UPV Digital RepositoryUPV-DRUniversity of the Philippines Visayas
 

Undergraduate Theses

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/13

Browse

Filters

2009 - 200922010 - 20113

Settings

Committee Chair: search.filters.chair.Cainglet, Rica P.SDG: search.filters.sdg.SDG 15 - Life on land

Search Results

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    In vitro antibacterial activity of Hibiscus rosa sinensis leaf extracts against some pathogens associated with urinary tract infections
    Cabayao, Coney B. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2011-04)
    The in vitro antibacterial activity of Hibiscus rosa sinensis leaf ( methanolic, dichloromethane, ethyl acetate, n-hexane, and aqueous ) extracts were studied against Gram-negative (Escherichia coli and Pseudomonas aeruginosa ) and Gram-positive ( Streptococcus faecalis) bacteria. The methanolic extract was subjected to sequential liquid-liquid extraction using solvents of varying polarity and concentrations. Out of the 5 extracts, methanolic and dichloromethane extracts exhibited the highest antibacterial activity as measured using the zone of inhibition. This was followed by ethyl acetate and n-hexane extracts. At 200 mg/ml concentration, all extracts were considered active when tested with E. coli and S. faecalis, and were partially active against P. aeruginosa. The aqueous extract was inactive towards the three bacteria. The 200 mg/ml concentration showed no significant difference when compared with the positive control, amoxicillin (12.51μg/ml). This shows that Hibiscus rosa sinensis exhibits a promising antibacterial activity. Phytochemical analysis of the active fraction- the methanolic extract- showed the presence of alkaloids, tannins, glycosides, saponins, steroids, flavonoids, terpenoids, and anthraquinones. These bioactive components could be responsible for the antibacterial activity of Hibiscus rosa sinensis leaf extracts.
  • Thumbnail Image
    Item
    The adsorption capacity of silica gel and rice hull ash on phenol and aniline
    Bulatao, Ben Fermin P. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2011-04)
    Chemical waste has been a problem here in the University of the Philippines Visayas, Miagao, Iloilo. Various methods of removal have been utilized. Extraction of silica gel from rice hull and rice hull ash was used to remove organic compounds (phenol and aniline). In this study, silica gel and rice hull ash adsorption on phenol and aniline were investigated with varying contact time and initial concentration. Silica gel reaches its optimum adsorption of both phenol and aniline at 60 minutes contact time. Silica gel was the basis for rice hull ash’s contact time because rice hull ash is 90% by weight silica gel.. Silica gel-phenol system decreases it adsorption capacity as the initial concentration is increased from 25 ppm to 100 ppm. Rice hull ash- phenol system, on the other hand, shows that the adsorption capacity increases as the initial concentration is increased. Both on silica gel-aniline system and rice hull ash- aniline system have increasing adsorption as initial concentration is increased. As the contact time is increased, adsorption increases only until it reaches its optimum adsorption which is 60 minutes contact time where saturation is reached. Increasing initial concentration however has different effect on adsorption on all system explained by the adsorption isotherms. The isotherms show that phenol has the fastest rate to form a monolayer (K and Q°) with the greatest binding strength (b) on silica gel. It is also observed that phenol and aniline formed a monolayer (1/n) on the surface of the silica gel and rice hull ash.
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    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.