Date of Publication


Document Type


Degree Name

Doctor of Philosophy in Chemistry

Subject Categories



College of Science



Thesis Adviser

Anamy Maria C. Paano

Defense Panel Chair

Nancy Lazaro-Llanos

Defense Panel Member

Jaime Raul O. Janairo
GlennV. Alea
Lourdes P. Guidote
Nelson Villarante


The process for optimum extraction of the Stevia glycosides was developed. Ethanol was found to selectively extract the important non-caloric Stevia glycoside Rebaudioside A (Reb A). The plant sample was defatted with isopropyl alcohol using a modified soxhlet extraction set up. Soxhlet extraction of the Stevia samples enhanced the relatively low ethanol glycoside extract. Ultrafiltration and nanofiltration using membranes NOVA 10K and DS-5 respectively, were established to clean up and concentrate the glycoside extract. The optimum parameters in spray drying the Stevia glycosides were established. A patent has been applied for the glycoside clean up and concentration in the United States Patenting Office. Chromatographic separation was done on the hexane and the chloroform extracts of S. rebaudiana. The GC-MS analysis of the hexane extract indicates the presence of heptacosane, hexatriacontane, 1-caryophyllene, spathulenol, phytol, m-Nitropthalic acid and B-Selinene. Stigmasterol was isolated pure from the chloroform extract of S. rebaudiana. The crude alcoholic extract of E. indica (EIA) was subjected to ultrafiltration using membranes of increasing pore size. This process efficiently separated the components of the sample. This result will be used to design a separation scheme for the physiologically active components. Separation of the ions from the rest of the extract (EIAq) components was successfully achieved by electrodialysis. This will serve as a preliminary step in the fractionation of the aqueous extract of E. indica. The quantities of Na+ and K+ ions were calculated from the atomic absorption spectrometry data. Sodium and potassium ions are present in 0.46% and 0.40% respectively, with respect to the plant sample and 0.36% and 0.32%, with respect to the freeze-dried retentate. Fractions from the hexane extract of E. indica (EIH) were found to contain campesterol, stigmasterol, sitosterol, and a series of alkanes. These compounds were inferred from their mass spectral data only. The membrane NOVA 1K has separated some of the components of the aqueous extract of P. betulinus. Polyporenic acid C was re-isolated from the chloroform extract P. betulinus. This isolate showed hemolytic property on blood type O. The isolate obtained from the chloroform extract from F. fomentarius was identified as betulin.

Abstract Format






Accession Number


Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall


Extracts; Membrane separation; Stevia rebaudiana; Fungi

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