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Undergraduate Theses

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    Optimization of parameters for the Fe-humic acid complex formation using cyclic voltammetry
    Bautista, Coleen M. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)
    Humic acid extracted from an artesian well located at Sta. Barbara, Iloilo was used to generate an Fe-HA complex as a potential additive to bio floc systems to augment the essential mineral Fe. The humic acid obtained was black in color and had a powdery texture after oven-drying. The Fe-HA complex were prepared using Fe3+ ions at different pH values specifically at pH 8, 9 and 10. Formation of the complex was investigated using the cyclic voltammetry to determine the ideal conditions to maximize the binding of the metal ion. The results showed that there are two oxidation and reduction cycles which suggests that there are two species undergoing oxidation and reduction. It is possible that the free iron and the Fe in the complex are undergoing a redox cycle although the quinone group in the humic acid can also act as a redox center. Atomic Absorption Spectroscopy can help corroborate the amount of complex formed to help deduce the redox active center.
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    Isolation and partial characterization of globulin from Cassava (Manihot esculenta Crantz) tubers
    Barbosa, May R. (Division of Physical Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2007-04)
    Soluble globulin was isolated using an extraction buffer (0.4 M NaCl in 35 mM potassium phosphate buffer, pH 7.6 with 0.02% Na azide). The isolated globulin was subjected to solubility tests with different NaCl concentrations. It has the highest solubility in 1.25M NaCl (1.09%), but no significant differences existed among the NaCl concentrations by analysis using one-way ANOVA at a = 0.05. Three major bands existed at LOOM NaCl dissolved globulin with molecular weight ranges of 28-33kDa, 38- 43kDa, and 65-70kDa relative to BSA. Two of these bands (38-43kDa and 65-70kDa) were observed in 0.50M and 0.75M NaCl soluble globulin. The 1.25M and 1.50M NaCl concentrations gave a single band (28-33kDa) each, while no clear bands were observed in other NaCl concentrations. Amino acid analysis revealed glutamic acid (12.09%) as the most abundant amino acid component of cassava globulin. Nine (9) essential amino acids were present. Of these nine, lysine (10.50%) is the most predominant. Cystine (0.39%) has the lowest percentage, followed by methionine (1.76%).
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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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    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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    Phytochemical screening, antioxidant activity, and comparative bioefficacy assessment of Camansi (Artocarpus camansi) seed extracts for in vitro antibacterial activity
    Bantayan, Andrea Marie B. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-06)
    This study was conducted to compare and assess the antibacterial and antioxidative properties, and to screen for the presence of phytochemical constituents in the different solvent-derived extracts of Artocarpus camansi seeds from Mintal, Davao City. Phytochemical analysis revealed the presence of alkaloids, flavonoids, glycosides, phenol, steroids, tannins, and terpenoids in the methanol extract. The antibacterial efficacy was determined by agar well diffusion method against B. subtilis and E. coli. Streptomycin was used as a standard drug for the study of antibacterial activity. Sensitivity in terms of zones of inhibition and phytochemical composition of the different extracts were also determined. Results showed that all extracts were effective against both of the bacteria tested with the pet. ether and DCM extracts showing moderate activity, and the methanol extract exhibiting strong activity against B. subtilis and E. coli. Furthermore, methanol extract of A. camansi seeds possessed strong DPPH radical scavenging activity. In the DPPH method, the pet. ether, DCM, and methanol extracts showed free radical inhibition of 18.96±0.16%, 21.62±0.14%, and 90.05±0.08%, respectively. The IC50 value obtained for the methanol seed extract at concentration 0.05 g/mL was 6.67±0.004 g/L. The current findings suggest that the phytochemicals present in the methanol extract of Artocarpus camansi seeds (alkaloids, flavonoids, glycosides, phenol, steroids, tannins, and terpenoids) may be responsible for the antibacterial and antioxidant activity.
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    Marketing of Pina fiber in Balete, Aklan
    Barrios, Jerson T. (Division of Social Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1995-12-01)
    This study describes and analyses the different marketing channels, functions, costs, margins, and the different problems encountered by both producers of pina and middlemen of pina fiber in Balete, Aklan. Of the four barangay sampled, primary data were obtained from ten (10) producers who were asked about their recent halved, and 34 middlemen were consequently interviewed based on their last week’s operations. Results of the study show that out of the 40.200 pina leaves harvested by producers, scrapers absorbed the bulk or 69.71 %(24,900), while the legist fraction of .99% was token by producer-scrapers-trader. Highest prices paid for pina leaves at P0.35 was accorded by producer-scrapper-knotter while scraper-knotter offered the least price at P.25. Despite of the five marketing activities performed, and corresponding costs on marketing Investments, producers still incurred positive financial net farm price of P.217. By marketing functions, seven types of middlemen were observed, namely: scrapers, producer-scrapers, scraper-knotters, producer-scraper-knotter, knotters, producer-scraper-trader, and traders—who essentially perform an overlap of functions. Though all types of middlemen incurred positive gross margin, not everyone experienced positive not margins and net returns. With the bulk of transactions disposed by traders (1,668.125 leaves) and producer-scraper trader (2,000 leaves), these two types of middlemen received positive financial net margins and returns. Of the different marketing problems cited, majority the majority of producers and middlemen were unanimous in pointing at low price of the product as their biggest constraint Other than the need to increase the price, organizing a cooperative and support from the local government, this study suggests, that due to foe duplication of function among types of middlemen, specialization on a particular function (e.g, scraper or knotter— alone) is a must in order to curb the circuitous and dragging flow of the product and lessen costs on labor.
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    Bioaccumulation of cadmium, copper and lead by Hydrilla (Hydrilla vericillata)
    Baniago, Arjay C. (Division of Pysical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2007-04)
    Bioaccumulation of cadmium, copper, and lead by Hydrilla (Hydrilla verticillata) were tested to 5 different initial concentrations. The water contaminant sample was composed of mixed cadmium, copper and lead metals supplied as nitrate salts. These were analyzed for the decrease in concentrations at 24-hour intervals for 5 days using the SpectrAA 55B Atomic Absorption Spectrometer. Plants exposed only for 5 days were digested and analyzed. The plant growth was normal at lower concentrations and showed higher removal efficiency. H. verticillata showed maximum removal percentage on the 5th day of exposure at 5 mg L-1 for cadmium (90.47%) and copper (95.20%) but for lead was on the 1st day (96.74%). The order of metal ion removal and the actual uptake for the three metals by H. verticillata is Pb>Cu>Cd, but at lower concentration, cadmium was absorbed more than copper. The copper and lead uptakes by H. verticillata are superior as compared to other aquatic plants uptakes. Lead uptake at higher concentrations might be due to physicochemical adsorption of the metal to the plant components and not on metabolism-mediated uptake, because plant condition does not have an adverse effect on the uptake
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    Karyotype analysis of garlic, Allium sativum L. (Alliales; Alliaceae)
    Bandiola, Ma. Florma A. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1994-03)
    The C-metaphase count of Allium sativum L. showed a chromosome number of 2n = 14, consisting of six long and eight short somatic chromosomes categorized into three distinct groups: ten m type chromosomes with centromeres at the median region, two sm type chromosomes with submedian centromere and two st type chromosomes with subterminal centromere, Mitotic index for the species was computed at 16.88%.
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    Antioxidative properties of the fruits of selected tomato (Lycopersicon esculentum Mill.) varieties
    Baltazar, Gleza Wae D. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-05)
    This study was conducted to compare the antioxidative properties of greenstage fruits of selected Lycopersicon esculentum Miller varieties (Diamante, Diamante Max, and Pidada) from Barangay Durog, Miagao, Iloilo. The fresh fruit samples were extracted with 95% ethanol. The crude extracts were concentrated using rotary evaporator. The antioxidant activity of the ethanolic fruit extracts was assayed for DPPH radical scavenging activity and the IC50 values were determined. The determination of the phenolic and flavonoid contents was done employing Folin- Ciocalteu method and aluminum chloride spectrophotometric method, respectively. The results show that the fruits of the studied L. esculentum varieties exhibit DPPH radical scavenging activity. The IC50 values, however, differ significantly among the varieties. The IC50 values for Diamante (24.22 ± 1.41 g/L) and Diamante Max (25.08 ± 0.45 g/L) are comparable but are significantly lower than Pidada (29.47 ± 1.33 g/L). These findings imply that Diamante and Diamante Max varieties have stronger antioxidative capacity than the Pidada variety. Moreover, the results indicate that the antioxidative property of L. esculentum is variety-dependent. The results of the determination of the total phenolic content, expressed in mg gallic acid equivalent (GAE) per g fresh sample, are in the order of 0.16 ± 0.02 mg GAE/g for Diamante > 0.15 ± 0.02 mg GAE/g for Diamante Max and Pidada. On the other hand, the results of the determination of the flavonoid content, expressed in μg quercetin equivalent (QE) per g fresh sample, are in the order of 6.31 ± 1.27 μg QE/g for Diamante >6.21 ± 0.88 μg QE/g for Diamante Max > 5.63 ± 0.94 pg QE/g for Pidada. No significant difference in the total phenolic and flavonoid contents was found among varieties. Nonetheless, the detection of phenolics and flavonoids, known antioxidants, supports the present results on the antioxidative property of the fruits of the L. esculentum varieties studied.
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    Antioxidant property, total phenolics, manganese and iron content of humic acid obtained from Sta. Barbara, Iloilo artesian well water
    Baltazar, Lenmark Anthony M. (Division of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-06)
    The town of Santa Barbara in Iloilo is famous for its reddish browncolored well water due to the presence of humic acid which makes up most of the water’s natural organic matter content. Because the well water is used by the local townsfolk for drinking and other domestic activities, it is imperative that a study must be made to assess its potential health benefits and risks. In this study, the DPPH radical scavenging activity of the extracted humic acid was investigated. It was determined that the sample contains antioxidants capable of reducing DPPH with an IC5o of 51.552± 0.652 ppm. Prussian Blue Assay for total phenolic content also showed that a 76.5 ppm humic acid sample has 14.169 ± 1.151 ppm in GAE. Flame-AAS analysis showed that the humic acid sample contains iron (0.8376 ± 0.0581 ppm). The manganese content of the sample was below the detection limit of the instrument. The results suggest that the humic acid extracted from the well water contains potential antioxidants which can be exploited for various commercial and medical applications.