Abstract: Mangroves are halophytic plants that are typically found along the intra-tidal regions. The coastal ecosystem of mangroves in Sri Lanka hold one of the most unique mangrove species that are yet to be studied. These ecosystems provide shelter to various organisms including humans. Fungal endophytes present in these plants have many medicinal properties that can be utilized in the development of drugs. Antibiotic resistance is a major concern in the pharmaceutical industry, hence alternative plant-based drugs with fewer costs and side effects show great potential. In the current investigation, the main objective was to test for antibacterial properties of fungal endophytes isolates from two mangroves: Avicennia marina and Excoecaria agallocha against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922). In both mangrove species, three endophytic species were identified based on their morphological characteristics: Aspergillus niger, Penicillium viticola and Aspergillus versicolor. Only P. viticola was obtained from E. agallocha. Based on the results obtained from antibiotic susceptibility tests, A. niger (stem) was the most active and showed the best bacteriostatic and bactericidal activity against both S. aureus and E. coli. P. viticola produced viable results (mean zone of inhibition of 21 mm against S. aureus) but were not as productive as A. niger. This study indicated that these endophytic fungi held medicinal properties that can be further evaluated. Published on 2022-12-31 00:00:00
Abstract: Excessive exposure to ultraviolet (UV) radiation in the sunlight has many deleterious consequences on human skin. In order to alleviate these harmful effects, sunscreen formulations are widely used. Although most of these synthetic sunscreens are highly effective, the adverse effects associated with these products should not be neglected. The current trend, therefore, is to explore natural sources to develop novel sunscreen formulations that are efficacious and more human-friendly. This study was conducted to formulate herbal sunscreens using two Sri Lankan medicinal plants used as remedies for dermatological conditions, hibiscus furcatus wild (nabiriththa) and olax zeylanica linn. (mella) and to evaluate their efficacy. Initially, aqueous-methanolic extracts were prepared from the leaves of the two plants, followed by the preparation of sunscreen formulations from each extract by incorporating different concentrations of the extracts into an aqueous cream base. Thereafter, the uv absorbance and sun protection factor (spf) were obtained. The sunscreen formulations containing 75% of each extract displayed high UV absorbance and the highest spf values. The photostability profiles indicated that some formulations prepared from o. zeyalnica were more effective than the formulations developed from h. furcatus. Therefore, this preliminary study demonstrated the suitability of h. furcatus and o. zeylanica extracts towards the development of commercial herbal sunscreens. Published on 2022-12-31 00:00:00
Abstract: The Tadpole graph Tn,k is a Lollipop type graph obtained by joining a one vertex of cycle graph Cn to the end vertex of a path graph Pk The normalized cut is a measure of disassociation between two groups which computes the cut cost as a fraction of the total edge connections to all the vertices in the graph. This research focuses on deriving a formula to find the minimum normalized cut value of Tadpole graphs. Published on 2022-12-31 00:00:00
Abstract: Plant-derived natural products provide many novel bioactive molecules that are available in the market today as medicines or food. Wild Green Leafy Vegetables (WGLVs) have essential nutrients which are necessary for a healthy life. Three WGLVs such as Allmania nodiflora, Borreria hispida, and Rivea ornata were selected for the proximate and phytochemical analysis based on the market survey. Selected dry WGLVs were used to investigate proximate such as moisture, ash, fat, and fiber and phytochemicals such as alkaloids, flavonoids, tannins, steroids, terpenoids, phenolic compounds, and saponins analysis by using standard methods. The results were shown as follows: moisture 71.7±0.95- 80.3±2.84%, ash 8.84±0.69 - 11.05±0.21 %, fat 1.36±0.48 - 2.56±0.28 % and fiber 6.85±0.46 - 8.04±0.11 %. The qualitative screening of water, ethanol, and acetone extracts revealed that select WGLVs contained alkaloids, flavonoids, tannins, steroids, terpenoids, phenolic compounds, and saponin. Rivea ornata lacked quinones, while anthraquinones were only found in the water extract of Borreria hispida, and none of the three WGLVs were found to contain glycosides. Published on 2022-12-31 00:00:00
Abstract: Oat (Avena sativa) is a healthy cereal that is high in fiber and minerals. This research aimed to develop an oat powder incorporated drinking yogurt. 0.25, 0.50, and 1.0 g of oat powder per 100 ml of milk were selected as concentrations. Gelatin was not included due to the stabilizing ability of oat powder. To evaluate consumer preference and proximate analysis, oat concentration selected from a sensory evaluation was compared to a commercial drinking yogurt. For a period of 21 days, physicochemical (pH, Titratable acidity, and Total soluble solids) properties and microbiological quality were examined. The data was statistically analyzed using SSPS and SAS at a significance level of P<0.05. The most consumer-preferred oat concentration was 0.5 g oat powder per 100 ml of milk, with sensory properties identical to commercial drinking yogurt. The fat (3.43), protein (3.30), solids non-fat (26.08), and fiber (0.05) contents of the selected oat concentration were significantly higher than those of the commercial drinking yogurt. According to the yeast and mold count, oat drinking yogurt had a shelf life of 14 days after manufacturing. In conclusion, oat powder including drinking yogurt can be developed with better sensory properties which is competitive with commercial drinking yogurt. Published on 2022-12-31 00:00:00
Abstract: Current issues associated with drug resistance and the adverse effects of synthetic agents have prompted researchers to focus on natural, medicinal agents such as mangroves and their associated fungal endophytes. The current study was developed to determine the antibacterial activities of crude extracts of endophytic fungi isolated from leaves, roots and stems of Acrostichum aureum, Karan koku in Sinhala and Sonneratia alba, Kirala in Sinhala. The endophytic fungal isolates were identified as Aspergillus niger, Aspergillus ochraceus, Aspergillus fumigatus, Aspergillus terreus, Penicillium citrium and Penicillium resticulosum and the respective crude extracts were generated using ethyl acetate. The crude extracts were subjected to antibiotic sensitivity tests (ABSTs) against two test organisms: Staphylococcus aureus (ATCC ®: 25923) and Escherichia coli (ATCC ®: 25922). The highest inhibitory action was exerted by Penicillium resticulosum against both the test organisms (E. coli: 15+0.05 mm; S. aureus 22+0.05 mm) which was the most abundantly identified endophyte in this study. The Minimum Inhibitory Concentration of the crude extracts was detected to be 1. 25 mg/ ml. However, the highest bactericidal action was noted from Penicillium citrinum. It is evident that the fungal endophytes isolated from mangrove plants possess antibacterial properties that can be used as a natural source for the generation of antimicrobial therapeutics. Published on 2022-12-31 00:00:00
Abstract: Consumption of bottled drinking water has dramatically increased among the community in recent years worldwide and also in Sri Lanka. The objective of this study was to assess microbiological and chemical quality of five liter volume bottled water during the shelf life period. Three five liter bottles each of three brands were collected for analysis. Microbiological and chemical analyses were carried out monthly after the date of manufacture throughout the first three months of the shelf life of the bottled water. The results indicated that Total Coliform [TC] and Faecal Coliform [FC] counts decreased with time over the first three months of shelf life. There were no significant differences (P > 0.05) in TC between the numbers of microorganisms initially present, with an average count of 107.19 cfu per 100 ml and those present after three months of storage, which decreased to 33.70 cfu per 100 ml, while the level permitted by SLSI for TC is zero cfu per 100 ml. According to national and international standards, the FC count should be zero per 100 ml for drinking water. However, bottled water samples tested exceeded this limit for presumptive FC, with an average count of 0.63 cfu per 100 ml, which declined to 0.3 cfu per 100 ml after three months, without exhibiting a significant difference (P > 0.05). Chemical parameters were within the permitted levels, except pH and hardness in water samples. Therefore, bottled water available for sale needs to be monitored continuously by relevant authorities, in order to provide safe bottled drinking water to consumers. Published on 2022-12-31 00:00:00
Abstract: Biodegradation of lignocellulosic materials by cellulolytic microbial consortia would be beneficial in cellulosic biofuel production. This study aimed at investigating the cellulose degradation potential of fungal-bacterial biofilms (FBBs) followed by bioethanol production. Fungi and bacteria were isolated from soil samples and their cellulolytic activity was analyzed in carboxy methylcellulose medium. FBBs were developed from the selected fungi and bacteria and their cellulolytic activity was evaluated using reducing sugar production through 3,5-Dinitro Salicylic acid method. Cellulolytic digestion followed by fermentation was performed with the selected biofilms by co-culturing Saccharomyces cerevisiae suspension. Ethanol content was quantified by dichromate method and confirmed through FTIR analysis. The highest significant (P < 0.05) cellulolytic activity was observed in Aspergillus niger (F6) and Pseudomonas aeruginosa (B7). Significantly (P < 0.05) the highest cellulolytic activity was recorded by A. niger-P. aeruginosa biofilm (FB2). Fermentation study confirmed higher production of ethanol by the biofilms co-cultured with S. cerevisiae over their single cultures and the highest was recorded by A. niger - Bacillus subtilis biofilm (FB1) co-cultured with S. cerevisiae. In this context, FBB can be considered as an important agent for bioethanol production from cellulosic materials through cellulolytic digestion followed by fermentation. Published on 2022-12-30 00:00:00
Abstract: Treacle from the palm trees of coconut, palmyra, and kithul exhibits antioxidant and medicinal properties as mentioned in Sri Lankan ethnomedicine however the research regarding the nutritional, physicochemical, sensory, and functional properties of palmyrah treacle are limited and the treacle remains underutilized compared to coconut and kithul treacle. The purpose of this study is to compare the antioxidant activity and physicochemical properties of coconut, kithul, and palmyra treacle and to provide comparative facts for the betterment of the palm treacle industry. Pooled sap samples of coconut, kithul, and palmyra were collected from respective collecting center and the treacle was prepared and kept in refrigerators for further analysis. Physicochemical properties, antioxidant activity, microbial quality, and sensory analysis were performed using triplicates from each sample. Significantly highest (p<0.05) total sugar (67.90%) and ash content [0.075(±0.002)] %was obtained for palmyrah treacle, while protein content was significantly highest for kithul [0.570 (±0.0120)] than coconut [0.410 (±0.0040)] and palmyrah [0.028 (±0.0070)] %. Total phenolic content was significantly highest for coconut [278.02 (±1.35)] while there were no significant differences between palmyrah [191.02(±4.80)] and kithul [190.23 (±2.71)] mg GAE/100g. DPPH's scavenging ability with the IC values of palmyrah, coconut, and kithul were 1.69 (±0.13), 2.91 (±0.04), and 2.21(±0.14) mg/mL respectively. This study could be useful to disseminate knowledge and create awareness among people on different treacle varieties and their antioxidant properties. This finding will uplift the utilization of palm treacle or the in-cooperation of palm treacle in other food products such as sweeteners. Published on 2022-11-28 00:00:00
Abstract: The maximum amount of losses retained by the insured under deductible policy modifications is usually set as part of the terms of the policy conditions. The objective of this study are to (i) estimate mean losses of an insured risk by means of the operational behavior of density function with deductible modifications and (ii) compare the mean severities under exponentially and log-normally distributed arbitrary policy in a cost per loss and cost per payment contingencies. The results show that despite the established fact in literature that log-normal severity distribution has a thicker tail than the exponential distribution, its cost per loss payment is correspondingly lower than the corresponding values of the exponential mean loss. Computational evidence over the trend of the change in the loss eliminated in the domain for which deductible has been defined revealed that the cost per loss amount is less than the cost per payment amount in the two models. The method can be used to estimate aggregate claims as the deductible level increases for every scheme holder and such that the estimated claims could be compared with the hypothetical observed claims which can be arrived at by applying the hypothetical deductible value to the background losses. Published on 2022-11-28 00:00:00
Open Access journal
