Basic and Applied Sciences

Estimation of Phenolic Content, Flavonoid Content, and Antioxidant Activities of Selected Fruits in Sri Lanka

Fri, 01 Sep 2023 00:00:00 GMT

Estimation of Phenolic Content, Flavonoid Content, and Antioxidant Activities of Selected Fruits in Sri Lanka Dharmasiri, PGNH; Samarakoon, KW; Ranasinghe, P; Jayasooriya, PT The aim of this study was to evaluate the Total Phenolic Content (TPC), Total Flavonoid Content (TFC), and in vitro antioxidant activity, of six underutilized fruits in Sri Lanka. The selected fruits are Elaeocarpus angustifolius L (Ceylon blue olive), Elaeocarpus serratus L (Veralu), Manikara zapota L (Sapadilla), Ziziphus mauritiana L (Masan), Flacourtia indica L (Ugurassa) , and Garcinia xanthochymus L (Ratagoraka). The fruit extracts were prepared with 100% methanol, and crude extract (CE) of fruit was fractionated into hexane (HX), ethyl acetate (EA), and aqueous (AQ ). TFC and TPC of each fraction were determined by aluminium chloride colourimetric and Folin-ciocalteu methods using 96 well microplates respectively. Antioxidant activities were determined using Ferric reducing power (FRAP), and Oxygen radical absorbance capacity (ORAC) assay methods. Among different fractions, the highest TPC and TFC were found in AQ of veralu (377.57 ± 65.65 mg GAE/ g of extract), CE of Masan (357.04 ± 9.63 mg GAE/ g of extract), EA of Ugurassa (173.47 ± 18.891 mg GAE/ g of extract), and EA of Ceylon blue olive (49.14 ± 1 .60 mg QE / g of extract). The highest FRAP was found in AQ of Ugurassa (745.90 ± 23.06 mg TE/ g of extract), CE of Veralu (668.75 ± 7.7 mg TE/ g of extract), and EA of Ratagoraka (650.51 ± 6.88 mg TE/ g of extract). The highest ORAC was shown in AQ of Ratagoraka (113.72 ± 17.78 mg TE/ g of extract), CE of Veralu (31.38 ± 0.25 mg TE/ g of extract), and EA of Ratagoraka (143.24 ± 3.09 mg TE/ g of extract). In conclusion, Sapadilla, Ratagoraka, and Veralu possessed the highest antioxidant capacity compared to other fruit types. Thus, the CE fraction of Masan, the AQ fraction of Ugurassa, and the EA fractions of Ratagoraka will be good sources of antioxidants for the formulation of food supplements.

Application of the Peak-to-Valley Method for in-situ Gamma Spectroscopy Using NaI(Tl) Detector

Fri, 01 Sep 2023 00:00:00 GMT

Application of the Peak-to-Valley Method for in-situ Gamma Spectroscopy Using NaI(Tl) Detector Rodrigo, Y; Sumithrarachchi, CS; Lamabadusuriya, MR The depth distribution in soil is required to quantify the radioactivity in environment using in-situ gamma spectroscopy. The conventional approach to determining depth distribution is the core sampling method, which requires samples from several depths in the soil and is a time-consuming process. In-situ gamma spectroscopy can be used as a rapid and e cient way to quantify radioactivity in large areas. The Peak-to-Valley (PTV) method which is based on the attenuation of gamma rays through matter, emerges as a novel approach, enabling the derivation of depth distribution information from insitu gamma spectra without having core samples. The present study aimed to validate the PTV method using the NaI(Tl) detector and obtained a correlation between the PTV ratio and depth distribution. Water was used as the attenuation medium to create different depths and 137Cs and 40K sources were kept at different depths. The NaI(Tl) detector was used to measure spectra at each depth and calculated the PTV ratios. The results show a higher correlation of 2nd order between the PTV ratio and the depth for both 137Cs and 40K. It reveals that the PTV ratio of the in-situ gamma spectrum can be used to derive the depth distribution parameter. The relationship between the PTV ratio and the depth distribution parameter was obtained for several locations. This relationship is used for calibrating in-situ gamma detector which can be used in a similar environment to determine radioactivity.

Identification of Pathogenic Bacteria (Escherichia coli) in Drinking Water Sources and Detection of their Antibiotic Resistant Genes in Gampaha District, Sri Lanka

Fri, 01 Sep 2023 00:00:00 GMT

Identification of Pathogenic Bacteria (Escherichia coli) in Drinking Water Sources and Detection of their Antibiotic Resistant Genes in Gampaha District, Sri Lanka Wijesooriya, R; Perera, ODK; Bodhinayaka, VA Water plays a critical role on Earth, and its significance is particularly evident in relation to human beings. The present study aimed to identification of Escherichia coli and detection of their antibiotic resistant genes in drinking water sources of five different regions Gampaha district, Sri Lanka. Five resources of randomly collect drinking water samples (n = 50) from every 10 samples from five different regions were used for analysis. The pathogenic microorganisms were isolated via membrane filtration technique (0.45 µm) and identified via conventional standard biochemical keys including Indole, Citrate, MRVP, TSI, Motility and Chromogenic culture and Gram stain. The DNA extraction was performed via column-based method. The disk diffusion method was performed to access the antibiotic sensitivity of the isolated Escherichia coli following CLSI guidelines via Ampicillin, Gentamicin and Tetracycline antibiotics (10 mg). From total sample 18% were positive with Escherichia coli in unprotected well, protected well and tap line samples. All nine samples exhibit resistance to Ampicillin (< 13 mm), sensitive to the Gentamicin (> 15 mm) and resistant to Tetracycline (< 11 mm). Molecular determination, 2% agarose gel image, confirmed the presence of E. coli DNA as evidenced by the presence 400 base pairs (bp) band size and UidA gene found in one sample confirmed the presence of different strains of isolated E. coli. The specific antibiotic resistant genes were analyzed and all three samples were negative for the tet (a), tet (C), tet (m) and blaTEM antibiotic resistant genes which confirms that isolated E. coli were not resistant for the Tetracycline and Ampicillin due to mentioned genes.

Morphological, Vocal, and Genetic Characterization of Motacilla flava – tschutschensis Allospecies Complex in Sri Lanka

Fri, 01 Sep 2023 00:00:00 GMT

Morphological, Vocal, and Genetic Characterization of Motacilla flava – tschutschensis Allospecies Complex in Sri Lanka Samarasinghe, RMNS; Allport, G; Weerakkody, SN; Gunasekara, VR; Seneviratne, SS Yellow wagtail complex was long considered a single species (Motacilla flava). Recent phylogenetic studies however, split this species into two; the Western Yellow Wagtail (Motacilla flava) and the Eastern Yellow Wagtail (Motacilla tschutschensis). Until 2020, there were no records of the Eastern Yellow Wagtail in Sri Lanka. Nonetheless, using several vocal, plumage, and a single genetic marker, a study in 2021 indicated that the Eastern Yellow Wagtail is wintering in Sri Lanka. In the present study, the yellow wagtail complex in Sri Lanka was critically evaluated using an assortment of phenotypic and genetic characteristics obtained from live-caught birds. The phylogenetic affinities of yellow wagtails wintering in Sri Lanka were constructed using Maximum likelihood inference and Bayesian inference using the mitochondrial ND2 gene region as the genetic marker. The morphological and vocal variations between Eastern (n = 15) and Western (n = 11) yellow wagtails were analyzed through the ANOVA test and the principal component analysis (PCA). The molecular phylogenetic trees and the number of peaks at the downstroke of the first flight call (p = 0.00015) of the yellow wagtail reveal that both Eastern and Western yellow wagtails are wintering in Sri Lanka. However, the morphological characteristics failed to separate the two species into two distinct clusters (Fn=26 = 3.9816, p = 0.0147). Our study revealed the migratory occurrence of both the Western Yellow and the Eastern Yellow wagtails in Sri Lanka. The studied Eastern Yellow Wagtails clustered to the North Asian tschutschensis clade.