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This study was a part of the ForestSpecs FP7 EU project. The aim of this project was to utilize the readily available, large volume and low price wood residues from the wood processing industry. The first part of this work involved a comparative study of three extraction techniques, shaking, soxhlet and microwave assisted extraction. The microwave extraction was found to be the most suitable method, as it allowed the results to be achieved with reduced level of solvents, lower energy consumption and faster processing time. The phytochemical investigation of six forestry species: Pinus sylvestris, Larix gmelinii, L. sibirica, L. sukaczewii, L. decidua, and Populus tremula was performed. This included many steps such as grinding, extraction of plant materials and separation, isolation and purification of a variety of compounds with potential use in pharmaceutical, cosmetic and also pest management applications. A total of ninety-three compounds were identified, with thirty-two being isolated from more than one source. Of these, four have not been described previously and are shown below. Compound 13 was isolated from L. gmelinii and compounds 32, 33 and 37 were isolated from L. sukaczewii. Components from the species investigated have been identified using ID, 2D NMR and IR spectroscopy, mass spectrometry and optical rotation measurements. The extracts and purified compounds were submitted to the consortium screening programme. The thirteen bark extracts Of the species investigated were tested for cytotoxic and apoptotic activity using the LDH and MTT assays, as well as Western blot analysis of protein p53. In both, A-375 human melanoma cells and CVI-P fibroblast cells, the following bark extracts showed selective cytotoxic effects against A-375 cancerous cells: L. gmelinii DCM (LGD) and P. sylvestris DCM (PSD), EtOAc (PSE) and MeOH (PSM) extracts. Further investigation demonstrated that L. gmelinii DCM and EtOAc and P. sylvestris DCM extracts induced the translocation of the p53 protein into the nucleus. This approach proved the significance of the use of natural products as chemopreventive agents and cancer therapeutics.

Gloeocapsa UTEX sp. LB 795, like other blue-green algae, was found to lack a functional citric acid cycle. This is probably due to the absence of an enzyme capable of oxidising 2-oxoglutarate to succinate. The significance of the incomplete citric acid cycle, particularly the conversion of acetate to 2-oxoglutarate, is discussed in terms of the provision of carbon skeletons for ammonia assimilation and the provision of reducing power for nitrogen fixation. It is concluded that the activity of isocitrate dehydrogenase is probably not sufficient on its own to provide all the reducing power for nitrogen fixation in vivo. A number of alternative oxidoreductases were examined and their activities measured at different stages of growth of the culture and compared to the activity of nitrogenase at the same stages of growth. These results are discussed in terms of the provision of reducing power for nitrogenase. In particular, glucose-6-phosphate dehydrogenase is suggested as being able to meet the requirement for nitrogen fixation. The assimilation of t4C-labelled citrate, glutamate, malate and pyruvate was found to be extremely slow, probably due to their inabillty to penetrate the cell membrane. The turnover of endogenously C-labelled intermediates was measured and the results discussed in terms of the rate of flow of carbon through various metabolic pathways. The intracellular concentration of NAD was found to be much lower than that of NADP and this finding is used to explain the apparent slow rate of interconversion of malate and oxaloacetate. The contribution of the various metabolic pathways to the provision of reducing power for nitrogenase is discussed.

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Procedures for the preliminary purification of plant nucleotide extracts before analysis by HPLC were evaluated for their efficiency in removing phenolics, pigments and other compounds which otherwise interfere. The extracts were obtained either by extracting with a monophasic mixture of methanol, chloroform, water and formic acid (12:5:2:1, by vol.), followed by re-extraction with methanol, water and formic acid (20:78:2, by vol.), or by extracting with 0.6 M perchloric acid followed by neutralization with tri-N-octylamine in Freon. The cleanest sample with respect to these interfering compounds was obtained using PVP (polyvinylpyrrolidone) batch treatment of a methanol:chloroform:formic acid extract followed by passage through a Cu<SUP>2+</SUP>-loaded Chelex column. This procedure also gave good recovery of nucleotides. Plant extracts were analysed for free nucleotides by HPLC using a weak anion-exchange microparticulate column (μBondapak NH_2) with a linear potassium phosphate gradient. The nucleotide contents of several fresh and processed plant foodstuffs were examined. Changes in the concentration of free nucleotides ascribable to food processing are discussed and in particular, reference is made to the observed changes in the concentrations of the nucleotide flavour-enhancers, GMP and IMP. Those changes which were attributed to processing, varied from tissue to tissue. In most cases, the differences in the concentration of GMP and/or IMP between unprocessed and processed tissue was > 20%. The data obtained from this survey were used to assess the total purine nucleotide content of a variety of common plant foodstuffs. For those foodstuffs analysed, the total purine nucleotide content ranged from 5 - 413 nmol.g^-1 tissue and, in foodstuffs which had been cooked, the purine nucleotide content had decreased by comparison with the uncooked foodstuffs. Quantitative analytical data for the free nucleotides of various mature and immature plant foodstuffs are discussed with special reference to the relationship of nucleotide profiles to the metabolic state of each tissue concerned. The HPLC studies were extended to include a preliminary examination of the occurrence of the pyrimidine glucoside 'vicine' in fresh and processed seeds of <i>Vicia faba</i> and other legume seeds. The results obtained represent the first documented occurrence of vicine in the mature dried seed tissue of <i>Glycine max</i> and <i>Phaseolus vulgaris</i>.

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