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Sangthong S Krusong K Ngamrojanavanich N Vilaivan T Puthong S Chandchawan S Muangsin N 《Bioorganic & medicinal chemistry letters》2011,21(16):4813-4818
6-Deoxyclitoriacetal (1) and a series of 11 further derivatives of it (2-12) were synthesized and evaluated for their cytotoxic and topoisomerase IIα inhibitory activities. Compounds bearing epoxide (2), morpholine (6) and benzylamine (10) moieties showed promising in vitro cytotoxic activities against four cancer cell lines, with IC50 values ranging from 0.38 to 0.73 μM. These three compounds also strongly inhibited topoisomerase II activity at 68.3-93.5% and showed a moderately high DNA intercalating property. 相似文献
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T cell responses in dengue hemorrhagic fever: are cross-reactive T cells suboptimal? 总被引:8,自引:0,他引:8
Mongkolsapaya J Duangchinda T Dejnirattisai W Vasanawathana S Avirutnan P Jairungsri A Khemnu N Tangthawornchaikul N Chotiyarnwong P Sae-Jang K Koch M Jones Y McMichael A Xu X Malasit P Screaton G 《Journal of immunology (Baltimore, Md. : 1950)》2006,176(6):3821-3829
Dengue virus infection poses a growing public health and economic burden in a number of tropical and subtropical countries. Dengue circulates as a number of quasispecies, which can be divided by serology into four groups or serotypes. An interesting feature of Dengue, recognized over five decades ago, is that most severe cases that show hemorrhagic fever are not suffering from a primary infection. Instead, they are reinfected with a virus of different serotype. This observation poses considerable problems in vaccine design, and it is therefore imperative to gain a full understanding of the mechanisms underlying this immunological enhancement of disease. In this study, we examined a T cell epitope restricted by HLA-A*24, a major MHC class I allele, in Southeast Asia in a cohort of children admitted to a hospital with acute Dengue infection. The cytokine profiles and the degranulation capacity of T cells generated to this epitope are defined and compared across different viral serotypes. Cross-reactive Dengue-specific T cells seem to show suboptimal degranulation but high cytokine production, which may contribute to the development of the vascular leak characteristic of Dengue hemorrhagic fever. 相似文献
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Porntep Chomcheon Suthep Wiyakrutta Nattaya Ngamrojanavanich Surapong Kengtong Somsak Ruchirawat Prasat Kittakoop 《Phytochemistry》2009,70(3):407-413
Isolation of a broth extract of the endophytic fungus Corynespora cassiicola L36 afforded three compounds, corynesidones A (1) and B (3), and corynether A (5), together with a known diaryl ether 7. Compounds 1, 3, 5, and 7 were relatively non-toxic against cancer cells, and inactive toward normal cell line, MRC-5. Corynesidone B (3) exhibited potent radical scavenging activity in the DPPH assay, whose activity was comparable to ascorbic acid. Based on the ORAC assay, compounds 1, 3, 5, and 7 showed potent antioxidant activity. However, the isolated natural substances and their methylated derivatives (1−8) neither inhibited superoxide anion radical formation in the XXO assay nor suppressed TPA-induced superoxide anion generation in HL-60 cell line. Corynesidone A (1) inhibited aromatase activity with an IC50 value of 5.30 μM. 相似文献
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Tanapan Prommool Pongpawan Sethanant Narodom Phaenthaisong Nattaya Tangthawornchaikul Adisak Songjaeng Panisadee Avirutnan Dumrong Mairiang Prasit Luangaram Chatchawan Srisawat Watchara Kasinrerk Sirijitt Vasanawathana Kanokwan Sriruksa Wannee Limpitikul Prida Malasit Chunya Puttikhunt 《PLoS neglected tropical diseases》2021,15(2)
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Avigad Vonshak Nattaya Kancharaksa Boosya Bunnag Morakot Tanticharoen 《Journal of applied phycology》1996,8(2):119-124
The response ofSpirulina platensis cells to salinity stress was studied. Once adapted to the higher osmoticum, photosynthetic parameters such as the maximum rate of photosynthesis under saturating irradiance (Pmax) and the initial slope of the P-I curve () are reduced by 15% and 25% in 0.5 M NaCl grown cells, respectively. Salt-adapted cells have a modified biochemical composition; reduced protein and chlorophyll content, and an increased level of carbohydrates. The reduction in the photosynthetic capacity of the salt-adaptedSpirulina cells reflects a lower ability to utilize light energy and results in an increase in the susceptibility of the stressed cells to photoinhibition. This conclusion is supported by the finding that cultures exposed to salt stress show not only a decrease in growth rate (), but lose the ability to respond to increased irradiance with an increase in growth. The use of variable fluorescence as a fast and reliable measurement to follow the changes in PSII of salt-stressesSpirulina cells enables following the early events of salinity shock. It indicates that as soon as the cells are exposed to salt, a protection mechanism is induced. This mechanism does not require any protein synthesis and may take place even in the dark, though at somewhat reduced effectiveness. The significance of the result in providing a better understanding of the interaction between two environmental stresses — light and salinity — and their application in the outdoor mass cultivation ofSpirulina are discussed.Author for correspondence 相似文献
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Porntep Chomcheon Suthep Wiyakrutta Nattaya Ngamrojanavanich Chulabhorn Mahidol Somsak Ruchirawat Prasat Kittakoop 《Phytochemistry》2009,70(1):121-127
The endophytic mitosporic Dothideomycete sp. LRUB20 was found to produce pyrone derivatives, dothideopyrones A-D (1, 3, 4, and 5), together with seven known compounds, including questin (9), asterric acid (10), methyl asterrate (11), sulochrin (12), and eugenitin (13), 6-hydroxymethyleugenitin (14), and cis, trans-muconic acid (15). Dothideopyrone D (5) and its acetate derivative 6 exhibited moderate cytotoxic activity. This is the first report on a naturally occurring muconic acid, which is commonly known as a biomarker in environments after exposure to benzene and phenol (or derivatives). Interestingly, the LRUB20 fungus could produce muconic acid in relatively high yield (47.8 mg/L). The utility of endophytic fungi in the field of white biotechnology is discussed. 相似文献
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Original antigenic sin and apoptosis in the pathogenesis of dengue hemorrhagic fever 总被引:22,自引:0,他引:22
Mongkolsapaya J Dejnirattisai W Xu XN Vasanawathana S Tangthawornchaikul N Chairunsri A Sawasdivorn S Duangchinda T Dong T Rowland-Jones S Yenchitsomanus PT McMichael A Malasit P Screaton G 《Nature medicine》2003,9(7):921-927
Dengue virus presents a growing threat to public health in the developing world. Four major serotypes of dengue virus have been characterized, and epidemiological evidence shows that dengue hemorrhagic fever (DHF), the more serious manifestation of the disease, occurs more frequently upon reinfection with a second serotype. We have studied dengue virus-specific T-cell responses in Thai children. During acute infection, few dengue-responsive CD8+ T cells were recovered; most of those present showed an activated phenotype and were undergoing programmed cell death. Many dengue-specific T cells were of low affinity for the infecting virus and showed higher affinity for other, probably previously encountered strains. Profound T-cell activation and death may contribute to the systemic disturbances leading to DHF, and original antigenic sin in the T-cell responses may suppress or delay viral elimination, leading to higher viral loads and increased immunopathology. 相似文献
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Wannapha Molee Anuchit Phanumartwiwath Chatchai Kesornpun Sanya Sureram Nattaya Ngamrojanavanich Kornkanok Ingkaninan Chulabhorn Mahidol Somsak Ruchirawat Prasat Kittakoop 《化学与生物多样性》2018,15(3)
New naphthalene derivatives ( 1 and 2 ) and a new isomer ( 3 ) of ventilagolin, together with known anthraquinones, chrysophanol ( 4 ), physcion or emodin 3‐methyl ether ( 5 ), and emodin ( 6 ), were isolated from vines of Ventilago denticulata. The isolated compounds exhibited cytotoxic activity with IC50 values of 1.15 – 40.54 μg/ml. Compounds 1 – 3 selectively exhibited weak antibacterial activity (MIC values of 200.0 – 400.0 μg/ml), while emodin ( 6 ) displayed moderate antibacterial activity with MIC value of 25.0 μg/ml. The isolated compounds showed nitric oxide and DPPH radical scavenging activities. Compounds 1 – 3 and 6 exhibited weak xanthine oxidase inhibitory activity, while emodin ( 6 ) acted as an aromatase inhibitor with the IC50 value of 10.1 μm . Compounds 1 and 2 exhibited phosphodiesterase 5 inhibitory activity with IC50 values of 8.28 μm and 6.48 μm , respectively. 相似文献
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Adisakwattana S Ngamrojanavanich N Kalampakorn K Tiravanit W Roengsumran S Yibchok-Anun S 《Journal of enzyme inhibition and medicinal chemistry》2004,19(4):313-316
Cyanidin-3-rutinoside, a natural anthocyanin, inhibited alpha-glucosidase from baker's yeast in dose-responsive manner. The IC50 value was 19.7 microM +/- 0.24 microM, compared with the IC50 value of voglibose (IC50 = 23.4 +/- 0.30 microM). Cyanidin-3-rutinoside was found to be a non-competitive inhibitor for yeast alpha-glucosidase with a Ki value in the range of 1.31-1.56 x 10(-5)M. These results indicated that cyanidin-3-rutinoside could be classed as a new alpha-glucosidase inhibitor. 相似文献