Chemistry
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Item Protective Effect of Coconut Oil Meal Phenolic Antioxidants against Macromolecular Damage: In Vitro and In Vivo Study(Journal of Chemistry, 2020) Karunasiri, A.N.; Senanayake, C.M.; Hapugaswatta, H.; Jayathilaka, N.; Seneviratne, K.N.Coconut oil meal, a cheap by-product of coconut oil production, is a rich source of phenolic antioxidants. Many age-related diseases are caused by reactive oxygen species- (ROS-) induced damage to macromolecules such as lipids, proteins, and DNA. In the present study, the protective effect of the phenolic extract of coconut oil meal (CMPE) against macromolecular oxidative damage was evaluated using in vitro and in vivo models. Sunflower oil, bovine serum albumin (BSA), and plasmid DNA were used in the in vitro study, and thiobarbituric acid reactive substances (TBARS), protein carbonyl, and nicked DNA were evaluated as oxidation products. The inhibitory effect of CMPE against H2O2-induced macromolecular damage was evaluated using cultured HEp-2 cells. The results indicate that CMPE inhibits macromolecular damage both in vitro and in vivo. In addition, CMPE regulates redox status of HEp-2 cells under oxidative stress conditions by maintaining higher reduced glutathione levels. There was no significant difference in the expression of glutathione peroxidase in stressed and unstressed cells suggesting that CMPE regulates the cellular oxidative stress responses without affecting the expression of oxidative stress response genes. Oral feeding of Wistar rats with CMPE improves the serum and plasma antioxidant status without causing any toxic effects.Item Phenolic extracts of the leaves of Psidium guineense Sw. improve the shelf life of sunflower oil and baked cake and antioxidant status of Wistar rats(J Food Biochem, 2018) Senanayake, C.M.; Hapugaswatta, H.; Jayathilaka, N.; Seneviratne, K.N.The potential of the ethanolic extract of Psidium guineense Sw. leaves (PGLE) to protect food from oxidation was evaluated using sunflower oil and baked cake as food models. The nutritional quality of PGLE was evaluated by feeding Wistar rats with PGLE for 150 days. Psidium guineense Sw. leaves contain 195.25 ± 9.56 mg g–1 phenolic substances, 51% of which are o‐diphenols. Protection factor, the ability of Psidium guineense Sw. leaves to protect sunflower oil against oxidation (1.82 ± 0.13), was not significantly affected by heat treatment compared to BHT. Formation of oxidation products, peroxide and hexanal in PGLE‐ and BHT‐added cake was significantly lower (<5 ppm over 28 days) compared to control with no added antioxidants. Therefore, addition of PGLE improved the shelf life of sunflower oil and oxidative stability of baked cake. PGLE also improves the serum antioxidant capacity and inhibits lipid and protein oxidation in Wistar rats. Practical applications PGLE is a rich source of phenolic substances. Due to high antioxidant activity, pleasant sensory quality and high thermal stability, PGLE can be used to improve the shelf life of baked cake and edible oils. As PGLE also improves serum and plasma antioxidant properties without causing any toxicity, nutritional food supplements can be developed based on PGLE.Item Effect of three edible oils on the intestinal absorption of caffeic acid: An in vivo and in vitro study.(PLoS ONE 12(6), 2017) Prasadani, W.C.; Senanayake., C.M; Jayathilaka., N; Ekanayake., S; Seneviratne, K.N.Polyphenolic antioxidants are mainly absorbed through passive paracellular permeation regulated by tight junctions. Some fatty acids are known to modulate tight junctions. Fatty acids resulting from the digestion of edible oils may improve the absorption of polyphenolic antioxidants. Therefore, we explored the effect of three edible oils on the intestinal absorption of caffeic acid. Rats were fed with soybean oil and caffeic acid dissolved in distilled water. Caffeic acid contents in the plasma collected up to 1 hr were quantified. The experiment was repeated with coconut oil and olive oil. Component fatty acids of the oils were individually tested in vitro for their effect on permeability of caffeic acid using Caco-2 cell monolayers. Highest absorption of caffeic acid was observed in animals fed with coconut oil. In vitro transport percentages of caffeic acid in 2.5 mmol/L solutions of fatty acids were 22.01±0.12 (lauric), 15.30 ± 0.25 (myristic acid), 13.59 ± 0.35 (linoleic acid), 3.70 ± 0.09 (oleic acid) and 0.10±2.0 (all other fatty acids). Lauric acid and myristic acid are the two major fatty acids present in coconut oil. Therefore, these fatty acids may contribute to the higher absorption of caffeic acid in the presence of coconut oil.Item Comparison of the basic nutritional characteristics of the first extract and second extract of coconut milk(2015) Nadeeshani, R.; Wijayaratna, U.N.; Prasadani, W.C.; Ekanayake, S.; Seneviratne, K.N.; Jayathilaka, N.Item Determination of thermal stabilities of guava leaf, coconut cake, rice bran and sesame cake extracts(Sri Lanka Association for the Advancement of Science, 2015) Senanayake, C.M.; Seneviratne, K.N.; Jayawardena, B.M.; Prasadani, W.C.Item Subcritical water extraction of phenolic compounds from coconut cake(Sri Lanka Association for the Advancement of Science, 2015) Prasadani, W.C.; Seneviratne, K.N.; Jayawardena, B.M.Item Enzyme assisted extraction, quantification and antioxidant activity of phenolic compounds of coconut cake(Sri Lanka Association for the Advancement of Science, 2013) Prasadani, W.C.; Seneviratne, K.N.; Jayawardena, B.M.Item Stabilization of stripped soybean oil using natural antioxidants(Sri Lanka Association for the Advancement of Science, 2013) Wickrama Arachchi, R.; Seneviratne, K.N.Item Preparation of Coconut oil blends and the evaluation of their health effects(Sri Lanka Association for the Advancement of Science, 2008) Seneviratne, K.N.; Ekanayake, S.; Kotuwegedara, R.T.Coconut oil prepared by pressing copra (copra oil, CO) is the major cooking oil in Sri Lanka. However, copra oil contains only less than 1.5 % of essential fatty acids. The objective of the project is to improve the quality of copra oil by blending copra oil with traditional Sri Lankan seed oils containing high percentages of polyunsaturated fatty acids. Oils of the seeds of Brassica juncea (Aba), Madhuca nerifolia (Mee) and Sessamum indicum (Thala) were used to prepare oil blends. The organoleptic acceptability of the prepared blends was checked by a panel and the oil blends selected by the panel were selected for the evaluation of health effects. The acceptable blends of coconut oil were aba oil (AO) (40%), thala oil (TO) (50%) and mee oil (MO) (60%) and by volume. Male Wistar rats were fed with a special diet containing these oil blends, coconut oil (CO), and soya oil (control) and their serum levels of total cholesterol (TC), HDL, LDL, and triglycerides (TG) were determined.Item Comparison of the in vivo antioxidant activity of traditional coconut oil, virgin coconut oil and soya oil(Sri Lanka Association for the Advancement of Science, 2008) Seneviratne, K.N.; Ekanayake, S.; Hapuarachchi, C.D.When the nutritional quality of cooking oils is considered, it is extremely important to evaluate the contribution of cooking oils to the antioxidant activity in blood. In the present study, the in vivo antioxidant potentials of three cooking oils are compared. Male Wistar rats were fed with a special diet containing traditional coconut oil (TCO, prepared by boiling coconut milk), virgin coconut oil (VCO) and soya oil (SO). The effect of the consumption of these oils on the total antioxidant activity in blood serum was analyzed and compared. The decolorization of ABTS•+ (radical cation of 2,2'-azinobis-(3-ethylbenzothiazoline- 6-sulfonic acid) was used as a measure of antioxidant activity and the antioxidant activity was expressed as trolox equivalent antioxidant capacity (TEAC).