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Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

published_or_final_version / abstract / Chinese Medicine / Master / Master of Philosophy

Wong, Ying Chun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 73-78). / Abstracts in English and Chinese. / Acknowledgements --- p.I / Abstract --- p.II / 摘要 --- p.IV / List of Tables --- p.VI / List of Figures --- p.VII / List of Abbreviations --- p.VIII / Chapter Chapter 1 --- Introduction --- p.3 / Chapter 1.1 --- Chemical Constituents of Rhodiola Genus --- p.5 / Chapter 1.1.1 --- Phenylethyl Derivatives --- p.5 / Chapter 1.1.2 --- Phenylpropanoids --- p.8 / Chapter 1.1.3 --- Phenolic Derivatives --- p.11 / Chapter 1.1.4 --- Flavonoids --- p.14 / Chapter 1.1.4.1 --- Flavone and Flavone Glycosides --- p.15 / Chapter 1.1.4.2 --- Flavonols and Their Glycosides --- p.17 / Chapter 1.1.4.3 --- Flavan-3-ol Derivatives --- p.23 / Chapter 1.1.5 --- Monoterpenoids --- p.26 / Chapter 1.1.6 --- Triterpenes --- p.30 / Chapter 1.1.7 --- Miscellaneous Compounds --- p.32 / Chapter 1.2 --- Biological Activities of Rhodiola Genus --- p.33 / Chapter 1.2.1 --- Anti-oxidative Effect --- p.34 / Chapter 1.2.1.1 --- Protective Effect on Ischemia and Reperfusion --- p.34 / Chapter 1.2.1.2 --- Anti-Aging Effect --- p.35 / Chapter 1.2.2 --- Learning and Memory --- p.36 / Chapter 1.2.3. --- Immune Response --- p.37 / Chapter 1.2.4 --- Anti-cancer Effect --- p.38 / Chapter 1.3 --- Objective --- p.39 / Chapter Chapter 2 --- Experimental --- p.40 / Chapter 2.1 --- General Experimental Procedures --- p.40 / Chapter 2.2 --- Plant Materials --- p.40 / Chapter 2.3 --- Extraction and Isolation --- p.41 / Chapter 2.3.1 --- Isolation and Purification of the Ethyl Acetate (E.A.) Fraction --- p.41 / Chapter 2.3.2 --- Isolation and Purification of the Butanol Fraction --- p.44 / Chapter 2.4 --- Characterization of the Isolated Compounds --- p.46 / Chapter 2.4.1 --- β-Sitosterol (1) --- p.46 / Chapter 2.4.2 --- Tyrosol (2) --- p.46 / Chapter 2.4.3 --- trans-Hydroxycinnamic acid (3) --- p.47 / Chapter 2.4.4 --- Geranyl-β-glucopyranoside (4) --- p.47 / Chapter 2.4.5 --- Neryl-β-glucopyranoside (5) --- p.48 / Chapter 2.4.6 --- Hexyl β-Glucopyranoside (6) --- p.48 / Chapter 2.4.7 --- Gallic Acid (7) --- p.49 / Chapter 2.4.8 --- Epigallocatechin-3-Gallate (8) --- p.49 / Chapter 2.4.9 --- Rhodiolgin (9) --- p.50 / Chapter 2.4.10 --- lsolariciresinol-9-β-Glucopyranoside (10) --- p.51 / Chapter 2.4.11 --- Rhodiooctanoside (11) --- p.52 / Chapter 2.4.12 --- Sacranoside B (12) --- p.52 / Chapter Chapter 3 --- Results and Discussion --- p.53 / Chapter 3.1 --- Structural Determination of the Isolated Compounds --- p.53 / Chapter 3.1.1 --- Identification of β-sitosterol (1) --- p.53 / Chapter 3.1.2 --- Identification of Tyrosol (2) --- p.54 / Chapter 3.1.3 --- Identification of trans-Hydroxycinnamic Acid (3) --- p.55 / Chapter 3.1.4 --- Identification of Geranyl-jS-glucopyranoside (4) --- p.56 / Chapter 3.1.5 --- Identification of Neryl-β-glucopyranoside (5) --- p.58 / Chapter 3.1.6 --- Identification of Hexyl β-Glucopyranoside (6) --- p.59 / Chapter 3.1.7 --- Identification of Gallic Acid (7) --- p.60 / Chapter 3.1.8 --- Identification of (-)-Epigallocatechin 3-Gallate (8) --- p.61 / Chapter 3.1.9 --- Identification of Rhodiolgin (9) --- p.63 / Chapter 3.1.10 --- Identification of lsolariciresinol-9-β-glucopyranoside (10) --- p.65 / Chapter 3.1.11 --- Identification of Rhodiooctanoside (11) --- p.67 / Chapter 3.1.12 --- Identification of Sacranoside B (12) --- p.69 / Chapter Chapter 4 --- Conclusion --- p.70 / References --- p.73

Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) é uma espécie muito empregada na medicina tradicional no Brasil e em outras partes do mundo, especialmente Índia, países da África e China. É indicada popularmente para diversos fins incluindo o tratamento de úlceras gástricas. A análise fitoquímica revelou a presença de vários constituintes, em especial os flavonoides. O tratamento de úlcera gástrica convencional apresenta diversos efeitos colaterais e, na maioria das vezes, não evita a recidiva da lesão. Dessa maneira, é interessante encontrar uma terapêutica mais segura e efetiva. Com o objetivo de avaliar a segurança, foi realizado ensaio de citotoxicidade do extrato bruto, in vitro, com valor de IC50 igual a 0,926 mg/mL, sendo possível predizer um valor de LD50 (1341,46 mg/kg). Já em relação ao ensaio de citotoxicidade, in vitro, da fração acetato de etila não foi encontrado um valor de IC50. Resultados de fototoxicidade, in vitro, mostraram que o extrato bruto e fração acetato de etila de K. pinnata não possuem potencial fototóxico. A contagem microbiana na droga vegetal para bactérias aeróbias/mesófilas foi de 6,9 x 104 UFC/g e a contagem de bolores e leveduras foi de 2,4 x 103 UFC/g, ambos valores dentro do limite estabelecido pela OMS. Análise de endotoxinas também foi realizada para o extrato bruto (<4,0.105 UE/kg) e fração acetato de etila (<2,7.105 EU/kg) de K. pinnata. Referente à fitoquímica, diversos flavonoides foram identificados no extrato bruto e fração acetato de etila de K. pinnata. Paralelamente ao estudo fitoquímico foi verificado que a atividade gastroprotetora do extrato bruto envolve a ação das prostaglandinas e grupamentos sulfidrila. Já o mecanismo de gastroproteção da fração acetato de etila é dependente de prostaglandinas e óxido nítrico. A atividade cicatrizante do extrato bruto de K. pinnata também foi avaliada. De acordo com os resultados macroscópicos, as doses de 200mg/kg e 400 mg/kg reduziram a área de lesão, com uma taxa de 33% e 39%, respectivamente, após 7 dias de tratamento (p<0,05). Análise histológica dos grupos tratados com o extrato bruto (200 e 400 mg/kg) indicou melhor recuperação da lesão, verificada pela regeneração da mucosa gástrica e pelo restabelecimento da arquitetura glandular. As enzimas antioxidantes (catalase, superóxido dismutase e glutationa peroxidase) e a expressão de VEGF foram avaliadas no mecanismo de cicatrização de úlceras gástricas. Os resultados mostraram que a atividade antiulcerogênica foi mediada pela ação antioxidante da enzima SOD. Não foi evidenciado in vivo o aumento da expressão de VEGF e nem o sequestro do radical peroxil nos animais tratados com o extrato bruto. Os resultados dos ensaios in vitro (ORAC) mostraram uma maior capacidade de sequestro de radicais peroxil da fração acetato de etila (1192,35 ± 112,61 &#181;mol equivalente de Trolox/g de amostra seca) quando comparado com o extrato bruto (431,32 ± 7,17 &#181;mol equivalente de Trolox/g de amostra seca). A atividade anti Helicobacter pylori também foi avaliada, no entanto, o extrato bruto não apresentou atividade anti H.pylori. Ademais, o extrato bruto demonstrou um potencial anti-inflamatório, pois foi observada uma redução nos níveis de TNF-&#945; e L-selectina, após o tratamento em neutrófilos estimulados com LPS. Analisando os resultados sugere-se que K. pinnata possui um potencial terapêutico no combate de úlceras gástricas e possivelmente, anti-inflamatório, sendo que os flavonoides podem estar relacionados com o efeito biológico observado. / Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) is a commonly used species in traditional medicine in Brazil and in other parts of the world, especially India, Africa and China, for the treatment of various diseases, including gastric ulcers. Phytochemical analysis revealed the presence of several constituents in this plant, especially flavonoids. The available pharmaceutical products to treat peptic ulcer have several side effects and, in most cases, do not prevent recurrence of the gastric lesions. Therefore, it is important to find a safer and more effective therapy. In order to evaluate safety, the in vitro cytotoxicity assay of crude extract from K. pinnata was performed. The IC50 value was 0,926 mg/mL corresponding to LD50 value (1341, 46 mg/kg). It was not determined IC50 value in vitro cytotoxicity assay for ethyl acetate fraction from K. pinnata. Neither the crude extract nor ethyl acetate fraction from K. pinnata showed phototoxicity. Microbial counting was performed on the K. pinnata-based drug in order to investigate microbiological contamination. The microbial count for aerobic / mesophilic bacteria was 6.9 x 104 CFU/g, and yeast count was 2.4 x 103 CFU/g, both values in agreement with the limits established by WHO. Endotoxin analysis was also performed for the crude extract (<4,0.105 UE/kg) and for ethyl acetate fraction (<2,7.105 UE/kg) from K. pinnata. In the phytochemical analysis several flavonoids were identified in the crude extract and ethyl acetate fraction of K. pinnata. In parallel to the phytochemical study, it was verified that the gastroprotective activity of the crude extract of K. pinnata involved prostaglandins and sulfhydril compounds. On the other hand, the mechanism of gastroprotection of the ethyl acetate fraction of K. pinnata is dependent on prostaglandins and nitric oxide. The healing activity of the crude extract of K. pinnata was also evaluated. According to the macroscopic results the dose of 200 mg/kg and 400mg/kg reduced the injury area, with a rate of 33% and 39%, respectively, after 7 days of treatment (p <0.05). Histological analysis showed regeneration of the gastric mucosa and re-establishment of the glandular architecture in groups treated with the crude extract (200 and 400 mg/kg). Antioxidant enzymes (catalase, superoxide dismutase and glutathione peroxidase) and VEGF expression were evaluated in the mechanism of gastric ulcer healing. The results showed that the antiulcerogenic activity was mediated by SOD. It was not demonstrated an increase in VEGF expression and nor in the in vivo sequestration of the peroxyl radical in the animals treated with crude extract. The results of in vitro assay (ORAC) showed a greater sequestering of peroxyl radical to the ethyl acetate fraction (1192,35 ± 112,61 &#181;mol equivalent of Trolox/g of ethyl acetate fraction) when compared to the crude extract (431,32 ± 7,17 &#181;mol equivalent of Trolox/g of crude extract) of K. pinnata. The anti Helicobacter pylori activity was also evaluated; however, the crude extract did not show anti H. pylori activity. However, the crude extract of K. pinnata demonstrated an anti-inflammatory potential, because TNF-&#945; and L-selectin levels were reduced after treatment in LPS-stimulated neutrophils. The analysis of the results suggests that K. pinnata has a therapeutic potential against gastric ulcers and possible anti-inflammatory properties, and the flavonoids may be linked to the biological effect.

Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) é uma espécie muito empregada na medicina tradicional no Brasil e em outras partes do mundo, especialmente Índia, países da África e China. É indicada popularmente para diversos fins incluindo o tratamento de úlceras gástricas. A análise fitoquímica revelou a presença de vários constituintes, em especial os flavonoides. O tratamento de úlcera gástrica convencional apresenta diversos efeitos colaterais e, na maioria das vezes, não evita a recidiva da lesão. Dessa maneira, é interessante encontrar uma terapêutica mais segura e efetiva. Com o objetivo de avaliar a segurança, foi realizado ensaio de citotoxicidade do extrato bruto, in vitro, com valor de IC50 igual a 0,926 mg/mL, sendo possível predizer um valor de LD50 (1341,46 mg/kg). Já em relação ao ensaio de citotoxicidade, in vitro, da fração acetato de etila não foi encontrado um valor de IC50. Resultados de fototoxicidade, in vitro, mostraram que o extrato bruto e fração acetato de etila de K. pinnata não possuem potencial fototóxico. A contagem microbiana na droga vegetal para bactérias aeróbias/mesófilas foi de 6,9 x 104 UFC/g e a contagem de bolores e leveduras foi de 2,4 x 103 UFC/g, ambos valores dentro do limite estabelecido pela OMS. Análise de endotoxinas também foi realizada para o extrato bruto (<4,0.105 UE/kg) e fração acetato de etila (<2,7.105 EU/kg) de K. pinnata. Referente à fitoquímica, diversos flavonoides foram identificados no extrato bruto e fração acetato de etila de K. pinnata. Paralelamente ao estudo fitoquímico foi verificado que a atividade gastroprotetora do extrato bruto envolve a ação das prostaglandinas e grupamentos sulfidrila. Já o mecanismo de gastroproteção da fração acetato de etila é dependente de prostaglandinas e óxido nítrico. A atividade cicatrizante do extrato bruto de K. pinnata também foi avaliada. De acordo com os resultados macroscópicos, as doses de 200mg/kg e 400 mg/kg reduziram a área de lesão, com uma taxa de 33% e 39%, respectivamente, após 7 dias de tratamento (p<0,05). Análise histológica dos grupos tratados com o extrato bruto (200 e 400 mg/kg) indicou melhor recuperação da lesão, verificada pela regeneração da mucosa gástrica e pelo restabelecimento da arquitetura glandular. As enzimas antioxidantes (catalase, superóxido dismutase e glutationa peroxidase) e a expressão de VEGF foram avaliadas no mecanismo de cicatrização de úlceras gástricas. Os resultados mostraram que a atividade antiulcerogênica foi mediada pela ação antioxidante da enzima SOD. Não foi evidenciado in vivo o aumento da expressão de VEGF e nem o sequestro do radical peroxil nos animais tratados com o extrato bruto. Os resultados dos ensaios in vitro (ORAC) mostraram uma maior capacidade de sequestro de radicais peroxil da fração acetato de etila (1192,35 ± 112,61 &#181;mol equivalente de Trolox/g de amostra seca) quando comparado com o extrato bruto (431,32 ± 7,17 &#181;mol equivalente de Trolox/g de amostra seca). A atividade anti Helicobacter pylori também foi avaliada, no entanto, o extrato bruto não apresentou atividade anti H.pylori. Ademais, o extrato bruto demonstrou um potencial anti-inflamatório, pois foi observada uma redução nos níveis de TNF-&#945; e L-selectina, após o tratamento em neutrófilos estimulados com LPS. Analisando os resultados sugere-se que K. pinnata possui um potencial terapêutico no combate de úlceras gástricas e possivelmente, anti-inflamatório, sendo que os flavonoides podem estar relacionados com o efeito biológico observado. / Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) is a commonly used species in traditional medicine in Brazil and in other parts of the world, especially India, Africa and China, for the treatment of various diseases, including gastric ulcers. Phytochemical analysis revealed the presence of several constituents in this plant, especially flavonoids. The available pharmaceutical products to treat peptic ulcer have several side effects and, in most cases, do not prevent recurrence of the gastric lesions. Therefore, it is important to find a safer and more effective therapy. In order to evaluate safety, the in vitro cytotoxicity assay of crude extract from K. pinnata was performed. The IC50 value was 0,926 mg/mL corresponding to LD50 value (1341, 46 mg/kg). It was not determined IC50 value in vitro cytotoxicity assay for ethyl acetate fraction from K. pinnata. Neither the crude extract nor ethyl acetate fraction from K. pinnata showed phototoxicity. Microbial counting was performed on the K. pinnata-based drug in order to investigate microbiological contamination. The microbial count for aerobic / mesophilic bacteria was 6.9 x 104 CFU/g, and yeast count was 2.4 x 103 CFU/g, both values in agreement with the limits established by WHO. Endotoxin analysis was also performed for the crude extract (<4,0.105 UE/kg) and for ethyl acetate fraction (<2,7.105 UE/kg) from K. pinnata. In the phytochemical analysis several flavonoids were identified in the crude extract and ethyl acetate fraction of K. pinnata. In parallel to the phytochemical study, it was verified that the gastroprotective activity of the crude extract of K. pinnata involved prostaglandins and sulfhydril compounds. On the other hand, the mechanism of gastroprotection of the ethyl acetate fraction of K. pinnata is dependent on prostaglandins and nitric oxide. The healing activity of the crude extract of K. pinnata was also evaluated. According to the macroscopic results the dose of 200 mg/kg and 400mg/kg reduced the injury area, with a rate of 33% and 39%, respectively, after 7 days of treatment (p <0.05). Histological analysis showed regeneration of the gastric mucosa and re-establishment of the glandular architecture in groups treated with the crude extract (200 and 400 mg/kg). Antioxidant enzymes (catalase, superoxide dismutase and glutathione peroxidase) and VEGF expression were evaluated in the mechanism of gastric ulcer healing. The results showed that the antiulcerogenic activity was mediated by SOD. It was not demonstrated an increase in VEGF expression and nor in the in vivo sequestration of the peroxyl radical in the animals treated with crude extract. The results of in vitro assay (ORAC) showed a greater sequestering of peroxyl radical to the ethyl acetate fraction (1192,35 ± 112,61 &#181;mol equivalent of Trolox/g of ethyl acetate fraction) when compared to the crude extract (431,32 ± 7,17 &#181;mol equivalent of Trolox/g of crude extract) of K. pinnata. The anti Helicobacter pylori activity was also evaluated; however, the crude extract did not show anti H. pylori activity. However, the crude extract of K. pinnata demonstrated an anti-inflammatory potential, because TNF-&#945; and L-selectin levels were reduced after treatment in LPS-stimulated neutrophils. The analysis of the results suggests that K. pinnata has a therapeutic potential against gastric ulcers and possible anti-inflammatory properties, and the flavonoids may be linked to the biological effect.

Storlapinių šeimos augalai šiuo laikotarpiu yra vieni populiariausių augalų. Jie labai lengvai prižiūrimi, nereikalauja didelių pastangų ir laiko. Storlapinių (Crassulaceae) šeimą sudaro 30 genčių ir 1500 rūšių iš kurių Lietuvoje savaime auga 5 šeimos rūšys iš 3 genčių: šiloko (Sedum L.), perkūnropės (Jovibarba Opiz) ir vilkpupės (Hylotelephium H. Ohba). Darbo tikslas – įvertinti storlapinių šeimos augalų auginimo Šiaulių miesto želdynuose ypatumus. Darbo uždaviniai: ištirti storlapinių šeimos augalų įvairovę gėlynuose; nustatyti storlapinių šeimos augalų gausumą ir dažnumą; įvertinti storlapinių šeimos augalų auginimo gėlynuose galimybes. Tyrimas atliktas 2009 m. Ginkūnų ir Talkšos kapinėse, Šiaulių miesto gėlynuose bei privačiuose Šiaulių miesto ir gyvenvietės gėlynuose. Buvo tiriama augalų rūšių sudėtis, storlapinių šeimos augalų gausumas želdynuose. Nustatyti kiekvieno tiriamojo objekto rūšių panašumai pagal P. Žakaro (Jaccard) koeficientą. Tirtuose gėlynuose ir kapinėse buvo aptikti penkių iš storlapinių (Crassulaceae) šeimos genčių ( Sedum, Sempervivum, Hylotelephium, Echeveria ir Rosularia) augalai Gėlynuose ir kapinėse buvo atpažintos aštuonios storlapinių šeimos augalų rūšys – aitrusis šilokas (Sedum acre), agavinė kalvorė (Echeveria agavoides), kaukazinis šilokas (Sedum spurium), puošnioji vilpupė (Hylotelephium spectabile), stoginė šilropė (Sempervivum tectorium), uolinis šilokas (Sedum reflexum), voratinklinė šilropė (Sempervivum arachnoideum), gajutinė skotenė... [toliau žr. visą tekstą] / Ornamental plants of the Crassulaceae family are among the most popular ornamental plants, because their care is simple and does not require much time. The Crassulaceae family includes 30 genera and 1500 species. In Lithuania this family is represented by 5 native species, belonging to 3 genera – Sedum L., Jovibarba Opiz and Hylotelephium H. Ohba. The aim of the research vas to estimate peculiarities of Crassulacea plants cultivation in ornamental plantations of Šiauliai city. The following tasks were formulated: to investigate diversity of Crassulaceae species in ornamental plantations, to reveal abundance and frequency of Crassulaceae species, to estimate peculiarities of Crassulaceae cultivation in ornamental plantations. This research was performed in 2009 in Ginkūnai and Talkša cemeteries, as well as in public and private ornamental plantations of Šiauliai city. Diversity of all ornamental plant species and Crassulaceae species and their abundance was estimated. Similarity of species composition in different ornamental plantations was estimated employing Jaccard coefficient of similarity. Species of 5 Crassulaceae genera (Sedum, Sempervivum, Hylotelephium, Echeveria ir Rosularia) were found in the investigated ornamental plantations. Eight species of the Crassulaceae family were identified: Sedum acre, Echeveria agavoides, Sedum spurium, Hylotelephium spectabile, Sempervivum tectorum, Sedum reflexum, Sempervivum arachnoideum, Rosuaria aizoon. Comparison of diversity of... [to full text]

This thesis considers the implications of changes in the supply of resources for photosynthesis, with regard for modes of carbon acquisition employed by aquatic plants of the River Murray. Carbon supplies are inherently more variable for aquatic plants than for those in terrestrial environments, and variations are intensified for plants in semi-arid regions, where water may be limiting. In changeable environments the most successful species are likely to be those with flexible carbon-uptake mechanisms, able to accommodate variations in the supply of resources. Studies were made of plants associated with wetland habitats of the Murray, including Crassula helmsii, Potamogeton tricarinatus, P. crispus and Vallisneria americana. The aim was to elucidate the mechanisms of carbon uptake and assimilation employed, and to determine how flexibility in carbon uptake and/or assimilation physiology affect survival and distribution. Stable carbon isotopes were used to explore the dynamics of carbon uptake and assimilation, and fluorescence was used to identify pathways and photosynthetic capacity. The studies suggest that physiological flexibility is adaptive survival in changeable environments, but probably does not enhance the spread or dominance of these species. V. americana is a known bicarbonate-user, and it is shown here that it uses the Crassulacean Acid Metabolism (CAM) photosynthetic pathway under specific conditions (high light intensity near the leaf tips) concurrently with HCO[subscript]3 - uptake, while leaves deeper in the water continue to use the C[subscript]3 pathway, with CO₂ as the main carbon source. However, V. americana does not use CAM when under stress, such as exposure to high light and temperature. The diversity of carbon uptake and assimilation mechanisms in this species may explain its competitive ability in habitats associated with the Murray. In this way it is able to maximise use of light throughout the water column. In shallow, warm water, where leaves are parallel to the surface, CAM ability is likely to be induced along the length of the leaf, allowing maximal use of carbon and light. The amphibious C. helmsii is shown to use CAM on submergence, even where water levels fluctuate within 24 hours. This allows continued photosynthesis in habitats where level fluctuations prevent access to atmospheric CO₂. It appears that stable conditions are most favourable for growth and dispersal, and that the spread of C. helmsii is mainly by the aerial form. Carbon uptake by P. tricarinatus under field conditions is compared with that of P. crispus to demonstrate differences in productivity associated with aqueous bicarbonate and atmospheric CO₂ use. P. tricarinatus uses HCO[subscript]3 - uptake to promote growth toward the surface, so that CO₂ can be accessed by floating leaves. Atmospheric contact provides access to light and removes the limitation of aqueous diffusive resistance to CO₂, thereby increasing photosynthetic capacity above that provided by submerged leaves. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320380 / Thesis (Ph.D) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

This thesis considers the implications of changes in the supply of resources for photosynthesis, with regard for modes of carbon acquisition employed by aquatic plants of the River Murray. Carbon supplies are inherently more variable for aquatic plants than for those in terrestrial environments, and variations are intensified for plants in semi-arid regions, where water may be limiting. In changeable environments the most successful species are likely to be those with flexible carbon-uptake mechanisms, able to accommodate variations in the supply of resources. Studies were made of plants associated with wetland habitats of the Murray, including Crassula helmsii, Potamogeton tricarinatus, P. crispus and Vallisneria americana. The aim was to elucidate the mechanisms of carbon uptake and assimilation employed, and to determine how flexibility in carbon uptake and/or assimilation physiology affect survival and distribution. Stable carbon isotopes were used to explore the dynamics of carbon uptake and assimilation, and fluorescence was used to identify pathways and photosynthetic capacity. The studies suggest that physiological flexibility is adaptive survival in changeable environments, but probably does not enhance the spread or dominance of these species. V. americana is a known bicarbonate-user, and it is shown here that it uses the Crassulacean Acid Metabolism (CAM) photosynthetic pathway under specific conditions (high light intensity near the leaf tips) concurrently with HCO[subscript]3 - uptake, while leaves deeper in the water continue to use the C[subscript]3 pathway, with CO₂ as the main carbon source. However, V. americana does not use CAM when under stress, such as exposure to high light and temperature. The diversity of carbon uptake and assimilation mechanisms in this species may explain its competitive ability in habitats associated with the Murray. In this way it is able to maximise use of light throughout the water column. In shallow, warm water, where leaves are parallel to the surface, CAM ability is likely to be induced along the length of the leaf, allowing maximal use of carbon and light. The amphibious C. helmsii is shown to use CAM on submergence, even where water levels fluctuate within 24 hours. This allows continued photosynthesis in habitats where level fluctuations prevent access to atmospheric CO₂. It appears that stable conditions are most favourable for growth and dispersal, and that the spread of C. helmsii is mainly by the aerial form. Carbon uptake by P. tricarinatus under field conditions is compared with that of P. crispus to demonstrate differences in productivity associated with aqueous bicarbonate and atmospheric CO₂ use. P. tricarinatus uses HCO[subscript]3 - uptake to promote growth toward the surface, so that CO₂ can be accessed by floating leaves. Atmospheric contact provides access to light and removes the limitation of aqueous diffusive resistance to CO₂, thereby increasing photosynthetic capacity above that provided by submerged leaves. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320380 / Thesis (Ph.D) -- University of Adelaide, School of Earth and Environmental Sciences, 2008

Made available in DSpace on 2014-06-12T16:31:58Z (GMT). No. of bitstreams: 2 arquivo6256_1.pdf: 1729667 bytes, checksum: d62ce5ef03ff18914736fc6bce682329 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2007 / Kalanchoe brasiliensis Cambess é uma Crassulácea conhecida popularmente como saião, coirama-branca, folha-grossa ou folha-suculenta. Na medicina popular é utilizada contra lesões teciduais, bronquites, inflamações e úlceras em muitas partes do mundo. Contra essas afecções, a folha é a parte mais utilizada. Este estudo reporta uma avaliação do extrato hidroetanólico das folhas de K. brasiliensis quanto ao seu potencial toxicológico in vivo e in vitro e sua propriedade antitumoral. Além disso, também foi avaliada a atividade antimicrobiana do extrato hidroetanólico e do óleo essencial das folhas, bem como a alcoolatura do caule de Kalanchoe brasiliensis. A citotoxicidade in vitro da planta foi realizada em larvas de Artemia salina. A CL50 determinada em 704,8 &#956;g/mL tornou o extrato tóxico ao microcrustáceo. Foram realizados ensaios de toxicidade aguda com camundongos fêmeas Albinos Swiss (Mus muscullus), por via intraperitoneal, para observação de parâmetros como alterações comportamentais e efeitos sobre os sistemas nervoso central e autônomo. Nas doses de 1000 mg/kg a 3000 mg/kg de peso corpóreo administradas, foram observadas ações estimulantes seguidas de efeitos depressores ao sistema nervoso central e alterações na locomoção. A DL50 determinada em 1925 mg/kg de peso corpóreo tornou o extrato nocivo por via intraperitoneal. Na análise macroscópica o fígado e os rins apresentaram-se empaledecidos nas doses 250 mg/kg e 125 mg/kg de peso corpóreo. Na dose 62,5 mg/kg foram observadas apenas alterações microscópicas. Na avaliação antitumoral foram testadas as linhagens de Carcinoma de Ehrlich e Sarcoma-180 nas doses 250 mg/kg e 62,5 mg/kg de peso corpóreo do extrato hidroetanólico de K. brasiliensis. Nessas doses a inibição do Sarcoma-180 foi superior a 50%, sendo ambas estatisticamente significantes em comparação ao controle. Para Carcinoma de Ehrlich a inibição foi de 66,59% na maior dose, e apenas esta se mostrou significativa estatisticamente. Na avaliação mascroscópica a massa tumoral apresentou-se delimitada em todas as doses. Dentre os órgãos avaliados nos camundongos com neoplasias, o baço mostrou-se hipotrofiado e o fígado com coloração escurecida no grupo tratado com 250 mg/kg do extrato, no controle e no grupo padrão, para os dois tumores testados. Na menor dose não houve nenhuma alteração nos órgãos dos animais com o tumor de Ehrlich, porém ocorreu esplenomegalia nos animais com Sarcoma-180. A análise fitoquímica foi realizada através de cromatografia em camada delgada analítica utilizando diversas fases móveis e reveladores específicos, indicando os flavonóides como os fitoconstituintes predominantes. No ensaio antimicrobiano foram utilizadas amostras bacterianas gram-positivas e gram-negativas, dentre elas algumas cepas multiresistentes, além de fungos leveduriformes. Entre o óleo essencial e extrato hidroalcoólico das folhas e alcoolatura do caule, apenas o óleo mostrou-se efetivo nas concentrações de 0,25% a 8%, com halos de inibição de até 17 mm. Na concentração de 8%, foi obtido um efeito bacteriostático bem pronunciado, após a sexta hora de exposição da amostra ao óleo essencial. O efeito antimicrobiano foi observado em amostras multiresistentes de Staphylococcus aureus