Browsing by Author "Wijesekara, K.B."
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Item Anticoagulant activity, antibacterial activity and toxicity effect of selected plant in Asteracea family(Uva Wellassa University of Sri Lanka, 2015) De Silva, H.S.U.; Wijesekara, K.B.; Premathilake, S.N.Traditional herbal medicine is used for maintain the health of people since ancient time. Herbal medicinal related drugs are safe and have fewer side effects. Due to that reason the usage of herbal medicine is popular in all around the world. Medicinal plants play major role in various types of medicinal activities (Ramya et al., 2009). Among those treatments medicinal plants have the wound healing activity and anticoagulation activity. Plants have the ability of management and treatment of wounds due to its antibacterial activity (Ukwueze et al., 2013). Various types of plant have the ability of anticoagulation and such plants claimed in the traditional system still remain to be scientifically investigated (Narjis, 2013). Among such medicinal plants Emilia sonchifolia, Ageratum conyzoides and Mikania micrantha have various medicinal activities. At the same time Emilia sonchifolia, Ageratum conyzoides and Mikania micrantha show some toxicity effect. Due to that reason it is necessary to identify toxic effect of these plants. Zebrafish eggs are used in toxicological and pharmacological activities due to its small size of fish and transparency of eggs and embryos. Changes in the morphology of development of zebrafish embryos can easily observed. Due to that reason zebrafish eggs is used as a toxicological model to test toxic effect of these three plants (Rahman et al., 2012). The aim of this research is to formulate and evaluate the antibacterial activity against Staphylococcus aureus which is one of the major wound infective pathogen, anticoagulation activity and toxicity effect of these three plants. Methodology Plants were collected from university premises with the consideration of environmental conditions. Powdered plant materials were extracted with methanol, using Soxhlet apparatus at a controlled temperature. The extracts were concentrated to dryness under reduced pressure using rotary vacuum evaporator at 40°C. Various concentration of extract solution were prepared using stock solutions. Agar well diffusion method was used to test antibacterial activity. MIC was determined for extracts lowest concentration that showed more than or equal 7 mm diameter growth inhibition zone. Prothrombin Test (PT) was used measure coagulation time for test anticoagulation activity. Zebrasfish eggs were used as toxicological model for test toxic activity of three plants. Results and Discussion Highest amount of plant extract were showed by leaves part of each plant while roots were given lowest amount of plant extracts.Item Antimicrobial Activity of Ageratum conyzoides against Staphylococcus aureus(Uva Wellassa University of Sri Lanka, 2013) Dilrukshi, P.A.D.M.; Premathilake, S.N.; Wijesekara, K.B.Ageratum conyzoides is a native annual branching herb, which grows to approximately 1 m in height and usually found open and abandoned areas . This plant is commonly used in traditional medicine, especially for wound healing (Sing et al., 2012). Methodswhich are usedinhealing wound infections include debridement, antibiotics, tissue grafts and proteolytic enzymes. However, these methods have major drawbacks and unwanted side effects. Recently there is a tendency towards the uses of traditional medicines as it shows the better cultural acceptability and better compatibility with the human body and also fewer side effects (Parekh et al., 2005). Fresh plant materials of A.conyzoides were collected and washed using tap water .Then they were separated into flowers, leaves, roots and stems and were air dried in shade for 7 days and powdered using mortar and pestle. The powdered plant materials were sieved and stored in airtight containers. Plant material extracts were obtained with 95% methanol using the soxhlet apparatus. Each extracts were concentrated and solvents were fully evaporated, by rotary evaporator (150 rpm) at 40 C. The obtained concentrates were transferred to McCarthy glass vials and placed under room temperature for complete dryness. Then they were stored in airtight vials under refrigerated conditions. Staphylococcus aureuspure cultures were collected from the Medical Research Institute (MRI) Colombo and from them liquid cultures were prepared using Nutrient broth. Then they were incubated at 37°C for 24 hrs. The powdered plant materials were measured into separate McCartney bottles and appropriate volume of the extracts were added to make a stock solution of 200mg/mL. Sterile nutrient agar plates were prepared and allowed to solidify. A 0.1 mL of liquid culture of S. aureuswas spread equally on the solidified nutrient agar plate. After one hour five wells were dug in each plates using a sterile cork borer (5mm diameter).Concentration series of extracts (200mg/mL, 100mg/mL,50 mg/mL, 25mg/mL and 12.5 mg/mL) were prepared and from them 0.5mLof extracts were added to wells in appropriately labelled plates. As the control 95% methanol was used. The plates were left on the bench for few minutes for the extract to diffuse into the agar and later incubated at 37°C for 24hours. After the incubation the zone of clearance around each well was measured using a metric ruler by taking measurement of the inhibition zones. Minimum inhibition concentration (MIC) was determined for extracts that showed less than 7 mm(<7 mm) diameter inhibition zone.Item Assessment of Geuda Heat Treatment Using Gas-fired and Electric(Uva Wellassa University of Sri Lanka, 2019) Jaliya, R.G.C.; Dharmaratna, P.G.R.; Wijesekara, K.B.“Geuda” (Al2O3) a variety of corundum gems, has the potential of converting into Blue Sapphires through heat treatment since it contains Fe and Ti as impurities. With high temperatures, Al, Fe, Ti atoms inside the “Geuda” get into excited state provides possibilities to make [FeTi]+6 complex that produces blue colour. Sri Lankan gem industry commonly adapts gas-fired furnaces for heat treading Geuda, yet recently introduced electric furnaces have also shown suitable because gas furnaces are superior to electric ones in achieving the desired colour in finished gems. However, proper investigation hasn’t been done to select the most suitable heating method. This study, the color development of Geuda is investigated under different heat treatment of gas furnace, electric furnace, separately and combination of them. In addition, soaking time and heat regimes are also used to investigate the colour development. Eighteen Geuda Samples were collected from Ratnapura, Niwithigala, Lunugala and Ambalangoda areas and were cut into three equal size pieces, separately. Two pieces were heat treated while keeping the other pieces as the control. Eighteen samples were treated using the gas furnace at 1750 °C for 30 min. Also, electric furnace was used to treat the samples under different temperatures such as 1300 °C, 1500 °C and 1750 °C, separately and 18 samples were treated in each temperature while changing the soaking time such as 3, 7 and 30 days, respectively. Similarly, treated pieces under gas furnace were again treated using the electric furnace under the above conditions. Finally, color changes were analyzed using the GIA color grading system. Color of the samples treated in gas furnace at 1750 °C for 30 min is enhanced than that of the samples treated in electric furnace at 1300°C and 1500 °C temperatures. However, significant colour enhancement is obtained for the samples treated at 1750 °C for 30 days under electric furnace. The best color change is obtained for the samples treated at 1750 °C for 30 days under combine heat treatment method.Item Assimilation of Phosphate Fertilizer derived from Eppawala Rock Phosphate on the Vegetative Growth of Corn (Zea mays L.)(Uva Wellassa University of Sri Lanka, 2016) Rathnayake, R.M.S.R.; Wijesekara, K.B.Phosphorus is one of the most important macronutrient in plant nutrition and wellbeing. Repeated cultivation has caused drastic depletion of nutrients in agricultural lands necessitating routine addition of costly commercial fertilizers to crops. Rock phosphate deposit at Eppawala Sri Lankan, provides a rich source of phosphorus from which phosphate grade fertilizer could be produced by the acidulation with con. HC1. However, pH of the fertilizer is needed to be adjusted to plant tolerable levels to reduce acid toxicity. This research used CaO to adjust pH of rock phosphate derived fertilizer enabling rapid assimilation by plants. Approximately 100 g of the acidified product was added with a predetermined quantity of 3. 7 g of lime to adjust the final pH value to 6.02. XRF analysis was performed to identify the elements of the final fertilizer mixture before and after CaO addition. A pot experiment was performed to determine the assimilation of newly developed fertilizer by corn plants. The experiment was arranged in a complete randomized block design with five treatments and 180 experimental units. Treatments were: Ti- Pants without any amendments, T2-Plants with commercial fertilizers excluding phosphates, T3-Plants with commercial fertilizers including phosphate, T4-Plants with commercial fertilizers+developed fertilizer without pH adjustment, T5-Plants with commercial fertilizers+developed fertilizer with pH adjustment. Plant height, root surface area, biomass at flowering and leaf chlorophyll content were measured to determine the plant performance after fertilization. X-ray fluorescence (XRF) analysis revealed that developed fertilizer contained 11.4% P2O5, 16.5% MgO, 14.9% K20 and 24.3% CaO as major constituents while providing plant with some important micronutrients such as, Mn, Fe, and Zn. Addition of lime was not only resulted in increasing the of pH to plant tolerable levels but also eliminated Cl and some heavy metal contaminants like As and Rh. Growth performance of T5 plants indicated that phosphate from developed fertilizer had readily assimilated by Corn plants. However, the commercial triple superphosphate used to supplement T3 plants showed significantly higher (p=0.00) performance over T5 plants. T4 plants supplemented with fertilizer without pH adjustment died prematurely while T5 plants showed normal growth suggesting pH adjustment with CaO was effective. Key words: Rock phosphate, Phosphat fertilizer, pH adjustment, Plant assimilationItem Characterization of Hydroxyapatite Derived from Sri Lankan Rock Phosphate for Biomedical Applications(Uva Wellassa University of Sri Lanka, 2016) Chrishanth, M.; Wijesekara, K.B.Hydroxyapatite (Ca,,,(PO4)6(OH)2, (HA) is an important inorganic biomaterial with a structural similarity to minerals of human bone and teeth. HA is widely used for repairing bone defects in dental and orthopedic sites as filler or as a coating to promote bone ingrowth into prosthetic implants. Rock phosphate deposit at Eppawela Sri Lanka provides a rich source of chlorofluoroapatite which could be converted to HA. Conversion of apatite into hydroxyapatite was done by mixing 19.9 g of calcium hydroxide with 250 g of apatite powder (3:1 ratio) with constant stirring to achieve a homogeneous mixture, followed by high temperature sintering at 1000°C for 3 hours. Sintered HA was subjected to physical and chemical analysis to confirm successful conversion of apatite to HA and to establish its suitability in biomedical applications. Test conditions used were similar to pH and temperature changes that may occur in oral cavity of humans. FTIR spectroscopy patterns confirmed the formation of a hydroxyl group to crystalline phase of HA. FTIR spectra showed a stretching bond at 3420 cm' which indicates the presence of HA. Peaks at 1030 to 1085 cm' corresponds to symmetric stretching mode of PO43- while peak at 564 cm' indicates the bending mode of NV-. The large separation bands indicate the presence of crystalline phase. Solubility (% weight loss) was high in pH 4 for all three temperatures tested (55°C, 30°C and 5°C) indicating acidulation of HA at low pH. At higher pH, solubility was insignificant. The % weight loss correlates with the amount of Ca2+ and PO43- ions dissolved in the solution. The calculated thermal expansion coefficient of HA was 17.436x 10-5 °C-' which is x3 higher than that of human teeth (i.e. 6.603x10-5 °C-'). Compressive strength of synthesized HA pellets was between 19-23 MPa which is lower than the expected value of 100 MPa of natural bones. Conversion method adapted in this study is simple and easy compared to popular Sol-gel method. Synthesized HA was stable at high pH between 5°C to 55°C. Lower compressive strength and high thermal expansion coefficient obtained with synthesized HA suggests that the conversion method needs optimization to make the product suitable for biomedical applications. Keywords: Rock Phosphate; Hydroxyapatite; High temperature sintering, Biomedical applicationsItem Degradation of Polymeric Components in Biodiesel Fuel System(Uva Wellassa University of Sri Lanka, 2010) Karuppu, K.A.D.D.; Wijesekara, K.B.; Ekanayake, R.M.T.C.B.The worldwide demand for energy is ever increasing and biodiesel is gaining momentum an alternative renewable fuel against the ever shrinking fossil fuel reserves in the world. However certain concerns must be addressed before manufacturers and the general public fully accept it. There is a strong public opinion that the use of biodiesel could harm the polymeric components in the diesel fuel system. The purpose of this research is to investigate whether there is any degradation in polymeric components of the diesel fuel system of automobiles, such as the rubber fuel hose, with long term use of biodiesel. Biodiesel was made after base catalyzed transesterification of extracted pure Domba (Calophyllum inophyllum) oil. Blends of biodiesel were made by mixing pure biodiesel with fossil diesel. Real fuel hose used in diesel automobiles and a garden rubber hose were treated with different blends of Biodiesel, B100 (pure Biodiesel), B80 (80% Biodiesel 20% Fossil fuel), B60, B40, B20 and BOO (Fossil diesel) using a special set-up to mimic the actual diesel fuel system of automobiles. Pre test and post test internal diameter changes, weight changes and length changes were measured for rubber and real fuel hoses. Internal surface observations were done under the magnification 4.0 x 10 of a Stereo Microscope with a digital imaging system, before and after the treatment with biodiesel blends. Degree of degradation in garden rubber hose and in real fuel hose was assessed using a five point grading system and the analysis of data was done using Minitab statistical software. Garden hose treated with blends over B80 underwent significant structural changes such as increase in diameter and weight loss while no significant structural changes were observed with real fuel hose. No significant surface degradation occurred in the fuel hose used in the diesel automobiles with all the blends tested, since it has been treated with an oil resistant coating. Conversely, garden rubber hose showed severe surface degradation with blends B100 and B 80 while no significant degradation was observed with blends 820, B40 and B60. Automobile fuel hose can be used with any blend of biodiesel without any modification in existing diesel fuel system of all automobiles as an alternative to fossil diesel. Key words: Bio diesel, PolymericItem Development of a Detector to Determine Presence of Formalin in Fish(Uva Wellassa University of Sri Lanka, 2011) Lindamulla, I.; Wijesekara, K.B.; Wasala, M.P.Note: See the PDF Version Formalin is an aqueous solution of the chemical compound formaldehyde. Formalin is used as a disinfectant solution. Formalin is commonly used in aquariums to present the growth of parasites. In some cases formaldehyde is produced naturally by certain types of fish. Overuse of formalin causes many health risks for human. Many of these health issues may occur due to illegal use of the formalin. Recently some cases of illegal use of formalin were reported in many coastal areas in Sri Lanka. However, there is no rapid and economical method for formalin detection. Most of the detection methods require expensive and highTechnology apparatus, a large amount of samples, long sample preparation and detection time. Therefore, it is necessary to develop a simple, rapid and a convenient method avoiding the above mentioned disadvantages. The instrument designed is a convenient, rapid and a simplified method of detecting formalin iii fish and can be handled easily. It works at a high accuracy in a range between 100 ppm to 1000 ppm. The design is portable. Samples can be tested within a short period of time. The design is also cost effective and simple.Item Development of Minimally Processed Banana Blossom (Musa acuminate colla)(Uva Wellassa University of Sri Lanka, 2011) Senevirathne, W.M.N.S.; Singhalage, I.D.; Madhusinghe, M.M.G.; Wijesekara, K.B.Note: See the PDF Version Minimally processing of fruits and vegetables is a i rapidly developing segment of the food industry. The manufacturing steps of minimally processed products involve washing, sorting, yelling, slicing, blanching and package "S IU fi I iris, The wound responses are the major problem of fresh cut development which case the enzymatic browning (Wickraiaiaiaclachii and Ramaiiitikaaracliclii, 2005) leaning to the reduction of visual and organoleptic quality. Control of wound responses are the key to produce minimally processed product if S°0d quality (Jaiiisicwicz e/ ml., 1999), Blanching is an important treatment which primarily aims at inacti voting the enzymes that cause undesirable changes (Kaui anti Kapoor, 2000). The increase in cut damaged surfaces ani4 availability of cell u nutrients (Delaqtiis e/ ri/., 2003) and i increase’s hand ling (Dat iiaabaudu c/ p/., 2007) of the products provide greater opportunity for contamination by pathogenic organisms. Minimally proceed vegetables are rare iii the Sri Lankan market. Therefore, the major objective of this research is to develop a minimally processed vegetable front consumption constricted local banana blossom.Item Development of Polylactic Acid Incorporated Hydroxyapatite Composite for Bio-medical Applications(Uva Wellassa University of Sri Lanka, 2019) Ekanayake, E.M.D.K.; Pitawala, H.M.J.C.; Wijesekara, K.B.Hydroxyapatite (HA) is one of the extensively used materials for bone replacements and tooth fillings because of its chemical and structural similarity to the main mineral component of human bone and teeth. However, poor mechanical properties such as load bearing ability limits the applications of pure hydroxyapatite. Developing new composite materials incorporating polymer into porous pure hydroxyapatite could significantly improve the mechanical properties of HA enabling it to be used in more load bearing applications. Polylactic acid (PLA) is a widely used biopolymer in biomedical engineering due to its excellent biocompatibility and biodegradability. In this study, we have developed a polymer-HA composite by incorporating PLA into hydroxyapatite matrix derived from Sri Lankan rock phosphate. This was done at room temperature. PLA was dissolved in dichloromethane and mixed with hydroxyapatite by constant stirring. Then the mixtures were left for drying at room temperature for 24 hrs. The developed material was then characterized by Fourier Transform Infrared (FTIR) spectroscopy, XRay diffraction (XRD) and Differential Scanning Calorimetry (DSC). FTIR results indicated that PLA has successfully incorporated into the HA matrix to form a stable composite. XRD spectra confirmed that the PLA-HA composite has a crystalline structure. DSC analysis showed that the developed PLA-HA composite has a higher thermal stability. The composite developed in this study has the potential of using in various biomedical applications and would bring more economic value to Sri Lankan rock phosphate.Item Development of Specific National Energy Benchmark Model for Sri Lankan Apparel Industries(Uva Wellassa University of Sri Lanka, 2018) Anurangi, W.A.J.; Wijesekara, K.B.The development of specific national energy benchmark model for apparel industries is a fundamental requirement for efficient assessment and monitoring of energy consumption of the Sri Lankan apparel sector. Thus, this model could be used as a base for the energy labelling and energy star programs, which would be implemented for the apparel sector in the near future. In the context of this study focuses on analysing the energy consumption data of significant number of reference apparel industries have been analysed in order to construct a relationship between the energy consumption and the significant factors, which would affect to the final energy consumption. The total energy consumption of the apparel sector does not only depend on its total production (output) and/or operating hours, but also several other factors such as age of the building or factory, the outside weather conditions, number of floors, occupants' behaviour, general maintenance, etc. The mostly used simple benchmarking method, which is normalized by means of the total production and/or operating hours, is not adequate in the process of effective recognition of the energy efficient apparel industries. Hence, the regression model developed with the above explanatory factors is necessary for identifying the energy performance. The final model developed with the above explanatory factors facilitates to determine whether an apparel industry uses energy more efficiently than other similar industries. And also the model could be used to encourage the poor energy performers in the apparel sector to improve their efficiency. Keywords: Energy benchmark, Energy efficiency, Apparel industryItem Effect of Methanolic Extracts of Emilia sonchifolia (Lilac tassel flower), Ageratum conyzoides (Billy goat weed) and Mikania micrantha (Bitter vine) on Protease Enzyme Inhibition(Uva Wellassa University of Sri Lanka, 2018) Nisrina, M.N.; Alakolanga, A.G.A.W.; Premetilake, M.M.S.N.; Wijesekara, K.B.According to previous studies, methanolic extracts of Emilia sonchifolia, Ageratum conyzoides and Mikania micrantha have shown significant antimicrobial activity against Staphylococcus aureus. But their mode of action on the microorganisms is still unknown. It is expected that these three plants may have acted as protease inhibitors in the respective microorganism. So in the present study, 40 g of shade dried leaves of each plants, E sonchifolia, A. conyzoides and M. micrantha were extracted using methanol and subsequently subjected to solvent-solvent partitioning using hexane, chloroform and ethyl acetate. Those fractions were evaporated to obtain concentrated fractions. Then these concentrated fractions were used to prepare four concentration gradients, such as: 250 𝜇g ml-1, 500 𝜇g m1-1, 750 𝜇g m1-1 and 1000 𝜇g m1-1 and tested against protease enzyme. The protease enzyme assay was carried out based on Kunitz method, using casein as the substrate. According to the results obtained, highest inhibitory percentage was shown by E. sonchifolia. Even though statistical output has shown a significant difference of inhibition percentage among the concentration gradient of the plant fractions used (p value = 0.000), the range of the values are narrowed from 83.8% and 93.5% only for all three plants. So the results do not confirm the protease inhibitory activity of the extracts of the selected plants. Protease inhibitors control the action of proteases that are vital for the growth and development of the organism. Therefore, the reason for the antimicrobial activity of the methanolic extracts of these plants may not be due to protease inhibitory reaction but due to some other reasons.Item Effects of Different Cooking Methods on Antioxidant Activity of Selected Underutilized Tuber Crops of Sri Lanka(Uva Wellassa University of Sri Lanka, 2018) Perera, P.P.M.; Wijesekara, K.B.This study was carried out to investigate the effect of cooking on antioxidant activity of five underutilized tuber crops of Sri Lanka namely, Dioscorea alata (raja ala), D.esculenta (kukulala), Amorphophallus paeoniifolius (kidaran), D. alata (kondol), D. alata (hingurala) The two cooking methods tested in the study were frying and boiling. Selected tubers were peeled, cut into strips of 0.5 W x 4 L x 0.5 H cm separately. Then the strips were cooked separately either by boiling in water until soft or fried in coconut oil until golden brown and crispy for 15 minutes. Uncooked strips from each tuber variety served as controls. Methanolic extracts were prepared for boiled, fried and fresh tuber strips by shaking (780 rpm) shade dried finely powdered samples (20 g) with 30 ml of methanol. Total ascorbic acid content of each extract was measured by Iodometric titration method and total antioxidant activity was measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assays. Each experiment was conducted as 3 replicates. Results indicated that total ascorbic acid content of boiled yam extracts were significantly lower (p < 0.05) than the control and fried tubers. Raw yam extracts of all five varieties had higher ascorbic acid and antioxidant contents than cooked tuber extracts. The DPPH and ABTS radical scavenging capacity of boiled yam extracts were significantly lower (p < 0.05) than fried tubers. Amongst five varieties, highest radical scavenging capacity was shown by Amorphophallus paeoniifolius raw yam extract and lowest value was obtained for D. alata (hingurala) boiled yam extract (p < 0.05). IC50 values (concentration for 50% inhibition of DPPH) and ABTS.discoloration percentage of each variety was 85.2±2.7 µg m1-1, 86±1% and 910.8±11.8 𝜇g m1-1, 9.57±1.89% respectively. Antioxidant activities of all cooked tubers are lower than the raw tubers. For all tubers boiling in water had lower antioxidant activity.Item Evaluation of Physicochemical Properties, Proximate Composition and Antioxidant Activity of Selected Underutilized Fruit Species(Uva Wellassa University of Sri Lanka, 2019) Galhenage, S.N.; Wijesekara, K.B.; Wijesinghe, W.A.J.P.Underutilized fruits are less known due to the commercialization of few, selected fruit crops. Recent studies have suggested that these underutilized fruits possess many health benefiting compounds such as cancer fighting antioxidants and phenolic compounds. However, detailed studies on underutilized local fruits to establish their usefulness as fruit crops are lacking. The main objective of this study was to determine the antioxidant activity, total phenolic content (TPC), proximate composition and physiochemical properties of four selected underutilized fruits namely, Sonneratia caseolaris (Kirala), Annona reticulata (Weli Anoda), Prunus persica (Peach), and Psidium cattleianum (Jam Pera). All experiments were done using standard methods. Antioxidant activity was determined by using DPPH and ABTS scavenging methods. The percentage of inhibition and IC50 were measured in both assays. The total phenolic content of the extracts was determined using the Folin-Ciocalteu Reactifi (FCR) method and calculated as mg Gallic acid equivalent (GAE) g-1 extract. Among the analyzed fruits, maximum amount of moisture was found in P. persica (88.000.18). P. cattleianum showed the highest ash and fat content among the selected fruit species. The highest ascorbic acid content was found in S. caseolaris (0.240.01) while P. persica showed the lowest (0.060.001). In DPPH and ABTS assays, the lowest IC50 was showed by S. caseolaris (40.80 µg ml-1 and 99.853.67, respectively). The highest and the lowest phenolic contents were found in S. caseolaris (0.850.01 mg GAE g-1) and A. reticulata (0.170.00289 mg GAE g-1), respectively. The results indicated that S. caseolaris can be considered as the best fruit to consume as it contains high amount of antioxidants. All selected underutilized fruits contained appreciable amounts of compounds which could provide health benefits and could be used in food and pharmaceutical industries.Item Extraction and Isolation of Anti-hyperglycemic Compounds from Cheilocostus speciosus to produce sustained release formulations(Uva Wellassa University of Sri Lanka, 2020) Induruwage, S.S.; Alakolanga, A.G.A.W.; Rathnayake, S.I.; Senarathna, K.G.C.; Wijesekara, K.B.Diabetes mellitus is one of the non-contagious diseases which has now become a major health problem all over the world. This study was conducted to identify a natural, safe, and reliable solution for “diabetes” with proper scientific validation. The objective of the study was to extract and isolate anti-hyperglycemic compounds from Cheilocostus speciosus leaves. For this, a successive extraction with diethyl ether, ethyl acetate, and ethanol using sonication at room temperature was performed to extract oven-dried (40 ℃, 48 h) leaves of C. speciosus. Percentage inhibition of the enzymes and the IC50 values were determined. But the extracts of diethyl ether and ethyl acetate did not exhibit proper percent inhibitions for both alpha-amylase and alpha-glucosidase activities. Porcine pancreatic alpha-amylase inhibitory activity was performed using the DNSA method and it was detected in ethanolic extract of C. speciosus leaves with an IC50 of 17.12 mg ml-1 and Saccharomyces cerevisiae alpha-glucosidase inhibitory activity was detected with an IC50 of 21.20 mg ml-1 . Both enzyme inhibitory activities were compared with that of commercial Acarbose (IC50 values for alpha-amylase and alpha-glucosidase enzymes are 65.44 µg ml-1 and 68.52 µg ml-1 , respectively). When comparing with acarbose, a crude extract of C. speciosus leaves show promising nature to isolate antihyperglycemic compounds. Results also indicate that the alpha-amylase and alpha-glucosidase inhibition by the ethanol extract of C. speciosus are dose dependent. Therefore, this study proves that the ethanolic leaf extract of C. speciosus has enzyme inhibitory activities toward alpha-glucosidase and alpha-amylase which may helpful for the development of an antihyperglycemic formulation to reduce the postprandial glucose level. This will be carried out by bioassay-guided fractionation and isolated active compounds will be intercalated to montmorillonite, an aluminosilicate clay with high cation exchange capacity, and large specific surface area to produce sustained release formulation. Keywords: Cheilocostus speciosus, Alpha-amylase, Alpha-glucosidase, Diabetes mellitusItem Identification and Characterization of Potassium Solubilizing Bacteria Grown on Old Mica Heaps(Uva Wellassa University of Sri Lanka, 2012) Dassanayake, D.L.K.L.M.; Wijesekara, K.B.Plants basically supplement nutrient requirements from soil. However, when cultivated in agricultural setup soil nutrient availability could be a limiting factor. In such situations it may be necessary to supplement nutrients additionally with agro fertilizers which incur large expenses to the farmer. Use of agro fertilizers in large amounts could results in environmental problems. Potassium is a key element that affects plant growth and potassium containing fertilizers are relatively expensive when compared to other forms of agro fertilizer. Mica is a rich natural source of potassium and mica processing, mainly for overseas market, produces large amount of decayed mica which is of no economic value. Mica could naturally release potassium to soil upon long term microbial degradation yet the process is low. Release of mica by microbial degradation could be expedited by the use of specific microbes that favor the release of potassium (Sugumaran, and Janarathanam, 2007; Archana, 2007). These microbes are naturally present associated with old and discarded Mica heaps from which some virulent strains can be isolated (Basak and Biswas, 2008). These strains have the potential to be used as inoculants with decayed mica which could serve as a bio fertilizer. This study aims at isolation and characterization of potassium leaching bacteria associated with old and discarded mica heaps and to investigate their potassium leaching potential on Biotite and Phlogopite Mica.Item Inhibitory Effect of Essential Oils Extracted from citrus Peel on Microbial Growth of Bread(Uva Wellassa University of Sri Lanka, 2011) Kandambi, H.H.; Pemathilake, S.N; Wijesekara, K.B.Shelf life i.e. the period it will preserve an acceptable level of eating quality from a safety is very important for both manufacturer and the consumer. Bread occupies an important place amongst all bakery products, because the ingredients that are used and the water activity (0.96-0.98) of breads are supportive of the growth of microorganism reducing the shell I life of bread (Salim-ur-Rehman ct nf., 2007). To enhance the shelf life of bread, chemical antimicrobial agents have been employed but they are considered responsible for many carcinogenic and teratogenic attributes and residual toxicity. Due to these reasons, consumers tend to be doubtful of chemical additives and thus the demand for natural preservatives has been intensified (Skandamis et at., 2001). The Citrus peel essential oil comprises one of the most versatile essential oils. It is well both bacteria and fungi (Sonorant et at., 2008). Also the Citrus peels are non-edible thus discarded after extracting the juice. Citrus spy. can be found in most of the regions in the world (i.e. commonly found in Sri Lanka).Item Intercalation of Acarbose into Sodium Montmorillonite for Sustained Release Formulation(Uva Wellassa University of Sri Lanka, 2020) Mihiravi, H.K.S.P.; Lochana, E.A.L.; Rathnayake, S.I.; Alakolanga, A.G.A.W.; Senarathna, K.G.C.; Premarathne, E.P.N.; Wijesekara, K.B.Among the numerous antidiabetic drugs, acarbose is the most extensively used digestive enzyme inhibitor for the treatment of Type-II diabetes. A simple and rapid UV-Vis spectroscopy method reported in the literature was modified and successfully implemented for the determination of acarbose in aqueous media. The method is based on the formation of a green-colored complex of acarbose with alkaline potassium permanganate. Concentration (in the range of 10-50 ppm) is proportional to the visible light absorbance at 426 nm wavelength, therefore, the above parameters were selected for the quantitative determination of acarbose in aqueous solution. The Beer–Lambert law is obeyed in the above-mentioned range with a coefficient of determination (r2 ) value of 0.9826. The acarbose concentration in commercial tablets was determined using this method and the recovery was 99.65 % for 40 ppm solution. Short biological half-life and more side effects of acarbose have been recurring problems, owing to its low bioavailability and low patient tolerance, respectively. The controlled release of a therapeutic agent to patients is gaining prodigious importance during the recent time and clay minerals play a major role in modulating drug delivery. The present work is focused on the intercalation of acarbose into montmorillonite (MMT) as a controlled release drug carrier. MMT is an aluminosilicate clay composed of tetrahedral layers of silica stacked between octahedral layers of alumina with negatively charged surfaces. Due to its high cation exchange capacity and large specific surface area, MMT is extensively used in the formulation of various pharmaceutical products. In this study, acarbose was successfully incorporated into MMT by stirring MMT in a 100 ppm acarbose solution and showed 22.4% intercalation at pH 6. Acarbose intercalated MMT was characterized by X-ray diffraction and Fourier transformed infrared and the presence of N-H stretching peak at 1632 cm-1 and increase of d-spacing confirmed the successful intercalation of acarbose into the interlayers of MMT. The releasing properties of the synthesized acarbose-MMT composite would be investigated in the future. .Keywords: Acarbose, Montmorillonite, Intercalation, Drug delivery, CharacterizationItem Microbial Aided Leaching of Potassium from Sri Lankan Feldspar(Uva Wellassa University of Sri Lanka, 2012) Dissanayake, D.M.S.; Wijesekara, K.B.; Attanayake, A.N.B.Potassium is an essential major plant nutrient and also a non-renewable resource. It plays a vital role in plant nutrition. Majority of the soils of the world are too low in available potassium for production of good yields. Potassium containing agrochemicals remains relatively expensive and supplementing potassium deficiency with agro fertilizers is costly. The uses of alternative indigenous resources such as feldspar and mica which are potassium rich naturally occurring minerals are gaining importance against costly agro fertilizers (Badr et al., 2006). Certain groups of microorganisms including bacteria such as Bacillus mucilaginosus and fungi like Aspergillus niger are known to solubilize potassic minerals into soluble form which can be utilized by the plants (Lin et al. 2002; Han, and Lee, 2006). Microbes can enhance mineral dissolution rate by producing and excreting metabolic by products that interact with mineral surface (Barker et al., 1998). Combination of potassic rock minerals with potassium solubilizing microorganisms could constitute a biofertiziler which provides a sustainable solution to improve plant nutrition and production. This study investigates the potassium solubilizing effect of Bacillus mucilaginosus, Bacillus cereus, and Aspergillus from Sri Lankan potassic rock mineral feldsfar.Item Phytoremediation potential of Brassica juncea Ac. 1774 for mitigation of Cu (II) and As (V)(Uva Wellassa University of Sri Lanka, 2015) Herath, H.M.S.D.; Wijesekara, K.B.Phytoremediation is an emerging technology that employs the use of higher plants to clean up contaminated environments. Use of plants to extract toxic metals from contaminated soil and water, has emerged as a cost-effective, environment-friendly clean up alternative. In Sri Lanka large areas of soil and water contain high levels of heavy metals such as Cd, Cu, Co, Ni and Zn and other pollutants (Dissanayake et al., 2002). Members of the Brasicaceae are promising candidates for phytoextraction of metals (Kumar et al. (1995, Weerakoon and Somaratne, 2009).Sri Lanka has genetically diverse mustard (B. juncea (L.) Cazen) germplasm of over sixty accessions (PGRC Catalogue, 1999) and their true phytoextarctive potentials are yet to be determined. Most of the previously reported research on phytoremediation has conducted in vivo using soil to establish plants. Use of soil which is a highly heterogeneous medium could not unveil the true phytoremediation potential of plants due to micro-variations in the composition of soil. Hence, this study was performed in vitro and the plants were grown in well-defined plant tissue culture media where all other physical parameters such as light intensity and relative humidity were kept constant. The main objectives of this study was to investigate the maximum accumulation level of copper Cu (II) and Arsenic As (V) by in vitro raised plants of Brassica juncea Ac:1774 which has already been identified as a hyper- accumulator of Cr (VI) and multiple metal bio-accumulator (Wijethunghe et al., 2010). Methodology Authenticated seed samples of Brassica juncea (Indian mustard) of AC: 1774 was obtained from the Plant Genetic Recourses Centre (PGRC) at Gannoruwa, Sri Lanka. Seeds were surface sterilized by rinsing with a 10% solution of commercial bleach for 5 min followed by rinsing with 70% ethanol solution for 2 min and three times through washings with sterilized distilled water. Sterilized seeds were briefly dried on filter papers and cultured on solid MS (Murashige and Skoog, 1962) media. One week old seedlings were transferred on to a wick placed in liquid MS media in 15 cm culture tubes supplemented with 0, 50, 150, 200 ppm Cu (II) and 0,5, 15, 25 ppm As (V) separately. Seedlings were allowed to grow for three weeks in this medium. After that plantlets were removed, washed with tap water and dried in an oven. Dried platelets were grounded separately to obtain a fine powder which was acid digested following dry-ash-method and the accumulated heavy metal concentration for each sample was determined using Atomic Absorption Spectrometer (Varian, Australia). Each treatment had three replicates within an experiment and each experimented was repeated three times. Result and Discussion Plants of Brassica juncea Ac:1774 demonstrated relatively a high bioaccumulation of two heavy metals tested, As (V) and Cu (II). For As (V) the maximum tolerance level was 25 ppm while for Cu (V) it was 150 ppm (Fig 1 and 2). Plants showed a significantly (p≤ 0.05) higher Cu (II) toleranc e than As (V). At high concentrations plants showed signs of necrosis and retarded growth due to toxic effects of As (V). There was no significant effect by replication (Table 1 and 2) and this provides evidence that by growing plants in vitro, plant to plant variations as well as environmental effects could be kept at a minimum levels. Sings of toxicity was shown by plants after two to three days from transfer to MS media supplemented with high concentrations of heavy metals. The effect of AS (V) was prominent and physiological breakdown of plants is so fast. It has been reported that Arsenate replaces phosphate when taken up by plants that disrupts the production of ATP which results in sudden cell death. Also arsenic is inhibitory towards cell function because it reacts with sulfhydryl enzymes and disrupts their activity (Luongo and Ma, 2005).Item Phytoremediation Potential of Indian Mustard (Brassica Juncea) genotypes for Cr (Vi) Mitigation(Uva Wellassa University of Sri Lanka, 2011) Wijethunga, W.M.K.T.; Wijesekara, K.B.; Weerasooriya, R.Note: See the PDF Version Phytoremediation is a low cost, environment friendly technology of using plants to mitigate hazardous contaminants front the environment (Diislicnkov e/ ml., 1997), Phytoremediation efficiency of selected nine accessions of Indian mustard (Brassica juncea) was examined at different experimental conditions, in vitro and in vivo. Phytoremediation ability of Indian mustard (Brassica juncea) is well established, thus a good candidate plant for Phytoremediation. (Weerakoon and Soniaratne, 2009), This investigation demonstrates Phytoremediation potential of Brassica juncea genotypes for Cr(VI) i mitigation.