Chemistry
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Item In vivo and in silico Antifungal Activity of Cinnamon Leaf Oil and Lemongrass Oil containing Chitosan Microcapsules against Aspergillus flavus(2024-04) Kumarathunga, P.G.J.D.; Chathurangi, S.; Rajapaksha, R.P.S.P.; Sooriyawansha, A.M.S.C.; Jayawardena, P.A.S.N.P.; Dananjaya, P.D.H.; Alwis, M.D.N.; Kadigamuwa, C.C.; Dahanayake, J.N.; Wickramarachchi, SurangaThis study aimed to examine the potentiality of microencapsulated cinnamon leaf oil (CNO-CS-MCs) and lemongrass oil (LGO-CS-MCs) as natural fungicides against Aspergillus flavus. Oil encapsulated microcapsules were synthesized using ionotropic gelation method. Cinnamon leaf oil (CNO) and lemongrass oil (LGO) were characterized using GC-MS. A. flavus was isolated and identified using DNA sequencing. The minimum inhibitory and minimum lethal doses of oil-loaded microcapsules against A. flavus were evaluated under in vivo conditions and the results were further confirmed by in silico analysis. The major constituents of CNO and LGO were eugenol and citral, respectively. The minimum inhibitory doses of CNO-CS-MCs and LGO-CS-MCs were 5 mg and 7.5 mg, respectively. The minimum lethal dose of CNO-CS-MCs was 12.5 mg. As CNO showed considerably high antifungal activity than LGO, Computational investigations were carried out on the action of CNO against A. flavus. The highest protein-ligand interaction was observed for squalene epoxidase (SQ)-benzyl benzoate (BEN) complex with the binding energy of -7.70 kcal/mol. Molecular dynamics simulations were performed on SQ-BEN complex for 10 ns using CHARMM36 force field. The Rg, RMSD and RMSF results indicated the stabilization of the SQ-BEN complex throughout the simulation time.Item Computational studies of antiviral properties of curry powder water extract against Norovirus infection(Society for Conservation and Resource Development of Medicinal Plant, New Delhi, India., 2023) Weerarathne, H.K.; Sooriyawansha, A.M.S.C.; Jayawardena, P.A.S.N.P.; Kumarathunga, P.G.J.D.; Dananjaya, P.D.H.; Sandaruwan, W.A.M.; Dahanayake, J.N.; Kadigamuwa, C.C.Curry powder is a mixture of ground spices that are typically used to enhance flavor, aroma, color, and consistency in curries. The Sri Lankan roasted curry powder “bedapu thuna paha” consists of coriander seeds (Coriandrum sativum L.), cumin seeds (Cuminum cyminum), fennel seeds (Foeniculum vulgare Mill.), cinnamon sticks (Cinnamomum zeylanicum) and curry leaves (Murraya koenigii) as the main ingredients. Norovirus (NoV) is a single-stranded RNA virus belonging to the family Caliciviridae. The P domain capsid protein of this virus plays an important role in the host immune response and receptor recognition because when protruding domain 1 binds with receptor molecules, it is easy to penetrate the host cell. Therefore, twenty potential ligands contained in the curry powder decoction, which were identified through literature review, were docked to the active site in the P domain from norovirus strain saga4 in complex with HBGA, and Mahanimbine, Mahanine, and Fenchone ligands binding energies were greater than -6.00 kcal/mol. According to these interactions between ligands and the protein, which were given binding energies greater than -6.00 kcal/mol, only the Mahanine ligand interacted with the highest number of amino acids in the binding pocket compared to the other two ligands (Asp374, His347, Gly346) and this ligand was subjected to Molecular Dynamics (MD) simulations. MD simulations were performed on the proteinligand complex for 10 ns using the CHARMM36 force field. Rg, RMSD. The RMSF results indicated the stability of the protein-ligand complex throughout the simulation time and suggested that Mahanine phytochemical may be used as a potential anti-virus agent against Norovirus.Item Efficacy of methanolic extract of Zingiber officinale against seed-born fungi(Society for Conservation and Resource Development of Medicinal Plant, New Delhi, India., 2023) Hansini, Navoda; Sooriyawansha, A.M.S.C.; Jayawardena, P.A.S.N.P.; Kumarathunga, P.G.J.D.; Dananjaya, P.D.H.; Edirisinghe, E.A.C.P.; Alwis, M.D.N.; Daranagama, D.A.; Dahanayake, J.N.; Kadigamuwa, C.C.This study is focused on determining the efficacy of natural compounds present in Zingiber officinale methanolic plant extraction in controlling seed-born fungal pathogens Aspergillus flavus and Rhizopus oryzae. The maximum percentage inhibition of 94.01% and 90.43% was reported against. A. flavus and R. oryzae respectively for the crude extract in the poison food agar method. These results were further confirmed by computational investigation. [4]-gingerol, [6]-gingerol, [8]-gingerol, [10]-gingerol, and [6]-dehydroginger phytochemicals identified in the extract were docked to the active sites in chitin synthase from A. flavus and squalene epoxidase from A. flavus and R.oryzae, and to the RNA dependent RNA polymerase (RdRp) enzyme from R. oryzae. The highest binding energy (BE) (-8.12 kcal/mol) was noticed between the interactions of squalene epoxidase and [6]-dehydroginger, and this complex was subjected to Molecular Dynamic (MD) analysis. MD simulations were performed on protein-ligand complexes for 10 ns using CHARMM36 force field. The mean radius of gyration (Rg), root mean square deviation (RMSD), and root mean square fluctuation (RMSF) were calculated and hydrogen bond analysis (HBA) was also performed. Rg and RMSD results indicated the stability of the protein-ligand complex throughout the simulation time.Item Antioxidant, anti-inflammatory, and antimicrobial actions of Paspanguwa: A decoction of traditional five medicinal herbal mixture(Society for Conservation and Resource Development of Medicinal Plants, 2023) Madushani, H.M.R.; Jayawardena, P.A.S.N.P.; Kadigamuwa, C.C.The name ‘Paspanguwa’ term comes from a combination of five primary herbs Zingiber officinale, Hedyotis corymbosa, Solanum xanthocarpum, Coscinium fenestratum, and Coriandrum sativum. In the present study, water extracts of the individual ingredient and the Paspanguwa decoction were screened for their total soluble phenolic (TPC) & flavonoid (TFC) contents, DPPH radical scavenging activity, and their ability to inhibit protein denaturation. Furthermore, this study focuses on the evaluation of antibacterial and antifungal activities against selected bacterial, and fungal strains. The highest TPC and TFC were seen in C. sativum as 12.76 (± 1.00) μg gallic acid equivalent/g dry weight, and S. xanthocarpum as 778.19 ± 1.40 μg catechin equivalent/g of dry weight respectively. The highest IC 50 value for the DPPH assay and reducing power percentage were seen in S. xanthocarpum as 609.7 (± 5.6) μg/mL and C. sativum as 22.95 (± 0.96) respectively. The ability to inhibit protein denaturation varied in the order of Paspanguwa decoction > Z. officinale > C. sativum > C. fenestratum > S. xanthocarpum > H. corymbosa at all three concentrations (625, 1250, and 2500 μg/mL). According to the agar disk diffusion method, the aqueous extracts derived from coriander 0.7 (± 0.1) cm and Paspanguwa mixture 0.7(± 0.1) cm had shown antibacterial potentials only against Staphylococcus aureus bacterial strain. When it comes to antifungal effects, only favourable results were achieved against Candida albicans due to the antifungal activity of ginger 0.8 (± 0.1) cm and Paspanguwa mixture 0.7(±0.1) cm. These results suggest that Paspanguwa water extract is a good source of antioxidants with TFC and TPC with a higher ability to inhibit protein denaturation, but it is not effective in antimicrobial activities.