https://ir.kdu.ac.lk/handle/345/6289 2026-04-21T23:43:01Z 2026-04-21T23:43:01Z Kumarasinghe, HS Gunathilaka, TL Jayasooriya, PT Ranasinghe, P Peiris, LDC Samarakoon, KW https://ir.kdu.ac.lk/handle/345/6497 2023-07-06T06:34:12Z 2022-09-01T00:00:00Z

Comparison of Phytochemicals and Antioxidant Activity of the Polysaccharide and de-polysaccharide Methanol Extracts of Brown Seaweed Chnoospora minima Kumarasinghe, HS; Gunathilaka, TL; Jayasooriya, PT; Ranasinghe, P; Peiris, LDC; Samarakoon, KW Chnoospora minima is a brown alga enriched with unique bioactive compounds which are ideal candidates for pharmaceutical, cosmeceutical and nutraceutical industries. During this study, C. minima was extracted using 80% methanol and de-polysaccharide crude methanol extract was obtained by ethanol precipitation followed by separation of the polysaccharide portion. The crude methanol extract of C. minima and its fractions were subjected to analyse phytochemicals and antioxidant activities. For the assessment of radical scavenging activity, DPPH, FRAP, ABTS+, and ORAC assays were conducted. Ethyl acetate fractions of both polysaccharide (IC50:0.67 ± 0.01 mg/mL) and depolysaccharide (IC50:0.59 ± 0.015 mg/mL) crude methanol extracts exhibited DPPH radical scavenging activity in terms of antioxidant activity. Similarly, the highest level of ORAC, FRAP, and ABTS+ activity was observed in the ethyl acetate fractions of de-polysaccharide (ORAC:19.73 ± 5.31 mg TE/g; FRAP: 20.34 ± 1.72 mg TE/g; ABTS+: 0.06 ± 0001 IC50(mg/ml)) and polysaccharide crude methanol extracts (ORAC:16.22 ± 4.31 mg TE/g; FRAP: 19.23 ± 1.98 mg TE/g; ABTS+:0.08 ± 0.002 IC50(mg/ml)). High TPC was observed in the depolysaccharide crude methanol extract (298.07 ± 0.003 mg GAE/g) and aqueous fraction (141.2 ± 0.002 mg GAE/g) of the polysaccharide crude methanol extract. Highest TFC was observed in both aqueous fractions of depolysaccharide (594.23 ± 0.001 mg QE/g) and polysaccharide (113.46 ± 0.001 mg QE/g) crude methanol extracts. Chloroform fractions exhibited the highest TAC for polysaccharide (2.20 ± 0.45 mg PE/g), and depolysaccharide (2.79 ± 0.31 mg PE/g) samples. Therefore, the depolysaccharide C. minima sample exhibited high level of antioxidant activity along with a high content of phytochemicals which can further be utilized to determine bioactivities that lead to future drug development.

2022-09-01T00:00:00Z Thaha, FH Bandaranayake, UE https://ir.kdu.ac.lk/handle/345/6496 2023-07-06T06:29:21Z 2022-09-01T00:00:00Z

Evaluation of the Antibacterial Activity of Miswak (Salvadora persica) and Persian Lime (Citrus latifolia) Extracts Against Escherichia coli and Staphylococcus aureus Thaha, FH; Bandaranayake, UE Despite advances in medicine, the phenomenon of emerging drug resistance provokes novel research on active botanical compounds and alternative therapy development. Bioactive compounds present in plants possess potent antibacterial properties. The current study aims to evaluate and compare the antibacterial activity between miswak (Salvadora persica) and Persian lime (Citrus latifolia) extracts, a novel combination. Miswak sources unique phytochemicals, making it a superior tool for oral hygiene, while the volatile oil harbored within lime is traditionally used as a flavoring and cosmetic agent. Crude extraction of phytochemicals was done via cold maceration, employing polar solvents methanol and ethanol. Varying concentrations (150 mg/mL and 200 mg/mL) of extracts were subjected to antibiotic susceptibility testing (ABST) using agar well diffusion, while gentamicin and vancomycin served as the positive controls. Both Escherichia coli and Staphylococcus aureus exhibited susceptibility toward all extracts that were assayed. Triplicate readings were statistically analyzed using twoway analysis of variance (ANOVA) and student’s t-test with 95% confidence interval (p≤0.05). Mean zones of inhibition (ZOI) varied, ranging from 10.7±0.6 mm to 13.7±0.6 mm for miswak and 16.7±0.6 mm to 19.7±1.2 mm for lime. Methanolic lime of 200 mg/mL (M/L2) demonstrated a pronounced ZOI against E. coli (19.7±1.2 mm), proving its supremacy over miswak. Upon further testing, lime extracts displayed a minimum inhibitory concentration (MIC) at 12.5 mg/mL and a minimum bactericidal concentration (MBC) at 25 mg/mL. Nonetheless, based on overall results, both miswak and lime extracts serve as potential candidates that can be developed into therapeutic drugs in the phytopharmaceutical industries.

2022-09-01T00:00:00Z Wijesuriya, ND Rathnayake, AMSI Wijesundera, WSS Thoradeniya, ST https://ir.kdu.ac.lk/handle/345/6495 2023-07-06T06:22:48Z 2022-09-01T00:00:00Z

Selection of RNA Aptamers to Distinguish the V600E Mutation Status of BRAF Protein: A Potential in silico Approach Wijesuriya, ND; Rathnayake, AMSI; Wijesundera, WSS; Thoradeniya, ST The valine to glutamate substitution at the 600th residue of B-type rapidly accelerated fibrosarcoma protein (BRAF V600E) is the most common mutation in the BRAF gene. Due to its high prevalence in a number of cancers, development of efficient diagnostic and prognostic assays and therapeutics is essential for their management. Aptamers have become promising candidates in a variety of biomedical applications due to many favourable properties. However, no aptamers have been experimentally determined that can distinguish the V600E mutation status of the BRAF protein. Therefore, this study was conducted to create an initial knowledge-base for in silico design of aptamers for wild-type and mutant (V600E) BRAF (mutant BRAF) proteins. It was achieved using molecular docking employing HADDOCK 2.4 web server. In the absence of aptamers for BRAF, five RNA aptamers targeted to the activation loop of ERK 1&2 proteins were selected for docking, considering the similarity of the 3D structure of the kinase domains of the above proteins to BRAF. Docking was done for ten protein-aptamer combinations (five aptamers with wild-type BRAF and mutant BRAF). Three complexes were selected based on the HADDOCK score and their intermolecular hydrogen bonds and salt bridges were determined. Three aptamers obtained negative HADDOCK scores signifying they presumably target the activation loop of wild-type and mutant BRAF. Considering the total of intermolecular hydrogen bonds and salt bridges, Aptamers_1 and 3 (Apta-Index IDs: 481 and 263) would preferably bind with wild-type and mutant BRAF, respectively. They have a potential to be used as starting structures in the in-silico aptamer modeling workflow for wild-type and mutant BRAF proteins.

2022-09-01T00:00:00Z Sandaruwani, IBI Abeygunawardana, RAB https://ir.kdu.ac.lk/handle/345/6494 2023-07-06T06:17:06Z 2022-09-01T00:00:00Z

A Comparison of Classical Time Series Models and Machine Learning LSTM Model to Forecast Paddy Production in Sri Lanka Sandaruwani, IBI; Abeygunawardana, RAB The most common & effective traditional methods of univariate time series forecasting are Autoregressive Integrated Moving Average (ARIMA) family models and Exponential Smoothing family models. With the recent advancement in more advanced machine learning algorithms and approaches such as Long-Short-Term-Memory modeling approaches, new algorithms are developed to analyze and forecast time series data. The objective of the study is to identify the best time series forecasting model among classical time series models and machine learning LSTM model to forecast the annual paddy production of Sri Lanka. Based on the RMSE, MAE and MAPE values, the results showed that the estimated error of ARIMA & Double Exponential Smoothing (DES) models are much higher than the estimated error of chosen LSTM model. Hence LSTM model outperforms to the traditional-based algorithms like ARIMA and smoothing models for forecasting the paddy production of Sri Lanka. The forecasts for paddy production from 2022 to 2024 were 4.92, 4.89 and 5.34 million Mt respectively. This model can be used by researchers for forecasting paddy production in Sri Lanka and it should be updated continuously with incorporation of recent data.

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