Thesis (Ph. D.)--Ohio State University, 2007.

Plantas parasitas são aquelas que retiram os recursos necessários para a sua sobrevivência de outras plantas (hospedeiras) por meio de uma estrutura denominada haustório, que permite que a parasita se conecte ao sistema vascular da hospedeira. As plantas podem responder ao ataque parasita ativando alguns mecanismos de defesa, dentre eles, a produção de substâncias fenólicas. Os viscos constituem um grupo de plantas parasitas aéreas pertencentes a Santalales que podem ser divididos em viscos holoparasitas ou hemiparasitas. Alguns gêneros de viscos são de importância econômica, dentre eles, Phoradendron, um gênero de visco hemiparasita. Esse trabalho teve como objetivos determinar os conteúdos de taninos, flavonoides, fenilpropanoides, carboidratos solúveis, amido, lipídeos, a razão carbono/nitrogênio e avaliar como a relação parasítica afeta o metabolismo das espécies envolvidas. Para tanto, coletou−se no município de Campanha (MG) folhas e ramos de seis indivíduos não parasitados de Tapirira guianensis (FT e RT) e, a partir de nove indivíduos parasitados de T. guianensis, foram coletados ramos e folhas de Phoradendron crassifolium (FP e RP), ramos não infestados da hospedeira e suas folhas (RNI e FRNI) e ramos infestados de T. guianensis e suas folhas (RI e FRI), sendo que ramos infestados foram divididos em região proximal, galha e distal (RPRI, RGRI e RDRI). Como principais resultados estão o aumento no teor de proantocianidinas e de carboidratos solúveis em FRNI e FRI em relação a FT. Ramos infestados sofreram redução nos conteúdos de carboidratos solúveis, amido, lipídeos, nitrogênio e substâncias fenólicas, exceto na região da galha (RGRI) em que aumentos de amido e flavonoides foram verificados. Observou-se ainda que RNI parece ter sofrido um acúmulo de substâncias fenólicas. O conjunto dos resultados obtidos mostra que P. crassifolium afeta o metabolismo primário e o secundário de T. guianensis, com influência mais pronunciada nos ramos do que nas folhas da hospedeira. Pode−se sugerir que a parasita obtêm nitrogênio e carboidratos solúveis de sua hospedeira e que pode ocorrer uma possível realocação de carbono para crescimento, desenvolvimento, manutenção e, ainda, defesa de ramos ainda não infestados. Além disso, sugere−se que o acúmulo de fenólicos em ramos não infestados (RNI) possa ser um mecanismo de defesa usado pela hospedeira com o objetivo de evitar, ou mesmo diminuir, novas infestações em ramos ainda não parasitados. / Parasitic plants are those that withdraw necessary resources for its survival from other plants (hosts) through a structure so-called haustorium which enables the parasite to connect to the host\'s vascular system. Plants can respond to the parasite attack activating some defense mechanisms, including the production of phenolic compounds. Mistletoes are a group of stem parasitic plants belonging to Santalales that can be grouped into holoparasite or hemiparasite mistletoes. Some mistletoes genera are of economic importance among them Phoradendron, a hemiparasite mistletoe. This study aimed to determine the contents of tannins, flavonoids, phenylpropanoids, soluble carbohydrates, starch, lipids, the carbon⁄nitrogen ratio and evaluate how the parasitic relationship affects the metabolism of the involved species. Were collected in Camapanha (MG) leaves and branches from six non−parasitized individuals of Tapirira guianensis, host plant (LT and BT). From nine parasitized individuals of T. guianensis were collected branches and leaves of Phoradendon crassifolium, the parasitic plant (LP and BP), non-infested host branches and their leaves (NIHB and NIHB-L) and infested branches and their leaves (IHB and IHB-L). Infested branches of T. guianensis were divided into proximal, gall, and distal regions (IHB-P, IHB-G and IHB-D). Main results were an increase in the proanthocyanidin and soluble carbohydrates content in NIHB−L and IHB−L in relation to LT. There was a reduction of soluble carbohydrate, starch, lipids, nitrogen, and phenolic compounds in infested branches, except in the gall region (IHB-G), which showed an increase of flavonoids and starch contents. It was also observed that NIHB appears to accumulate phenolic compounds. Results showed that P. crassifolium affects the primary and secondary metabolism of T. guianensis, and branches were affected more intense than the leaves. It can be suggested that the parasite withdraws nitrogen and soluble carbohydrates from its host and this could result in possible carbon relocation for growth, development, maintenance, and also defense of branches not yet infested. In addition, it could be suggested the accumulation of phenolic compounds in non−infested branches (NIHB) as a defense mechanism used by the host in order to prevent or even reduce new infestations of an individual already parasitized.

Parasitic weeds of the family Orobanchaceae attach to the roots of host plants via haustoria capable of drawing nutrients from host vascular tissue. Species in this family span the spectrum of host nutrient dependency, allowing comparisons that provide insight into parasite adaptation. A key aspect of this is the relationship between parasite metabolism and the metabolite profile of its host. To what extent does the metabolite profile of the parasite depend on that of the host? Do parasites that differ in host-dependency also differ in their metabolism or do they use common metabolic strategies? These questions were addressed using comparative profiling of primary metabolites to gain insight into carbon and nitrogen assimilation by the obligate holoparasite Phelipanche aegyptiaca and the facultative hemiparasite Triphysaria versicolor. First, metabolite profiles of these parasites and their hosts were compared during the key life stages before and after haustorial attachment. Second, the impact of specific variations in host metabolism was analyzed for P. aegyptiaca growing on Arabidopsis thaliana hosts that had mutations in amino acid metabolism but otherwise identical genetic backgrounds. Comparison of P. aegyptiaca and T. versicolor metabolite profiles identified substantial differences in the stages spanning the transition from pre-haustorial development through post-haustorial feeding. Each parasite species is distinct from the other and from their hosts. For parasites growing on host lines that differ in amino acid content, the size of P. aegyptiaca tubercles decreased when grown on the aap6 mutant line, which has decreased levels of asparagine in the phloem sap compared to the wild type. However, altered amino acid levels in other lines did not impact P. aegyptiaca growth, indicating that this parasite has ability to compensate for variation in host metabolic composition. This research highlights the importance of aspartate and asparagine to early post-attachment metabolism in both P. aegyptiaca and T. versicolor and through host deficiencies possibly associated with decreased growth in P. aegyptiaca. Overall, this work provides insights both into the metabolism of parasitic plants and lays the foundation for the development of new metabolism-based control strategies. / Ph. D. / Parasitic weeds of the plant family Orobanchaceae attach to the roots of host plants via haustoria. Parasite haustoria embed into the host plant and are capable of drawing nutrients from host vascular tissue. Species in this family span the spectrum of the extent to which a parasitic plant may depend on its host for nutrients. This allows comparisons that provide insight into the ways in which parasites adapt. A key aspect of this is the relationship between the metabolite profile of the parasite and the metabolite profile of the host. To what extent does the metabolite profile of the parasite depend on that of the host? Do parasites that differ in host-dependency also differ in their metabolism or do they use common metabolic strategies? These questions were addressed using comparative profiling of primary metabolites to gain insight into carbon and nitrogen assimilation by the obligate parasite Phelipanche aegyptiaca (which cannot perform photosynthesis) and the facultative parasite Triphysaria versicolor (which can perform photosynthesis). First, metabolite profiles of these parasites and their hosts were compared during the key life stages before and after haustorial attachment. Second, the impact of specific variations in host metabolism was analyzed for P. aegyptiaca growing on Arabidopsis thaliana hosts. These hosts had mutations in enzymes related to amino acid metabolism but otherwise identical genetic backgrounds. Comparison of P. aegyptiaca and T. versicolor metabolite profiles identified substantial differences in the stages spanning the transition from pre-haustorial development through post-haustorial feeding. Each parasite species is distinct from the other and from their hosts. For parasites growing on host lines that differ in amino acid content, the size of P. aegyptiaca tubercles decreased when grown on the aap6 mutant line, which has decreased levels of asparagine in the phloem sap compared to the wild type. However, altered amino acid levels in other lines did not impact P. aegyptiaca growth, indicating that this parasite has ability to compensate for variation in host metabolic composition. Overall, this work provides insights both into the metabolism of parasitic plants and lays the foundation for the development of new metabolism-based control strategies.

O gênero Phoradendron é um dos mais diversos entre as plantas parasitas, agrupando cerca de 230 espécies, que apresentam grande variedade quanto à morfologia e padrões de infestação. A presente dissertação comparou os padrões de infestação de duas espécies de Phoradendron parasitando diferentes hospedeiras: Tapirira guianensis e Cedrela fissilis, além de analisar os efeitos causados por tais parasitas na funcionalidade e na anatomia da madeira destas hospedeiras. Foram realizadas análises tradicionais de anatomia da madeira, análises de microtomografia e experimentos de anatomia funcional com infiltração de corante através da madeira da hospedeira. Os resultados mostraram que, enquanto P. crassifolium forma uma galha concisa sobre os ramos de T. guianensis, Phoradendron sp. é mais agressivo ao espalhar seu sistema endofítico através da madeira de C. fissilis, causando maiores rupturas dos tecidos xilemático e floemático da hospedeira. Sugere-se que tais rupturas poderiam levar a uma alteração local do balanço auxina/citocinina e à liberação de etileno. Esta hipótese é reforçada pelas alterações anatômicas observadas em ambos os casos na interface parasita-hospedeira, tais como hiperplasia e/ou hipertrofia, maior densidade de vasos, alterações no agrupamento dos vasos e redução da espessura da parede celular das fibras. P. crassifolium também provocou severo aumento da densidade de vasos embolisados na madeira de T. guianensis, aumentando também a densidade de vasos e o tamanho de raios, além de reduzir o diâmetro transversal dos vasos e a espessura da parede celular de fibras. Tais efeitos também podem estar relacionados às altas taxas de transpiração e aos potenciais hídricos extremamente baixos apresentados por plantas parasitas, o que pode culminar no aumento da transpiração total da hospedeira, elevando a formação de embolismos, causando estresse hídrico e consequente baixa pressão de turgor nas células derivadas do câmbio. Conclui-se que cada uma das espécies de parasita aqui analisada estabeleceu uma relação única com sua hospedeira, formando diferentes padrões de infestação e alterando de modo particular a xilogênese da hospedeira / Phoradendron is one of the most diverse genera among parasitic plants, comprising ca. 230 species and showing a great variety of morphologies and infestation patterns. The present work compared the infestation patterns of two Phoradendron species on different hosts: Tapirira guianensis and Cedrela fissilis, and also analyzed their effects on the hosts\' functionality and wood anatomy. Traditional wood anatomy procedures were used, along with the technique of microtomography analysis and functional anatomy experiments using a dye ascent through host wood. Results showed that while P. crassifolium forms a defined gall in branches of T. guianensis, Phoradendron sp. is more aggressive when spreading its endophytic tissue trough the wood of C. fissilis, causing major disruptions on both xylem and phloem tissues of the host. Such disruptions could lead to a local change of the auxin/cytokinin balance and probably ethylene liberation. This hypothesis is reinforced by the anatomical alterations observed in both cases at the host-parasite interface, such as hyperplasia and/or hypertrophy, higher vessel density, alterations of vessel grouping and thin cell-walled fibres. P. crassifolium also provoked a severe increase in embolism density on the wood of T. guianensis, along with increases on vessel density and ray size, besides reductions in vessel lumen diameter and fibre cell-wall thickness. These effects could also be related to the high transpiration rates and extremely low water potential presented by parasitic plants, which may increase the host\'s total transpiration, enhancing embolism formation, causing water stress and consequent low turgor in differentiating cambium derivates. In conclusion, each parasitic plant species analyzed established a unique relationship with its host, forming different infestation patterns and differently altering its host xylogenesis

Bibliography: leaves 87-96. This thesis investigates non-proteinaceous low molecular weight flavonoid and alkaloid compounds in Scurulla oortiana (Korth.) Danser grown on Camellia sinens. Three flavonols are identified in S. oortiana (Korth.) Danser growing on different hosts. The identification and characterisation of these flavonoids are carried out using various chromatographic and spectrometric procedures. Two purine alkaloids are isolated from and identified in S. oortiana (Korth.) Danser parasitizing tea plant, C. Sinensis. The antifungal activity of the phenolic compounds isolated from mistletoe parasitizing tea plant is examined.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Most terrestrial plants make use of beneficial symbiotic associations to obtain nutrients (eg. nitrogen (N) and phosphorous (P)) from fungi in exchange for photoautotrophic carbon. However, plant parasitism (defined here as the ability of certain plants to parasitize other living material) has evolved in the plant kingdom and such plants obtain some, or all, of their nutritional needs from a host, which is severely negatively impacted by the parasite. While the physiological adaptations are well studied, the underlying molecular and biochemical mechanisms of plant parasitism remain largely unknown. As a first approach, a biochemical blueprint of primary metabolites present within parasitic plant species was constructed. The metabolomes of nineteen parasitic plants, ranging from hemi- and holoparasitism to mycoheterotrophism, were profiled via gas chromatography mass spectrometry (GC MS) based technology and targeted spectrophotometric assays. Based on these analyses, three important observations were made. First, parasitic plants were severely carbon deprived, despite being successful in colonizing and exploiting their hosts. Second, the levels of organic acids participating in mitochondrial respiration decreased and certain amino acids and soluble protein content increased. This suggests that parasitic plants utilize alternative respiratory substrates to compensate for a limitation in carbon supply. Third, although characterized by reduced carbohydrate pools, minor sugars normally not associated with plant metabolism, dominated the soluble sugar pool. The presence and significance of one of these sugars, namely turanose (α-D-glucopyranosyl-(1→3)-α-D-fructofuranose), was further investigated. Turanose biosynthetic reactions could be demonstrated in Orobanche minor extracts. Protein purification and mass spectrometry identification suggested that turanose biosynthesis occurred uniquely in parasitic plants. Future work will elucidate the functional significance of turanose metabolism in plant parasitism. Taken together, this study significantly contributes to our understanding of plant parasitism through development of metabolic signatures associated with distinct parasitic classes. These biochemical profiles highlighted several important strategies and alternative metabolic pathways that are either expressed or constitutively activated during parasitism. This knowledge broadens the scope of using parasitic plants in several biotechnological applications or as a novel research tool to address fundamental questions in plant science. / AFRIKAANSE OPSOMMING: Meeste landelike plante maak gebruik van voordelige simbiotiese assosiasies met swamme om voedinsgtowwe (bv. stikstof (N) en fosfor (P)) van hulle te verkry in ruil vir koolstof geproduseer deur die plant. Plant parasitisme (gedefinieer hier as die vermoë van sekere plante om ander lewende materiaal te parasiteer) het ontwikkel in die planteryk waar hulle sommige, of al hul voedings stowwe van 'n gasheer plant ontvang, wat erg negatief geraak word deur die parasiet. Terwyl die fisiologiese aanpassings goed gebestudeer is, is die onderliggende molekulêre en biochemiese meganismes van plant parasitisme steeds grootliks onbekend. As 'n eerste benadering, was hierdie projek geïnisieer om 'n biochemiese bloudruk op te bou van primêre metaboliete teenwoordig in parasitiese plante. Die metabolome van negentien parasitiese spesies, wat wissel van hemi - en holoparasiete tot mikoheterotrofiese plante, is ondersoek deur gas chromatografie – massa spektrometrie (GC MS) gebaseerde tegnologie en geteikende spektrofotometriese toetse. Gebaseer op hierdie ontledings was drie belangrike waarnemings gemaak. Eerstens, parasitiese plante was erg koolstof arm, ten spyte daarvan dat hulle suksesvol is in die aanhegting en ontginning van voedingstowwe vanaf gasheer plante. Tweedens, die vlakke van organiese sure wat deelneem aan mitochondriale respirasie het afgeneem, terwyl sekere aminosure en oplosbare proteïen inhoude toegeneem het. Dit dui daarop dat parasitiese plante gebruik maak van alternatiewe respiratoriese substrate om te vergoed vir 'n beperking in koolstof aanbod. Derde, alhoewel parasitiese plante gekenmerk word deur verminderde koolhidraat inhoude, het skaarse suikers wat normaalweg nie verband hou met plant metabolisme nie, hulle oplosbare suiker inhoud oorheers. Die teenwoordigheid en betekenis van een van hierdie suikers, naamlik turanose (α -D -glucopyranosyl-(1→3)-α-D-fructofuranose), was verder ondersoek. Die sintese reaksie van turanose kan gedemonstreer word in Orobanche hederae uittreksels. Proteïen suiwering en massa spektrometrie identifikasie het voorgestel dat turanose biosintese uniek plaasvind in parasitiese plante. Toekomstige werk sal aandui wat die betekenis is van turanose metabolisme in plant parasitisme. Saamgevat het hierdie studie aansienlik bygedra tot ons begrip van plant parasitisme deur ontwikkeling van metaboliese handtekeninge wat verband hou met onderskeie parasitiese klasse. Hierdie biochemiese profiele beklemtoon verskeie belangrike strategieë en alternatiewe metaboliese paaie wat óf uitgedruk of konstitutief geaktiveer word tydens parasitisme. Hierdie kennis verbreed die omvang van die gebruik van parasitiese plante in verskeie biotegnologiese toepassings of as 'n nuwe navorsings instrument om fundamentele vrae in plant wetenskap aan te spreek.

O gênero Phoradendron é um dos mais diversos entre as plantas parasitas, agrupando cerca de 230 espécies, que apresentam grande variedade quanto à morfologia e padrões de infestação. A presente dissertação comparou os padrões de infestação de duas espécies de Phoradendron parasitando diferentes hospedeiras: Tapirira guianensis e Cedrela fissilis, além de analisar os efeitos causados por tais parasitas na funcionalidade e na anatomia da madeira destas hospedeiras. Foram realizadas análises tradicionais de anatomia da madeira, análises de microtomografia e experimentos de anatomia funcional com infiltração de corante através da madeira da hospedeira. Os resultados mostraram que, enquanto P. crassifolium forma uma galha concisa sobre os ramos de T. guianensis, Phoradendron sp. é mais agressivo ao espalhar seu sistema endofítico através da madeira de C. fissilis, causando maiores rupturas dos tecidos xilemático e floemático da hospedeira. Sugere-se que tais rupturas poderiam levar a uma alteração local do balanço auxina/citocinina e à liberação de etileno. Esta hipótese é reforçada pelas alterações anatômicas observadas em ambos os casos na interface parasita-hospedeira, tais como hiperplasia e/ou hipertrofia, maior densidade de vasos, alterações no agrupamento dos vasos e redução da espessura da parede celular das fibras. P. crassifolium também provocou severo aumento da densidade de vasos embolisados na madeira de T. guianensis, aumentando também a densidade de vasos e o tamanho de raios, além de reduzir o diâmetro transversal dos vasos e a espessura da parede celular de fibras. Tais efeitos também podem estar relacionados às altas taxas de transpiração e aos potenciais hídricos extremamente baixos apresentados por plantas parasitas, o que pode culminar no aumento da transpiração total da hospedeira, elevando a formação de embolismos, causando estresse hídrico e consequente baixa pressão de turgor nas células derivadas do câmbio. Conclui-se que cada uma das espécies de parasita aqui analisada estabeleceu uma relação única com sua hospedeira, formando diferentes padrões de infestação e alterando de modo particular a xilogênese da hospedeira / Phoradendron is one of the most diverse genera among parasitic plants, comprising ca. 230 species and showing a great variety of morphologies and infestation patterns. The present work compared the infestation patterns of two Phoradendron species on different hosts: Tapirira guianensis and Cedrela fissilis, and also analyzed their effects on the hosts\' functionality and wood anatomy. Traditional wood anatomy procedures were used, along with the technique of microtomography analysis and functional anatomy experiments using a dye ascent through host wood. Results showed that while P. crassifolium forms a defined gall in branches of T. guianensis, Phoradendron sp. is more aggressive when spreading its endophytic tissue trough the wood of C. fissilis, causing major disruptions on both xylem and phloem tissues of the host. Such disruptions could lead to a local change of the auxin/cytokinin balance and probably ethylene liberation. This hypothesis is reinforced by the anatomical alterations observed in both cases at the host-parasite interface, such as hyperplasia and/or hypertrophy, higher vessel density, alterations of vessel grouping and thin cell-walled fibres. P. crassifolium also provoked a severe increase in embolism density on the wood of T. guianensis, along with increases on vessel density and ray size, besides reductions in vessel lumen diameter and fibre cell-wall thickness. These effects could also be related to the high transpiration rates and extremely low water potential presented by parasitic plants, which may increase the host\'s total transpiration, enhancing embolism formation, causing water stress and consequent low turgor in differentiating cambium derivates. In conclusion, each parasitic plant species analyzed established a unique relationship with its host, forming different infestation patterns and differently altering its host xylogenesis

No description available.

Seeds of the root parasitic plants of the genus Orobanche germinate specifically in response to host-derived germination signals, which enables parasites to detect and attack preferred hosts. The best characterized class of germination stimulants is the strigolactones (SLs), although some species respond to non-SL compounds, such as dehydrocostus lactone (DCL). Recent work indicates that SLs are perceived by members of the KARRIKIN-INSENSITIVE2 (KAI2) gene family, and suggests that within parasitic Orobanchaceae the KAI2 genes have undergone duplication and specialization. The "diverged" clade of these genes, termed KAI2d, has been shown to bind SL germination stimulants in model system assays, but the precise role for KAI2d in regulating germination specificity in a parasitic plant has not been demonstrated. To address this issue, we used genetic and genomic approaches involving two closely related species, Orobanche cernua and O. cumana, which differ primarily in host range and stimulant preference. Orobanche cernua parasitizes tomato (and other Solanaceous crops) and responds to orobanchol, the major SL from tomato roots, whereas O. cumana specifically parasitizes sunflower and responds to DCL. Crosses between O. cernua and O. cumana produced hybrid populations that segregate for stimulant specificity, creating a tractable genetic system. Orobanche cernua contains four KAI2d genes (numbered OrceKAI2d1-4), while O. cumana contains six genes (OrcuKAI2d1-6). The DNA from 94 F2 hybrids was genotyped to identify the KAI2d gene composition and these were correlated with germination phenotype. The pattern of segregation indicated that the KAI2d genes are linked, but pointed to OrceKAI2d2 as a likely orobanchol receptor. Response to DCL was associated with inheritance of all O. cumana KAI2d genes together. Each KAI2d gene was expressed in the Arabidopsis thaliana kai2 mutant background and tested for ability to recover the mutant phenotype when exposed to SLs (including orobanchol, 5-deoxystrigol and GR24) or DCL. One O. cernua gene, OrceKAI2d2, responded to all SLs, but not DCL in this system. No DCL-specific KAI2 genes were identified. In summary, we have identified the likely SL receptor in O. cernua, and show evidence that the DCL receptor is either not a KAI2d protein, or uses KAI2d in combination with other signaling pathway components. / Ph. D.

In many developing countries, farmers and pastoralists still rely on their indigenous knowledge, practices and locally available plants to control nematode parasitic infections, both in livestock and humans. The overall aim of my thesis was to undertake bioassay-guided phyto-chemical study of extracts and their constituents from Ethiopian anti-parasitic plants used by healers to control gastrointestinal nematode parasites in livestock to validate their ethno-medicinal use and to characterise and identify their active ingredients. As a first experiment (Chapter Three), four types of crude extracts (water, 70% methyl-alcohol, absolute methanol and acetone) of four indigenous Ethiopian medicinal plants (Adenia species, Cissus ruspolii, Ipomoea eriocarpa and Euphorbia thymifolia) were screened against Teladorsagia circumcincta egg hatching in vitro, not only as a first step to validate the traditional healers claim but also to choose the most promising plant extract(s) for further phyto-chemical studies. The egg hatching inhibition (EHI) test results revealed that the anti-parasitic properties of these plants depended on plant species, dose, and solvent polarity. The water extracts of both C. ruspolii and Adenia sp. exhibited largest, up to 100% EHI but also larval migration inhibition activities, and were selected for further studies. The second experiment (Chapter Four) assessed the nature of active constituents in these extracts by physico-chemical methods. It was observed that the major constituents of both plant extracts responsible for the EHI activities are likely highly polar, water-soluble, small and moderately heat-labile molecules. The third and fourth experiments (Chapters Five and Six) consisted of separating Cissus ruspolii and Adenia sp. water extracts into discrete fractions by gel-permeation chromatography, EHI tests of Bio-Gel P-2 fractions followed by thin layer chromatography (TLC) profiling of these fractions to detect separated spots (in day light, under UV-light or after staining with various staining reagents) and also to see how elution patterns of separated spots affected by column parameters. The EHI tests on the fractions obtained revealed that the active constituents of C. ruspolii and Adenia sp. water crude extracts were eluted into few fractions based on their molecular sizes. The TLC profilings of these fractions identified spot patterns of active and inactive fractions, which allowed pooling of active constituents based on their EHI and TLC profiling into three pools for each plant. The fifth experiment (Chapter Seven) was to isolate and purify compounds from these pools using various preparative planar and column chromatographic methods. Sequential applications of column chromatography followed by preparative thin layer chromatography isolated and purified five active compounds from C. ruspolii and two active compounds from Adenia sp. The sixth experiment (Chapter Eight) was to characterize and propose/elucidate structures of compounds from the active fractions using chromatographic, analytical and spectroscopic methods. In this regard, the structures of two oleanane type triterpenoid saponins isolated from one of active fractions of Adenia sp. were proposed based on their mass spectrometry (MS) and nuclear magnetic resonance (NMR) data with support of compounds property, TLC and literature. Similar outcomes for C. ruspolii were not achieved due to lack of sufficient sample to run 13C-nuclear magnetic resonance spectroscopy and distortionless enhancement by polarization transfer (DEPT), contamination of some purified compounds with ill-characterised substance from the preparative TLC matrix and in some cases mass spectrometry (MS) and nuclear magnetic resonance (NMR) data did not support each other. The last experiment (Chapter Nine) was to assess anthelmintic efficacy and safety of C. ruspolii and Adenia sp. crude water extracts in Heligmosomoides bakeri infected mice. This in vivo test revealed that both plant extracts exhibited significant reduction in worm burdens and worm egg excretion, with moderate effects on haematology and organ weights at tolerated dosages. In conclusion, both in vitro and in vivo data revealed that Adenia sp. and C. ruspolii have anthelmintic properties, thus validating traditional healer claims and supporting ethno-medicinal use. The bioassay-guided phytochemical study resulted in the isolation of a number of active compounds from these plants, for some of which a structure has been proposed.