Undergraduate Theses
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Item A novel water-in-oil-in-water emulsion to encapsulate antibacterial agentsBalcarcel, 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 processItem A preliminary investigation of the antibacterial activity of the alkaloidal constituent of Hyptis suaveolens Poit (Family Labiatae)Alcayde, Glenn G. (Division of Physical Sciences & Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 1999-03)This study determined the effectiveness of the alkaloidal constituent on the leaves ofHyptis suaveolens against the four bacteria namely S. aureus, B. subtil is E. coli, and P. aeruginosa, and two fungi namely C. albicans and S. cerevisae. The alkaloidal constituent was first detected using the Culvenor-Fitzgerald method. It was then separated in the form of an alkaloidal residue. The residue was separated further using column chromatography. This process resulted in three fraction isolates.These three fraction isolates were purified and determined their physical properties. Finally, each fraction isolate was prepared into three concentrations, 100%, 50%, and 25%. The isolates of three concentrations were then tested on six microorganisms and growth of inhibition was measured. Results showed that the three fraction isolates in three different concentrations exhibited no antibacterial and antifungal effectItem Antibacterial agent-loaded water-in-oil-water (W/O/W) emulsionAguilar, Ma. Arianne Lou C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)In this study, a water-in-oil-in-water (W/O/W) emulsion incorporated with an antibacterial agent using polyglycerol polyricinoleate (PGPR), whey protein isolate (WPI) and lecithin as emulsifying agents under ultrasonication was prepared. Micrographs of the emulsions formed showed small droplet sizes with an average range of 0.07 — 8.7 μm which indicates that the emulsification process was effective. However, the emulsion was only stable for 7 days. Natural and synthetic antibacterial agents were then loaded into the W/O/W emulsion. A solution of chlorhexidine gluconate (CHG) was chosen as the synthetic antibacterial agent to be loaded into the W/O/W emulsion because of its established stability and antibacterial efficacy against Gram—positive and Gram—negative bacteria. On the other hand, Psidium guajava (guava) was chosen as the natural antibacterial agent to be loaded because of its abundance and folkloric use to treat wounds. The CHG—loaded emulsion showed a mean zone of inhibition equal to 11.3 ± 2.1 mm against Staphylococcus aureus and 12.0 ±1.0 mm against Escherichia coli. The Psidium guajava (guava) — loaded emulsion on the other hand showed no inhibitory activity which suggests that the bioactive component of the guava may have been destroyed during sonication process. The results of this study showed that a synthetic antibacterial agent loaded - W/O/W emulsion was more effective than the natural antibacterial agent loaded — W/O/W emulsion.
