DSpace 7

DSpace is the world leading open source repository platform that enables organisations to:

easily ingest documents, audio, video, datasets and their corresponding Dublin Core metadata
open up this content to local and global audiences, thanks to the OAI-PMH interface and Google Scholar optimizations
issue permanent urls and trustworthy identifiers, including optional integrations with handle.net and DataCite DOI

Join an international community of leading institutions using DSpace.

The test user accounts below have their password set to the name of this software in lowercase.

Demo Site Administrator = dspacedemo+admin@gmail.com
Demo Community Administrator = dspacedemo+commadmin@gmail.com
Demo Collection Administrator = dspacedemo+colladmin@gmail.com
Demo Submitter = dspacedemo+submit@gmail.com

Photo by @inspiredimages

Communities in DSpace

Select a community to browse its collections.

Now showing 1 - 5 of 5

Recent Submissions

Multi-target inhibitory activity of Salicornia brachiata and Suaeda maritima seed on α-amylase, tyrosinase and lipase
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2023-11-03) Herath, H.M.N.P.; Perera,D.; Jayasinghe, L.; Attanayake,R.N.; Paranagama, P.A.
Diabetes mellitus is a complex metabolic disorder that involves enzymes like α-amylase, tyrosinase, and lipase. Since currently used antidiabetic drugs have undesirable contraindications, plant metabolites, particularly seed-based metabolites, has gained special attention in scientific research as a promising source of enzyme inhibitors. With previous reports of promising activities of Salicornia brachiata and Suaeda maritima, this study aimed to explore the enzyme inhibition potential of extracts derived from the seeds of these two halophytic plant species. The seeds were sequentially extracted using hexane, dichloromethane (DCM), and methanol by cold maceration and tested for in-vitro inhibitory activity against αamylase, tyrosinase, and lipase. The extracts of S. brachiata and S. maritima seeds effectively inhibited α-amylase activity by 52-83% and 18-73%, respectively, at 0.2 mg mL⁻¹. The hexane fraction of S. brachiata showed 83.50 ± 1.09% (at 0.2 mg mL⁻¹) inhibition activity that was not significantly different from the inhibition activity of acarbose, the positive control (at 0.2 mg mL⁻¹ 84.23 ± 0.88%; p=0.05). It is reported that inhibiting this enzyme slows carbohydrate digestion, lowering postprandial glucose levels. DCM fraction of S. brachiata and S. maritima seeds showed tyrosinase inhibitory activity of 57.90 ± 0.84% and 17.80 ± 0.94%, respectively, at 0.2 mg mL⁻¹, whereas Kojic acid, the positive control had an inhibitory activity of 86.00 ± 0.43% (at 0.2 mg mL⁻¹). Since tyrosinase inhibitors are directly involved with melanin biosynthesis, the findings are useful in managing hyperpigmentation caused by oxidative stress in diabetic patients. Moderate inhibition of lipase was observed in the hexane and methanol extracts of S. brachiata seeds (33-38%, at 0.4 mg mL⁻¹), while the DCM fraction showed activity of 54.39 ± 3.40% at 0.4 mg mL⁻¹, comparable to orlistat (60.83 ± 0.22%, at 0.4 mg mL⁻¹ ), the positive control. The three extracts from S. maritima seeds exhibited 36-43% (at 0.4 mg mL⁻¹) inhibition towards lipase, which is important for managing fasting glucose and insulin levels and reducing the risk of obesity-related type 2 diabetes. The obtained results prompt a preliminary conclusion towards the potential use of S. brachiata and S. maritima seeds as multitarget enzyme inhibitors for the modulation of metabolic diseases such as diabetes and associated complications.
Model validation of cu(Ⅱ)- kaolinite systems by in-situ measurement of free metal ion activities
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2023-11-03) Mudannayake, N.; Heenkenda, K.; Weerasooriya, R.
Surface complexation modelling methods are extensively used to quantify the chemical speciation at the mineral-water interface. However, the input parameters are often not uniquely defined. In 1-pK modelling of metal ions adsorption, the basic Stern layer model (1-pK SLM) calculations require six parameters, viz., specific surface area, site density, inner and outer layer capacitance, and intrinsic acidity/binding constants. The number of input parameters by introducing free Cu²⁺ ions as an observation to determine its binding constants was reduced by 1-pK SLM. The copper selective electrode (Cu-ISE) was calibrated using ethylenediamine/Cu²⁺ metal ions buffer to extend the Nernstian Cu²⁺ detection limit to 10-15 M. Spectral data also suggests bidentate complexation of Cu²⁺ with =AlOH⁻⁰‧⁵ and ion exchange complexes between Cu²⁺ and ≡Si-OH sites as follows, ={AlOH}₂Cu⁺ pK = -2.8, (≡SiO₂)Cu⁰ pK= - 8.4 and (--X)₂Cu pK = -2.02. The ISE measurements of free Cu²⁺ seem to interfere with the presence of CuOH⁺, particularly when the solution is pH > 7.0. When the analytical data are corrected for CuOH⁺ interference, the measured {Cu²⁺} of the Cu-kaolinite system is predicted well with 1-pK SLM modelled data. Using this method, the number of input parameters reduced to five while simulating Cu²⁺ - kaolinite interface processes reasonably well is considered a novel method concerning the experiment results. Quantifying chemical speciation at mineral-water interfaces could be done using consistent parameters with reference to the above experiment.
Removal of magnesium ions by functionalized carbon nanotube
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2023-11-03) Kirushnah, A.B.; Sivanayani, S.
Functionalized carbon nanotubes (CNTs) have been extensively studied for various applications, including environmental remediation. One such application is the removal of magnesium ions (Mg2+) from water. The physicochemical characteristics of carbon nanotubes make them suitable for ion adsorption. The functionalization of carbon nanotubes involves modifying their surface properties by attaching different functional groups or molecules to enhance their performance. Magnesium can be removed from water through various treatment processes. In specific industrial applications, such as manufacturing or chemical processes, magnesium in water becomes necessary to ensure the quality and functionality of the products or processes. Carbon nanotubes were synthesized from camphor by chemical vapour deposition at 700 °C.. Carbon nanotubes were characterized and confirmed with SEM, PXRD, Raman spectroscopy, and UV-Vis spectroscopy. Carbon nanotubes thus synthesized were functionalized with carboxylic and hydroxyl groups by using KMnO₄ solution, characterized and confirmed by using FT-IR analysis. The magnesium removal efficiency of functionalized carbon nanotube was examined with different concentrations of magnesium solution such as 1000, 800, 600, 400, and 200 mg L⁻¹ showed removal efficiency 28.3%, 33.4%, 35.5%, 45%, and 57.5%, respectively. Further, it showed increased efficiency with the increased amount of functionalized carbon nanotubes.
Determination of brine shrimp lethality of different solvent extracts of soft stems of different banana (Musa sp.) cultivars
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2023-11-03) Liyadipitiya, L.R.M.K.N.; Marikkar, J.M.N.; Jayasinghe, U.L.B.
Banana stems are a waste product once the fruit bunches are harvested, and they have also lost their significance among the current generation due to the lack of awareness of their values. In this study, the soft stems of the Ambulkesel, Seenikesel, Suvandel, and Alukesel cultivars of the Musa sp. (banana plant) were investigated for their brine shrimp lethality effect against Artemia salina nauplii. Powdered soft stems of four cultivars were sequentially extracted with dichloromethane (DCM), ethyl acetate (EtOAc), and methanol (MeOH). The crude extracts were tested for brine shrimp lethality (BSL) using A. salina nauplii of the second instar. This work used seawater and 1% dimethyl sulphoxide (DMSO) as the negative control and potassium dichromate (K₂Cr₂O₇) as the positive control. The soft stems of four banana cultivars showed moderate toxicity (LD₅₀ ˂ 2000 mg L⁻¹) toward A. salina, according to the results of the BSLA, while the overall lethality percentage was discovered to be dose-dependent of the crude extract within the chosen range of 62.5–2000 mg L⁻¹. The toxicity properties of DCM, EtOAc, and MeOH extracts of these soft stems showed LD50 values ranging from 891.1-1071.4 mg L⁻¹, 1246.8-1428 mg L⁻¹, and 696.5-822.2 mg L⁻¹, respectively. The DCM crude extracts of banana soft stems of the Ambulkesel, Seenikesel, and Alukesel cultivars and the MeOH extracts of all four cultivars showed toxic activity against the second nauplii of A. salina in accordance with literature, that classified crude extracts and pure substances into toxic (LD₅₀ value 1000 mg L⁻¹) and non-toxic (LD₅₀ > 1000 mg L⁻¹). The BSL assay showed that the most active fraction is the methanol fraction of the Seenikesel cultivar, with an LD₅₀ value of 696.5 mg L⁻¹ . Compared to potassium dichromate, DCM and MeOH extracts of four cultivars displayed moderate toxicity against A. salina. No lethality percentage was detected in the negative control. The LD₅₀ values of soft stems of banana plant extracts to brine shrimps indicate the presence of potent components, which will be explored further.
Assessment of cytotoxicity of selected edible leafy plants of Sri Lanka
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2023-11-03) Ulpathakumbura, B.S.K.; Marikkar, J.M.N.; Jayasinghe, U.L.B.
This study was carried out to assess the cytotoxicity of extracts of leafy plants, namely Premna procumbens Moon (Le-kola pala: LE), Memecylon umbellatum (Kora kaha: KK), Polyscias scutellaria Fosberg (Koppa: KO), Stevia rebaudiana Bertoni (Stevia: ST) and Atlantia ceylanica (Yaki naran: YK) using brine shrimp (Artemia salina) lethality bioassay. According to traditional knowledge, these plants may be believed to have medicinal properties. However, scientific evidence is scarce on their biological properties. Therefore, these plants were selected to assess their cytotoxic property. Plant leaves were sequentially extracted with hexane, ethyl acetate (EtOAc), and methanol (MeOH) as solvents. Brine shrimp eggs were hatched and the active nauplii were used in the bioassay. The cytotoxicity of plant extracts was reported as lethal concentration (LC₅₀). A concentration series (62.5-2000 mg L⁻¹) of crude extracts was prepared by dissolving the crude plant extracts in artificial seawater. Ten active nauplii were added to each 1 mL of extract in 24 well semi microplate and kept at room temperature for 24 h under illumination. The lethal concentration (LC₅₀) was determined by counting surviving nauplii after 24 h. Among hexane extracts, the strongest cytotoxicity was observed for YK (LC50 = 190.98 ± 4.92 mg L⁻¹), while KO and ST showed moderate cytotoxicity with LC₅₀of 500.00 ± 0.00 mg L⁻¹ and 1724.70 ± 80.65 mg L⁻¹, respectively. No cytotoxicity was observed for hexane extract of LE and KK. Among EtOAc extracts, the strongest cytotoxicity was displayed by YK (LC₅₀ = 234.18 ± 13.79 mg L-1), while lower cytotoxicity potential was observed for KO and ST. EtOAc extracts of LE and KK did not show any cytotoxicity. All MeOH extracts showed moderate to weak cytotoxicity. Among them, the strongest activity was observed for KO (LC₅₀ =486.16 ± 30.23 mg L⁻¹). When compared with all plant extracts, the positive control (K₂Cr₂O₇) showed significantly (p < 0.05) higher cytotoxic activity (LC₅₀ = 14.62 ± 0.87 mg L⁻¹). This study concludes that YK and KO have higher cytotoxicity when compared to other leafy plants. Therefore, YK and KO maybe sources of anti-cancer compounds and can have the potential to be used to develop drugs against cancers.