Undergraduate Theses
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Item Antidiarrheal activity of Pterocarpus indicus bark extracts using castor oil-induced diarrhea model on miceCabatea, Norberto C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2010-04)This study evaluated the antidiarrheal activity of the bark of Pterocarpus indicus (Narra). The crude methanolic extract of the bark was subjected to sequential extraction using hexane, DCM, and ethyl acetate. These extracts were tested for antidiarrheal activity in vitro using the castor oil induced diarrhea model in mice employing charcoal tracing method. Thin Layer Chromatography (TLC) was used in determining the chemical constituents present in every extracts using spraying reagents to aid in the visualization of spots. Crude methanolic extract dosage 200 mg/kg body weight is the comparable dosage to the reference drug loperamide (2 mg/kg body weight). The hexane extract was the most active fraction and 200 mg/kg dosage was more effective than with the positive control loperamide (2 mg/kg). No antidiarrheal activity found in the fraction of DCM and ethyl acetate extracts. Phytochemical screening revealed positive tests for tannins, phenolics, terpenes, cardiac glycosides, saponins and reducing sugars in all fractions. Tests for flavonoids and alkaloids, however, were negative.Item In vitro antibacterial activity of Hibiscus rosa sinensis leaf extracts against some pathogens associated with urinary tract infectionsCabayao, Coney B. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2011-04)The in vitro antibacterial activity of Hibiscus rosa sinensis leaf ( methanolic, dichloromethane, ethyl acetate, n-hexane, and aqueous ) extracts were studied against Gram-negative (Escherichia coli and Pseudomonas aeruginosa ) and Gram-positive ( Streptococcus faecalis) bacteria. The methanolic extract was subjected to sequential liquid-liquid extraction using solvents of varying polarity and concentrations. Out of the 5 extracts, methanolic and dichloromethane extracts exhibited the highest antibacterial activity as measured using the zone of inhibition. This was followed by ethyl acetate and n-hexane extracts. At 200 mg/ml concentration, all extracts were considered active when tested with E. coli and S. faecalis, and were partially active against P. aeruginosa. The aqueous extract was inactive towards the three bacteria. The 200 mg/ml concentration showed no significant difference when compared with the positive control, amoxicillin (12.51μg/ml). This shows that Hibiscus rosa sinensis exhibits a promising antibacterial activity. Phytochemical analysis of the active fraction- the methanolic extract- showed the presence of alkaloids, tannins, glycosides, saponins, steroids, flavonoids, terpenoids, and anthraquinones. These bioactive components could be responsible for the antibacterial activity of Hibiscus rosa sinensis leaf extracts.Item Abundance, composition and vertical distribution of calanoid copepods in Central Sulu seaBurgos, Lora A. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)Calanoid copepods are dominant component of the copepod community, which in turn highlights their influence on the overall zooplankton assemblage of the water column. Studying their abundance and distribution, is important on understanding their role in the dynamics of commercially important organism like the fish. Calanoid samples in study, were part of the zooplankton samples taken during the Joint PhilEx oceanographic cruise on board RAZ Melville in December 2007 in the Central Sulu Sea from MOCNESS station 29. Calanoid abundance, composition and distribution were investigated. Fifteen (15) calanoid families were identified all throughout the water column (0 - 400 m). The calanoid assemblage was dominated by 27 % Eucalanidae, 12 % Rhincalanidae, Scolecitrichidae with 7 % and other families contributing to roughly 19 % of the total. The water column was divided into 2 distinct depth cluster based on species distributions; (1) layers above thermocline (0 - 150m) and (2) deeper layers (200 - 400m). Furthermore, upper layers were characterized by distinctive calanoid family assemblage which includes; Calanidae, Euchaetidae, Eucalanidae, Candaciidae, Rhincalanidae, and Temoridae. While deeper layers, calanoid families includes; Metridinidae, Scolecitrichidae, Rhincalanidae, and Euchaetidae. ANOSIM results showed significant differences between these depth clusters, with global R = 0.81 and p = 0.01. These appear to be highly related to the thermocline in both stations, where typically higher upper-layer primary productivity can support dense communities of zooplankton.Item The pharmacological screening of Moringa oleifera Lam.Burgos, Karen J. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1998-07)Moringa oleifera, Lam, or malunggay, belongs to Family Moringaceae. The medicinal value of this plant has long been recognized in folk medicine. Not all the claims, however, are proven scientifically. This study aimed to (1) test the crude extracts from the seeds and leaves of M. oleifera for pharmacological properties and (2) to compare its efficacy with the drugs commonly used to alleviate particular ailment. Phytochemical assay for alkaloid using Culvenor-Fitzgerald method was done to test the presence of alkaloids. The dried seeds and young leaves were extracted with methanol and concentrated under reduced pressure at 45°C. The resulting extracts were partitioned and used for the different assays: Brine shrimp assay for cytotoxicity, Acetic acid-induced writhing assay for analgesic activity, Charcoal tracing assay for antispasmodic activity and paper disc diffusion method for antimicrobial activity. Result showed that only the seeds have alkaloids. Toxicity test revealed that the seeds are practically non-toxic but the leaves were toxic with an LC50 of 550 μg/mL after 24 hours of exposure. Of the two extracts, only the leaves exhibited analgesic activity although not as effective as Mefenamic Acid in reducing pain. The leaf extract, was also found active against Bacillus subtilis, Staphylococcus aureus , Escherichia coli,and Pseudomonas aeruginosa. The seed extract was active only against B. subtilis. Both extracts, however, are not as effective as the antibiotic drug, Amoxicillin. Results also showed that both extracts do not have antispasmodic activity. The study confirmed the antimicrobial and analgesic activities for the use of the leaves of this plant in folk medicine.Item The adsorption capacity of silica gel and rice hull ash on phenol and anilineBulatao, Ben Fermin P. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2011-04)Chemical waste has been a problem here in the University of the Philippines Visayas, Miagao, Iloilo. Various methods of removal have been utilized. Extraction of silica gel from rice hull and rice hull ash was used to remove organic compounds (phenol and aniline). In this study, silica gel and rice hull ash adsorption on phenol and aniline were investigated with varying contact time and initial concentration. Silica gel reaches its optimum adsorption of both phenol and aniline at 60 minutes contact time. Silica gel was the basis for rice hull ash’s contact time because rice hull ash is 90% by weight silica gel.. Silica gel-phenol system decreases it adsorption capacity as the initial concentration is increased from 25 ppm to 100 ppm. Rice hull ash- phenol system, on the other hand, shows that the adsorption capacity increases as the initial concentration is increased. Both on silica gel-aniline system and rice hull ash- aniline system have increasing adsorption as initial concentration is increased. As the contact time is increased, adsorption increases only until it reaches its optimum adsorption which is 60 minutes contact time where saturation is reached. Increasing initial concentration however has different effect on adsorption on all system explained by the adsorption isotherms. The isotherms show that phenol has the fastest rate to form a monolayer (K and Q°) with the greatest binding strength (b) on silica gel. It is also observed that phenol and aniline formed a monolayer (1/n) on the surface of the silica gel and rice hull ash.Item Physicochemical characterization and FTIR Analysis of the essential oil from Almaciga (Agathis philippinensis Warb) gumBriones, 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.Item Extraction of humic substances from vermicompost and application as component matrix for slow-release fertilizersBoloron, Nina Loren R. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)Humic acid was extracted from vermicomposts (hereafter referred as VCHAs) by alkali/acid fractionation and their concentration were determined to be 54.79 (± 0.25) g HS/kg vermicompost in average. The extracted humic substances from vermicomposts were also determined to contain an average K+ of 0.0671 (± 0.0053) g K/kg vermicompost. The Fourier transform infrared spectra of crude VCHSs show similar spectral features with humic acids extracted from vermicomposted materials. The VCHSs were complex with K nutrient and encapsulated in cross-linked Ca-alginate to form vermicompost humic substance — potassium slow-release fertilizer bead (VCHS-K SRF). The synthesized VCHS-K SRF were subjected to total nutrient analysis, swelling kinetics, and slow release test to evaluate the role of nutrient compositions on its capability and capacity as slow- release fertilizer. Results for total nutrient analysis show that with an increase in nutrient loading, encapsulation efficiency is low and nutrient concentration is low. These findings imply that at neutral pH of HS solution, binding sites are saturated with Na+, therefore with having the same affinity as K+ , minimal ion exchange took place and it became difficult for K+ to bind to the HS complex. It also suggests that the amount of polymer coating and the degree of crosslinking were not sufficient to hold all nutrients. Discrepancies on the amount of released K+ was also observed on the release profile as a product of errors on acid digestion and matrix effect, this lead to elevated amounts of release by the VCHS-K SRF. The result of the release behavior profile of VCHS-K SRF shows that with an increase in enriched nutrient load, the release rate is faster. The results on the release profile of the VCHS-K SRF exhibited a parabolic and burst release. This finding in relation to the observed fluctuations on the absorbency pattern suggests that internal pressure build-up on the polymer matrix caused abrasions on the surface of the polymer coating resulting to the instantaneous release of nutrient and absorbed water. Overall, the VCHS-K SRF cannot be classified as a slow-release fertilizer. The present findings suggest the need for further improvement on the study of VCHS-K SRF from vermicompost.Item DPPH free radical scavenging activity and total phenolic content of Talisay (Terminalia catappa) seedsBohol, Lyan Jean B. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2013-04)Free radicals, a class of highly reactive molecules derived from the metabolism of oxygen is believed to be involved in many health disorders. It is generated as by-products of biological reactions or from the environment. Antioxidant-based drugs and formulations for the prevention and treatment of complex diseases have attracted a great deal of research interest in natural antioxidants. It is deemed necessary to screen medicinal plants for their antioxidant potential. Terminalia catappa is a widely-distributed tree in the Philippines with promising potentials in pharmacology. Evaluation of the in vitro antioxidant activity of methanolic, dichloromethane, and hexane extracts of Terminalia catappa seeds were carried out using two assays: 1, l-diphenyl-2-pycrylhydrazyl (DPPH) free radical scavenging assay and total phenolic content assay. Results revealed that methanolic extracts showed a significantly higher free radical scavenging activity and a four-fold increase in its activity relative to the standard Butylated Hydroxytoluene (BHT). Furthermore, methanol, DCM and hexane extracts have high total phenolic content. Present results indicate that Terminalia catappa is a potential source of antioxidant and a good candidate for the development of new nutraceuticals for treatment of diseases. Phytochemical screening to determine the group of secondary metabolites present and toxicity evaluation for recommendation as nutritional substitutes and human consumption are recommended.Item Meiofaunal assemblages in the mangrove habitat in Taklong Island, Nueva Valencia, GuimarasBocoran, Mary Grace G. (Division of Biological Sciences, College of Arts and Sciences, University of the Philippines Visayas, 1999-03)Meiofauna are metazoans that can pass through a sieve with a mesh of 0.5mm but retained in a mesh of 0.063mm sieve. These organism are interesting to benthic scientist due to its capacity to determine the extent of pollution in the area and its role in the food web of an ecosystem. This study aims (1) to come up with a list of meiofaunal species present in the mangrove substratum, (2) to determine its density and abundance, and (3) to describe the meiofaunal environment in terms of temperature, salinity , pH, and oxygen content. The study was conducted in the mangrove habitat in Taklong Island Guimaras in February 1997. Thirty core samples were collected with a modified PVC core ( diameter=2.0 cm, length=15cm) from 3 areas: seaward, middle, and landward portions of the mangrove. There were eight broad groupings of meiofauna considered: nematodes, copepods, malacostracans, polychaetes, gastrotrichs, kinorhynchs, sipunculids, and others (including forams). The nematodes, of which there were 2 species observed, were the most abundant and comprised 42.14%. The copepods had 3 species observed and comprised 31.05%, 2 species of polychaetes comprised 5.04%,2species of gastrotrychs comprised 3.86% and malacostracans were 6.66%, kinorhynchs were 3.26%, and sipunculids were 0.89%. Unidentified organism which included foraminiferans, were 8.01 %. Range of meiofaunal density (number of individuals per cm'3 ) in three transects were 0.0042-0.1549 in the seaward area,0.0085-0.0785 in the middle area and 0.0021-0.0679 in the landward area. The nematodes had the highest density, and the sipunculids had the lowest density from the seaward to the landward area.Item Antimicrobial, antioxidant and phytochemical properties of ethanolic and water extracts of selected local spices from Miagao, IloiloBesinga, 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.