IRSPAS 2019
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/20453
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Item Assessment of in vitro antioxidant activity and flavonoid content Vernonia cinerea(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Weerasinghe, P.; Abeysinghe, T.; Paranagama, P. A.Leafy greens are an essential part of a healthy diet. Eating a diet rich in leafy greens can offer numerous health benefits including reduced risk of obesity, heart diseases, high blood pressure and mental decline. In Sri Lanka, Kola kanda or herbal porridge is a traditional breakfast made up of green leaves or herbs. Out of many herbs used for Kola kanda, Vernonia cinerea (Monarakudumbiya) is used to treat various diseases on folklore levels in Sri Lanka. However, no much scientific validation is found for V. cinerea for its medicinal uses. The present study was carried out to access the in vitro antioxidant activities and flavonoid content of leaf, root, stem and flower parts of V. cinerea. In vitro antioxidant potential of methanolic extracts of V. cinerea was evaluated by means of total phenolics by the Folin-Ciocalteu assay and the DPPH radical scavenging assay using standard procedures with slight modifications. The highest phenolic content of 101.80 ± 7.74 mg GAE/g was observed in flowers and the stem having the least phenolic content (71.95 ± 5.72 mg GAE/g). The flavonoid content ranged from 17.67 mg GAE/g to 12.76 mg GAE/g in all parts. DPPH radical scavenging activity of extracts of V. cinerea increased in a dose dependent manner with IC50 values ranging from 800 μg/mL to 2350 μg/mL in different parts. The leafy green, V. cinerea under this study contains a significant amount of essential phytochemicals which possess anti-oxidant properties supporting its use as a medicinal herb.Item Antioxidant activity and physicochemical properties of Flacourtia indica (Uguressa) at different maturity stages(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Kasunmala, I. G. G.; Navarathne, S. B.; Wickramasinghe, I.Flacourta indica is an underutilized fruit, which grows wild in bush and its fruits are generally consumed fresh at fully matured and ripe stages. Physicochemical, antioxidant and sensory properties of fruits shows a significant different between each maturity stage. The aim of this study was to analyze the physicochemical and antioxidant properties of fruits at different maturity stages and to identify the best maturity stage for harvesting. Fruits were collected from Galle, Sri Lanka and three maturity stages were selected according to the progressive colour change during fruit development, such as immature – fully green in colour, mature - purple and green in colour and ripen – dark purple in colour. Fruits at each maturity stage were randomly divided into two subgroups for antioxidant analysis and physiochemical testing. Antioxidant analysis was performed on freeze dried fruit samples. Results revealed that weight, volume, length, width, total soluble solids and moisture content of fruits were increased while decreasing pH significantly (P < 0.05) with the maturation and ripening of the fruit. Color of the fruits in terms of lightness (L*) and yellowness (b*) decreased significantly (P < 0.05) while increasing the redness (a*) with maturity. According to antioxidant activity analysis, total phenol content (TPC) value (3.731 ± 0.20 mg gallic acid equivalents/g of dry powder) by Folin-Ciocalteu method showed no significant difference between immature and ripen stages but showed a slight increment in mature stage. 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, ferric reducing antioxidant power (FRAP) and Oxygen radical absorbance capacity (ORAC) values increased with the maturation and ripening of Flacourtia indica fruit. The study also revealed that dark purple (fully ripen) fruits contained significantly high amount of antioxidant activity in terms of, DPPH, FRAP, ORAC values which were 2280.701 ± 53.05 ppm, 141.775 ± 2.04 mg trolox equivalents/g of dry powder, 31.376 ± 1.35 mg trolox equivalents /g of dry powder respectively. Based on results it can be concluded that fully ripening stage was the best maturity stage for harvesting and can be used as a natural antioxidant in food industryItem Bioactive properties of Rambutan (Nephelium lappaceum L.) and Durian (Durio zibethinus Murr.) peel extracts(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Silva, A.G.; Wickramaarachchi, S.; Attanayake, R. N.; Rajapakse, C. S. K.Although these fruits are seasonal, a considerable amount of Rambutan (Nephelium lappaceum L.) and Durian (Durio zibethinus Murr.) fruit residues (mainly peels) are collected each year as waste materials, due to the significant volume of trade of these fruits. Therefore, present work was initiated with the aim of evaluating the impact of these residues lying as waste and possible re-use, by investigating the bioactive properties in peels of rambutan and durian. Methanol extracts of Rambutan and Durian peels were sequentially extracted with hexane, chloroform and methanol. First, methanol extracts of peels were subjected to phytochemical screening following standard procedures and results revealed that rambutan and durian peels were rich in polyphenols, flavonoids, steroids, coumarin, etc. Total phenolic content (TPC) and total flavonoid content (TFC) of methanol extracts of peels were determined using Folin-Ciocalteu and aluminium chloride method, respectively. Results showed that TPC and TFC in methanol extract of durian peels were (11.39 ± 0.49 mg GAE/g dry weight, 257.20 ± 5.14 mg Catechin /g dry weight) higher than those of Rambutan peels (2.73 ± 0.15 mg GAE/g dry weight, 198.00 ± 1.89 mg Catechin /g dry weight). Further, the antioxidant activity of methanol extracts of peels and its fractions were investigated using 1, 1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging assay and the correlation with their TPC and TFC were examined using Pearson’s correlation analysis. The strongest antioxidant activity was observed in hexane fraction of Rambutan peels with IC50 value of 13.49 ± 0.52 μg/mL, and which was lower than that of the control, butylated hydroxytoluene (43.70 ± 0.89 μg/mL). Significant positive correlations were observed between TPC and TFC in fractions of rambutan and durian peels with their DPPH radical scavenging activity indicating that phenolics and flavonoids in rambutan and durian peels may contribute to their strong antioxidant activities. The antimicrobial activity of the extracts of peels and its fractions were assessed by using disc diffusion method against a bacterial species of Staphylococcus aureus and fungal species, Fusarium oxyporum and Aspergillus flavus. The lowest concentration of methanolic extract of durian and rambutan peels that showed an inhibition against Staphylococcus aureus was 31.25 μg/mL. It was also found out that neither peels of rambutan nor durian had antifungal activity against the two selected fungal species. Results revealed that the peels of rambutan and durian are potential sources of antioxidants and antibacterial agents