provided a source of medicine from the beginning of human history and are the core of modern medicine. Moreover, plant-based drug discovery has led to the development of various anticancer drugs (such as vincristine, vinblastine, etoposide, paclitaxel, camptothecin, topotecan and irinotecan). The use of botanical, photochemical, biological and molecular techniques have facilitated the discovery of novel secondary metabolites from native and indigenous plants that can inhibit the human topoisomerase II enzyme (target for anticancer drugs) and kill cancer cells. Therefore, the aim of this review was to further investigate the anticancer activity of secondary metabolites from native and indigenous plants and determine the classes of compounds that contributed towards its activity.Item Crystallography, in silico studies, and In vitro antifungal studies of 2,4,5 trisubstituted 1,2,3-triazole analogues(MDPI AG, 2020-06-20) Venugopala, Katharigatta N.; Khedr, Mohammed A.; Girish, Yarabahally R.; Bhandary, Subhrajyoti; Chopra, Deepak; Morsy, Mohamed A.; Aldhubiab, Bandar E.; Deb, Pran Kishore; Attimarad, Mahesh; Nair, Anroop B.; Sreeharsha, Nagaraja; V, Rashmi; Kandeel, Mahmoud; Akrawi, Sabah H.; Reddy M B, Madhusudana; Shashikanth, Sheena; Alwassil, Osama I.; Mohanlall, VireshA series of 2,4,5 trisubstituted-1,2,3-triazole analogues have been screened for their antifungal activity against five fungal strains, Candida parapsilosis, Candida albicans, Candida tropicalis, Aspergillus niger, and Trichophyton rubrum, via a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) microdilution assay. Compounds GKV10, GKV11, and GKV15 emerged as promising antifungal agents against all the fungal strains used in the current study. One of the highly active antifungal compounds, GKV10, was selected for a single-crystal X-ray diffraction analysis to unequivocally establish its molecular structure, conformation, and to understand the presence of different intermolecular interactions in its crystal lattice. A cooperative synergy of the C-H···O, C-H···N, C-H···S, C-H···π, and π···π intermolecular interactions was present in the crystal structure, which contributed towards the overall stabilization of the lattice. A molecular docking study was conducted for all the test compounds against Candida albicans lanosterol-14α-demethylase (pdb = 5 tzl). The binding stability of the highly promising antifungal test compound, GKV15, from the series was then evaluated by molecular dynamics studies.Item An overview of tropane alkaloids from Datura stramonium L.(AkiNik Publications, 2020-05-13) Mohanlall, Viresh; Ally, FarnaazDatura stramonium L., a wild-growing plant of the Solanaceae family, is widely distributed throughout the world. It contains a variety of tropane alkaloids such as atropine, hyoscyamine, and scopolamine In Ayurvedic medicine, D. stramonium has been used for curing various human ailments, including ulcers, wounds, inflammation, rheumatism and gout, sciatica, bruises and swellings, fever, asthma and toothache. A few previous studies have reported on the pharmacological effects of D. stramonium; however, complete information regarding the phytochemistry remains unclear. This comprehensive review includes information on botany and phytochemistry of the major tropane alkaloids produced by D. stramonium.Item Plant cell culture systems for the production of secondary metabolites : a review(International Organization Of Scientific Research (IOSR), 2020-03-09) Mohanlall, VireshPlant cell culture systems represent a potential source of valuable secondary metabolites which can be used as food flavourants, colorants, cosmeceuticals, nutraceuticals and pharmaceuticals. Environmental parameters that effect the cultivation of plants for the production of secondary metabolites include environmental factors, political and labour instabilities in the producing countries, uncontrollable variations in the crop quality, crop adulteration, and losses in post-harvest storage and handling. In most cases, the chemical synthesis of secondary metabolites is either extremely difficult or not economically feasible. The production of useful and valuable secondary metabolites from cell cultures is an attractive alternative to conventional plant cultivation techniques. Cell culture technology was developed as a possible tool to both study and produce plant secondary metabolites. The evolving importance of the secondary metabolites has resulted in a high level of interest in the possibility of altering their production through improving cultivation technology.This review summarizes conventional and alternative plant cell culture techniques for the production of secondary metabolites.Item Antibacterial screening of gunnera perpensa-Mediated silver nanoparticles(Hindawi Limited, 2020-05-21) Patel, Naazlene; Kasumbwe, Kabange; Mohanlall, VireshThe 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.