M.Sc. (Botany) / Please refer to full text to view abstract

The alkaloid content of three Crinum species namely C. bulbispermum, C. macowanii and C. moorei was investigated. The ethanolic extracts of C. bulbispermum yielded seven compounds. The new alkaloids 8α-ethoxyprecriwelline, N-desmethyl-8α-ethoxypretazettine and N-desmethyl-8β-ethoxypretazettine were isolated for the first time from a natural source. In addition, the known alkaloids bulbispermine, crinamine, 6-hydroxycrinamine and 3-O-acetylhamayne were isolated in this study. The ethanolic extracts of C. moorei were found to contain Iycorine, 1-O-acetyllycorine, crinine, 3-O-acetyllycrinine, epibuphanisine, powelline, crinamidine, undulatine, epivittatine, 1-epideacetylbowdensine, cherylline and the new alkaloids mooreine and 3-[4'-(2'-aminoethyl)phenoxy]bulbispermine. The alkaloids crinine, lycorine, bulbispermine, cherylline and hamayne were obtained from the ethanolic extracts of C. macowanii. In addition, the amine tyramine was identified during the isolation process. Dilute HCl solution extraction followed by GC analysis was used to investigate organ-to-organ and seasonal variation of alkaloids in each Crinum species, as well as the interspecific variation in these alkaloids over two consecutive years. Twelve alkaloids were identified, including crinine, epibuphanisine, powelline, crinamine, crinamidine, 6-hydroxycrinamine, 1-epideacetylbowdensine, 3-O-acetylhamayne, undulatine, Iycorine, 1-O-acetyllycorine and cherylline. Alkaloids were detected in all organs of C. moorei and C. macowanii. However, alkaloids were not detected in the leaves of C. bulbispermum. Organ-to-organ and seasonal variations in the total yield and total ring types of these alkaloids were noticed. Organ-to-organ and seasonal statistical variations were also detected for some of the individual alkaloids detected in each of these species. The results also showed that C. moorei had the highest levels of all individual alkaloids except crinamine when compared to C. bulbispermum and C. macowanii. Quantitatively, the detected alkaloids chemotaxonomically separated C. moorei from C. bulbispermum and C. macowanii. The results also indicated that C. macowanii is more closely related to C. bulbispermum. Qualitatively, Iycorine, 1-O-acetyllycorine, cherylline, crinamidine, 1-epideacetylbowdensine, crinine, crinamine and 3-O-acetylhamayne were detected in both C. moorei and C. macowanii, indicating the close relationship of these species. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2000.

As an alternative to conventional methods of vegetative propagation, micropropagation attracts much attention, because the levels of multiplication are increased, somaclonal variation is limited and disease-free material can be obtained. The technique is invaluable to the conservation of Crinum species belonging to the Amaryllidaceae which, as a group, possesses several biological features that make them particularly vulnerable. This is in addition to other problems relating to their value as horticultural material, traditional medicines and sources of phytochemicals of interest to medical science. Two in vitro systems are widely used for the propagation of amaryllidaceous species; regeneration from young floral stem explants and from twin-scales excised from bulbs. Although plantlet regeneration could be obtained from peduncle explants of Crinum moorei, a complex of factors including: the age of the floral stem; explant position and; hormonal factors, limited growth. Callus production was poor and indirect organogenesis could not be achieved. Twin-scales were used for the induction of somatic embryos. Morphologically these were different depending on the concentrations of 2,4-D and BA used in the induction medium. Although some of them went on to germinate, the use of somatic embryos for large-scale culture is not an efficient micropropagation route, owing to the low frequency of both embryo production and germination and to the long culture times. Regeneration of shoots and bulblets could, however, be readily induced from twin-scales using a series of modified MS media, and this despite the fact that explants from the bulb were more difficult to decontaminate than the above ground parts. Shoots arose in the axes of the twin-scales close to the basal plate. Initiation was greatest on a basic Murashige and Skoog medium, containing 4 g ℓ ¯¹ sucrose, and in the dark. No hormones were required. At high concentrations, the hormones stimulated abnormal organogenesis. Bulbing of the shoots was further enhanced using higher than normal levels of sucrose i.e. 6% and 5 g ℓ ¯¹ activated charcoal. The response was also influenced by the size of the twin-scale and its position in the parent bulb. Greater numbers of bulblets with larger diameters developed in large twin-scales from an intermediate position between the inner and outer scales. Furthermore, light, and a temperature of 25°C were required for normal bulblet development. Bulblets grown in this manner were used as a source of secondary explants by splitting them vertically in half. The addition of 10 mg ℓ ¯¹ BA resulted in multiple shoot development. In a liquid-shake culture system, this same multiplication medium induced the formation of meristemoid clusters whose rates of proliferation were higher than that achieved for shoot multiplication on either solid or static liquid media. The advantage of using meristematic clusters is that shoot hyperhydricity is avoided. Furthermore, the clusters can be mechanically separated; making the system ideal for automated plant production. Shoot morphogenesis, followed by the formation of bulblets occurred on solid MS media containing activated charcoal or high concentrations (6%) of sucrose. The induction of bulblets by sucrose was, however, slower, which may be beneficial for long-term storage and conservation ex situ. Compared to smaller bulblets, bulblets with a diameter of approximately 9 mm, acclimatized readily and grew rapidly after transferring them to the soil in greenhouse conditions. Biotechnological processes such as cell and tissue culture provide an ideal system for producing secondary metabolites, especially where their production in situ is hampered by poor resource availability or when chemical synthesis is difficult. In vitro produced Crinum moorei bulblets were found to contain nine alkaloids of the Amaryllidaceae type; three of which were released into the culture medium. Light was essential for alkaloid biosynthesis while the inclusion of BA and activated charcoal stimulated the production of specific alkaloids. / Thesis (Ph.D.)-University of KwaZulu- Natal, Pietermaritzburg, 2002.

Thesis (MSc.(Chemistry)) - University of Pretoria, 2008. / Summary in English. Includes bibliographical references.

As a part of the continuing search for bioactive compounds with the Madagascar International Cooperative Biodiversity Group (ICBG), and in collaboration with the Natural Products Discovery Institute of the Institute for Hepatitis and Virus Research (IHVR), thirteen plant extracts were investigated for antiplasmodial activity, thirteen plant extracts were investigated for antiproliferative activity, and one extract was investigated for inhibitors of the shikimate pathway in Plasmodium falciparum. Bioassay-guided fractionation of the extracts led to the identification of nineteen compounds with both antiplasmodial and antiproliferative activity, and thirteen compounds with only antiproliferative activity. Thirteen of these compounds (2.1 – 2.9, 3.3, 3.4, 4.5, and 5.1) were previously unknown. In addition total synthesis was used to confirm the structure of one new compound (4.5) and two other new natural-product like compounds (4.6 and 4.7) were also synthesized and investigated for antiplasmodial activity. / Ph. D.

Submitted by Cássio da Cruz Nogueira (cassionogueirakk@gmail.com) on 2017-01-26T13:50:02Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_CorrelacaoMetalobicaFungos.pdf: 2029628 bytes, checksum: 8feab0d533f4d04b3afb09538d403b20 (MD5) / Approved for entry into archive by Edisangela Bastos (edisangela@ufpa.br) on 2017-01-27T13:25:47Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_CorrelacaoMetalobicaFungos.pdf: 2029628 bytes, checksum: 8feab0d533f4d04b3afb09538d403b20 (MD5) / Made available in DSpace on 2017-01-27T13:25:47Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_CorrelacaoMetalobicaFungos.pdf: 2029628 bytes, checksum: 8feab0d533f4d04b3afb09538d403b20 (MD5) Previous issue date: 2016-06-30 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os fungos endofíticos são uma fonte promissora de metabólitos secundários com aplicações biotecnológicas. Esses micro-organismos habitam o interior dos tecidos vegetais sem causar nenhum dano ao hospedeiro e como fruto dessa interação podem produzir algumas das substâncias sintetizadas pelas plantas hospedeiras. Neste contexto o uso de fungos endofíticos como fonte de biomoléculas em substituição as de planta representa vantagens econômicas e ambientais. Espécies da família Amaryllidaceae produzem alcaloides e outros metabólitos com atividades biológicas. Entre estas espécies destacam-se Crinum americanum L. E Hymenocallis littoralis (Jacq.) Salisb. No entanto, não há dados sobre fungos endofíticos de espécies da família. Diante dos exposto o objetivo deste trabalho foi investigar o potencial biotecnológico de fungos endofíticos de C. americanum e H. littoralis em comparação com as plantas hospedeiras e estudar a interação entre endofíticos e a planta hospedeira. Como resultados foram isolados 94 fungos endofíticos das duas espécies de Amaryllidaceae investigadas, dos quais 49 foram identificados e pertencem aos gêneros Colettotrichum, Acremonium, Trichoderma e Fusarium. Constatou-se que do total das linhagens analisadas 56 apresentaram lipídios em seus extratos, 21 cumarinas, 29 anronas e 2 apresentaram alcaloides. Foram selecionadas 12 linhagens de fungos endofíticos que apresentaram os melhores resultados na detecção de classes de metabólitos e os extratos foram analisados por Cromatografia em Camada Delgada e por Cromatografia Gasosa acoplada a Espectrometria de Massas em comparação com os extratos metanólicos das plantas hospedeiras. Constatou-se a correlação ente as classes de metabólitos detectados nos extratos dos fungos endofíticos e das plantas hospedeiras, indicando que estes micro-organismos são capazes de produzir algumas das mesmas substâncias que as plantas hospedeiras e a avaliação da atividade antimicrobiana destacou alguns extratos com atividade contra Candida parapsilosis. O extrato metanólico das folhas de H. littoralis e do fungo endofítico MIBA 0796 apresentaram os resultados mais relevantes com percentual de inibição acima de 60% contra a levedura. Com o estudo da interação entre fungos endofíticos de C. americanum e a planta hospedeira pode-se constatar que os micro-organismos ocorrem no interior das células vegetais e em condições favoráveis se desenvolveram e ocuparam também os espaços intercelulares. Esta localização dos endofíticos nos tecidos vegetais pode facilitar a troca de material genético entre o vegetal e os micro-organismos o que explicaria a correlação metabólica constatada nesta pesquisa. / The endophytic fungi are a promising source of secondary metabolites with biotechnological applications. These microorganisms inhabit the interior of plant tissues without causing any damage to the host and as a result of this interaction can produce some of the substances synthesized by the host plant. In this context the use of endophytic fungi as a source of biomolecules in the replacement of plant represents economic and environmental advantages. Species in the Amaryllidaceae family produce alkaloids and other metabolites with biological activities. Among these species include Crinum americanum L. and Hymenocallis littoralis (Jacq.) Salisb. However, no data on endophytic fungi from species of the family were found. In the view of the above stated the aim of this work was to scrutinize the biotechnological potential of endophytes of C. americanum and H. littoralis as compared to host plants and to study the interactions between endophytes and host plant. As results 94 endophytic fungi were isolated from two species of the investigated Amaryllidaceae, of which 49 were identified and belonging to the Colettotrichum class, Acremonium, Trichoderma and Fusarium. It was noted that of the total strains tested 56 showed lipids in its extracts, 21coumarins, 29 anthrones and 2 showed alkaloids. 12 strains of endophytic fungi were selected which presented the best results in the detection of classes of metabolites and the extracts were analyzed by Thin-layer chromatography and by Gas chromatography-mass spectrometry in comparison with the methanolic extracts of host plants. It was noted the correlation between the classes of metabolites detected in extracts of the endophytic fungi and host plants, indicating that these micro-organisms are able to produce some of the same substances that the host plants and the assessment of antimicrobial activity highlighted some extracts with activity against Candida parapsilosis. The methanolic extract of leaves of H. littoralis and endophytic fungus MIBA 0796 presented the most relevant outcomes with percentage of inhibition above 60% against yeast. With the study of the interaction between C. americanum endophytes and the host plant it can observe that microorganisms act within the plant cells and in favorable conditions develop and occupy intercellular spaces as well. This location of the Endophytes in plant tissues may facilitate the exchange of genetic material between plants and microorganisms explaining how metabolic correlation found in this research.