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Faculty of Applied Sciences

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Author: search.filters.author.Venugopala, Katharigatta NarayanaswamyHas files: No

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    Antimycobacterial, docking and molecular dynamic studies of pentacyclic triterpenes from Buddleja saligna leaves
    (Taylor and Fancis Online, 2017) Singh, Alveera; Venugopala, Katharigatta Narayanaswamy; Khedr, Mohammed A.; Pillay, Mellendran; Nwaeze, Kenneth U.; Coovadia, Yacoob; Shode, Francis; Odhav, Bharti
    Buddleja saligna (family Buddlejaceae) is a medicinal plant endemic to South Africa. Two isomeric pentacyclic triterpenes, oleanolic acid and ursolic acid, were isolated from the leaves of B. saligna using silica gel column chromatography. Compounds oleanolic acid and ursolic acid were subjected to derivatization with acetic anhydride in the presence of pyridine to obtain oleanolic acid-3-acetate and ursolic acid-3-acetate, respectively. The structures of these compounds were fully characterized by detailed nuclear magnetic resonance (NMR) investigations, which included 1H and 13C NMR. Molecular docking studies predicted the free binding energy of the four triterpenes inside the steroid binding pocket of Mycobacterium tuberculosis fadA5 thiolase compared to a reported inhibitor. Thus, their ability to inhibit the growth of M. tuberculosis was predicted and was confirmed to possess significant antimycobacterial activity when tested against Mycobacterium smegmatis, M. tuberculosis H37Rv (ATCC 25177), clinical isolates of multi-drug-resistant M. tuberculosis (MDR-TB) and extensively drug-resistant M. tuberculosis (XDR-TB) using the Micro Alamar Blue Assay. Ursolic acid was isolated from this plant for the first time.
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    Synthesis, polymorphism, and insecticidal activity of Methyl 4-(4-chlorophenyl)-8-iodo-2-methyl-6-oxo-1,6-dihydro-4H-pyrimido[2,1-b]quinazoline-3-Carboxylate against Anopheles arabiensis mosquito.
    (Wiley Online Library, 2016-07) Venugopala, Katharigatta Narayanaswamy; Nayak, Susanta K.; Gleiser, Raquel M.; Sanchez-Borzone, M. E.; Garcia, D. A.; Odhav, Bharti
    Mosquitoes are the major vectors of pathogens and parasites including those causing malaria, the most deadly vector-borne disease. The negative environmental effects of most synthetic compounds combined with widespread development of insecticide resistance encourage an interest in finding and developing alternative products against mosquitoes. In this study, pyrimido[2,1-b]quinazoline derivative DHPM3 has been synthesized by three-step chemical reaction and screened for larvicide, adulticide, and repellent properties against Anopheles arabiensis, one of the dominant vectors of malaria in Africa. The title compound emerged as potential larvicide agent for further research and development, because it exerted 100% mortality, while adulticide activity was considered moderate.
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    Synthesis and antimosquito properties of 2,6-substituted benzo[ d ] thiazole and 2,4-substituted benzo[ d ]thiazole analogues against Anopheles arabiensis
    (Elsevier, 2013-07) Venugopala, Katharigatta Narayanaswamy; Krishnappa, Krishnappa; Nayak, Susanta K.; Subrahmanya, Bhat K.; Vaderapura, Jayashankaragowda P.; Chalannavar, Raju K.; Gleiser, Raquel M.; Odhav, Bharti
    A novel and efficient one pot synthesis was developed for 2,6-substituted-benzo[d]thiazole analogues 4a–k and 2,4-substituted-benzo[d]thiazole analogues 4l–pvia three component condensation reaction of substituted arylaldehyde, 2-amino-6-halo/4-methyl-benzo[d]thiazole and 2-naphthol or 6-hydroxyquinoline in presence of 10% w/v NaCl in water by microwave method. This method enabled for short reaction times, easy work-up and significant high yields. The title compound 4b was used for single crystal X-ray studies in order to understand its conformation and packing features. The title compounds 4a–p were screened for antimosquito properties such as repellency, insecticidal and larvicidal activity against Anopheles arabiensis by mosquito feeding-probing assay, cone bio-assay and standard WHO larvicidal assay, respectively. Among these analogous 4b, 4d and 4p exhibit the highest repellent activity comparable to the positive control DEET, and 4a and 4k knockdown most mosquitoes on repellent assays.