隨著社會發展, 各種病毒、環境致癌物, 以及不健康食等多種因素導致諸種頑症高發, 並以人類獲得牲免疫缺陷綜合症(艾滋病)和各種腫瘤為代表。從天然產物, 特別是傳統中藥中, 篩選藥用有效成分是治療這類疾病的有效途徑之一。研究發現, 核糖體失活蛋白, 核糖核酸酶, 凝集素, 蛋白酪抑制劑等具有良好的藥用開發前景。本論文著重於從不同植物種于中篩選藥用蛋白, 並對其藥用機制進行研究。 / 是吹研究共純化出六種藥用蛋白。第一, 從苦瓜種子中純化出一種二型核糖體失活蛋白MCL。體外細胞試驗和體內裸鼠試驗顯示MCL 能夠有效抑制鼻咽癌細胞CNE-l 和CNE-2 生長。第二, 苦瓜種于中一個新的核糖核酸酪RNase MC2被分離出來。RNase MC2 通過調控半胱氨酸依賴性細胞死亡蛋白晦(Caspase)信號途徑和絲裂原活化蛋白激酶(MAPKs) 信號途徑誘導乳腺癌MCF-7 細胞凋亡。第三, 從宮粉羊蹄甲種子中提取一種具有抑制腫瘤細胞生長的蛋白酪抑制劑BvvTI 。第四, 從紅花羊蹄甲種子中提取出一與BvvTI 類似的具有抗腫瘤生長的蛋白酶抑制劑BPLTI。 第五，特長秋紫莢豆中存在一個血液凝集素EAPl。EAPL具有制止HIV-l 逆轉錄酶活性, 抗腫瘤, 誘導一氧化氮生成功效。第六, 從另外一種四季豆, 藍虎王, 中提取出一個血液凝集素BTKL。BTKL 通過誘導肝癌HepG2細胞出現DNA 斷裂, 細胞核破壞, 升高線粒體膜通透性, 誘導一氧化氮和細胞因予的表達, 從而導致其凋亡。 / 總之, 上述實驗結果表明, 這六種蛋白具有一定的藥用前景, 可以作為治療艾滋病和不同腫瘤的候造藥物或者候選輔助藥物。進一步體內實驗和臨床實驗評價其療效值得開展。 / Viral pathogens, environmental carcinogens, and unhealthy diets cause severe damage to humans, leading to the acquirement of different stubborn diseases exemplified by AIDS/HIV and neoplasms. Screening of new drugs from natural products, especially from traditional Chinese medicine, provides a promising strategy for these patients. Proteins with potential medicinal applications include ribosome-inactivating proteins (RIPs), ribonucleases, lectins, protease inhibitors and others. The intent of this research proposal is to isolate and characterize proteins with therapeutic potential from plant seeds. / In this project, six medicinal proteins of different origins have been purified by liquid chromatography. One of them is Momordica charantia lectin (MCL), which is a type 11 RIP from the seeds of bitter gourd (M. charantia, BG), with antitumor activity toward human nasopharyngeal carcinoma cells in vitro and in vivo. We have purified a new ribonuclease, named RNase MC2, from BG seeds. It selectively induces apoptosis in breast cancer cells associated with caspase pathways induction and MAPKs activation. Two Kunitz-type trypsin inhibitors, termed BvvTI and BPLTI, have been purified and characterized from the seeds of Bauhinia variegata var. variegata, and B. purpurea L., respectively. EAPL, a lectin with anti-HIV-l reverse transcriptase, antitumor, and nitric oxide (NO) inducing activities was purified from seeds of Phaseolus vulgaris cv. Extralong autumn purple bean. Finally, BTKL is a new P. vulgaris lectin that induced selective toxicity on human liver carcinoma Hep G2 cells. / In conclusion, the above results evince that these proteins are good candidates for the exploration of anti-HIV and/or antitumor drugs or adjuvants. Further research on their efficacies in in vivo as well as clinical trials is warranted. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Fang, Fei. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 162-187). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / ABSTRACT --- p.ii / 中文摘要 (CHINESE ABSTRACT) --- p.iii / ACKNOWLEDGEMENTS --- p.iv / PUBLICATIONS --- p.v / LIST OF ABBREViATIONS --- p.ix / LIST OF FIGURES --- p.x / LIST OF TABLES --- p.xii / Chapter CHAPTER1 --- GENERAL INTRODUCTION --- p.1 / Chapter 1.1 --- Prelude --- p.2 / Chapter 1.2 --- Literature review of bitter gourd --- p.4 / Chapter 1.2.1 --- Anti-diabetic property of BG --- p.5 / Chapter 1.2.2 --- Anti-HIV activity of BG --- p.15 / Chapter 1.2.3 --- Antitumor activity of BG --- p.18 / Chapter 1.2.4 --- Looking forward --- p.25 / Chapter 1.2.5 --- Conclusions --- p.29 / Chapter 1.3 --- Research rationale, design, and brief results --- p.35 / Chapter CHAPTER2 --- PURIFICATION AND CHARACTERIZATION OF RIBOSOME INACTIVATING PROTEIN --- p.39 / Chapter 2.1 --- Momordica charantia lectin, a type 11 ribosome inactivating protein, exhibits antitumor activity toward human nasopharyngeal carcinoma cells in vitro and in vivo --- p.40 / Chapter 2.1.1 --- Introduction --- p.40 / Chapter 2.1.2 --- Materials and methods --- p.42 / Chapter 2.1.3 --- Results --- p.46 / Chapter 2.1.4 --- Discussion --- p.59 / Chapter CHAPTER 3 --- PURIFICATION AND CHARACTERIZATION OF RIBONUCLEASE --- p.64 / Chapter 3.1 --- RNase MC2: A new Momordica charantia ribonuclease that selectively induces apoptosis in breast cancer cells associated with MAPKs activation and caspase pathways induction --- p.66 / Chapter 3.1.1 --- Introduction --- p.66 / Chapter 3.1.2 --- Materials and methods --- p.67 / Chapter 3.1.3 --- Results --- p.69 / Chapter 3.1.4 --- Discussion --- p.79 / Chapter CHAPTER 4 --- PURIFICATION AND CHARACTERIZATION OF PROTEASE INHIBITORS --- p.84 / Chapter 4.1 --- Bauhinia variegata var variegata trypsin inhibitor: from isolation to potential medicinal applications --- p.86 / Chapter 4.1.1 --- Introduction --- p.86 / Chapter 4.1.2 --- Materials and methods --- p.86 / Chapter 4.1.3 --- Results --- p.89 / Chapter 4.1.4 --- Discussion --- p.97 / Chapter 4.2 --- A potential human hepatocellular carcinoma inhibitor from Bauhinia purpurea L.seeds: From purification to mechanism exploration --- p.99 / Chapter 4.2.1 --- Introduction --- p.99 / Chapter 4.2.2 --- Materials and methods --- p.100 / Chapter 4.2.3 --- Results --- p.101 / Chapter 4.2.4 --- Discussion --- p.112 / Chapter CHAPTER 5 --- PURIFICATION AND CHARACTERIZATION OF MEDICINAL LECTINS --- p.114 / Chapter 5.1 --- A Lectin with Anti-HIV-l Reverse Transcriptase, Antitumor and Nitric Oxide Inducing Activities from Seeds of Phaseolus vulgaris cv Extra-long Autumn Purple Bean --- p.116 / Chapter 5.1.1 --- Introduction --- p.118 / Chapter 5.1.2 --- Materials and methods --- p.119 / Chapter 5.1.3 --- Results --- p.123 / Chapter 5.1.4 --- Discussion --- p.132 / Chapter 5.2 --- A new Phaseolus vulgaris lectin induces selective toxicity on human liver carcinoma Hep G2 cells --- p.136 / Chapter 5.2.1 --- Introduction --- p.136 / Chapter 5.2.2 --- Materials and methods --- p.137 / Chapter 5.2.3 --- Results --- p.138 / Chapter 5.2.4 --- Discussion --- p.150 / Chapter CHAPTER6 --- CONCLUSION AND FUTURE PERSPECTiVES --- p.154 / Chapter 6.1 --- Conclusions --- p.156 / Chapter 6.2 --- Future perspectives --- p.159 / References --- p.162