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Undergraduate Theses

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

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Committee Member: search.filters.committeemember.Rojo, Josie B.Department: search.filters.department.College of Arts and Sciences

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    Hydrogel composites loaded with plant extract as an antibacterial and quorum sensing inhibiting wound dressing
    Baranda, Marivic M. (Division of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)
    Delayed wound healing is often caused by bacterial infection. Furthermore, the persistent inflammation brought by the formation of biofilm via quorum sensing causes pain and discomfort. In a novel effort, this study fabricated an antibacterial and quorum sensing inhibiting hydrogel dressing loaded with plant extracts. KC-PVP hydrogel composites were loaded separately with lg/mL C. longa and H. durvillei extract under optimized conditions. The hydrogels were characterized through swelling test and FTIR analysis. It was determined that C. longa-loaded and H. durvillei-loaded hydrogels have a maximum swelling capacity of 175% and 135%, respectively. The antibacterial efficacy and the quorum sensing inhibition activity of extract-loaded hydrogels were evaluated using soft-layer agar well diffusion method. Hydrogel loaded with C. longa extract displayed 47.0 (±1.0), 45.0 (±1.0), and 32.33 (±0.58) mm mean growth inhibition against S. aureus, E. coli, and P. aeruginosa, respectively. H. durvillei extract-loaded hydrogels inhibited the growth of S. aureus, E. coli, and P. aeruginosa by 45.33 (±0.58), 43.67 (±1.52), and 33.33 (±0.58) mm in diameter, respectively. The quorum-sensing inhibition zone of C. longa extract and H. durvillei extract-loaded hydrogels were 49.63 (±0.40) and 49.37 (±1.11) mm in diameter, respectively. Overall, the extract-loaded hydrogel composites exhibited good antibacterial and quorum-sensing inhibiting activity, potentially for wound treatment.
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    Development of a high-performance thin layer chromatography (HPTLC)-densitometric method for the estimation of quercetin and kaempferol in Euphorbia hirta (Tawa-tawa) extract
    Baladjay, Diane Monique S. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2017-06)
    A sensitive, fast, efficient, and repeatable high-performance thin-layer chromatographic (HPTLC) method has been developed for simultaneous analysis of quercetin and kaempferol from the extracts of the aerial parts of Euphorbia hirta. In the development of the HPTLC method, different extraction parameters were evaluated and quantification of quercetin and kaempferol in the extract of E.hirta was performed using a densitometric software, Quantiscan™. Among the different combinations of mobile phases used, best separation was achieved in toluene: ethyl acetate: formic acid: methanol (5: 6: 2: 1) solvent system. E.hirta was extracted using the developed extraction method which involves the use of 80% ethanol, 8 minutes of sonication and serial extraction until 3rd extraction. This determined method provides a maximum yield of the compounds at minimum time and cost. The method was also validated for linearity and precision specifically repeatability. The results show that the produced calibration is linear, as supported by the obtained correlation coefficient (r) of > 0.999 and coefficient of determination (R2) of > 0.997. Moreover, the obtained slopes of the calibration curves show that the method is most sensitive towards quercetin and least sensitive to gallic acid. The method was also found out to be repeatable and precise as the %RSD for both the inter-day and intra-day trials obtained a value less than <2%. The present method is being reported for the first time and can be used for routine quality control and quantification of quercetin and kaempferol in various plant samples, extracts, and market formulations.
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    A novel water-in-oil-in-water emulsion to encapsulate antibacterial agents
    Balcarcel, Angelica V. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)
    Encapsulating bioactive compounds can protect them from adverse conditions. This study aimed to encapsulate bioactive agents in a stable multiple emulsion system using a material that can be recovered easily from a product abundant here in the country. Results of the study revealed that the method of encapsulation used is effective in encapsulating and releasing the bioactive compound encapsulated. The antibacterial activity determination showed that encapsulated chlorhexidine is effective against both S. aureus and E. coli bacteria. Further investigation was made by encapsulating aqueous guava (Psidium guajava) extract in the same emulsion system (water-in-oil- in-water) using recovered coconut milk protein (CMP) as a gelling agent. The evaluation of the stability of the emulsions revealed that the treatment with 40% guava extract in the aqueous phase of its primary emulsion (Emulsion 3) is the most stable among the other treatments. This treatment showed the smallest droplet size range and most uniformed droplet sizes. The creaming index of this treatment also showed the lowest values after three (3) weeks of storage. On the other hand, the treatment with 60% guava extract in the aqueous phase of its primary emulsion (Emulsion 4) appeared to be the most stable against heating. However, no antibacterial activity was observed for any of the emulsion systems both S. aureus and E. coli bacteria. Additional test revealed that the bioactive compound present in the plant extract was disrupted by the sonication process
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    Determination of the concentration of essential minerals (Ca, Fe, K, Mg, Na, Zn) in honey samples from Negros Occidental
    Arellano, Lory Mae F. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)
    Honey is a natural, sweet and highly nutritional substance produced by bees through a series of nectar collection and chemical processes. Due to the popularity of the product, certain regions in the Philippines has been producing honey and recently, different apiaries from Negros Occidental has been producing its own share of popular product in the market. The products are well received by the consumers, but the problem is the lack of characterization which gives the product doubtful and unconfirmed nutritional value. This study focuses on the quantification of essential minerals (Ca, Fe, K, Mg, Na, Zn) present in local honey samples from Negros Occidental. Eight honey samples were obtained from the different apiaries including an external sample from Mindoro. Samples were acid digested using HNO3/H2O2 solution at 130 °C. The concentration of each minerals in the honey samples were analyzed using AAS. The data reported high concentration (5.71 to 93.20 ppm) of K on most of the samples. The second most abundant mineral in the local honey is Ca ranging from 13.67 to 45.88 ppm. The Mg concentration ranges from 1.19 to 4.09 ppm while Na is in between 0.82 to 3.14 ppm. The mineral Zn and Fe contained the lowest concentration in most of the samples with Zn at 0.46 to 0.86 ppm and Fe at 0.04 to 0.30 ppm.