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Search Results: 1 - 10 of 3979 matches for " Tzi Bun Ng "
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Antitumor and HIV-1 Reverse Transcriptase Inhibitory Activities of a Hemagglutinin and a Protease Inhibitor from Mini-Black Soybean
Xiu Juan Ye,Tzi Bun Ng
Evidence-Based Complementary and Alternative Medicine , 2011, DOI: 10.1155/2011/851396
Abstract: Protease inhibitors (PIs) and hemagglutinins are defense proteins produced by many organisms. From Chinese mini-black soybeans, a 17.5-kDa PI was isolated using chromatography on Q-Sepharose, SP-Sepharose, and DEAE-cellulose. A 25-kDa hemagglutinin was purified similarly, but using Superdex 75 instead of DEAE-cellulose in the final step. The PI inhibited trypsin and chymotrypsin (IC50 = 7.2 and 8.8 μM). Its trypsin inhibitory activity was stable from pH 2 to pH 13 and from 0∘C to 70∘C. The hemagglutinin activity of the hemagglutinin was stable from pH 2 to pH 13 and from 0∘C to 75∘C. The results indicated that both PI and hemagglutinin were relatively thermostable and pH-stable. The trypsin inhibitory activity was inhibited by dithiothreitol, signifying the importance of the disulfide bond to the activity. The hemagglutinating activity was inhibited most potently by D (
Trypsin Isoinhibitors with Antiproliferative Activity toward Leukemia Cells from Phaseolus vulgaris cv “White Cloud Bean”
Jian Sun,Hexiang Wang,Tzi Bun Ng
Journal of Biomedicine and Biotechnology , 2010, DOI: 10.1155/2010/219793
Abstract: A purification protocol that comprised ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on SP-Sepharose, and gel filtration by FPLC on Superdex 75 was complied to isolate two trypsin inhibitors from Phaseolus vulgaris cv “White Cloud Bean”. Both trypsin inhibitors exhibited a molecular mass of 16 kDa and reduced the activity of trypsin with an IC50 value of about 0.6 M. Dithiothreitol attenuated the trypsin inhibitory activity, signifying that an intact disulfide bond is indispensable to the activity. [Methyl-3H] thymidine incorporation by leukemia L1210 cells was inhibited with an IC50 value of 28.8 M and 21.5 M, respectively. They were lacking in activity toward lymphoma MBL2 cells and inhibitory effect on HIV-1 reverse transcriptase and fungal growth when tested up to 100 M.
A Review of the Potential Issues of Pollution Caused by the Mineral Elements, Mercury, Lead and Arsenic, Its Possible Impacts on the Human Beings and the Suggested Solutions  [PDF]
Yau Lam, Cho Wing Sze, Yao Tong, Tzi Bun Ng, Pang Chui Shaw, Yanbo Zhang
Chinese Medicine (CM) , 2012, DOI: 10.4236/cm.2012.34026
Abstract:

Objective: This paper mainly discusses and summarises the potential issues of pollution caused by the Mineral elements, Mercury, Lead and Arsenic, its possible impacts on the human beings and the suggested solutions. Methods: This paper is prepared by reviewing the latest academic literatures. Result: First, this article discusses two aspects including the effects of Mercury, Lead and Arsenic on the Chinese herbal medicine and the potential issues of causing the environmental pollution. And then further study its toxicity effects and the side impacts on the human bodies in order to realize the actual circumstances people are encountering nowadays. This paper will also the corresponding its treatment method of reviews. Hope this will provide a valuable reference. Conclusion: Theses issues caused by the Mineral elements are prominent nowadays, thus the ongoing researches on the impacts of pollution and the possible solutions are regarded as highly valued in order to conserve the natural environment and meanwhile safeguard the well beings of people and the future offspring.

A Lectin with Highly Potent Inhibitory Activity toward Breast Cancer Cells from Edible Tubers of Dioscorea opposita cv. Nagaimo
Yau Sang Chan, Tzi Bun Ng
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0054212
Abstract: A 70-kDa galactose-specific lectin was purified from the tubers of Dioscorea opposita cv. nagaimo. The purification involved three chromatographic steps: anion exchange chromatography on a Q-Sepharose column, FPLC-anion exchange chromatography on a Mono Q column, and FPLC-gel filtration on a Superdex 75 column. The purified nagaimo lectin presented as a single 35-kDa band in reducing SDS-PAGE while it exhibited a 70-kDa single band in non-reducing SDS-PAGE suggesting its dimeric nature. Nagaimo lectin displayed moderate thermostability, retaining full hemagglutinating activity after heating up to 62°C for 30 minutes. It also manifested stability over a wide pH range from pH 2 to 13. Nagaimo lectin was a galactose-specific lectin, as evidenced by binding with galactose and galactose-containing sugars such as lactose and raffinose. The minimum concentration of galactose, lactose and raffinose required to exert an inhibitory effect on hemagglutinating activity of nagaimo lectin was 20 mM, 5 mM and 40 mM, respectively. Nagaimo lectin inhibited the growth of some cancer cell lines including breast cancer MCF7 cells, hepatoma HepG2 cells and nasopharyngeal carcinoma CNE2 cells, with IC50 values of 3.71 μM, 7.12 μM and 19.79 μM, respectively, after 24 hour treatment with nagaimo lectin. The induction of phosphatidylserine externalization and mitochondrial depolarization indicated that nagaimo lectin evoked apoptosis in MCF7 cells. However, the anti-proliferative activity of nagaimo lectin was not blocked by application of galactose, signifying that the activity was not related to the carbohydrate binding specificity of the lectin.
Purification and Characterization of a Lectin from Phaseolus vulgaris cv. (Anasazi Beans)
Arishya Sharma,Tzi Bun Ng,Jack Ho Wong,Peng Lin
Journal of Biomedicine and Biotechnology , 2009, DOI: 10.1155/2009/929568
Abstract: A lectin has been isolated from seeds of the Phaseolus vulgaris cv. “Anasazi beans” using a procedure that involved affinity chromatography on Affi-gel blue gel, fast protein liquid chromatography (FPLC)-ion exchange chromatography on Mono S, and FPLC-gel filtration on Superdex 200. The lectin was comprised of two 30-kDa subunits with substantial N-terminal sequence similarity to other Phaseolus lectins. The hemagglutinating activity of the lectin was stable within the pH range of 1–14 and the temperature range of 0–80°C. The lectin potently suppressed proliferation of MCF-7 (breast cancer) cells with an IC50 of 1.3 M, and inhibited the activity of HIV-1 reverse transcriptase with an IC50 of 7.6 M. The lectin evoked a mitogenic response from murine splenocytes as evidenced by an increase in [3H-methyl]-thymidine incorporation. The lectin had no antifungal activity. It did not stimulate nitric oxide production by murine peritoneal macrophages. Chemical modification results indicated that tryptophan was crucial for the hemagglutinating activity of the lectin.
A Novel Lectin with Antiproliferative and HIV-1 Reverse Transcriptase Inhibitory Activities from Dried Fruiting Bodies of the Monkey Head Mushroom Hericium erinaceum
Yanrui Li,Guoqing Zhang,Tzi Bun Ng,Hexiang Wang
Journal of Biomedicine and Biotechnology , 2010, DOI: 10.1155/2010/716515
Abstract: A lectin designated as Hericium erinaceum agglutinin (HEA) was isolated from dried fruiting bodies of the mushroom Hericium erinaceum with a chromatographic procedure which entailed DEAE-cellulose, CM-cellulose, Q-Sepharose, and FPLC Superdex 75. Its molecular mass was estimated to be 51 kDa and its N-terminal amino acid sequences was distinctly different from those of other isolated mushroom lectins. The hemagglutinating activity of HEA was inhibited at the minimum concentration of 12.5 mM by inulin. The lectin was stable at pH 1.9–12.1 and at temperatures up to 70°C, but was inhibited by Hg2
Research on the allelopathic potential of wheat  [PDF]
Yau Lam, Cho Wing Sze, Yao Tong, Tzi Bun Ng, Sydney Chi Wai Tang, James Chung Man Ho, Qiaoqing Xiang, Xiao Lin, Yanbo Zhang
Agricultural Sciences (AS) , 2012, DOI: 10.4236/as.2012.38119
Abstract: Objective: This paper mainly discusses the Allelopathic potential of Wheat. Methods: This paper is prepared by reviewing the latest academic literatures. Result: The green revolution in the 1960s caused an increase in the demand for food. The agricultural sector and farmers tended to spend more time on the agricultural work but the crop yield was suppressed by the weeds. Hence, the usage of herbicide insecticides, fungicides and others chemicals had been increased. Although herbicides are efficient for weed controls, the continuous uses had gradually stimulated the weeds developing an effecttive resistance to the chemicals. Wheat (Triticum aestivum L.) is known as allelopathic against crops and weeds. Allelopathy of wheat (Triticum aestivum L.) has been extensively examined for its potentials in weeds management. The allelopathic activity of wheat has been attributed to hydroxamic acids, the related compounds and phenolic acids. Therefore, it could effectively reduce herbicide uses in order to maintain an eco-friendly environment and a cost-effective weed control.
Isolation of a Glucosamine Binding Leguminous Lectin with Mitogenic Activity towards Splenocytes and Anti-Proliferative Activity towards Tumor Cells
Yau Sang Chan, Jack Ho Wong, Evandro Fei Fang, Wenliang Pan, Tzi Bun Ng
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038961
Abstract: A dimeric 64-kDa glucosamine-specific lectin was purified from seeds of Phaseolus vulgaris cv. “brown kidney bean.” The simple 2-step purification protocol involved affinity chromatography on Affi-gel blue gel and gel filtration by FPLC on Superdex 75. The lectin was absorbed on Affi-gel blue gel and desorbed using 1M NaCl in the starting buffer. Gel filtration on Superdex 75 yielded a major absorbance peak that gave a single 32-kDa band in SDS-PAGE. Hemagglutinating activity was completely preserved when the ambient temperature was in the range of 20°C–60°C. However, drastic reduction of the activity occurred at temperatures above 65°C. Full hemagglutinating activity of the lectin was observed at an ambient pH of 3 to 12. About 50% activity remained at pH 0–2, and only residual activity was observed at pH 13–14. Hemagglutinating activity of the lectin was inhibited by glucosamine. The brown kidney bean lectin elicited maximum mitogenic activity toward murine splenocytes at 2.5 μM. The mitogenic activity was nearly completely eliminated in the presence of 250 mM glucosamine. The lectin also increased mRNA expression of the cytokines IL-2, TNF-α and IFN-γ. The lectin exhibited antiproliferative activity toward human breast cancer (MCF7) cells, hepatoma (HepG2) cells and nasopharyngeal carcinoma (CNE1 and CNE2) cells with IC50 of 5.12 μM, 32.85 μM, 3.12 μM and 40.12 μM respectively after treatment for 24 hours. Flow cytometry with Annexin V and propidum iodide staining indicated apoptosis of MCF7 cells. Hoechst 33342 staining also indicated formation of apoptotic bodies in MCF7 cells after exposure to brown kidney bean lectin. Western blotting revealed that the lectin-induced apoptosis involved ER stress and unfolded protein response.
Herba Epimedii: Anti-Oxidative Properties and Its Medical Implications
Stephen Cho Wing Sze,Yao Tong,Tzi Bun Ng,Chris Lok Yin Cheng,Ho Pan Cheung
Molecules , 2010, DOI: 10.3390/molecules15117861
Abstract: Herba Epimedii is a Chinese herbal medicine with proven efficacy in treating cardiovascular diseases and osteoporosis, and in improving sexual and neurological functions. This efficacy is found to be related to the potent anti-oxidative ability of Herba Epimedii and its flavonoid components, with icarrin as the main effective constituent, along with polysaccharides and vitamin C. These ingredients have been proven to be effective against oxidative-stress related pathologies (cardiovascular diseases, Alzheimer’s disease and inflammation) in animal rodent models and in vitro studies. Their anti-oxidative properties are found to be related to an inductive effect on endogenous free-radical scavenging enzymes such as catalase and glutathione peroxidase and the inherent electron-donating ability of flavonoids.
Baicalein antagonizes rotenone-induced apoptosis in dopaminergic SH-SY5Y cells related to Parkinsonism
Ju-Xian Song, Mandy Choi, Kavin Wong, Winkie Chung, Stephen Sze, Tzi-Bun Ng, Kalin Zhang
Chinese Medicine , 2012, DOI: 10.1186/1749-8546-7-1
Abstract: Cell viability and cytotoxicity were determined by MTT assay. The degree of nuclear apoptosis was evaluated with a fluorescent DNA-binding probe Hoechst 33258. The production of reactive oxidative species (ROS) and loss of mitochondrial membrane potential (ΔΨm) were determined by fluorescent staining with DCFH-DA and Rhodanmine 123, respectively. The expression of Bax, Bcl-2, cleaved caspase-3 and phosphorylated ERK1/2 was determined by the Western blots.Baicalein significantly increased viability and decreased rotenone-induced death of SH-SY5Y cells in a dose-dependent manner. Pre- and subsequent co-treatment with baicalein preserved the cell morphology and attenuated the nuclear apoptotic characteristics triggered by rotenone. Baicalein antagonized rotenone-induced overproduction of ROS, loss of ΔΨm, the increased expression of Bax, cleaved caspase-3 and phosphorylated ERK1/2 and the decreased expression of Bcl-2.The antioxidative effect, mitochondrial protection and modulation of anti-and pro-apoptotic proteins are related to the neuroprotective effects of baicalein against rotenone induced cell death in SH-SY5Y cells.Parkinson's disease (PD) is a neurodegenerative disease mainly characterized by loss of dopaminergic neurons in the substantia nigra pars compacta [1]. Although the pathology of PD is not understood well, the neurotoxic animal models of PD represent some key neurobehavioral or pathological features [2]. Three neurotoxins, 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and rotenone, are the agents to induce parkinsonism in vitro and in vivo [3]. An extensive study of these models defined important cellular actions of cell death and offered a basis for the development of novel therapeutic strategies [4]. Rotenone, a lipophilic pesticide, can cross cell membrane easily to induce systemic inhibition of mitochondrial complex I and cause selective nigrostriatal dopaminergic degeneration [5]. Rotenone-induced apoptosis in h
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