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当代肿瘤药物靶点

Editor-in-Chief

ISSN (Print): 1568-0096
ISSN (Online): 1873-5576

Review Article

去甲去氢愈创木酸在治疗中的应用:有利于毒性谱及其类似物的搜索

卷 20, 期 2, 2020

页: [86 - 103] 页: 18

弟呕挨: 10.2174/1568009619666191022141547

价格: $65

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摘要

去甲双氢愈创木酸(NDGA)是一种植物木脂素,得自杂草丛生的Larrea tridentata,具有抗氧化,抗癌活性,在北美和墨西哥被用于传统医学。但是,长时间食用会导致肝损伤和肾功能不全。尽管其毒性和副作用,但几乎没有意识来禁止它的消费,并且多年来一直在治疗医学疾病中使用它。迄今为止,有几篇报道讨论了其治疗效率,其医学应用正在极大地兴起。最近对于用于治疗应用的NDGA衍生物的化学合成产生了兴趣。 NDGA衍生物已被开发为NDGA的更好替代品。尽管如最近的文献所证明,已经化学合成了几种NDGA衍生物,但是关于其治疗功效的信息很少。这篇综述旨在突出NDGA的医学应用,其毒性评估,并讨论迄今为止合成和研究的NDGA的化学衍生物,并建议在开发用于治疗用途的NDGA类似物方面继续进行研究。我们建议对NDGA衍生物进行化学合成方面的研究,以其优选的构象结构进行研究,并利用其生物学潜能与未来的见识,探索这一方向,以设计和开发具有潜在药理特性的结构修饰的NDGA衍生物。

关键词: 抗癌活性,抗氧化活性,抗病毒活性,去甲二氢愈创木酸,合成类似物,毒性。

图形摘要

[1]
Arteaga, S.; Andrade-Cetto, A.; Cárdenas, R. Larrea tridentata (Creosote bush), an abundant plant of Mexican and US-American deserts and its metabolite nordihydroguaiaretic acid. J. Ethnopharmacol., 2005, 98(3), 231-239.
[http://dx.doi.org/10.1016/j.jep.2005.02.002] [PMID: 15814253]
[2]
Agarwal, R.; Wang, Z.Y.; Bik, D.P.; Mukhtar, H. Nordihydroguaiaretic acid, an inhibitor of lipoxygenase, also inhibits cytochrome P-450-mediated monooxygenase activity in rat epidermal and hepatic microsomes. Drug Metab. Dispos., 1991, 19(3), 620-624.
[PMID: 1680628]
[3]
Abou-Gazar, H.; Bedir, E.; Takamatsu, S.; Ferreira, D.; Khan, I.A. Antioxidant lignans from Larrea tridentata. Phytochemistry, 2004, 65(17), 2499-2505.
[http://dx.doi.org/10.1016/j.phytochem.2004.07.009] [PMID: 15381414]
[4]
Birkenfeld, S.; Zaltsman, Y.A.; Krispin, M.; Zakut, H.; Zor, U.; Kohen, F. Antitumor effects of inhibitors of arachidonic acid cascade on experimentally induced intestinal tumors. Dis. Colon Rectum, 1987, 30(1), 43-46.
[http://dx.doi.org/10.1007/BF02556922] [PMID: 3803107]
[5]
Timmermann, B. Practical uses of Larrea.Creosote bush: Biology and Chemistry of Larrea in new world desserts; Mabry, T.; Hunziker, J; Difio, D., Ed.; Dowden Hutchinson Ross Inc, 1977, pp. 252-257.
[6]
Obermeyer, W.R.; Musser, S.M.; Betz, J.M.; Casey, R.E.; Pohland, A.E.; Page, S.W. Chemical studies of phytoestrogens and related compounds in dietary supplements: flax and chaparral. Proc. Soc. Exp. Biol. Med., 1995, 208(1), 6-12.
[http://dx.doi.org/10.3181/00379727-208-43824] [PMID: 7892296]
[7]
Sheikh, N.M.; Philen, R.M.; Love, L.A. Chaparral-associated hepatotoxicity. Arch. Intern. Med., 1997, 157(8), 913-919.
[http://dx.doi.org/10.1001/archinte.1997.00440290099011] [PMID: 9129552]
[8]
Gordon, D.W.; Rosenthal, G.; Hart, J.; Sirota, R.; Baker, A.L. Chaparral ingestion. The broadening spectrum of liver injury caused by herbal medications. JAMA, 1995, 273(6), 489-490.
[http://dx.doi.org/10.1001/jama.1995.03520300063038] [PMID: 7837368]
[9]
Li, X.; Jiang, J.H.; Chen, Q.; Xiao, S-X.; Li, C-H.; Gu, H-W.; Zhang, H.; Hu, J-L.; Yao, F-H.; Li, Q-G. Synthesis of nordihydroguaiaretic acid derivatives and their bioactivities on S. pombe and K562 cell lines. Eur. J. Med. Chem., 2013, 62, 605-613.
[http://dx.doi.org/10.1016/j.ejmech.2013.01.028] [PMID: 23434529]
[10]
Luo, J.; Chuang, T.; Cheung, J.; Quan, J.; Tsai, J.; Sullivan, C.; Hector, R.F.; Reed, M.J.; Meszaros, K.; King, S.R.; Carlson, T.J.; Reaven, G.M. Masoprocol (nordihydroguaiaretic acid): A new antihyperglycemic agent isolated from the creosote bush (Larrea tridentata). Eur. J. Pharmacol., 1998, 346(1), 77-79.
[http://dx.doi.org/10.1016/S0014-2999(98)00139-3] [PMID: 9617755]
[11]
Reed, M.J.; Meszaros, K.; Entes, L.J.; Claypool, M.D.; Pinkett, J.G.; Brignetti, D.; Luo, J.; Khandwala, A.; Reaven, G.M. Effect of masoprocol on carbohydrate and lipid metabolism in a rat model of Type II diabetes. Diabetologia, 1999, 42(1), 102-106.
[http://dx.doi.org/10.1007/s001250051121] [PMID: 10027587]
[12]
Tyler, V.; Foster, S. Tyler’s Honest Herbal: A sensible guide to the use of herbs and related remedies; Haworth Herbal Press: New York, 1999.
[13]
Soriano, A.; Helfrich, B.; Chan, D.; Heasley, L.; Bunn, P.; Chou, T. Synergist effects of new chemopreventive agents against human lung cancer cell lines. Cancer Res., 1999, 59, 6178-6184.
[PMID: 10626810]
[14]
Verástegui, M.A.; Sánchez, C.A.; Heredia, N.L.; García-Alvarado, J.S. Antimicrobial activity of extracts of three major plants from the Chihuahuan desert. J. Ethnopharmacol., 1996, 52(3), 175-177.
[http://dx.doi.org/10.1016/0378-8741(96)84802-1] [PMID: 8771460]
[15]
Argueta, V. Atlas of the traditional mexican medicinal plants national indigenous institute.Ed. Mexico, Vol. II., 1994.
[16]
Ansar, S.; Iqbal, M.; Athar, M. Nordihydroguairetic acid is a potent inhibitor of ferric-nitrilotriacetate-mediated hepatic and renal toxicity, and renal tumour promotion, in mice. Carcinogenesis, 1999, 20(4), 599-606.
[http://dx.doi.org/10.1093/carcin/20.4.599] [PMID: 10223187]
[17]
Smith, A.Y.; Feddersen, R.M.; Gardner, K.D., Jr; Davis, C.J., Jr Cystic renal cell carcinoma and acquired renal cystic disease associated with consumption of chaparral tea: A case report. J. Urol., 1994, 152(6 Pt 1), 2089-2091.
[http://dx.doi.org/10.1016/S0022-5347(17)32317-0] [PMID: 7966683]
[18]
Chen, Q. Nordihydroguaiaretic acid analogues: Their chemical synthesis and biological activities. Curr. Top. Med. Chem., 2009, 9(17), 1636-1659.
[http://dx.doi.org/10.2174/156802609789941915] [PMID: 19903157]
[19]
Lambert, J.D.; Zhao, D.; Meyers, R.O.; Kuester, R.K.; Timmermann, B.N.; Dorr, R.T. Nordihydroguaiaretic acid: Hepatotoxicity and detoxification in the mouse. Toxicon, 2002, 40(12), 1701-1708.
[http://dx.doi.org/10.1016/S0041-0101(02)00203-9] [PMID: 12457882]
[20]
Sahu, S.C.; Ruggles, D.I.; O’Donnell, M.W. Prooxidant activity and toxicity of nordihydroguaiaretic acid in clone-9 rat hepatocyte cultures. Food Chem. Toxicol., 2006, 44(10), 1751-1757.
[http://dx.doi.org/10.1016/j.fct.2006.05.016] [PMID: 16839654]
[21]
Alderman, S.; Kailas, S.; Goldfarb, S.; Singaram, C.; Malone, D.G. Cholestatic hepatitis after ingestion of chaparral leaf: Confirmation by endoscopic retrograde cholangiopancreatography and liver biopsy. J. Clin. Gastroenterol., 1994, 19(3), 242-247.
[http://dx.doi.org/10.1097/00004836-199410000-00016] [PMID: 7806838]
[22]
Whiting, P.W.; Clouston, A.; Kerlin, P. Black cohosh and other herbal remedies associated with acute hepatitis. Med. J. Aust., 2002, 177(8), 440-443.
[PMID: 12381254]
[23]
Lambert, J.; Dorr, R.; Timmermann, B. Nordihydroguaiaretic acid: A review of its numerous and varied biological activities. Pharm. Biol., 2004, 42, 149-158.
[http://dx.doi.org/10.1080/13880200490512016]
[24]
Jones, S. Sistematica Vegetal; McGraw-Hill: Mexico, 1987.
[25]
Hyder, P.W.; Fredrickson, E.L.; Estell, R.E.; Tellez, M.; Gibbens, R.P. Distribution and concentration of total phenolics, condensed tannins and nordihydroguaiaretic acid (NDGA) in creosote bush (Larrea tridentata). Biochem. Syst. Ecol., 2002, 30, 905-912.
[http://dx.doi.org/10.1016/S0305-1978(02)00050-9]
[26]
Azwanida, N.N. A review on the extraction methods use in Medicinal plants, Principle, Strength and Limitation. Med. Aromat. Plants, 2015, 4, 196.
[http://dx.doi.org/10.4172/2167-0412.1000196]
[27]
Lopez-Aguirre, S.; Garcia-Lopez, J.C.; Pinos-Rodriguez, J.M.; Yanez-Estrada, L.; Lopez-Hernandez, Y. Chemical characterization and oral toxicity of an aqueous extract of Larrea tridentata. J. Nat. Prod. Resour., 2016, 2, 79-82.
[28]
Gezginci, M.H.; Timmermann, B.N. A short synthetic route to nordihydroguaiaretic acid (NDGA) and its stereoisomer using Ti-induced carbonyl-coupling reaction. Tetrahedron Lett., 2001, 42, 6083-6085.
[http://dx.doi.org/10.1016/S0040-4039(01)01182-0]
[29]
Son, J.K.; Lee, S.H.; Nagarapu, L.; Jahug, Y. A simple synthesis of nordihydroguaiaretic acid and its analogues. Bull. Korean Chem. Soc., 2005, 26, 1117-1120.
[http://dx.doi.org/10.5012/bkcs.2005.26.7.1117]
[30]
Meyers, R.O.; Lambert, J.D.; Hajicek, N.; Pourpak, A.; Kalaitzis, J.A.; Dorr, R.T. Synthesis, characterization, and anti-melanoma activity of tetra-O-substituted analogs of nordihydroguaiaretic acid. Bioorg. Med. Chem. Lett., 2009, 19(16), 4752-4755.
[http://dx.doi.org/10.1016/j.bmcl.2009.06.063] [PMID: 19615898]
[31]
Hwu, J.R.; Hsu, C.I.; Hsu, M.H.; Liang, Y.C.; Huang, R.C.C.; Lee, Y.C. Glycosylated nordihydroguaiaretic acids as anti-cancer agents. Bioorg. Med. Chem. Lett., 2011, 21(1), 380-382.
[http://dx.doi.org/10.1016/j.bmcl.2010.10.137] [PMID: 21123067]
[32]
Paracatu, L.C.; de Faria, C.M.; Zeraik, M.L.; Quinello, C.; Rennó, C.; Palmeira, P.; da Fonseca, L.M.; Ximenes, V.F. Hydrophobicity and antioxidant activity acting together for the beneficial health properties of nordihydroguaiaretic acid. Food Funct., 2015, 6(6), 1818-1831.
[http://dx.doi.org/10.1039/C5FO00091B] [PMID: 25927268]
[33]
Spencer, J.; Jacobs, J. Complimentary Alternative Medicine: An evidence-based approach; Mosby: Toronto, 1999.
[34]
Fujiwara, T.; Misumi, Y.; Ikehara, Y. Dynamic recycling of ERGIC53 between the endoplasmic reticulum and the Golgi complex is disrupted by nordihydroguaiaretic acid. Biochem. Biophys. Res. Commun., 1998, 253(3), 869-876.
[http://dx.doi.org/10.1006/bbrc.1998.9868] [PMID: 9918822]
[35]
Ballatori, N.; Wang, W. Nordihydroguaiaretic acid depletes ATP and inhibits a swelling-activated, ATP-sensitive taurine channel. Am. J. Physiol., 1997, 272(5 Pt 1), C1429-C1436.
[http://dx.doi.org/10.1152/ajpcell.1997.272.5.C1429] [PMID: 9176131]
[36]
Jan, C.R.; Tseng, C.J. Mechanisms of nordihydroguaiaretic acid-induced [Ca2+]i increases in MDCK cells. Life Sci., 2000, 66(18), 1753-1762.
[http://dx.doi.org/10.1016/S0024-3205(00)00498-7] [PMID: 10809172]
[37]
Nusrat, S.; Siddiqi, M.K.; Zaman, M.; Zaidi, N.; Ajmal, M.R.; Alam, P.; Qadeer, A.; Abdelhameed, A.S.; Khan, R.H. A comprehensive spectroscopic and computational investigation to probe the interaction of antineoplastic drug Nordihydroguaiaretic acid with serum albumins. PLoS One, 2016, 11(7)e0158833
[http://dx.doi.org/10.1371/journal.pone.0158833] [PMID: 27391941]
[38]
Perry, J.L.; Il’ichev, Y.V.; Kempf, V.R.; McClendon, J.; Park, G.; Manderville, R.A.; Ruker, F.; Dockal, M.; Simon, A.D. Binding of ochratoxin A derivatives to human serum albumin. J. Phys. Chem. B, 2003, 107, 6644-6647.
[http://dx.doi.org/10.1021/jp034284w]
[39]
Olson, R.E.; Christ, D.D. Plasma protein binding of drugs. Annu. Rep. Med. Chem., 1996, 31, 327-336.
[http://dx.doi.org/10.1016/S0065-7743(08)60472-8]
[40]
Zsila, F.; Bikádi, Z.; Simonyi, M. Probing the binding of the flavonoid, quercetin to human serum albumin by circular dichroism, electronic absorption spectroscopy and molecular modelling methods. Biochem. Pharmacol., 2003, 65(3), 447-456.
[http://dx.doi.org/10.1016/S0006-2952(02)01521-6] [PMID: 12527338]
[41]
Awasthi, S.; Preethy, R.; Saraswathi, N.T. Nordihydroguaiaretic acid prevents glycation induced structural alterations and aggregation of albumin. Int. J. Biol. Macromol., 2019, 122, 479-484.
[http://dx.doi.org/10.1016/j.ijbiomac.2018.10.173] [PMID: 30416092]
[42]
Lambert, J.D.; Meyers, R.O.; Timmermann, B.N.; Dorr, R.T. Pharmacokinetic analysis by high-performance liquid chromatography of intravenous nordihydroguaiaretic acid in the mouse. J. Chromatogr. B Biomed. Sci. Appl., 2001, 754(1), 85-90.
[http://dx.doi.org/10.1016/S0378-4347(00)00592-2] [PMID: 11318430]
[43]
Mangione, A.M.; Dearing, D.; Karasov, W. Detoxification in relation to toxin tolerance in desert woodrats eating creosote bush. J. Chem. Ecol., 2001, 27(12), 2559-2578.
[http://dx.doi.org/10.1023/A:1013639817958] [PMID: 11789959]
[44]
Hagmann, W. Lipoxygenase in human tumor cells. Pathol. Oncol. Res., 1997, 3(2), 83-88.
[http://dx.doi.org/10.1007/BF02907800] [PMID: 11173632]
[45]
Timár, J.; Rásó, E.; Döme, B.; Li, L.; Grignon, D.; Nie, D.; Honn, K.V.; Hagmann, W. Expression, subcellular localization and putative function of platelet-type 12-lipoxygenase in human prostate cancer cell lines of different metastatic potential. Int. J. Cancer, 2000, 87(1), 37-43.
[http://dx.doi.org/10.1002/1097-0215(20000701)87:1<37:AID-IJC6>3.0.CO;2-L] [PMID: 10861450]
[46]
Shureiqi, I.; Lippman, S.M. Lipoxygenase modulation to reverse carcinogenesis. Cancer Res., 2001, 61(17), 6307-6312.
[PMID: 11522616]
[47]
Safayhi, H.; Mack, T.; Sabieraj, J.; Anazodo, M.I.; Subramanian, L.R.; Ammon, H.P. Boswellic acids: Novel, specific, nonredox inhibitors of 5-lipoxygenase. J. Pharmacol. Exp. Ther., 1992, 261(3), 1143-1146.
[PMID: 1602379]
[48]
Orafaie, A.; Matin, M.M.; Sadeghian, H. The importance of 15-lipoxygenase inhibitors in cancer treatment. Cancer Metastasis Rev., 2018, 37(2-3), 397-408.
[http://dx.doi.org/10.1007/s10555-018-9738-9] [PMID: 29882120]
[49]
Floriano-Sánchez, E.; Villanueva, C.; Medina-Campos, O.N.; Rocha, D.; Sánchez-González, D.J.; Cárdenas-Rodríguez, N.; Pedraza-Chaverrí, J. Nordihydroguaiaretic acid is a potent in vitro scavenger of peroxynitrite, singlet oxygen, hydroxyl radical, superoxide anion and hypochlorous acid and prevents in vivo ozone-induced tyrosine nitration in lungs. Free Radic. Res., 2006, 40(5), 523-533.
[http://dx.doi.org/10.1080/10715760500419365] [PMID: 16551579]
[50]
Yam-Canul, P.; Chirino, Y.I.; Sánchez-González, D.J.; Martínez-Martínez, C.M.; Cruz, C.; Villanueva, C.; Pedraza-Chaverri, J. Nordihydroguaiaretic acid attenuates potassium dichromate-induced oxidative stress and nephrotoxicity. Food Chem. Toxicol., 2008, 46(3), 1089-1096.
[http://dx.doi.org/10.1016/j.fct.2007.11.003] [PMID: 18155343]
[51]
Robison, T.W.; Sevanian, A.; Forman, H.J. Inhibition of arachidonic acid release by nordihydroguaiaretic acid and its antioxidant action in rat alveolar macrophages and Chinese hamster lung fibroblasts. Toxicol. Appl. Pharmacol., 1990, 105(1), 113-122.
[http://dx.doi.org/10.1016/0041-008X(90)90363-Y] [PMID: 2118282]
[52]
Youngren, J.F.; Gable, K.; Penaranda, C.; Maddux, B.A.; Zavodovskaya, M.; Lobo, M.; Campbell, M.; Kerner, J.; Goldfine, I.D. Nordihydroguaiaretic acid (NDGA) inhibits the IGF-1 and c-erbB2/HER2/neu receptors and suppresses growth in breast cancer cells. Breast Cancer Res. Treat., 2005, 94(1), 37-46.
[http://dx.doi.org/10.1007/s10549-005-6939-z] [PMID: 16142439]
[53]
Tong, W.G.; Ding, X.Z.; Witt, R.C.; Adrian, T.E. Lipoxygenase inhibitors attenuate growth of human pancreatic cancer xenografts and induce apoptosis through the mitochondrial pathway. Mol. Cancer Ther., 2002, 1(11), 929-935.
[PMID: 12481414]
[54]
Yoshida, T.; Shiraishi, T.; Horinaka, M.; Nakata, S.; Yasuda, T.; Goda, A.E.; Wakada, M.; Mizutani, Y.; Miki, T.; Nishikawa, A.; Sakai, T. Lipoxygenase inhibitors induce death receptor 5/TRAIL-R2 expression and sensitize malignant tumor cells to TRAIL-induced apoptosis. Cancer Sci., 2007, 98(9), 1417-1423.
[http://dx.doi.org/10.1111/j.1349-7006.2007.00559.x] [PMID: 17645780]
[55]
Ding, X.Z.; Kuszynski, C.A.; El-Metwally, T.H.; Adrian, T.E. Lipoxygenase inhibition induced apoptosis, morphological changes, and carbonic anhydrase expression in human pancreatic cancer cells. Biochem. Biophys. Res. Commun., 1999, 266(2), 392-399.
[http://dx.doi.org/10.1006/bbrc.1999.1824] [PMID: 10600514]
[56]
Gonzales, M.; Bowden, G.T. Nordihydroguaiaretic acid-mediated inhibition of ultraviolet B-induced activator protein-1 activation in human keratinocytes. Mol. Carcinog., 2002, 34(2), 102-111.
[http://dx.doi.org/10.1002/mc.10052] [PMID: 12112316]
[57]
Earashi, M.; Noguchi, M.; Kinoshita, K.; Tanaka, M. Effects of eicosanoid synthesis inhibitors on the in vitro growth and prostaglandin E and leukotriene B secretion of a human breast cancer cell line. Oncology, 1995, 52(2), 150-155.
[http://dx.doi.org/10.1159/000227447] [PMID: 7854776]
[58]
Xue, H.; Zhang, X.Y.; Liu, J.M.; Song, Y.; Liu, T.T.; Chen, D. NDGA reduces secondary damage after spinal cord injury in rats via anti-inflammatory effects. Brain Res., 2013, 1516, 83-92.
[http://dx.doi.org/10.1016/j.brainres.2013.04.016] [PMID: 23603407]
[59]
Rahman, S.; Ansari, R.A.; Rehman, H.; Parvez, S.; Raisuddin, S. Nordihydroguaiaretic acid from creosote bush (Larrea tridentata) mitigates 12-O-Tetradecanoylphorbol-13-acetate-induced inflammatory and oxidative stress responses of tumor promotion cascade in mouse skin; Evidence-based Complement Alternat. Med, 2011.
[http://dx.doi.org/10.1093/ecam/nep076]
[60]
Min, K-W.; Song, M.O.; Park, S-R.; Oh, Y-S.; Lee, C-H. Nordihydroguaiaretic acid suppresses the lipopolysaccharide-induced activation of macrophage through the down-regulation of TAK1. Anim. Cells Syst., 2013, 17, 15-22.
[http://dx.doi.org/10.1080/19768354.2012.745449]
[61]
Li, X.; Fan, S.; Pan, X.; Xiaokaiti, Y.; Duan, J.; Shi, Y.; Pan, Y.; Tie, L.; Wang, X.; Li, Y.; Li, X. Nordihydroguaiaretic acid impairs prostate cancer cell migration and tumor metastasis by suppressing neuropilin 1. Oncotarget, 2016, 7(52), 86225-86238.
[http://dx.doi.org/10.18632/oncotarget.13368] [PMID: 27863391]
[62]
Staton, C.A.; Kumar, I.; Reed, M.W.; Brown, N.J. Neuropilins in physiological and pathological angiogenesis. J. Pathol., 2007, 212(3), 237-248.
[http://dx.doi.org/10.1002/path.2182] [PMID: 17503412]
[63]
Yaqoob, U.; Cao, S.; Shergill, U.; Jagavelu, K.; Geng, Z.; Yin, M.; de Assuncao, T.M.; Cao, Y.; Szabolcs, A.; Thorgeirsson, S.; Schwartz, M.; Yang, J.D.; Ehman, R.; Roberts, L.; Mukhopadhyay, D.; Shah, V.H. Neuropilin-1 stimulates tumor growth by increasing fibronectin fibril assembly in the tumor microenvironment. Cancer Res., 2012, 72(16), 4047-4059.
[http://dx.doi.org/10.1158/0008-5472.CAN-11-3907] [PMID: 22738912]
[64]
Seufferlein, T.; Seckl, M.J.; Schwarz, E.; Beil, M.; v Wichert, G.; Baust, H.; Lührs, H.; Schmid, R.M.; Adler, G. Mechanisms of nordihydroguaiaretic acid-induced growth inhibition and apoptosis in human cancer cells. Br. J. Cancer, 2002, 86(7), 1188-1196.
[http://dx.doi.org/10.1038/sj.bjc.6600186] [PMID: 11953870]
[65]
Wagenknecht, B.; Schulz, J.B.; Gulbins, E.; Weller, M. Crm-A, bcl-2 and NDGA inhibit CD95L-induced apoptosis of malignant glioma cells at the level of caspase 8 processing. Cell Death Differ., 1998, 5(10), 894-900.
[http://dx.doi.org/10.1038/sj.cdd.4400435] [PMID: 10203695]
[66]
Siddique, Y.H.; Beg, T.; Afzal, M. Protective effect of nordihydroguaiaretic acid (NDGA) against norgestrel induced genotoxic damage. Toxicol. In Vitro, 2006, 20(2), 227-233.
[http://dx.doi.org/10.1016/j.tiv.2005.06.027] [PMID: 16061348]
[67]
Siddique, Y.H.; Ara, G.; Beg, T.; Afzal, M. Protective role of nordihydroguaiaretic acid (NDGA) against the genotoxic damage induced by ethynodiol diacetate in human lymphocytes in vitro. J. Environ. Biol., 2007, 28(2), 279-282.
[PMID: 17915765]
[68]
Madrigal-Bujaidar, E.; Díaz Barriga, S.; Cassani, M.; Molina, D.; Ponce, G. In vivo and in vitro induction of sister-chromatid exchanges by nordihydroguaiaretic acid. Mutat. Res., 1998a, 412(2), 139-144.
[http://dx.doi.org/10.1016/S1383-5718(97)00195-2] [PMID: 9539967]
[69]
Madrigal-Bujaidar, E.; Díaz Barriga, S.; Cassani, M.; Márquez, P.; Revuelta, P. In vivo and in vitro antigenotoxic effect of nordihydroguaiaretic acid against SCEs induced by methyl methanesulfonate. Mutat. Res., 1998b, 419(1-3), 163-168.
[http://dx.doi.org/10.1016/S1383-5718(98)00128-4] [PMID: 9804941]
[70]
Ahmad, M.E.; Shadab, G.G.H.A.; Azfer, M.A.; Afzal, M. Evaluation of genotoxic potential of synthetic progestins-norethindrone and norgestrel in human lymphocytes in vitro. Mutat. Res., 2001, 494(1-2), 13-20.
[http://dx.doi.org/10.1016/S1383-5718(01)00164-4] [PMID: 11423341]
[71]
Ramoner, R.; Rieser, C.; Bartsch, G.; Thurnher, M. Nordihydroguaiaretic acid blocks secretory and endocytic pathways in human dendritic cells. J. Leukoc. Biol., 1998, 64(6), 747-752.
[http://dx.doi.org/10.1002/jlb.64.6.747] [PMID: 9850156]
[72]
Ito, H.; Ueda, H.; Iwamoto, I.; Inaguma, Y.; Takizawa, T.; Asano, T.; Kato, K. Nordihydroguaiaretic acid (NDGA) blocks the differentiation of C2C12 myoblast cells. J. Cell. Physiol., 2005, 202(3), 874-879.
[http://dx.doi.org/10.1002/jcp.20177] [PMID: 15389564]
[73]
Zavodovskaya, M.; Campbell, M.J.; Maddux, B.A.; Shiry, L.; Allan, G.; Hodges, L.; Kushner, P.; Kerner, J.A.; Youngren, J.F.; Goldfine, I.D. Nordihydroguaiaretic acid (NDGA), an inhibitor of the HER2 and IGF-1 receptor tyrosine kinases, blocks the growth of HER2-overexpressing human breast cancer cells. J. Cell. Biochem., 2008, 103(2), 624-635.
[http://dx.doi.org/10.1002/jcb.21435] [PMID: 17562544]
[74]
Rowe, D.L.; Ozbay, T.; Bender, L.M.; Nahta, R. Nordihydroguaiaretic acid, a cytotoxic IGF-1R/HER2 inhibitor in Trastuzumab-resistant breast cancer. Mol. Cancer Ther., 2008, 7, 1900-1908.
[http://dx.doi.org/10.1158/1535-7163.MCT-08-0012] [PMID: 18645000]
[75]
Gao, P.; Guan, L.; Zhai, F.; Zheng, J. NDGA upregulates the expression of p27 and p53 in cervical cancer SiHa cells. Chin. J. Cell. Biol., 2010, 32, 617-620.
[76]
Gao, P.; Zhai, F.; Guan, L.; Zheng, J. Nordihydroguaiaretic acid inhibits growth of cervical cancer SiHa cells by up-regulating p21. Oncol. Lett., 2011, 2(1), 123-128.
[http://dx.doi.org/10.3892/ol.2010.205] [PMID: 22870140]
[77]
Sare, M.; Bozkurt, S.; Onuk, E.; Oguz, M.; Gurel, M.; Ercan, S. The effects of indomethacin, NDGA, allopurinol and superoxide dismutase on prostaglandin E2 and leukotriene C4 levels after mesenteric ischemia-reperfusion injury. Prostaglandins Leukot. Essent. Fatty Acids, 1996, 55(6), 379-383.
[http://dx.doi.org/10.1016/S0952-3278(96)90120-9] [PMID: 9014215]
[78]
Liu, Y.; Wang, H.; Zhu, Y.; Chen, L.; Qu, Y.; Zhu, Y. The protective effect of nordihydroguaiaretic acid on cerebral ischemia/reperfusion injury is mediated by the JNK pathway. Brain Res., 2012, 1445, 73-81.
[http://dx.doi.org/10.1016/j.brainres.2012.01.031] [PMID: 22325100]
[79]
Okboy, N.; Yegen, C.; Aktan, A.O.; Dosluoglu, H.H.; Sav, A.; Yalin, R.; Ercan, S. The effect of iloprost and NDGA in ischemia reperfusion injury in rat liver. Prostaglandins Leukot. Essent. Fatty Acids, 1992, 47(4), 291-295.
[http://dx.doi.org/10.1016/0952-3278(92)90200-3] [PMID: 1283466]
[80]
Ramasamy, S.; Drummond, G.R.; Ahn, J.; Storek, M.; Pohl, J.; Parthasarathy, S.; Harrison, D.G. Modulation of expression of endothelial nitric oxide synthase by nordihydroguaiaretic acid, a phenolic antioxidant in cultured endothelial cells. Mol. Pharmacol., 1999, 56(1), 116-123.
[http://dx.doi.org/10.1124/mol.56.1.116] [PMID: 10385691]
[81]
Ebrahimi, A.; Schluesener, H. Natural polyphenols against neurodegenerative disorders: Potentials and pitfalls. Ageing Res. Rev., 2012, 11(2), 329-345.
[http://dx.doi.org/10.1016/j.arr.2012.01.006] [PMID: 22336470]
[82]
Siddique, Y.H.; Ali, F. Protective effect of nordihydroguaiaretic acid (NDGA) on the transgenic Drosophila model of Alzheimer’s disease. Chem. Biol. Interact., 2017, 269, 59-66.
[http://dx.doi.org/10.1016/j.cbi.2017.04.005] [PMID: 28392391]
[83]
Ma, C.J.; Lee, M.K.; Kim, Y.C. meso-Dihydroguaiaretic acid attenuates the neurotoxic effect of staurosporine in primary rat cortical cultures. Neuropharmacology, 2006, 50(6), 733-740.
[http://dx.doi.org/10.1016/j.neuropharm.2005.11.025] [PMID: 16427665]
[84]
Culver, C.A.; Michalowski, S.M.; Maia, R.C.; Laster, S.M. The anti-apoptotic effects of nordihydroguaiaretic acid: Inhibition of cPLA(2) activation during TNF-induced apoptosis arises from inhibition of calcium signaling. Life Sci., 2005, 77(19), 2457-2470.
[http://dx.doi.org/10.1016/j.lfs.2005.03.023] [PMID: 15950244]
[85]
Huang, J-K.; Chen, W-C.; Huang, C-J.; Hsu, S-S.; Chen, J-S.; Cheng, H-H.; Chang, H-T.; Jiann, B-P.; Jan, C-R. Nordihydroguaiaretic acid-induced Ca2+ handling and cytotoxicity in human prostate cancer cells. Life Sci., 2004, 75(19), 2341-2351.
[http://dx.doi.org/10.1016/j.lfs.2004.04.043] [PMID: 15350831]
[86]
Su, W.; Tseng, L-L.; Lin, M-C.; Chang, H-J.; Lee, K-C.; Chou, K-J.; Lo, Y-K.; Cheng, J-S.; Chang, H-T.; Wang, J-L.; Liu, C-P.; Chen, W-C.; Jan, C-R. Effect of nordihydroguaiaretic acid on intracellular Ca(2+) concentrations in C6 glioma cells. Neurochem. Int., 2002, 40(3), 249-254.
[http://dx.doi.org/10.1016/S0197-0186(01)00089-4] [PMID: 11741008]
[87]
Korn, S.J.; Horn, R. Nordihydroguaiaretic acid inhibits voltage-activated Ca2+ currents independently of lipoxygenase inhibition. Mol. Pharmacol., 1990, 38(4), 524-530.
[PMID: 2172768]
[88]
Leon, D.; Parada, D.; Vargas-Uribe, M.; Perez, A.A.; Ojeda, L.; Zambrano, A.; Reyes, A.M.; Salas, M. Effect of nordihydroguaiaretic acid on cell viability and glucose transport in human leukemic cell lines. FEBS Open Bio, 2016, 6(10), 1000-1007.
[http://dx.doi.org/10.1002/2211-5463.12106] [PMID: 27761359]
[89]
Zhang, H.; Shen, W.J.; Cortez, Y.; Kraemer, F.B.; Azhar, S. Nordihydroguaiaretic acid improves metabolic dysregulation and aberrant hepatic lipid metabolism in mice by both PPARα-dependent and –independent pathways. Am. J. Physiol. Gastrointest. Liver Physiol., 2013, 304, 72-86.
[http://dx.doi.org/10.1152/ajpgi.00328.2012]
[90]
Zhang, H.; Li, Y.; Hu, J.; Shen, W.J.; Singh, M.; Hou, X.; Bittner, A.; Bittner, S.; Cortez, Y.; Tabassum, J.; Kraemer, F.B.; Azhar, S. Effect of creosote bush-derived NDGA on expression of genes involved in lipid metabolism in liver of high fructose-fed rats: Relevance to NDGA amelioration of hypertriglyceridemia and hepatic steatosis. PLoS One, 2015, 10(9)e0138203
[http://dx.doi.org/10.1371/journal.pone.0138203] [PMID: 26394137]
[91]
Zhang, H.; Shen, W-J.; Li, Y.; Bittner, A.; Bittner, S.; Tabassum, J.; Cortez, Y.F.; Kraemer, F.B.; Azhar, S. Microarray analysis of gene expression in liver, adipose tissue and skeletal muscle I response to chronic dietary administration of NDGA to high-frucose fed dyslipidemic rats. Nutr. Metab. (Lond.), 2016, 13, 1-26.
[http://dx.doi.org/10.1186/s12986-016-0121-y]
[92]
Kang, I.; Park, M.; Yang, S.J.; Lee, M. Lipoprotein lipase inhibitor, Nordihydroguaiaretic acid, aggravates metabolic phenotypes and alters HDL particle size in Western diet-fed db/db mice. Int. J. Mol. Sci., 2019, 20(12), 3057-3070.
[http://dx.doi.org/10.3390/ijms20123057] [PMID: 31234537]
[93]
Fujimoto, N.; Kohta, R.; Kitamura, S.; Honda, H. Estrogenic activity of an antioxidant, nordihydroguaiaretic acid (NDGA). Life Sci., 2004, 74(11), 1417-1425.
[http://dx.doi.org/10.1016/j.lfs.2003.08.012] [PMID: 14706572]
[94]
Koob, T.J.; Willis, T.A.; Qiu, Y.S.; Hernandez, D.J. Biocompatibility of NDGA-polymerized collagen fibers. II. Attachment, proliferation, and migration of tendon fibroblasts in vitro. J. Biomed. Mater. Res., 2001, 56(1), 40-48.
[http://dx.doi.org/10.1002/1097-4636(200107)56:1<40:AID-JBM1066>3.0.CO;2-I] [PMID: 11309789]
[95]
Koob, T.J.; Hernandez, D.J. Material properties of polymerized NDGA-collagen composite fibers: Development of biologically based tendon constructs. Biomaterials, 2002, 23(1), 203-212.
[http://dx.doi.org/10.1016/S0142-9612(01)00096-5] [PMID: 11762839]
[96]
Rioja, A.Y.; Muniz-Maisonet, M.; Koob, T.J.; Gallant, N.D. Effect of nordihydroguaiaretic acid cross-linking on fibrillar collagen: In vitro evaluation of fibroblast adhesion strength and migration. AIMS Bioeng., 2017, 4, 300-317.
[http://dx.doi.org/10.3934/bioeng.2017.2.300]
[97]
Koob, T.J.; Hernandez, D.J. Mechanical and thermal properties of novel polymerized NDGA-gelatin hydrogels. Biomaterials, 2003, 24(7), 1285-1292.
[http://dx.doi.org/10.1016/S0142-9612(02)00465-9] [PMID: 12527270]
[98]
Gong, S.Q.; Xue, Z.J.; Liao, S.T.; Wu, Y.B.; Liu, Y. The effect of NDGA-modified etchant on the enzymatic degradation resistance and mechanical properties of the collagen matrix. Chin. Chem. Lett., 2018, 29, 205-208.
[http://dx.doi.org/10.1016/j.cclet.2017.08.036]
[99]
Kato, Y.P.; Christiansen, D.L.; Hahn, R.A.; Shieh, S.J.; Goldstein, J.D.; Silver, F.H. Mechanical properties of collagen fibres: A comparison of reconstituted and rat tail tendon fibres. Biomaterials, 1989, 10(1), 38-42.
[http://dx.doi.org/10.1016/0142-9612(89)90007-0] [PMID: 2713432]
[100]
Schmidt, M.; Schmitz, H.J.; Baumgart, A.; Guédon, D.; Netsch, M.I.; Kreuter, M-H.; Schmidlin, C.B.; Schrenk, D. Toxicity of green tea extracts and their constituents in rat hepatocytes in primary culture. Food Chem. Toxicol., 2005, 43(2), 307-314.
[http://dx.doi.org/10.1016/j.fct.2004.11.001] [PMID: 15621343]
[101]
Galati, G.; Lin, A.; Sultan, A.M.; O’Brien, P.J. Cellular and in vivo hepatotoxicity caused by green tea phenolic acids and catechins. Free Radic. Biol. Med., 2006, 40(4), 570-580.
[http://dx.doi.org/10.1016/j.freeradbiomed.2005.09.014] [PMID: 16458187]
[102]
Liu, Y.; Flynn, T.J.; Ferguson, M.S.; Hoagland, E.M.; Yu, L.L. Effects of dietary phenolics and botanical extracts on hepatotoxicity-related endpoints in human and rat hepatoma cells and statistical models for prediction of hepatotoxicity. Food Chem. Toxicol., 2011, 49(8), 1820-1827.
[http://dx.doi.org/10.1016/j.fct.2011.04.034] [PMID: 21569817]
[103]
Sahu, S.C.; Flynn, T.J.; Bradlaw, J.A.; Roth, W.L.; Barton, C.N.; Yates, J.G. Pro-oxidant effects of the flavonoid myricetin on rat hepatocytes in culture. Toxicol. Methods, 2001, 11, 277-283.
[http://dx.doi.org/10.1080/1537-650291895829]
[104]
Frei, B.; Higdon, J.V. Antioxidant activity of tea polyphenols in vivo: evidence from animal studies. J. Nutr., 2003, 133(10), 3275S-3284S.
[http://dx.doi.org/10.1093/jn/133.10.3275S] [PMID: 14519826]
[105]
McDonald, R.W.; Bunjobpon, W.; Liu, T.; Fessler, S.; Pardo, O.E.; Freer, I.K.A.; Glaser, M.; Seckl, M.J.; Robins, D.J. Synthesis and anticancer activity of nordihydroguaiaretic acid (NDGA) and analogues. Anticancer Drug Des., 2001, 16(6), 261-270.
[PMID: 12375879]
[106]
Asiamah, I.; Hodgson, H.L.; Maloney, K.; Allen, K.J.H.; Krol, E.S. Ring substitution influences oxidative cyclisation and reactive metabolite formation of nordihydroguaiaretic acid analogues. Bioorg. Med. Chem., 2015, 23(21), 7007-7014.
[http://dx.doi.org/10.1016/j.bmc.2015.09.039] [PMID: 26439661]
[107]
Huang, L-C.S.; Chuang, H.; Kapoor, M.; Hsieh, C-Y.; Chou, S-C.; Lin, H-H.; Chen, Y-W.; Chang, C-C.; Hwu, J-R.; Liang, Y-C.; Hsu, M-H. Development of nordihydroguaiaretic acid derivatives as potential multidrug-resistant selective agents for cancer treatment. RSC Advances, 2015, 5, 107833-107838.
[http://dx.doi.org/10.1039/C5RA18827J]
[108]
Heller, J.D.; Chen, Q.; Lopez, R.A.; Morris, A.J. Tetra-Osubstituted butane-bridge modified NDGA derivatives, their synthesis and pharmaceutical use U.S. Patent Application Publication No. US 2017/0044121 A1, 2017.
[109]
Huang, R.C.C.; Mold, D.; Ruland, C.; Liang, Y.C.; Chun, J.H. Compositions comprising NDGA derivatives and Sorafenib and their use in treatment of cancer U.S.Patent 9877978 B2 2018.
[110]
Haworth, R.D.; Mavin, C.R.; Sheldrick, G. The constitutes of guaiacum resin. Part II. Synthesis of dl-guaiaretic acid dimethyl ether. J. Chem. Soc., 1934, 1423-1429.
[http://dx.doi.org/10.1039/jr9340001423]
[111]
Waller, C.W.; Gisvold, O. A phytochemical investigation of Larrea divaricata Cav. J. Am. Pharm. Assoc., 1945, 34, 78-81.
[http://dx.doi.org/10.1002/jps.3030340305]
[112]
Gisvold, O.; Thaker, E. Lignans from larrea divaricata. J. Pharm. Sci., 1974, 63(12), 1905-1907.
[http://dx.doi.org/10.1002/jps.2600631216] [PMID: 4217824]
[113]
Haworth, R.D.; Lamberton, A.H. Some derivatives of catechol and pyrogallol. J. Chem. Soc., 1946 (Nov), 1003-1005.
[http://dx.doi.org/10.1039/jr9460001003] [PMID: 20282478]
[114]
Lara, F.; Marquez, C. Medicinal plants from Mexico: Composition, uses and biological activity; UNAM: Mexico, 1996.
[115]
Xia, Y.M.; Bi, W.H.; Zhang, Y.Y. Synthesis of dibenzyl butane diol lignans and their anti-HIV, anti-HSV, anti-tumor activities. J. Chil. Chem. Soc., 2009, 54, 428-431.
[116]
Plaza, C.; Pavani, M.; Faundez, M.; Maya, J.D.; Morello, A.; Becker, M.I.; de Joannes, A.; Cumsille, M.A.; Ferreira, J. Inhibitory effect of nordihydroguaiaretic acid and its tetra-acetylated derivative on respiration and growth of adenocarcinoma TA3 and its multiresistant variant TA3MTX-R in vivo. 2008, 22, 353-362.
[117]
Plaza, C.; Pavani, M.; Araya-Maturana, R.; Pezoa, J.; Maya, J.D.; Morello, A.; Becker, M.I.; de Joannes, A.; Ferreira, J. Chemosensitizing effect of nordihydroguaiaretic acid and its tetraacetylated derivative on parental and multiresistant TA3 mouse mammary adenocarcinoma cells in vivo. 2009, 23, 959-968.
[118]
Gnabre, J.N.; Huang, R.C.C.; Bates, R.B. Characterization of Anti-HIV lignans from Larrea tridentata. Tetrahed., 1995a, 51, 12203-12210.
[http://dx.doi.org/10.1016/0040-4020(95)00794-9]
[119]
Gnabre, J.N.; Brady, J.N.; Clanton, D.J.; Ito, Y.; Dittmer, J.; Bates, R.B.; Huang, R.C. Inhibition of human immunodeficiency virus type 1 transcription and replication by DNA sequence-selective plant lignans. Proc. Natl. Acad. Sci. USA, 1995b, 92(24), 11239-11243.
[http://dx.doi.org/10.1073/pnas.92.24.11239] [PMID: 7479972]
[120]
Chen, H.; Teng, L.; Li, J-N.; Park, R.; Mold, D.E.; Gnabre, J.; Hwu, J.R.; Tseng, W.N.; Huang, R.C.C. Antiviral activities of methylated nordihydroguaiaretic acids. 2. Targeting herpes simplex virus replication by the mutation insensitive transcription inhibitor tetra-O-methyl-NDGA. J. Med. Chem., 1998, 41(16), 3001-3007.
[http://dx.doi.org/10.1021/jm980182w] [PMID: 9685239]
[121]
Craigo, J.; Callahan, M.; Huang, R.C.C.; DeLucia, A.L. Inhibition of human papillomavirus type 16 gene expression by nordihydroguaiaretic acid plant lignan derivatives. Antiviral Res., 2000, 47(1), 19-28.
[http://dx.doi.org/10.1016/S0166-3542(00)00089-9] [PMID: 10930643]
[122]
Huang, R.C.C.; Chang, C.C.; Mold, D. Survivin-dependent and -independent pathways and the induction of cancer cell death by tetra-O-methyl nordihydroguaiaretic acid. Semin. Oncol., 2006, 33(4), 479-485.
[http://dx.doi.org/10.1053/j.seminoncol.2006.04.010] [PMID: 16890802]
[123]
Hwu, J.R.; Tseng, W.N.; Gnabre, J.; Giza, P.; Huang, R.C. Antiviral activities of methylated nordihydroguaiaretic acids. 1. Synthesis, structure identification, and inhibition of tat-regulated HIV transactivation. J. Med. Chem., 1998, 41(16), 2994-3000.
[http://dx.doi.org/10.1021/jm970819w] [PMID: 9685238]
[124]
Dohm, J.A.; Hsu, M.H.; Hwu, J.R.; Huang, R.C.; Moudrianakis, E.N.; Lattman, E.E.; Gittis, A.G. Influence of ions, hydration, and the transcriptional inhibitor P4N on the conformations of the Sp1 binding site. J. Mol. Biol., 2005, 349(4), 731-744.
[http://dx.doi.org/10.1016/j.jmb.2005.04.001] [PMID: 15896803]
[125]
Heller, J.D.; Kuo, J.; Wu, T.C.; Kast, W.M.; Huang, R.C. Tetra-O-methyl nordihydroguaiaretic acid induces G2 arrest in mammalian cells and exhibits tumoricidal activity in vivo. Cancer Res., 2001, 61(14), 5499-5504.
[PMID: 11454698]
[126]
Merino-Ramos, T.; Jiménez de Oya, N.; Saiz, J-C.; Martín-Acebes, M.A. Antiviral activity of nordihydroguaiaretic acid and its derivative tetra-O-methyl nordihydroguaiaretic acid against West Nile virus and Zika virus. Antimicrob. Agents Chemother., 2017, 61(8), e00376-e17.
[http://dx.doi.org/10.1128/AAC.00376-17] [PMID: 28507114]
[127]
Park, R.; Giza, P.E.; Mold, D.E.; Huang, R.C.C. Inhibition of HSV-1 replication and reactivation by the mutation-insensitive transcription inhibitor tetra-O-glycyl-nordihydroguaiaretic acid. Antiviral Res., 2003, 58(1), 35-45.
[http://dx.doi.org/10.1016/S0166-3542(02)00165-1] [PMID: 12719005]
[128]
Blecha, J.E.; Anderson, M.O.; Chow, J.M.; Guevarra, C.C.; Pender, C.; Penaranda, C.; Zavodovskaya, M.; Youngren, J.F.; Berkman, C.E. Inhibition of IGF-1R and lipoxygenase by nordihydroguaiaretic acid (NDGA) analogs. Bioorg. Med. Chem. Lett., 2007, 17(14), 4026-4029.
[http://dx.doi.org/10.1016/j.bmcl.2007.04.092] [PMID: 17502145]
[129]
Lü, J.M.; Nurko, J.; Weakley, S.M.; Jiang, J.; Kougias, P.; Lin, P.H.; Yao, Q.; Chen, C. Molecular mechanisms and clinical applications of nordihydroguaiaretic acid (NDGA) and its derivatives: an update. Med. Sci. Monit., 2010, 16(5), RA93-RA100.
[PMID: 20424564]
[130]
Eads, D.; Hansen, R.; Oyegunwa, A.; Cecil, C.; Culver, C.; Scholle, F.; Petty, I.; Laster, S. Terameprocol, a methylated derivative of nordihydroguaiaretic acid, inhibits production of prostaglandins and several key inflammatory cytokines and chemokines. J. Inflamm. (Lond.), 2009, 6, 2.
[http://dx.doi.org/10.1186/1476-9255-6-2] [PMID: 19133137]

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