Date of Award
Master of Science in Pharmaceutical Sciences
Biomedical and Pharmaceutical Sciences
The objective of this research was to search for an antiviral compound, garcinol (or guttiferone F) from the Garcinia kola nuts using two different extraction techniques and formulate a suitable liposome for control release using an antiviral compound. The two extraction techniques used were: liquid-liquid extraction (for simplicity purposes, the term solvent-solvent, S-S, will be used interchangeable) and Supercritical Fluid Extraction (SFE). Both techniques were used to profile compounds found in Garcinia kola and for statistical comparison purposes. Extracts from both techniques were collected and analyzed for separation using Reversed-Phase High Performance Liquid Chromatography (RP-HPLC) using Ultraviolet Photodiode Array (UV-PDA) detection, determined physical and chemical properties by proton and phosphorus Nuclear Magnetic Resonance (1HNMR and 31P-NMR), and quantify by Ultra Performance Convergence Chromatography (UPC2) coupled to Quadrupole Time of Flight Mass Spectroscopy (Q-ToF/MS). The UPC2 Q-ToF/MS data was processed using TransOmics Informatics for Metabolomics and Lipidomics (TOIML) and statistical analysis was performed interrogating similarities and dissimilarities of each extraction techniques. Biological assay were conducted on three of the S-S extracts and compared to know antiviral inhibiting drugs as controls. For the formulation study, Dynamic Light Scattering (DLS), Differential Scanning Calorimetry (DSC) and release studies were conducted in order to characterize the garcinol liposomes. Initial RP-HPLC results showed no compounds with photodiode array (PDA) fingerprints characteristic of garcinol were found in either of the extracts from both extraction techniques. NMR confirmed what was already observed: garcinol has the same molecular formula, weight and chemical structure as the previously reported guttiferone F and both names (garcinol and guttiferone F) are used interchangeable. Comparison of the different extraction techniques by UPC2 Q-ToF/MS resulted in the identification of 1291 chemical features and the features were grouped together statistically based on their relative extraction solvents and techniques. Of the 1291 detectable mass constituents, 43.81% can be extracted by S-S technique and 40.09% can be extracted by SFE technique, relatively similar extraction profile. Approximately 20.99% of the mass constituents were detected using both extraction techniques. Overall, results from the SFE showed the comprehensive profile of all mass constituents found within this natural product and each mass grouped statistically based on their relative extraction solvents to determine extraction coverage. In addition, these statistical analysis and extraction techniques have never been performed simultaneously and or compared on Garcinia kola seeds. Biological data revealed that extracts from the S-S technique was negative for the inhabitation of antiviral activities as compare to the controls. The results of the liposome release studies indicated initial rapid release of less than 1% of garcinol from the liposomes, followed by a sharp drop in concentration at 4 hours, suggesting precipitation in the dissolution medium with no further release as the concentration leveled off to 140 hours. DSC results indicated that the surface charge of the liposome was -10.5 mV and remained relatively constant for 7 days suggesting stability issues. DLS results indicated an increase in particle size and Polydispersity index over a 7 day period which also suggests stability issues. Overall, the formulation study showed garcinol released less than 1% and may interact significantly with the DPPC phosphate head groups, as indicated by the large increase in net negative surface charge. Although no antiviral activities were active in Garcinia kola, this edible plant could serve as an abundant source of naturally-occurring, bioactive compounds for further pharmaceutical development for other biological activities.
Vezele, Yasah, "GARCINIA KOLA: PHYTOCHEMICAL, BIOLOGICAL AND FORMULATION STUDIES" (2015). Open Access Master's Theses. Paper 476.