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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 ChemistrySDG: search.filters.sdg.SDG 11 - Sustainable cities and communities

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    Phytochemical screening, antibacterial and antioxidant activity of Ethanolic seed extract of Kadios (Cajanus cajan) from Igbaras, Iloilo, Philippines
    Bautista, Lance Ruther E. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-06)
    Natural products are products which may have been chemically synthesized, through semi- or total synthesis. The presence of these natural sources gave us greater opportunity for discovery and different innovations, as answers to the emerging needs of the people. This study focused on the chemical properties, antibacterial and antioxidant activity, of Cajanus cajan, popularly known as Kadios, from Igbaras, Iloilo, Philippines. A total of 371.98 grams of air-dried C. cajan seeds was macerated to 1000 mL of ethanol for 72 hours. The concentrated extract was subjected to three tests and assays. All tests were done in triplicates. The test for phytochemicals, which served as the preliminary screening, revealed that the ethanolic extract of Kadios seeds contains alkaloids, flavonoids, phenols, saponins, tannins, quinones, and steroids. The antibacterial assay showed that the ethanolic seed extract of C. cajan can inhibit the growth of Gram-negative bacteria, E. coli, with zone of inhibition equal to 10.3 ±2.15 mm to 33 ± 1.63 mm. The antioxidant assay revealed that the extract has positive inhibition only at high concentration against DPPH, and so IC50 was further determined to be 27,310 ug/mL. Statistical analyses were also done, and confirmed that there is significant difference among the data at (P<0.05). Summing up, the extract has antibacterial activity and minimal or almost close to zero antioxidant activity, while containing a remarkable number of secondary metabolites causing the chemical activities of the extract.
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    Antifungal activities of lemongrass (Cymbopogon citratus) essential oil -B-cyclodextrin inclusion complex incorporated in commercial fish feeds
    Baure, Jiaren G. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)
    During the wet season in the Philippines, fish feeds can be contaminated with mycotoxins, affecting fish production. The addition of essential oil (EO) is one of the ways to prevent this, but it is prone to physical and chemical reactions. Thus, this study aims to encapsulate lemongrass essential oil (LGEO) in B-cyclodextrin (B-CD) to produce an inclusion complex (IC) that can be used as an additive in commercial tilapia feeds to prevent or minimize fungal contamination. The inclusion complex was made using the co-precipitation method and was characterized by Fourier Transform Infrared (FTIR) Spectroscopy. The spectrum was similar to that of citral, a major component of lemongrass essential oil that is responsible for inhibiting fungi. The antifungal activities of pure and encapsulated LGEO at varying concentrations against Aspergillus species were carried out by the Agar Well Diffusion assay. Results showed that A. flavus was more susceptible in LGEO and IC compared with A. fumigatus. The tested concentration of EO could inhibit both fungi. However, it would take 50% IC to effectively inhibit the growth of both fungi. The stability of the inclusion complex in commercial fish feeds was also evaluated. The feeds were stored in an area with the appropriate conditions that could promote the growth of molds, such as temperature (>27°C), moisture levels (14%), and relative humidity levels (>70%). The results showed that the encapsulated LGEO was effective in extending the shelf life of the feeds and was best observed at a concentration of 5 g kg-1 IC. The oil remained active for nine days, wherein about 10- 40% of the feeds with 5 g kg-1 IC were covered with molds. On the other hand, about 70-100% of the surface of the feeds with essential oil was contaminated with molds after nine days, which indicated that encapsulation of EO was needed to maintain its effectiveness as an antifungal agent.
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    Isolation and purification and bioactive components from the fruit of Morinda citrifolia
    Barbarona, Hazel M. (Division of Phyisical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2000-10)
    Phytochemical screening done on the fruit of “noni” Morinda citrifolia revealed the presence of saponins and the absence of alkaloids. Sequential extraction of active components of noni using n-hexane, dichloromethane and ethyl acetate solvents gave yields of 0.09%, 0.31% and 0.11% as yields respectively. Crude methanolic concentrate of the noni fruit was subjected into four bioactivity tests. Toxicity bioassay showed 251.19 g/ml to be the LC50. Antimicrobial bioassay showed that S. aureus, B. subtilis, E. coli, and P. auruginosa organisms have no activity against the crude methanolic concentrate. In analgesic bioassay, the crude methanolic concentrate (16.37) is no better or has the same activity with the positive control mefenamic acid (17.51) based on the percentage reduction in squirms of the Swiss Websters mice. Antispasmodic activity showed that the crude methanolic concentrate of the fruit (55.47%) is as active as the positive control, loperamide (58.02%). In the three fractions, antispasmodic activity of n-hexane and dichloromethane have greater effect than the positive control (loperamide) while ethyl acetate has the same activity with it. The percentages traveled by charcoal in n-hexane (39.929) and dichloromethane (45.908) were lower than that of the positive control, loperamide (60.130) and ethyl acetate fraction (48.352). Antispasmodic bioassay on n-hexane purified through Vacuum Liquid Chromatography showed that the nine fractions (F1-F9) showed no significant difference with the positive control. Thin Layer Chromatography showed the presence of mono-, di-, and triterpenes; steroid glycosides and saponins in the noni fruit extract.
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    Determination of the anthocyanin content in Hibiscus sabdariffa L. (Roselle) calyses from fresh to spray-dried form
    Arganioza, Hannah Mae C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    Hibiscus sabdariffa L. is an agricultural herb with calyces as the commercially important part this plant. The calyces is a good source of anthocyanin (pigments) with several potential applications in the food, pharmaceutical and cosmetic industries. These pigments are used worldwide in the production of drinks and as a source of natural food coloring. However, these pigments are very unstable due to processing and storage conditions. Thus, this present study investigated the amount of anthocyanin as it is processed into a commercial product in the form of spray-dried powder. The Roselle plant samples were obtained from Herbanext Laboratories farm. The fresh extract has 493.45 mg/L total monomeric anthocyanin. Compared to the fresh extract, concentrated aqueous spray-dried extract (261.06 mg/L) contains lower anthocyanin content, however, this is significantly higher than aqueous concentrate (124.41 mg/L). Both the aqueous extract and ethanolic extract contains the smallest amount of anthocyanin for each sets. Spray drying techniques increases the amount of anthocyanin which helps to prevent further degradation of the compound due to the influences of the storage environment and processing conditions.