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Full Text, Thesis (PhD Doctorate), Doctor of Philosophy (PhD), School of Medical Science, Griffith Health, Amphibians are storehouse of bioactive compounds. Among them, the skin of toad species is rich in biologically active compounds such as peptides, proteins, steroids, alkaloids and opioids. Some of these compounds have found significant therapeutic applications, for example as antibacterials, antifungals, antiprotozoals, antidiabetics, antineoplastics, analgesics and sleep inducing agents. In Traditional Chinese Medicine (TCM) aqueous extracts of Chinese toad skins have been used for centuries to treat pain, swelling, heart failure and several types of cancer with minimal to no side effects, generating a 10 billion USD market in China. Numerous compounds have been identified from these Chinese toad skin extracts, which have reported therapeutic activities in various disease conditions, either as a single compound or as a group of compounds. In Traditional Korean Medicine, toad extracts have also been reported to show potential activity against anxiety and depression. In Australia and America cane toad skins have a history of recreational use for euphoric purposes. This information coupled with knowledge of its use in China and Korea enabled us to hypothesise that Queensland cane toad skin extracts would likely contain similar ‘biologically-active’ compounds in selective extracts. This thesis reports on research work carried out to identify such ‘biologically-active’ extracts and/or compounds, then functionally characterise these in cultured cells for investigation of their therapeutic relevance to neuropsychiatric disorders, especially in obsessive compulsive disorder (OCD) - potentially identifying potent therapeutics for future development.

Full Text, Thesis (PhD Doctorate), Doctor of Philosophy (PhD), Institute for Glycomics, Science, Environment, Engineering and Technology, This thesis describes the isolation and characterisation of novel lectins from Australian indigenous mushroom species and evaluation of their antiproliferative activity against human colon adenocarcinoma (HT29) cell line. In this project, eighteen (18) Australian mushrooms were selected for screening of lectin activity based on published data, availability, distribution, native or exotic, and were collected from the Royal Botanical Garden, Melbourne. The results of the project identified eight (08) mushrooms with lectin activity that led to the isolation and purification of three (03) lectins from three mushroom species. Of these three lectins isolated, two lectins those of, Phlebopus marginatus (PML) and Phaeolus schweinitzii (PSL-2), are novel and one lectin was isolated for the first time from Psathyrella asperospora (PAL). All mushroom species were homogenated with PBS and then were screened for hemagglutination and lectin activity. Hemagglutination activity was evaluated using both neuraminidase treated and untreated rabbit and human A, B, and O erythrocytes. Lectin activity was determined by the ability of various mono- and di-saccharides to inhibit hemagglutination activity. The results of this screening study identified eight (08) mushroom species that showed lectin activity, Agaricus bitorquis, Chlorophyllum brunneum, Coprinus comatus, Cortinarius sp. TWM 1710, Omphalotus nidiformis, Phlebopus marginatus, Psathyrella asperospora and Phaeolus schweinitzii. The remaining ten (10) mushroom species only showed hemagglutination activity devoid of any lectin activity.

Full Text, Thesis (PhD Doctorate), Doctor of Philosophy (PhD), Institute for Glycomics, Science, Environment, Engineering and Technology, Driven by forensic intelligence, illicit drug chemical profiling via Gas Chromatography-Mass Spectrometry (GC-MS) remains the leading approach that forensic scientists and law enforcement agencies pursue in a bid to counteract the ever-increasing drug epidemic. An alternative approach for forensic drug investigations that delivers intelligence at a more specific level than that of chemical profiling is isotopic profiling via Isotope Ratio Mass Spectrometry (IRMS). The analysis of selected stable isotopes (18O:16O,15N:14N, 13C:12C and 2H:1H, for example) that compose drug molecules has been suggested as a credible technique that can aid in forensic drug investigations. This research, consisting of four individual projects, was designed to investigate the potential of using isotopic profiling for source, synthetic procedure and batch linkage or discrimination of selected designer drugs/Novel Psychoactive Drugs (NPDs).

Full Text, Thesis (PhD Doctorate), Doctor of Philosophy (PhD), School of Pharmacy, Griffith Health, The present study describes the bioactivity guided isolation and structural elucidation of novel anticancer compounds from the Bangladeshi medicinal plant Blumera lacera. At the outset nineteen Bangladeshi medicinal plants were selected and collected from different parts of Bangladesh. Plants underwent preliminary cytotoxicity screening based on their traditional medicinal uses, limited previous research on them, and their availability. The selected plants were extracted with methanol and screened for their cytotoxic potential using the MTT assay against two healthy cell lines (mouse fibroblast (NIH3T3), a healthy monkey kidney (VERO)) and four cancer cell lines namely, gastric (AGS), colon (HT-29), two breast (estrogen-dependent: MCF-7 and estrogen non-dependent: MDA-MB-231). Preliminary cytotoxicity assessment led to the identification of seven plants with significant cytotoxic potential, having IC50 < 1.0 mg/mL against a minimum of one cancer cell line. The identified plants were: Avicennia alba, Caesalpinia pulcherrima, Diospyros peregrina, Ecbolium viride, Jasminum sambac, Clitoria terantea, and Saraca asoca. The bioactivity detected correlated with their traditional uses as anticancer agents. Comparing cytotoxicity effects of the selected plants with that of Blumea lacera which was previously screened for cytotoxic potential in our research lab, Blumea lacera was found to be more cytotoxic and thus selected for bioassay-guided isolation of constituents.

Full Text, Thesis (PhD Doctorate), Doctor of Philosophy (PhD), School of Pharmacy, Griffith Health, This thesis describes the cytotoxicity and phytochemical screening of 16 selected medicinal plants collected from the tidal forests of the coastal Sundarban and locations within the Khulna district of Bangladesh. The selected plants were successively extracted with n-hexane, dichloromethane, methanol and water. The methanol and aqueous extracts were then screened for cytotoxic activity (MTT assay) against one normal mouse fibroblast and three human cancer cell lines (gastric, colon and breast cancer). The results supported some of the traditional uses and reported cytotoxic activity for some of these plants. It identified some plant extracts (Hygrophila auriculata, Hibiscus tiliaceous and Limnophila indica) with selective cytotoxic activity to cancer cells (IC50 1.1 - 1.6 mg/mL) but non-toxic to normal mouse fibroblast cells. Some extracts (Acrostichum aureum, Ammannia baccifera, Argemone mexicana, Limnophila indica, Clerodendron inerme, Cynometra ramiflora and Xylocarpus moluccensis) showed low cytotoxicity against mouse fibroblast (IC50 > 2.5 mg/mL) but selective potent toxicity against cancer cells (IC50 0.2 - 2.3 mg/mL). Four extracts (Adiantum caudatum, Hibiscus tiliaceous and Blumea lacera) showed cytotoxic activity against all the cell lines tested in the study. The methanolic and aqueous extracts of B. lacera were identified as having the most potent cytotoxic activity against all cell lines with IC50 0.01 - 0.08 mg/mL. Reversed-phase analytical HPLC profiling of all extracts was carried out with extracts, demonstrating low toxicity against normal mouse fibroblast cells, but selective high toxicity against the three cancerous cell lines (A. aureum and A. baccifera) and highest toxicity against all the cell lines (B. lacera). Extracts from these plants were further investigated by LC-MS. A. aureum was then selected and further investigated with one compound subsequently being isolated from n-hexane fraction and twelve compounds from the methanolic fraction. T

Full Text, Thesis (PhD Doctorate), Doctor of Philosophy (PhD), School of Environmental and Applied Science, Sewage pollution from humans, animal and domestic sources (land and agricultural run-off) are recognized as a major cause of deteriorating water quality along Australia's coastline. Management of water quality has primarily relied on the use of bacterial indicator methods. However the validity and source-specificity of these methods have been met with increasing reservations for several years now. A relatively recent methodology uses a different chemical biomarker approach using 'sterols', a group of compounds related to the common bio-membrane lipid cholesterol and its derivatives. Sterols can offer an additional diagnostic tool to distinguish and discriminate between sources of faecal contamination in marine, freshwater and estuarine environments in both sediments and the water column. This study investigates for the first time, the degradation of coprostanol and selected faecal sterols in 'natural' sediments from a highly mixed (marine and estuarine) sub-tropical environment following a simulated pollution event (primary effluent); the use of faecal sterols as an additional indicator for determining non-point source sewage discharges at popular anchorages in the Moreton Bay and Gold Coast Broadwater system; and the use of sterol ratios in the determination of the fate and transportation of nutrients from a Sewage Treatment Plant (STP) point-source outlet pipe during plant malfunction. The microcosm degradation experiment revealed that faecal and selected sterols are continually synthesised and degraded over time by auto- and hetero trophic organisms within the sediment matrix. Coprostanol was the only sterol to degrade continually, with only minor fluctuations over a time period of two months. Results from this degradation experiment further revealed a sharp decline of coprostanol within the first week. From this it could be concluded that, without any further addition, external inputs of coprostanol are reduced to background levels within this time period. There