背景黃芪是中醫藥中最常用的補益藥之一，現代研究發現其多糖類成分具有抗疲勞、抗氧他和免疫調節等作用，因此研究黃芪多糖的生理活性已成為研究黃芪藥理作用新的主流方向。由於多糖類物質分子量較大，單糖組成及組成方式多樣，所以對多糖的研究除生理活性外還需探討解析其他學特征。目的初步驗證黃芪多糖對免疫系統的生理活性及其自身他學組成，探討展望未來對黃芪多糖研究的新方向。方法本實驗採用水提醇沉法提取分離除黃芪粗多糖，經除蛋白及透析等操作純忙得到黃百多糖。採用高效凝膠色譜分離法及超高效液相色譜法分別求得黃芪多糖相對分子量大小及其單糖組成成分免疫活性探究使用RAW264.7 細胞系巨噬細胞，以脂多糖為陽性對照，採用MTT 法測試細胞毒性，計算加藥后一氧化氮及細胞因子IL-6 和TNF－α 生成量，評價黃芪多糖的免疫調節作用。結果黃芪多糖相對分子量為108.02kDa(±2.73kDa），由阿拉伯糖、葡萄糖、半乳糖、葡萄糖醛酸和半乳糖醛酸組成。MTT 實驗表明黃芪多糖對細胞無明顯毒性﹔ NO 及細胞因子IL-6 和TNF－α 生成量表明其具有免疫調節功能，且作用強度與黃芪多糖濃度在一定範圍內呈正相關。結論黃芪多糖具有免疫調節活性，但其組成成分較多，他學結構複雜，仍需要進行更多研究探討其作用機制及其他學結構與免疫調節機制的關係。【關鍵詞】黃芪多糖﹔化學組成﹔免疫活性

Astragalus gombo Bunge (Fabaceae) est une plante bien représentée dans le Sahara Septentrional Est Algérien (région de Ouargla, Algérie) et couramment utilisée comme fourrage pour les animaux ou en médecine traditionnelle. Malgré de nombreuses publications sur la richesse en polysaccharides d’autres espèces appartenant au genre Astragalus et la description de leurs propriétés biologiques putatives ou avérées, aucune étude ne s’est intéressée à l’espèce gombo. L’objectif de ce travail de thèse a donc été de réaliser des investigations sur plusieurs parties de cette plante en vue d’extraire, identifier et caractériser son contenu en polysaccharides. Dans un second temps les propriétés biologiques et rhéologiques de ces polymères ont été étudiées afin d’identifier d’éventuelles voies de valorisation. Les résultats obtenus ont permis de détecter la présence de composés pectiques et hémicellulosiques dans la tige d’Astragalus gombo et celle d’un galactomannane dans les graines. Le galactomannane est de haute masse moléculaire (1,1x106 Da) et est constitué d’une chaine principale de β-(1→4)-D-mannane ramifiée en α-(1→6) par des résidus Dgalactopyranoses avec un rapport M/G de 1,7. La caractérisation de ses propriétés rhéologiques a révélé un comportement typique rhéofluidifiant et des propriétés viscoélastiques. L’étude des activités biologiques associées à ce biopolymère a révélé son potentiel comme prébiotique et antioxydant. / Astragalus gombo Bunge (Fabaceae) is a terrestrial plant occuring in the East Septentrional Sahara (Ouargla, Algeria). It is commonly used as fodder or in traditional medicine by local populations. Despite numerous publications focusing on polysaccharidic contents of Astragalus species and the designation of their putative or proved biological activities, no study has examined those of A. gombo. The objective of this thesis was firstly to investigate several organs of this plant for their polysaccharide contents. In a second step, the biological and rheological properties of these biopolymers have been studied to identify ways of adding value. Results led to the identification of pectic compounds and hemicelluloses in the rods of Astragalus gombo whereas a galactomannan was detected in its seeds. This galactomannan was a high molecular weight macromolecule composed of a β-(1→4)-D-mannan skeleton ramified by residues of D-galactopyranoses. The M/G ratio was of 1.7. The characterization of its rheological behavior was typic of that of a rheofluidifiant fluid with viscoelastic properties. The study of its biological properties showed its potential as prebiotic and antioxidant agent.

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Thesis (M.S.)--Brigham Young University. Dept. of Plant and Wildlife Sciences, 2007. / Includes bibliographical references.

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Although tremendous efforts have been made to search for other novel growth factors in promoting marrow recovery after irradiation or chemotherapy, there have not been any efficient and safe agents discovered so far. Danggui Buxue Tang (當歸補血湯) as a traditional Chinese herbal decoction, is commonly used for replenishing blood loss in menstruating women, or enhancing erythropoiesis and immune responses in various settings. Our previous study confirmed that Danggui Buxue Tang promotes haematopoiesis and thrombopoiesis both in vitro & in vivo. Recent studies also showed that parenteral Astragalus regulates haematopoiesis in myelosuppressed mice and has protection effect on UV irradiated human dermal fibroblasts. However, astragaloside IV, as the major component of Astragalus, the "Monarch" (君葯) in Danggui Buxue Tang, the bioactivity and its possible mechanism on haematopoiesis remains unclear. My studies showed that astragaloside IV had promoting effect on different lineages of haematopoietic CFUs forming including erythrocytes, granulocytes, monocytes and megakaryocytes both in normal and irradiated mice. In the K562 and CHRF apoptotic model, astragaloside IV exerted proliferation effect and induced K562 into megakaryocytic differentiation. Astragaloside IV up-regulated phosphorylation of ERK and it was abolished by PD98059. Meanwhile, astragaloside IV increased phosphorylated ERK migration into nuclei which enhanced cell survival and differentiation. EGFR inhibitor also attenuated the enhancing effect of astragaloside IV on ERK phosphorylation. It suggested that astragaloside IV is likely to function through EGFR with subsequent activation of ERK1/2 pathway. Furthermore, astragaloside IV also increased Bcl-2/Bax ratio by up-regulating Bcl-2 alone. Bone marrow derived mesenchymal stromal cells are the major supporting cells involved in the haematopoietic microenvironment. My studies demonstrated that astragaloside IV also indirectly enhanced haematopoiesis by stimulating cytokine release from MSCs, especially IL-6, IL-8, MCP-1 and GRO1. I also found that matured and activated population of neutrophils was increased after cultured with mesenchymal stromal cells conditional medium stimulated by astragaloside IV. This finding further supported why there was a significant increment of CFU-GM in vitro culture with murine bone marrow collected from mouse model after astragaloside IV treatment, where MSCs serve as the feeder layer in such system in mice. In conclusion, my studies explored the directly and indirectly dynamic and multiple targeted function of astragaloside IV on haematopoiesis. In addition to activating haematopoietic cells, astragaloside IV also stimulated mesenchymal stromal cells to secret cytokines that could modulate haematopoiesis and up-regulated neutrophil production and maturation. It provided a holistic view on how astragaloside IV induced synergistic effect on haematopoietic cells and mesenchymal stromal cells in the marrow microenvironment. / published_or_final_version / Chinese Medicine / Doctoral / Doctor of Philosophy

Uncontrolled cell growth may lead to pathological conditions such as cancer. During the progression of cancer, cancer cells stimulate endothelial cells for angiogenesis to support their growth and migration. Previous studies suggest that Astragalus membranaceus, of which the dried root [Astragali Radix] is used as a traditional Chinese medicine, and its bioactive components, astragalus saponins (AST), astragaloside IV (AS IV) and isoflavonoid calycosin, inhibit cancer growth. The present study aimed to examine whether or not these components inhibit the growth and/or metastasis of colon cancer cells and/or angiogenesis of endothelial cells, and to determine the possible mechanisms involved. The growth of HCT 116 colon cancer cells and human umbilical vein endothelial cells (HUVEC) after 72 hours incubation with AST (1 to 25 μg/ml), AS IV (0.5 to 100 μM) or calycosin (10 to 200 μM) were detected with thiazolyl blue tetrazolium bromide assay. Wound healing migration and tube formation assays were used to examine the metastatic and angiogenic potential of HCT 116 cells and HUVEC. Moreover, the expressions of apoptotic [B-cell lymphoma 2 and procaspase-3] and metastasis/angiogenesis-related proteins [matrix metalloproteinase (MMP)-2, MMP-9 and vascular endothelial growth factor (VEGF)] were measured with Western immunoblotting. To investigate the potential mechanism(s) through which astragalus components affect the proliferation and/or migration of HCT 116 cells and HUVEC, the activities of mitogen-activated protein (MAP) kinases [extracellular signal-regulated kinase 1 and 2 (ERK1/2), p38 MAP kinase (p38) and c-Jun amino-terminal kinases] were studied by measuring the expressions of their phosphorylated and total proteins with Western immunoblotting. Calycosin (200 μM) inhibited the growth of HCT 116 cells without affecting that of HUVEC. While it inhibited the migration of both cell types, it stimulated tube formation only in HUVEC. In HCT 116 cells, calycosin downregulated the expressions of procaspase-3, VEGF, MMP-2 and MMP-9 proteins, inhibited ERK1/2 but activated p38. These effects of calycosin were not observed in HUVEC. Neither AST nor AS IV had any significant effects on the parameters studied in HCT 116 cells. AST also showed no effect in HUVEC; AS IV, at 100 μM, appeared to increase the number of tube formation by HUVEC. In conclusion, the present findings suggest that AST has no significant effect on both cancer and endothelial cells while AS IV may promote angiogenesis without any direct action in colon cancer cells. In colon cancer cells, calycosin induces apoptosis, possibly through activation of caspase-3 and p38, and inhibits metastasis, possibly by downregulating MMP-2 and MMP-9, and inhibiting ERK1/2. However, in endothelial cells, the effect of calycosin is not conclusive as it promotes tube formation but inhibits migration. These findings provide the pharmacological basis for the use of Astragali Radix in the treatment of colon cancer, and the scientific evidence for a therapeutic potential of calycosin in the management of this disorder. Further studies are needed to verify the effect of calycosin on endothelial cells. In order to better mimic the clinical situation, the interaction between cancer and endothelial cells [for example, tumor-induced angiogenesis] needs to be taken into consideration. / published_or_final_version / Pharmacology and Pharmacy / Master / Master of Philosophy

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This investigation was concerned with the taxonomic relationship between Astragalus beckwithii (Torr. & Gray) var. beckwithii, Astragalus oophorus (S. Wats) var. caulescens (Jones) Jones, and Astragalus megacarpus (A. Gray). An attempt was made to relate some chemical constituents and the toxic effects on rats to the taxonomy. A number of parameters were used; rat toxicity, lipid analysis, selenium atomic absorption, various salts and glucose percentages, as well as the usual morphological measurements taken from herbarium specimens, field observations, and pollen measurements. While the weight of the data indicates that A. beckwithii is a type of intermediary or intergressory product of A. oophorus and A. megacarpus, and that it very closely resembles A. oophorus, it would be premature to suggest combining A. beckwithii and A. oophorus until the related varieties in each species are also studied. Evidence shows definite symptoms of locoism in the white rats tested. A hypothesis was made that the toxic principles in these plants are associated with the nitrile compounds.