Browsing by Author "Dayarathna, A.G.S."

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Determination of selenium content in conventional leafy green vegetables consumed by Sri Lankans.
(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Dayarathna, A.G.S.; De Silva, D.S.M.
Selenium is an essential micro-nutrient for both humans and animals, specially incorporated in the form of amino acids. It is an important trace element required for humans for proper thyroid functioning and to promote their immune system. Most of the South Asian communities, especially Sri Lankans frequently have plant-derived food as the main component in their diet. Since it is widely believed that conventional leafy vegetables are a rich nutrient source, this study was carried out to determine the selenium content in seven selected types of abundant conventional leafy green vegetables that are consumed by Sri Lankans. Centella asiatica (Sin. Gotukola), Alternanthra sessilis (Sin. Mukunuwenna), Basella alba (Sin. Nivithi / Spinach), Boerhavia diffusa (Sin. Sarana), Ipomoea aquatica (Sin. Kankun), Amaranthus spinosus (Sin. Thampala) and Hygrophila schulli (Sin. Neeramulliya) are the leafy vegetable samples that were selected for the evaluation of selenium content. The samples were collected from five districts, (Gampaha, Kandy, Kurunegala, Anuradhapura and Puttalam) which have different environmental and climatic conditions. Soil samples corresponding to each leafy vegetable sample were also collected, and analyzed to identify the relationship between the selenium content in plants and soil. The sample analysis was carried out using Hydride Generation Atomic Absorption Spectrometer (HGAAS). Prior to the analysis, cleaned leafy vegetable samples and corresponding soil samples were subjected to acid digestion with nitric acid. Selenium concentrations in leafy vegetable samples analyzed were found to be in the range of 31.2 -103.2 μg kg-1 on dry weight basis. Centella asiatica (84.1 μg kg-1) and Hygrophila schulli (103.2 μg kg-1) varieties showed relatively high selenium concentrations, highest value of Selenium (103.2 μg kg-1) was reported from Hygrophila schulli and the lowest was from Boerhavia diffusa (31.2 μg kg-1). The selenium content in corresponding soil samples ranged from 96.4 to 133.9 μg kg-1 in dry weight basis. The measured soil selenium content was always higher than the corresponding plant selenium content; however the plants that were grown in selenium rich soils have not shown greater absorption of selenium. Hence, there may be no positive correlation between the uptake of selenium by leafy vegetables and the selenium content in soil.
Determination of selenium content in selected edible green leaves
(Ceylon Journal of Science, 2019) De Silva, D.S.M.; Dayarathna, A.G.S.
The selenium (Se) contents in seven conventional Edible Green Leaves (EGL) that consumed by Sri Lankans were determined using Hydride Generation Atomic Absorption Spectrometric method (HGAAS). The EGLs that were grown in five districts under different climatic conditions in Sri Lanka were collected from Gampaha, Kandy, Kurunegala, Anuradhapura and Puttalam areas. The EGL that were subjected to current study are Centella asiatica (Sin. Gotukola), Alternanthra sessilis (Sin. Mukunuwenna), Basella alba (Sin. Nivithi/ Spinach), Boerhavia diffusa (Sin. Sarana), Ipomoea aquatica (Sin. Kankun), Amaranthus spinosus (Sin. Thampala) and Hygrophila schulli (Sin. Neeramulliya). Soil samples corresponding to each EGL sample were also collected from Gampaha, Kandy and Anuradhapura districts in order identify a relationship between the Se content in plants and soils. Prior to the analysis EGL samples and corresponding soil samples were subjected to acid digestion with nitric acid. Se contents in the EGL were in the range of 31.2 – 103.2 μg kg-1on dry weight basis. According to the results, Centella asiatica and Hygrophila schulli varieties showed relatively higher Se content, while Hygrophila schulli shown the highest value and the lowest was reported in Boerhavia diffusa. The Se content in corresponding soil samples were ranged from 96.4 to 133.9 μg kg-1on dry weight basis. The Se content in soil was higher than that in plants, but there was no significant correlation between the Se content in soil and EGLs.