Symposia & Conferences
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Item Enhancing the water solubility of curcumin by encapsulating in Carrageenan using excipients(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Weerasinghe, N. N.; Jayathilake, N. S.; Perera, A. D. L. C.; Jayasinghe, S.Curcumin is a polyphenolic compound known to alleviate several ailments and can be used as a drug. However, its practical application as a nutraceutical/drug is limited due to problems such as high hydrophobicity, high photosensitivity, and low bioavailability. Therefore, encapsulation of curcumin into nanoparticle (NP) carriers has been developed to increase the aqueous (physiological) solubility of curcumin. Carrageenan, a natural polysaccharide, is widely used in the formulation of nanoparticles as a controlled-release drug delivery system. In this study, a water-soluble product was developed by encapsulating curcumin in a carrageenan matrix using surfactant excipients (Tween 20 & Tween 80). Encapsulation provides protection to drugs against physiological degradation and ensures effective release at targeted sites. The role of the surfactant excipients is to help increase the water solubility and the stability of the particles. Curcumin-encapsulated carrageenan nanoparticles were prepared via the ionic gelation method, varying the mass of the curcumin, the mass of the carrageenan, and the type of excipient used. A water solubility test for NPs was conducted to evaluate the solubility of NPs in water. The average particle sizes of the NPs were obtained as 470.4 nm. The highest encapsulation efficiency of curcumin-encapsulated carrageenan NPs was calculated as 90% for NPs prepared using both excipients. In-vitro release studies were performed on the drug-loaded NPs and the results showed that the release was pH dependant and had a high release (50%-60%) of curcumin in intestinal fluid compared to free curcumin. Confirmation of successful encapsulation and characterisation of the curcumin-encapsulated carrageenan NPs was carried out using fourier transform infrared spectroscopy (FTIR) analysis. The stability of the NPs against photodegradation and thermal degradation was checked using the accelerated shelf life method. Scanning electron microscope (SEM) images of both nanoparticles prepared using both excipients displayed a nearly spherical shape. These empirical data proved that newly formulated NPs could preserve the activities of curcumin and hence could be used in functional food production to increase the nutritional value without changing texture and colour. Also, this study successfully demonstrated that even though the hydrophilic–lipophilic balance (HLB) values of tween 20 (16.7) and tween 80 (15.0) are different, both are equally effective in enhancing the solubility, encapsulation efficiency, and stability of curcumin-loaded carrageenan NPs. Future studies could investigate the scalability of the nanoparticle formulation process for industrial applications and explore the potential of combining these NPs with other bioactive compounds to develop multifunctional delivery systems.Item Developing a natural fungicide from O/W Emulsion using essential oils and MgO nanoparticles(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Wewalage, I. U.; Perera, A. D. L. C.; Jayasinghe, S.For the farmers and cultivators to boost their crop yield in cultivation, preventing fungal attacks is an indispensable measure. In Sri Lanka as well as worldwide, vegetable and fruit cultivation and also ornamental plant cultivation are being extensively attacked by diseases like powdery mildew, downy mildew, grey mold, black spot disease, early blight disease, late blight diseases, etc., which are caused by fungal pathogens. Here in, a Pickering emulsion (PE) was formulated using trace amounts of magnesium oxide (MgO) nanoparticles (NPs) and cinnamon leaf (CL) oil as a natural fungicide. MgO NPs were synthesised by the sol-gel method using magnesium chloride (MgCl2) and sodium hydroxide (NaOH). The experimental yield of MgO NPs was achieved as 73.8%. The PE was formulated by mixing CL oil, deionised water and MgO NPs to get a homogeneous mixture. A polysorbate 80 emulsifier was used to enhance the stability of the emulsion. The most suitable emulsion system was comprised of 20% CL oil and 80% deionised water by mass percentage, and it was doped with 50 mg of MgO NPs to achieve a total mass of 50 g. To check the efficacy of the formulated PE, an antifungal susceptibility test was conducted against the fungus Aspergillus niger, a widely used model organism. Based on the inhibition zones, it was determined that the 1:10 dilution of the formulated PE exhibits the Minimum Inhibitory Concentration (MIC) required to inhibit the growth of the fungus Aspergillus niger, relative to the known positive standard, Fluconazole, at a concentration of 15,000 ppm. In the field, the diluted emulsion should be sprayed on the crops once every five days to get the best results. This method provides a natural and effective solution for managing fungal infections in cultivation, potentially leading to increased crop yields and healthier plants. A unique application for sustainable agriculture is offered by the combination of MgO NPs and CL oil in PE, which act as natural antifungal agents to lessen the need for synthetic fungicides. Future directions could investigate the feasibility of commercialising emulsion, particularly aimed at identified plant fungal pathogens, by integrating economically viable essential oilsItem Comparative desorption efficiency of Cd(II) and Pb(II) from used plasma-functionalized coconut coir biochar(Faculty of Science, University of Kelaniya Sri Lanka, 2024) De Alwis, B.; Rathnayake, I.; Munaweera, I.; Perera, A. D. L. C.; Jayasinghe, S.This study investigates the desorption of Cadmium (Cd(II)) and Lead (Pb(II)) ions from used plasmafunctionalized coconut coir biochar (PBC), a process crucial for wastewater treatment. The improper disposal of used adsorbents laden with Cd(II) and Pb(II) contributes to environmental pollution, making this research significant. Coconut coir biochar (BC) was prepared using coconut coir dust via pyrolysis at 500 °C for 3 h under controlled N2 environment. The BC was subjected to atmospheric air plasma treatment (AAPT) for 30 min to produce PBC. Both BC and PBC were characterized using Fourier Transform Infrared Spectroscopy (FTIR), point of zero charge (pHPZC), methylene blue (MB) and iodine number, moisture and ash content. The quantitative analysis was performed using a flame atomic absorption spectrometer (FAAS). At pH 7, PBC adsorbs 130.00 mg g-1 of Cd(II) from a 250 ppm solution, and at pH 5, it adsorbs 80.97 mg g-1 of Pb(II) from a 500 ppm solution within 1 minute. In comparison, BC shows lower adsorption capacities of 96.00 mg g-1for Cd(II) and 50.01 mg g-1for Pb(II) under the same conditions. Desorption experiments were conducted using 25.0 mg of Cd(II) and Pb(II) adsorbed BC and PBC, which were shaken with HNO3 as the desorbing agent at 30 °C. The pH and contact time were optimized to evaluate the maximum desorption capacity of both BC and PBC. The maximum desorption capacity of Pb(II) for PBC was 73.80 mg g-1 within a contact time of 15-minute and for Cd(II), it was 8.91 mg g-1 under the optimum conditions of pH 1 and 1-minute contact time. For BC maximum desorption capacity of Pb(II) was 47.63 mg g-1 with a 30-minute contact time and for Cd(II), it was 8.54 mg g-1 under the pH 1 and 1-minute contact time. The desorption percentage from the adsorbed amount was 91.14% for Pb(II) and 6.85% for Cd(II) for PBC. For BC, it was 95.24% for Pb(II) and 8.83% for Cd(II). These results highlight the potential of PBC as an efficient adsorbent for the remediation of Pb(II) and Cd(II) in wastewater, demonstrating high efficiency in Pb(II) desorption but limited efficiency in Cd(II) desorption.Item Synthesis of C-11 and C-12 oxidized derivatives of3β-[(α-Larabinopyranosyl)oxy]olean-12-en-28-oic acid and evaluation of their cytotoxic activity in human non-small cell lung cancer (NCI-H292) cells using Sulforhodamine B assay(Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Jayasundara, J.M.J.; Wickramasinghe, A.; Karunaratne, D.N.; Wickramaratne, N.S.; Samarakoon, S.R.; Jayasinghe, S.The most common cancer, lung cancer is the foremost reason for cancer deaths in both males and females throughout the world. The two major categories of lung cancer which propagate differently are Non-small cell lung cancer (NSCLC) and Small cell lung cancer (SCLC). Among those NSCLCs are the most prevalent lung cancers, contributing 80% of all lung cancers. Natural products represent the bedrock of drug discovery, providing novel scaffold structures that serve as a starting point for developing novel therapeutic agents. A number of new drugs with improved therapeutic potential have been obtained from natural sources, by functional group modifications or by the synthesis of new compounds, following lead natural compounds as models. The recurrence of cancer due to the drug resistance and undesirable side effects which have limited the use of anticancer drugs, have increased the demand for novel alternative therapeutics with enhanced pharmacological activity and fewer side effects. Hence, the synthesis of natural product derived compound libraries in the discovery of novel drugs is still a key aspect of cancer therapy. 3β-[(α-L-arabinopyranosyl)oxy]olean-12-en-28-oic acid (APOA) is a triterpenoid saponin with the oleanolic acid aglycone linked to arabinopyranose sugar moiety and can be easily isolated from endemic plant extracts of genus Schumacheria. This compound exerts potent cytotoxic and apoptotic potential in human NSCLC cells (NCI-H292) with an IC50 value of 5.977 μgmL-1 while exhibiting a comparable toxicity value (IC50 = 5.702 μgmL-1 ) against normal lung (MRC-5) cells. The objective of this study was to synthesize oxidized structural analogues at C-11 and C-12 positions of the APOA and to evaluate their cytotoxic effect. Sulforhodamine B (SRB) assay is used to evaluate in-vitro cytotoxic efficacy of the synthesized analogues on NCI-H292 cells and MRC-5 cells. The methylene group at the C-11 and methine group at C-12 of the ethyl ester of acetylated APOA (Ee-Ac-APOA) was oxidized to afford respective ketones and followed by deacetylation of the afforded analogues resulted in the oxidized analogues with free sugar hydroxyls (Ee-APOA). Chemical structures of the synthesized analogues were confirmed with spectroscopic data and comparative cytotoxic effects of the synthesized analogues were assessed using SRB assay against APOA. GraphPad Prism 7.00 software was used for statistical analysis and the results indicated that the oxidized analogues of Ee-APOA exhibit higher cytotoxicity against NCI-H292 cells than the oxidized derivatives of Ee-Ac-APOA while exhibiting comparable toxicity values against normal lung (MRC-5) cells. However, the α, β-unsaturated derivative of Ee-Ac-APOA exhibited potent cytotoxic activity against NCI-H292 cells while being less toxic to normal MRC-5 cells compared to the parental saponin indicating better activity. These empirical data suggest that the oxidized compounds at C-11 and C-12 of APOA could be a lead to develop promising new anticancer agents.Item Determination of antibacterial activity of 6β-hydroxybetunolic acid and interaction with oxacillin(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Wickramasingha, W. G. D.; Jayasinghe, S.; Karunaratne, D. N.; Liyanapathirana, V.; Ekanayake, A.; Karunaratne, V.Various strides have been undertaken with successful results in the treatment and cure of significant number of bacterial infections. However, many bacteria are becoming resistant to some of the prevailing drugs due to either the misuse or the prolonged use of the available antibiotics increasing the necessity for discovering new antibiotics to combat resistant microorganisms. Plants and their secondary metabolites can be considered as good sources of scaffolds to provide structurally diverse bioactive compounds as potential therapeutic agents and combination of them with standard antibiotic to obtain synergistic effect. The objective of this study was to determine the antibacterial activity of one of a lupeol type triterpenoid (6β-hydroxybetunolic acid) isolated from the bark of Schumacheria castaneifolia Vahl. which is an endemic plant to Sri Lanka and to determine the synergistic effect with Oxacillin. Antimicrobial activity of 6β-hydroxybetunolic acid was evaluated utilizing micro broth dilution assay in 96 well plates against two standard strains of Staphylococcus aureus, 4 strains of clinically isolated Methicillin resistant S. aureus, standard strains of Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, carbepenemas producing Kebsiella pneumonia and carbepenemas non-producing Kebsiella pneumonia and four strains of clinically isolated Acinetobacter sp. Synergistic effect of the combination of 6β-hydroxybetunolic acid and Oxacillin was tested against Standard strain of S. aureus and MRSA using checker board method. Results revealed that 6β-hydroxybetunolic acid shows significant antibacterial activity only against the Gram positive strains; MIC values of S. aureus (ATCC 29213), S. aureus (ATCC 29213), E. faecalis (ATCC 29212) and four MRSA strains were 32, 16, 32, 32, 32, 32, 16 ppm respectively. However MIC value of Oxacilin against S. aureus (ATCC 29213) was 0.25 ppm. 6β-hydroxybetunolic acid has synergistic effect with Oxacillin against S. aureus and additive effect against all the tested MRSA. These results concluded that the antibacterial activity of 6β-hydroxybetunolic acid is predominantly depending on the cell wall difference of the bacteria.