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Undergraduate Theses

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

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Degree: search.filters.degree.Bachelor of Science in ChemistryKeyword: search.filters.keyword.Garlic

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    Antimicrobial, antioxidant and phytochemical properties of ethanolic and water extracts of selected local spices from Miagao, Iloilo
    Besinga, Yvonne Grace M. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-06)
    Spices such as garlic, pepper and turmeric are indispensable in the daily food preparation and are reported to have compounds which prevent the microbial spoilage of food. This study evaluates the antimicrobial and antioxidant activities as well as the phytochemical properties of the ethanol and aqueous spice extracts of garlic, pepper and turmeric. The antioxidant activity was performed using l,l-diphenyl-2-picryl- hydrazyl (DPPH) Radical Scavenging Method and the antimicrobial activity was evaluated by Disk Diffusion Assay. Phytochemical compounds tested were alkaloids, flavonoids, terpenoids, phenol and saponins. In decreasing order, the potency of the antioxidant activities showed Ascorbic acid > turmeric ethanol extract >pepper water extract> pepper ethanol extract> turmeric water extract> garlic ethanol extract> garlic water extract. The antimicrobial activity was highest in turmeric aqueous extract in terms of mean inhibition zone (7.5±2.10) against E. coli. The most effective treatment against B. subtilis was turmeric ethanol with highest mean inhibition zone (6.87±1.13). And for S. aureus, garlic ethanol extract has the highest mean inhibition zone (7.80±1.32). Phytochemical screening tests showed that in all treatments, the most abundant phytochemical were alkaloids and terpenoids. This study indicates that the spices like garlic, pepper and turmeric have antimicrobial and antioxidant activity.
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    Comparing the quercetin content of different Allium sp. by spectrophotometry
    Asuelo, Allen Daryl F. (Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2007-04)
    Quercetin from two Allium sp. was extracted sequentially with solvents of varying degrees of polarity. The crude quercetin was subjected to chemical tests and the concentration determined by using Shimadzu mini UV-Vis 1240 Spectrophotometer. Results of the study showed that the extraction procedure used was effective in extracting quercetin. This was verified by the identical spectrum obtained with quercetin from the standard (Quercetin Complex) with the IR spectrum of quercetin obtained from the literature. The crude quercetin was positive to the both chemical tests, namely Baeyer's and Ferric chloride tests, subjected to it. Quercetin content in red onions was obtained with mean concentrations of 10.60 mg/kg at 362nm and 7.429 mg/kg at 370nm. Quercetin content in garlic was obtained with mean concentrations of 9.692 mg/kg at 362nm and 5.689 mg/kg at 370nm. The quercetin concentration measured at 370nm was quercetin another wavelength at 362nm measured the concentration of quercetin as flavonols. The result of One-way ANOVA at 0.05a showed that there is a significant difference in the quercetin content between red onions and garlic.