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UPV Theses and Dissertations

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    Sodium and potassium concentration ratio in mangrove leaves as sublethal indicator of oil stress in mangrove trees, Taklong Island National Marine Reserve (TINMAR), Nueva Valencia, Guimaras
    Alianza, Carmen Gabrielle H. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2009-04)
    This study is in the second year of the five-year research that was assigned to UPV to monitor the effects of the oil spill in TINMAR. This research primarily focuses on the Sodium and Potassium ion concentration ratios in the leaves of the mangroves which will be used as sub-lethal indicators of oil stress in the mangrove trees. Specifically, this study determined the total amount of Sodium and Potassium ions present in the mangrove leaves using Flame-Atomic Absorption Spectrometer, compared the Potassium and Sodium ion concentrations among the different species and between sampling sites and determined the sensitivity of the species based on the changes in Na/K ratio. Results showed that the total Sodium concentrations were within the values under normal conditions except for Rhizophora apiculata and Rhizophora mucronata and the total Potassium concentrations were also within the values under normal conditions except for the Sonneratia alba species in Bagatnan. The Na/K ratio determined the sensitivity of the mangrove species studied to oils stress. A lower ratio of Na/K compared to the control area means that the mangroves trees were able to cope up with stress and an elevated Na/K ratio means the mangrove trees are still undergoing stress. The Control area, however, have elevated Na/K ratio because of high Sodium concentrations and very low concentrations of Potassium in the plant leaves tissues.
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    Anti-inflammatory and antibacterial activities of Batuan (Garcinia binucao) fruits
    Albano, Zella Faye (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2010)
    In this study, fresh fruits of batuan (Garcinia binucao) was evaluated for its antiinflammatory and antibacterial activities. The anti-inflammatory assay using Carrageenan-Induced Paw Edema Method showed that n-hexane extracts (65.79%) and dichloromethane extracts (64.91%) exhibited anti-inflammatory activities comparable to Indomethacin, the positive control (67.11%). The antibacterial assay using Paper Disk Diffusion Method showed that crude methanolic extracts, n-hexane extracts and dichloromethane extracts at 1000pg/mL were most effective against Staphylococcus aureus. The microbial indexes were 0.39, 0.47 and 0.50 respectively. The positive control, Amoxicillin has a 3.39 microbial index. The components of the three most active extracts (crude methanolic, n-hexane and DCM extracts) from both assays were separated through Thin Layer Chromatography and subjected to phytochemical tests. Crude methanolic extracts contained alkaloids, phenolic compounds and cardiac glycosides. Both n-hexane and DCM extracts contained terpenes, alkaloids, saponins, phenolic compounds and cardiac glycosides. These bioactive compounds present may have been responsible for the antiinflammatory and antibacterial activities of the extracts.
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    Partial purification of pH indicator extracted from Rhoeo spathacea
    Apa, Junna T. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2009-04)
    pH test papers are still utilized nowadays despite the prevalence of pH meters, because it is more convenient to use in measuring the pH of a certain substance. The use of natural dye as a pH indicator can serve as a good substitute for an expensive commercial dye that most high schools cannot afford. The pH test papers were prepared by impregnation of 0.03% pure dye extracted from Rhoeo spathacea. TLC was performed to partially remove other plant dye components from the pH active ingredient. The color transition chart was then created at pH ranging from 1.0-13.0 at one unit interval using phosphate buffer. The color transition chart of pure dye extract was compared to the color transition chart of crude dye extract at different pH. Paper impregnated with 0.03% partially purified indicator dye extracted from Rhoeo spathacea showed color transitions from pink to red violet at pH 1.0-3.0; red violet to lavender at pH 3.0-4.0; lavender to blue at pH 4.0-7.0; blue to blue green at pH 7.0-8.0; blue green to green at pH 8.0-11.0; green to yellow green at pH 11.0-12.0; and yellow green to yellow at pH 12.0-13.0. Results also showed that the purified dye extract is a better pH indicator in comparison with the crude dye extract. Spectrophotometric determination of pKa of the indicator was unsuccessful due to the strong overlapping of the UV-Vis spectrum of the acidic and basic forms of the plant dye extract. Titration results showed that the plant indicator can serve as a substitute for the methyl red and phenolphthalein indicators for strong acid-strong base and weak acid-strong base titration, but not for weak acid-weak base titration.