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Undergraduate Theses

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

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Adviser: search.filters.advisor.Ortillo, Danilo O.Committee Chair: search.filters.chair.Janagap, Steve P.

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    Physicochemical characterization and FTIR Analysis of the essential oil from Almaciga (Agathis philippinensis Warb) gum
    Briones, Kathleen Faith C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-02)
    Almaciga (Agathis philippinensis ) is one of the few conifer timber species endemic to the Philippines. It is highly valued for its resin which is the world- renowned Manila copal (hard resin). Manila copal have been reportedly employed in treating asthma, headaches, myalgia and even arthritis. An ethnomedical documentation of Manila copal usage also reported the utilization of the resin for stomachache, ulcers and dysentery. However, there is only limited literature regarding the Almaciga gum (the softer resin). To provide supplemental data regarding the Almaciga gum, this study was conducted to characterize the physicochemical properties and to identify the major functional groups of the essential oil extracted from its resin. The essential oil was extracted using a makeshift steam distillation set- up with a total yield of 3.20%. The essential oil was found to have a refractive index of 1.4731± 0.0002, a density of 0.8502±0.0039 g/mL, and a specific gravity of 0.8527±0.0039. Odor, color and appearance were evaluated using the organoleptic method. Major functional groups were identified from Fourier Transform - Infrared Spectroscopy (FTIR) which suggested that limonene is the major component.
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    Phytochemical screening, antibacterial and antioxidant activities of the crude ethanolic extract of calamansi (Citrus microcarpa) peels
    Baquiano, Clarie Dean C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    Citrus fruits are well-known sources of vitamin C, and like most other whole foods, they also contain an impressive list of other essential nutrients and high amounts of phytochemicals. Calamansi, scientifically known as Citrus microcarpa, is a native citrus plant cultivated throughout the Philippines. Calamansi is chiefly utilized for its pulp and juice but the peels and pressed pulp, covering each individual segment of the edible portion and seeds are considered as wastes and thrown away. To further utilize the rind or peels, this study was conducted to investigate the antioxidant and antibacterial properties of the crude ethanolic extract of C. microcarpa peels. Presence of select phytochemicals was also tested. The antioxidant and antibacterial activities were investigated using the DPPH (2,2-diphenyl-picrylhydrazyl) free radical scavenging assay and Kirby-Bauer disc diffusion susceptibility method, respectively. Results of the phytochemical screening have confirmed the presence of alkaloids, flavonoids, tannins, terpenoids, steroids and saponins in the extract. Crude ethanolic extract of C. microcarpa peels also showed activity against DPPH radicals with a half maximal inhibitory concentration (IC50) of 14.46 pL/mL, a much higher IC50 value compared to the positive control, ascorbic acid, with 8.36 pL/mL. The antibacterial activity assay of the extract showed minimal inhibition against E. coli and S. aureus.
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    Antibacterial activity, antioxidant property and photochemical analysis of crude ethanolic extract from Dalanghita (Citrus nobilis) peels
    Aglobo, Jastine S. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2015-05)
    The crude ethanolic extract of Dalanghita (Citrus nobilis) was studied for their antibacterial activity, antioxidant and phytochemical properties. The DPPH free radical scavenging assay of extracts with varying concentrations showed strong antioxidant activity with a maximum % inhibition of 92.30 at 80.70 ug/mL concentration. The IC50 was calculated to be 26.26 pg/mL against 12.48 ug/mL for Ascorbic acid, the positive control. The antibacterial activity of the extract was determined against Escherichia coli and Staphylococcus aureus by measuring the mean zones of inhibition using the paper disc diffusion assay at different concentration of crude ethanolic extract. The crude ethanol extract at 100% concentration yielded the highest inhibition for E. coli at 21.50±0.50 mm which is comparable to tetracycline, the positive control. The presence of phytochemicals in the extract were evaluated and the phytochemicals identified were: alkaloids, flavonoids, saponins, steroids, tannins, and terpenes.