Momordica foetida Schum. & Sond. (Cucurbitaceae), locally known as iNtshungu, is widely used by the Zulu people of Natal-KwaZulu for the treatment of a variety of ailments. The dried leaves leaves and stems of this plant was subjected to soxhlet extraction by refluxing with hexane, chloroform and methanol successively. Thin layer chromatography of the chloroform extract of the leaves revealed a multiplicity of compounds. The chloroform extract was further partitioned with sodium hydroxide resulting in an organic and aqueous phase. The organic phase, containing extract A, afforded two compounds, viz. compounds 1 and 2. The basic aqueous fraction was neutralised and re-extracted with chloroform to give extract B, affording five compounds, viz. compounds 3,4,5,6 and 7. Structural elucidation was accomplished by techniques such as IH and 13C NMR spectroscopy, HETCOR, COSY, FTIR and High Resolution Mass Spectrometry. Compounds 1 and 2 were identified as cucurbitane triterpenoids known as momordicines which had been previously discovered in the related species of this plant, Momordica charantia L. The remaining five compounds were identified as novel compounds, although natural derivatives of compounds 6 and 7 had been isolated previously from Momordica charantia L. Compounds 3-7 were each isolated as an epimeric mixture but it was possible to select the resonances corresponding to the major epimer. These five epimers were respectively identified as 5, 19-epoxy-19(R)-hydroxy-25-methoxy-5β- cucurbita-6,23-diene-3β-ol [102], 5,19-epoxy-19(R),25-dihydroxy-5β-cucurbita- 6,23-diene-3β-ol [103], 5,19-epoxy-19(R)-methoxy-25-hydroxy-5β-cucrbita- 6,23-diene-3β-ol [104], 5,19-epoxy-25-methoxy-5β-cucurbita-6,23diene- 3β-ol [105] and 5,19-epoxy-19(R),25-dimethoxy-5β-cucurbita-6,23diene- 3β-ol [106]. Appropriate reactions were performed, where possible, on the compounds isolated in order to confirm their identity. / Thesis (M.Sc.)-University of Natal, Durban, 1994.

Chan Hiu-ki. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 97-112). / Abstracts in English and Chinese. / Thesis Committee --- p.i / 摘要 --- p.ii / Abstract --- p.iii / Acknowledgements --- p.v / Abbreviations --- p.vi / Table of Contents --- p.vii / List of figures --- p.xi / List of tables --- p.xiii / Chapter Chapter 1 --- Literature Review --- p.1 / Chapter 1.1 --- Nitrogen assimilation in plants --- p.1 / Chapter 1.2 --- Importance of asparagine in plants --- p.5 / Chapter 1.3 --- Enzymatic reaction of asparagine synthetase (AS) --- p.8 / Chapter 1.4 --- Asparagine synthetase of non-plant organisms --- p.10 / Chapter 1.5 --- Biochemistry background of plant asparagine synthetases --- p.12 / Chapter 1.6 --- Molecular studies of asparagine synthetase genes in plants --- p.15 / Chapter 1.7 --- Arabidopsis thaliana as a model plant --- p.24 / Chapter 1.8 --- ASN studies in Arabidopsis thaliana --- p.24 / Chapter 1.9 --- Hypothesis --- p.27 / Chapter Chapter 2 --- Materials and Methods --- p.29 / Chapter 2.1 --- Chemicals --- p.29 / Chapter 2.2 --- Plant materials and growth conditions --- p.29 / Chapter 2.2.1 --- Surface sterilization of Arabidopsis seeds --- p.29 / Chapter 2.2.2 --- "Growth conditions of Arabidopsis seeds for total RNA extraction, enzyme assay, chlorophyll content measurement and dry weight measurement" --- p.30 / Chapter 2.3 --- Agrobacterium mediated transformation via vacuum infiltration method --- p.30 / Chapter 2.3.1 --- Principles --- p.30 / Chapter 2.3.2 --- Plant materials and bacterial strains of Agrobacterium mediated transformation --- p.31 / Chapter 2.3.2.1 --- Plant materials --- p.31 / Chapter 2.3.2.2 --- Gene constructs --- p.31 / Chapter 2.3.2.2 --- Bacterial strains --- p.32 / Chapter 2.3.3 --- Agrobacterium mediated transformation via vacuum infilitration --- p.32 / Chapter 2.4 --- Screening of transformants --- p.33 / Chapter 2.5 --- DNA and RNA manipulation --- p.34 / Chapter 2.5.1 --- DNA extraction and quantitation --- p.34 / Chapter 2.5.2 --- PCR amplification and detection of transgenes --- p.36 / Chapter 2.5.2.1 --- PCR amplification and detection of transgenes --- p.36 / Chapter 2.5.2.2 --- Primer sequence --- p.37 / Chapter 2.6 --- RNA analysis of transormants --- p.38 / Chapter 2.6.1 --- General introduction --- p.38 / Chapter 2.6.2 --- RNA extraction --- p.39 / Chapter 2.6.3 --- Making single-strand DIG PCR probes --- p.40 / Chapter 2.6.4 --- Quantitation of single-strand DIG-labeled probes --- p.42 / Chapter 2.7 --- Northern blot analysis --- p.42 / Chapter 2.7.1 --- Detection --- p.43 / Chapter 2.7.2 --- Film development --- p.43 / Chapter 2.8 --- "Amino acid, protein, dry weight and total nitrogen analysis" --- p.43 / Chapter 2.8.1 --- Extraction of free amino acids --- p.43 / Chapter 2.8.2 --- Protein assay --- p.44 / Chapter 2.8.3 --- Determination of nitrogen and carbon content in seeds --- p.45 / Chapter 2.8.4 --- Dry weight measurement --- p.45 / Chapter 2.8.5 --- Seed storage protein analyses --- p.45 / Chapter 2.8.6 --- Detection of chlorophyll content --- p.46 / Chapter 2.9 --- Asparagine synthetase activity analysis --- p.46 / Chapter 2.9.1 --- Crude extracts preparation --- p.46 / Chapter 2.9.2 --- AS enzyme assay --- p.47 / Chapter 2.9.3 --- Asparagine content measurement --- p.47 / Chapter 2.10 --- In situ hybridization --- p.48 / Chapter 2.10.1 --- Making cRNA probe --- p.48 / Chapter 2.10.2 --- In situ hybridization --- p.48 / Chapter Chapter 3 --- Results --- p.50 / Chapter 3.1 --- Construction of ASN1 overexpressing lines --- p.50 / Chapter 3.2 --- Changes in nitrogen status during vegetative growth of ASN1 overexpressing lines --- p.53 / Chapter 3.3 --- Changes in nitrogen status during seed development of ASN1 overexpressing lines --- p.55 / Chapter Chapter 4 --- Discussion --- p.76 / Chapter Chapter 5 --- Conclusion --- p.85 / Chapter Chapter 6 --- Perspective --- p.86 / Appendix --- p.87 / References --- p.97

Infectious diarrhoea is the second largest single cause of mortality in children under the age of five globally. Bacteria are responsible for most diarrhoeal episodes especially in developing countries, and progressive increase in antimicrobial resistance has given rise to the need to investigate other sources of therapy such as medicinal plants. Ten plant extracts were analysed for their antimicrobial activities using the agar well diffusion and broth microdilution method. Their phytochemical contents were screened, and their effect on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) was used to assess their antioxidant activities. Their toxicity profiles were evaluated using the XTT Cytotoxicity Assay. Water and methanol extracts of Adansonia digitata v ABSTRACT Infectious diarrhoea is the second largest single cause of mortality in children under the age of five globally. Bacteria are responsible for most diarrhoeal episodes especially in developing countries, and progressive increase in antimicrobial resistance has given rise to the need to investigate other sources of therapy such as medicinal plants. Ten plant extracts were analysed for their antimicrobial activities using the agar well diffusion and broth microdilution method. Their phytochemical contents were screened, and their effect on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) was used to assess their antioxidant activities. Their toxicity profiles were evaluated using the XTT Cytotoxicity Assay. Water and methanol extracts of Adansonia digitata seeds and pulp showed no inhibition against all the test organisms, while water and methanol extracts of A. digitata leaves showed inhibition, with minimum inhibitory concentration (MIC) ranging from 0.39 to 6.25mg/ml. Water and methanol extracts of Garcinia livingstonei and Sclerocarya birrea barks showed good activity against all the test organisms, with MICs between 0.39 and 1.56 mg/ml. Alkaloids, phenols, flavonoids, saponins, tannins, and terpenoids were found in one or more of the plant extracts, and all the plant extracts demonstrated scavenging power against DPPH.The cytotoxicity of extracts of Garcinia livingstonei, and Sclerocarya birrea barks ranged between 105.9 μg/ml and 769.9 μg/ml. The results obtained in this study validate the traditional use of A. digitata leaves, G. livingstonei and S. birrea bark in treating bacteria causing diarrhoea. / Life Sciences / M. Sc. (Life Sciences)

The overall objective of this thesis was to investigate how the arbuscular mycorrhizal (AM) symbiosis can affect the production of phytochemicals (antioxidants; rosmarinic and caffeic acid, RA & CA) in the shoots of basil (Ocimum basilicum L.). As a result of an increasing interest in natural/herbal medicines, more effort is now needed to produce herbal products of better quality, i.e. higher and standardised phytochemical concentrations. Thus, it was hypothesised that the naturally occurring AM fungi (AMF) could play an important role in improving the growth and phytochemical concentrations in medicinal herbs such as basil, as organic methods of cultivation are increasingly sought after to grow such plants. Despite a reasonable amount of information available in the literature on the changes of phytochemical concentrations in the roots of host plants following AM colonisation, very little is known about such processes in the aerial part of such plants. Furthermore, basil has hardly been studied as a host plant in AM research, and very little is known of its responsiveness to AM colonisation. As AMF are well known to improve phosphorus (P) uptake in their host plant, the first objective of this work was to obtain AM and non-mycorrhizal (NM) plants matched for tissue P concentrations and growth rates. Only under such conditions would it then be possible to separate benefits derived from improved plant P uptake from non-nutritional benefits. It was found that basil is highly responsive to P, and that under low or little P supply it is quite dependent on the AM symbiosis in order to grow. However, growth depressions were observed when growing basil in winter with Glomus intraradices, suggesting that the fungal symbiont can act as a strong sink of carbon (C) under such conditions. Thus, in order to obtain AM and NM plants with matched growth rates and tissue P concentrations, it was found that basil needed to be cultivated in summer in a soil/sand mixture with a ratio of 1:3 (w/w), along with 0.2 g/kg CaHPO4 and 25% of AM inoculum (AM plants). Under these conditions, AM plants grew as well as NM plants and G. caledonium and G. mosseae were shown to increase the concentrations of RA and CA in the shoots of basil, but not in roots. Such results were not an indirect effect of improved P uptake. In order to understand the mechanisms by which AMF increased RA and CA concentrations in basil, further experiments were set up to investigate the effect of 1) AM developmental stages, 2) nitrogen (N) supply and 3) phytohormone changes on the production of RA and CA in the shoots. None of these factors was found to contribute to increases in antioxidants in basil under AM symbiosis. Therefore, the mechanisms by which AMF affect RA and CA concentrations in basil still remain unknown. A final experiment was carried out to investigate the potential of an AM fungus to improve the growth of basil when challenged with a specific pathogen Fusarium oxysporum f.sp. basilici (Fob), which causes significant production losses. The results showed that inoculation of basil with G. mosseae not only improved plant growth compared to NM plants, but also conferred a protective effect against Fob. However, shoot antioxidant concentrations (RA, CA, total phenolics and essential oils) were not increased in AM plants compared to NM plants, and the mechanism of protection against Fob could not be elucidated. Due to the high variability of RA and CA concentrations obtained in AM plants in different experiments, it cannot be concluded that AMF confer an absolute advantage over uninoculated plants if the main concern is to obtain standardised concentrations of phytochemical in basil. On the other hand, the key results presented in this thesis do indicate that inoculating basil with AMF can be beneficial to improve its growth as well as antioxidant concentrations, compared to NM plants grown under similar conditions. Such results could be of potential interest to basil growers who wish to cultivate this medicinal herb organically (i.e. low P supply and no chemical fertilisers added). / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1330324 / Thesis (Ph.D) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

This work is an account of the investigations into the chemistry of two Cedrelopsis species from the Ptaeroxylaceae, Cedrelopsis grevei and Cedrelopsis microfoliata and a species from the Mesembryanthemaceae, Khadia alticola, as well as investigations into the synthesis of hydroxylated and prenylated chalcones. Cedrelopsis grevei, commonly called Katrafay, is amongst the many medicinal plants of Madagascar, being used to relieve muscle fatigue when the bark is soaked in hot water. Previous investigations of the wood and stem bark of this plant, have yielded chromones and coumarins and a recent investigation of the stem bark of a specimen collected in the north of Madagascar has yielded two novel limonoids of unusual structure, cedmilinol and cedmiline. The fruit and seed of Cedrelopsis grevei have not been studied previously and a phytochemical investigation of these plant parts was undertaken in this work. The dichloromethane extract of the fruit and seeds yielded, after column chromatography, a dihydrochalcone, uvangoletin, a flavanone, 5,7dimethoxypinocembrin, two simple chalcones, cardamonin and flavokawin Band three prenylated chalcones, 2’-methoxyhelikrausichalcone, cedreprenone and cedrediprenone. Three of these compounds, 2’-methoxyhelikrausichalcone, cedreprenone and cedrediprenone have not been isolated previously. Cedrelopsis microfoliata is another medicinal plant used in Madagascar. The leaves of this plant are used to prepare a decoction for woman to drink after childbirth. This is the first phytochemical investigation of Cedrelopsis microfoliata. The hexane extract of the dried stem bark yielded three compounds after column chromatography, a chalcone, microfolian and two flavanones, microfolione and (+)-agrandol. The dicholoromethane extract of this compound yielded four compounds after column chromatography, three coumarins, cedrecoumarin A, obliquin and microfolicoumarin and a sesquiterpenoid, sesquichamaenol. Four of the compounds isolated from Cedrelopsis microfoliata, microfolidione, microfolione, (+)-agrandol and microfolicoumarin have not been isolated previously. Khadia alticola is one of the species added to "Khadi", a Tswana/South Sotho name for beer brewed traditionally using the fleshy roots of a variety of taxa. Khadia is also reported to be used medicinally by the Manyika people of the Umtali district of Zimbabwe. The phytochemical investigation of the roots of Khadia alticola, which have not been studied previously, was undertaken to determine whether mesembrine type alkaloids were present in this species and thus contributing to the "potency" of the beer brewed traditionally. No mesembrine alkaloids were isolated in this work, however, a common sterol, sitosterol was isolated from the acidic chloroform fraction of the roots of this species and a flavonoid, 3,4',5,7-tetrahydroxyflavan was isolated from the basic chloroform fraction. Two chalcones, 3’,5’-dihydroxychalcone and 2’-hydroxychalcone were synthesised using the Claisen condensation. An isoprenylated acetophenone intermediate and an isoprenylated chalcone were also synthesised. / Thesis (Ph.D.)-University of Natal, Durban, 2001.

This thesis examines the interaction of xyloglucan, the major hemicellulosic component of type I primary plant cell walls, with cellulose. Initial attempts to form xyloglucan-cellulose complexes by in vitro association methods are described, which gave low levels of interaction, with features not similar to those found in primary wall networks. The majority of the work focusses on the use of the bacterium Acetobacter aceti ssp. xylinum (ATCC 53524), which synthesise highly pure, crystalline cellulose as an extracellular polysaccharide. Addition of xyloglucan to a cellulose-synthesising bacterial culture results in the formation of cellulose-xyloglucan networks with ultrastructural and molecular features similar to those of the networks of higher plants. Applicatioon of the bacterial fermentation system is extended to incorporate the polysaccharides glucomannan, galactomannan, xylan, mixed-linkage glucan, pectin and carboxymethylcellulose, all of which impart unique architectural and molecular effects on the composistes formed. Preliminary data on the mechanical properties of composite structures under large and small deformation conditions are also described.

Bibliography: leaves 200-225 / xxiii, 225 leaves, [39] leaves of plates : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, 1984

Thesis (Ph.D.) -- University of Western Sydney, 2002. / A thesis submitted to fulfil the requirements for the degree of Doctor of Philosophy, School of Science, Food and Horticulture, University of Western Sydney, August, 2002. Includes bibliographical references (leaves 247-260).

Thesis (Ph. D.)--Ohio State University, 2005. / Available online via OhioLINK's ETD Center; full text release delayed at author's request until 2008 Jul 28.

O capim annoni-2, Eragrostis plana Nees, é uma espécie vegetal africana conhecida por sua capacidade invasora e, por este motivo, classificada como planta daninha, sendo considerada a mais agressiva e de mais difícil controle nos campos sulinos. Esta espécie ativa mecanismos de inibição de crescimento e germinação de outras espécies vizinhas no fenômeno denominado alelopatia. O estudo fitoquímico de E. plana Nees, justifica-se por se tratar de uma espécie com suposta atividade alelopática, bem como, em função de suas características e do impacto biológico e econômico causado por ela. Com o objetivo de identificar e caracterizar moléculas bioativas e avaliar seus efeitos alelopáticos, foram realizados os experimentos. As folhas de E. plana Nees, foram coletadas no inverno e verão, para análise fitoquímica, e a obtenção do óleo essencial das amostras foi feita por hidrodestilação e, posteriormente, filtrados e refrigerados até a análise cromatográfica gasosa acoplada a espectrometria de massas. Para os metabólitos secundários não voláteis, o material botânico foi submetido a extração exaustiva a frio, com éter de petróleo e acetato de etila. Os extratos foram submetidos à técnica de Infravermelho. Na identificação alelopática foram utilizadas sementes da espécie Ipomoea grandifolia em dois bioensaios comumente realizados em estudos alelopáticos. Os testes, de germinação e alongamento de radícula e hipocótilo foram monitorados diariamente por 7 dias, em condições controladas e realizados em câmaras BOD (Demanda Bioquímica de Oxigênio). Para os dois testes foram empregados 5 doses com diferentes concentrações de cada extrato em volume de 5 mL em cada placa de Petri. O delineamento utilizado foi o inteiramente casualizado com 4 repetições, sendo água destilada e Tween 80 + solvente extratores como testemunhas. Os dados foram submetidos ao teste de homogeneidade de variâncias, pelo teste de Cochran C e à análise de normalidade pelo teste de Shapiro–Wilk, com posterior análise de variância, ANOVA e teste de Tukey a 5% de significância para as variáveis homogêneas. O efeito alelopático apresentado pelas folhas de E. plana Nees, pode estar relacionado com os teores de terpenos observados na análise do óleo essencial, uma vez que os mesmos, possuem propriedades alelopáticas, conforme relatos da literatura. Os extratos brutos expressaram o potencial alelopático da E. plana Nees, interferindo no desenvolvimento da espécie receptora. A utilização destes extratos de forma direta ou como fonte de moléculas químicas, pode colaborar no desenvolvimento de novos bio-herbicidas. / The grass - 2 lovegrass , Eragrostis plana Nees , is an African plant species known for its invasive capacity and , therefore , classified as a weed , and is considered the most aggressive and more difficult to control in the southern fields . This species active mechanisms of inhibition of germination and growth of neighboring species in the phenomenon called allelopathy . The phytochemical study of E. plana Nees , is justified because it is a species with alleged allelopathic activity and, depending on its characteristics and the biological and economic impact caused by it . In order to identify and characterize bioactive molecules and evaluate their allelopathic effects , the experiments were performed . The leaves of E. plana Nees were collected in winter and summer , for phytochemical analysis , and obtain the essential oil sample was taken by hydrodistillation and subsequently filtered and chilled to the gas chromatographic analysis coupled with mass spectrometry . For non- volatile secondary metabolites , the plant material was subjected to exhaustive cold extraction with petroleum ether and ethyl acetate . The extracts were subjected to IR technique . In allelopathic identification seeds of Ipomoea grandifolia species commonly performed in two bioassays in allelopathic studies were used . The tests , germination and radicle and hypocotyl elongation were monitored daily for 7 days under controlled and conducted in chambers BOD ( Biochemical Oxygen Demand ) conditions . For both tests 5 doses with different concentrations of each extract volume of 5 mL in each Petri dish were used. The experimental design was completely randomized with 4 replications, with distilled water and Tween 80 + solvent extractors as witnesses . The data were submitted to variance homogeneity test, the Cochran C and analysis of normality by the Shapiro - Wilk test, with subsequent analysis of variance , ANOVA and Tukey test at 5 % significance level for the homogeneous variables. The allelopathic effect exhibited by the leaves of E. Nees plane can be related to the levels observed in the analysis of terpenes of essential oil , since they possess allelopathic effects , as reported in the literature. The extracts expressed the allelopathic potential of E. plana Nees , interfering with the development of the receiving species . The use of these extracts directly or as a source of chemical molecules , can collaborate in developing new bio - herbicides.