http://dspace.cas.upm.edu.ph:8080/xmlui/handle/123456789/2823 Bachelor of Science in Biochemistry Wed, 08 Apr 2026 05:11:09 GMT 2026-04-08T05:11:09Z http://dspace.cas.upm.edu.ph:8080/xmlui/handle/123456789/3611 Title: The Antimicrobial Property of Psidium guajava Linn. (Guava) Leaf and Fruit on the Periodontopathogen Porphyromonas gingivalis and the Partial Characterization of its Active Component Authors: Henson, Karl Evans R. Abstract: The various components of Psidium guajava Linn. (Guava) leaves and fruit were extracted using a Soxhlet extractor (organic) and by boiling (aqueous). The crude extracts were subjected to further fractionation using organic solvents. The fractions obtained were tested on Porphyromonas gingivalis, one of the major pathogens causing periodontitis. The bioactive fraction, the aqueous water layer of the leaf, was characterized by phytochemical screening. Results showed that guava leaves exhibit antimicrobial effect on P. gingivalis, as shown by the 14-mm zone of inhibition of the crude aqueous extract of the leaf and the 12.33-mm zone of inhibition of the aqueous water layer of the leaf. All other fractions, including all fruit fractions, did not exhibit microbicidal properties. Phytochemical screening revealed that the bioactive fraction contains tannins, plant acids, reducing substances, and flavonoids. Fri, 01 Mar 2002 00:00:00 GMT http://dspace.cas.upm.edu.ph:8080/xmlui/handle/123456789/3611 2002-03-01T00:00:00Z http://dspace.cas.upm.edu.ph:8080/xmlui/handle/123456789/3103 Title: Synthesis and Physico-chemical Characterization of Alkyd Resin from Lumbang Derived Oil Authors: Lola, Lisette Joyce U. Abstract: Oil was successfully extracted from Lumbang kernels in which it was characterized for its properties. FT-IR spectrum showed pertinent peaks corresponding the presence of functional groups such as ester and sp® C-H stretching. The alkyd resin from Lumbang-derived oil was also successfully synthesized by first undergoing alcoholysis reaction of Lumbang oil and glycerol followed by esterification reaction in the presence of phthalic anhydride. The properties of synthesized alkyd resin were shown in the FT-IR and GC-MS analyses. FT-IR showed pertinent peaks corresponding to the presence of O-H C-O, C=0, C-H and C=C stretching frequencies. GC-MS data confirmed the presence of saturated and unsaturated fatty acid in the structure of the Lumbang oil and alkyd resin. Alkyd resin was also synthesized in which its oil was first purified by deep eutectic solvent (DES, 1:2:1 choline chloride:ethylene glycol:glycerol). The synthesized alkyd resins were then characterized based on its adhesive property and chemical resistance. It was found out that presence of alkyd resin with paint leads to longer drying time. In terms of chemical resistance, paint is not chemically resistant to basic and acidic media. Moreover, with the presence of the alkyd resin, paint quality showed to be improved in terms of its adhesive property. Being an additive to paint, results showed that addition of even a small amount of alkyd resin would enhance the quality of the coating. Thus, with all the ratio of alkyd resin to paint that was tested, a ratio of one alkyd resin to five paint possessed the least drying time, most chemical resistant to acidic and basic medium, and have a good adhesive property. Sun, 01 Jul 2018 00:00:00 GMT http://dspace.cas.upm.edu.ph:8080/xmlui/handle/123456789/3103 2018-07-01T00:00:00Z http://dspace.cas.upm.edu.ph:8080/xmlui/handle/123456789/2825 Title: Green and Rapid Synthesis of N-acetyl-L-cysteinecapped ZnSe Quantum Dots in the Aqueous Phase via Microwave Irradiation. Authors: Estaris, Mylene P. Abstract: A green and rapid approach was applied in synthesizing water-soluble N-acetyl-Lcysteine (NAC)-capped ZnSe quantum dots (QDs) in the aqueous phase via microwave irradiation. The precursors used were relatively less toxic and did not need pre-treatment prior to reaction. Using IR spectroscopy, NAC molecules were revealed to be successfully mounted on the surface of core ZnSe QDs making the nanoclusters water-soluble. Absorption and emission measurements revealed that the size of the products increases as the duration of reflux increases. The sharp excitonic feature of the absorption spectra was also indicative of the narrow size distribution of the synthesized quantum dots. The as-per synthesized NAC-capped ZnSe QD was determined to possess photoluminescence quantum yield (PLQY) of up to 18% in reference to Rhodamine 6G without post-treatments. Optimum %PLQY was revealed to occur after 60 minutes of reflux. The method employed in synthesizing water-soluble ZnSe quantum dots was proven to be fast and less toxic and showed to improve the optical properties of quantum dots with respect to conventional heating. Mon, 01 Apr 2013 00:00:00 GMT http://dspace.cas.upm.edu.ph:8080/xmlui/handle/123456789/2825 2013-04-01T00:00:00Z http://dspace.cas.upm.edu.ph:8080/xmlui/handle/123456789/2824 Title: Cobalamin as Colorimetric Sensor for Gas Pollutants Authors: Pabilane, Alma L. Abstract: Cobalamin (Cbl) exposed to gases resulted in color changes visible to the naked eye. These reactions were further analyzed by UV-Vis and IR spectroscopies. Among gases tested, carbon dioxide, sulfur dioxide and nitrogen dioxide, only SO, and NO; induced color changes to the cobalamin. It is proposed that color changes observed were due to metal-gas binding (for NO) and protonation of the benzimidazole group of the cobalamin (for SO,). It was further observed that initial color of cobalamin solution upon introduction of gases changes as time elapses. It is suggested that Cbl-NO; binding, which caused the initial color change from red to yellow-orange is possibly reversible due to photolysis and the color change undergone by cobalamin exposed to SO, that is initially orange and turned yellow afterwards is due to slow protonation of cobalamin, forming a cobalamin species with protonated benzimidazole group which has yellow appearance. Mon, 01 Apr 2013 00:00:00 GMT http://dspace.cas.upm.edu.ph:8080/xmlui/handle/123456789/2824 2013-04-01T00:00:00Z