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The aim of this study was to investigate the anti-inflammatory activity of a previously un-studied wild mushroom, Echinodontium tinctorium, collected from the forests of north-central British Columbia. The lipopolysaccharide (LPS)-induced RAW264.7 macrophage model was used to study the in vitro anti-inflammatory activity. The crude alkaline extract demonstrated potent anti-inflammatory activity, and was further purified using a “bio-activity-guided-purification” approach. The size-exclusion and ion-exchange chromatography yielded a water-soluble anti-inflammatory polysaccharide (AIPetinc). AIPetinc has an average molecular weight of 5 kDa, and is a heteroglucan composed of mainly glucose (88.6%) with a small amount of galactose (4.0%), mannose (4.4%), fucose (0.7%), and xylose (2.3%). In in vivo settings, AIPetinc restored the histamine-induced inflammatory event in mouse gluteus maximus muscle, thus confirming its anti-inflammatory activity in an animal model. This study constitutes the first report on the bioactivity of Echinodontium tinctorium, and highlights the potential medicinal benefits of fungi from the wild forests of northern British Columbia. Furthermore, it also reiterates the need to explore natural resources for alternative treatment to modern world diseases.

Mushrooms, the fruiting bodies of fungi, are known for a long time in different cultures around the world to possess medicinal properties and are used to treat various human diseases. Mushrooms that are parts of traditional medicine in Asia had been extensively studied and this has led to identification of their bioactive ingredients. North America, while home to one of the world’s largest and diverse ecological systems, has not subjected its natural resources especially its diverse array of mushroom species for bioprospecting purposes: Are mushrooms native to North America a good source for drug discovery? In this review, we compile all the published studies up to September 2020 on the bioprospecting of North American mushrooms. Out of the 79 species that have been investigated for medicinal properties, 48 species (60%) have bioactivities that have not been previously reported. For a mere 16 selected species, 17 new bioactive compounds (10 small molecules, six polysaccharides and one protein) have already been isolated. The results from our literature search suggest that mushrooms native to North America are indeed a good source for drug discovery.

A novel polysaccharide EtGIPL1a was purified from fruiting bodies of Echinodontium tinctorium, a fungus unique to western North America. EtGIPL1a has an estimated weight average molecular weight of 275 kDa and is composed of glucose (54.3%), galactose (19.6%), mannose (11.1%), fucose (10.3%), glucuronic acid (4%), and rhamnose (0.6%). It has multiple glycosidic linkages, with 3-Glcp (28.9%), 6-Glcp (18.3%), 3,6-Glcp (13%), 4-GlcpA (9.2%), 6-Galp (3.9%), 2,6-Galp (2.6%), 3-Fucp (2.5%), 6-Manp (2.4%) being the most prominent, and unsubstituted glucose (15.3%), mannose (1.3%) and fucose (0.9%) as major terminal sugars. EtGIPL1a has a backbone containing mostly 3-substituted β-glucopyranose with 4-substituted glucopyranosyluronic acid. EtGIPL1a showed anti-proliferative activity against multiple cancer cell lines, with IC50 ranging from 50.6 to 1446 nM. Flow cytometry analyses confirmed that apoptosis induction is one mechanism for its anti-proliferative activity. EtGIPL1a should be further investigated for its potential anti-cancer activity in animal models, and for its possible utility in differentiation cancer therapy.

Mushrooms, the fruiting bodies of fungi, are known to be powerful sources of nutraceuticals and pharmaceuticals but there are limited studies focusing on exploring the medicinal value of mushrooms native to North America. Here, I describe the isolation of two novel bioactive polysaccharides from the aqueous extracts of the fungus Echinodontium tinctorium: an immunostimulatory complex polysaccharide (EtISPFa) of 1354 kDa, and a growth-inhibitory β-glucan of 275 kDa. In addition, six small molecules including a phenol derivative, a new diphenylmethane derivative and three lanostane-type triterpenes were isolated from the organic extracts of E. tinctorium. The molar mass of these isolated small molecules (labelled 1-6) was determined to be 124, 260, 506, 498, 496, and 440 g/mol respectively.Phase separation, Sephadex LH-20 size exclusion, Sephadex DEAE ion exchange chromatography, Sephacryl S-500 HR size exclusion, silica column chromatography, and HPLC were used for bioactivity-guided purification. Chemical structures and linkages of EtISPFa and EtGIPL1a polysaccharides were determined by gas chromatography mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). Final structures of small molecules were determined by Fourier transform infrared spectroscopy (FTIR), electrospray ionization mass spectrometry (ESI-MS), NMR, and X-ray crystallography.Immuno-stimulatory activity of EtISPFa was assessed by immunoassay in Raw 264.7 murine macrophage cells and growth-inhibitory activity of EtGIPL1a and small molecules were assessed by MTT growth-inhibitory assay in cancer cell lines. The mechanism of growth inhibition was assessed via apoptosis and cell cycle assays. EtISPFa stimulated the immune response by inducing TNF-α and other inflammatory cytokines in murine macrophage cells. In contrast, EtGIPL1a showed promising anti-proliferative activity against U251 glioblastoma cells and on iii ten other cancer cell lines. EtGIPL1a induced apoptosis in U251 cells with an increased cleaved caspase-3 apoptotic marker and significant DNA fragmentation in cell cycle analysis. Amongst the small molecules, compounds (2), (4) and (5) caused growth-inhibition in U251 cells; compound (4) also showed promising effects on multiple other cancer cell lines; all its bioactivities are reported here for the first time. The crystal structures of compounds (2), (4) and(5) have also been reported for the first time. Molecular targets of (1), ( 2), (4) and (5) by MolTarPred were predicted and warrants further experimental investigation. iv PREFACE This current PhD dissertation has yielded two manuscripts where Chapter 1 and Chapter 2 have been published as: