Usuário(a):SA RS BRASIL/Projeto 04

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ÁREA DE TRADUÇÂO NÂO APAGAR[editar | editar código-fonte]

SA RS BRASIL/Projeto 04
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250
Nome IUPAC (2E,4E,6E,8E)-10-{[(3R,4S,5S,6R)-5-methoxy- 4-[(2R)-2-methyl-3-(3-methylbut-2-enyl)oxiran-2-yl]-1- oxaspiro[2.5]octan-6-yl]oxy}-10 -oxodeca-2,4,6,8-tetraenoic acid
Identificadores
Número CAS 23110-15-8
PubChem 6917655
DrugBank DB02640
ChEBI 48635
Código ATC P01AX10,QP51AX23
Propriedades
Fórmula molecular C26H34O7
Massa molar 458.54 g/mol
Farmacologia
Exceto onde denotado, os dados referem-se a
materiais sob condições normais de temperatura e pressão
Referências e avisos gerais sobre esta caixa.
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Propriedades físicas e químicas[editar | editar código-fonte]

Crystallized honey: The inset shows a close-up of the honey, showing the individual glucose grains in the fructose mixture.

The physical properties of honey vary, depending on water content, the type of flora used to produce it (pasturage), temperature, and the proportion of the specific sugars it contains. Fresh honey is a supersaturated liquid, containing more sugar than the water can typically dissolve at ambient temperatures. At room temperature, honey is a supercooled liquid, in which the glucose will precipitate into solid granules. This forms a semisolid solution of precipitated glucose crystals in a solution of fructose and other ingredients.

As propriedades físicas do mel variam, dependendo do teor de água, do tipo de flora utilizada para produzi-lo (pastagem), da temperatura e da proporção dos açúcares específicos que contém. O mel fresco é um líquido supersaturado, contendo mais açúcar do que a água pode normalmente dissolver à temperatura ambiente. À temperatura ambiente, o mel é um líquido super-arrefecido, no qual a glicose precipitará em grânulos sólidos. Isso forma uma solução semissólida de cristais de glicose precipitados em uma solução de frutose e outros ingredientes.


At the temperature of 20 °C, density of honey typically ranges between 1.38 and 1.45 kg/l.[1]

Phase transitions[editar | editar código-fonte]

The melting point of crystallized honey is between Predefinição:Convert/Dual/LoffAoffDbSoffT, depending on its composition. Below this temperature, honey can be either in a metastable state, meaning that it will not crystallize until a seed crystal is added, or, more often, it is in a "labile" state, being saturated with enough sugars to crystallize spontaneously.[2] The rate of crystallization is affected by many factors, but the primary factor is the ratio of the main sugars: fructose to glucose. Honeys that are supersaturated with a very high percentage of glucose, such as brassica honey, crystallize almost immediately after harvesting, while honeys with a low percentage of glucose, such as chestnut or tupelo honey, do not crystallize. Some types of honey may produce very large but few crystals, while others produce many small crystals.[3]

Crystallization is also affected by water content, because a high percentage of water inhibits crystallization, as does a high dextrin content. Temperature also affects the rate of crystallization, with the fastest growth occurring between Predefinição:Convert/Dual/LoffAoffDbSoffT. Crystal nuclei (seeds) tend to form more readily if the honey is disturbed, by stirring, shaking, or agitating, rather than if left at rest. However, the nucleation of microscopic seed-crystals is greatest between Predefinição:Convert/Dual/LoffAoffDbSoffT. Therefore, larger but fewer crystals tend to form at higher temperatures, while smaller but more-numerous crystals usually form at lower temperatures. Below 5 °C, the honey will not crystallize, thus the original texture and flavor can be preserved indefinitely.[3]

Since honey normally exists below its melting point, it is a supercooled liquid. At very low temperatures, honey does not freeze solid. Instead, as the temperatures become lower, the viscosity of honey increases. Like most viscous liquids, the honey becomes thick and sluggish with decreasing temperature. At −20 °C (−4,0  °F), honey may appear or even feel solid, but it continues to flow at very low rates. Honey has a glass transition between Predefinição:Convert/Dual/LoffAoffDbSoffT. Below this temperature, honey enters a glassy state and becomes an amorphous solid (noncrystalline).[4][5]

Viscosity[editar | editar código-fonte]

Pouring raw honey. The sheet-like appearance of the flow is the result of high viscosity and low surface tension, contributing to the stickiness of honey.

The viscosity of honey is affected greatly by both temperature and water content. The higher the water percentage, the more easily honey flows. Above its melting point, however, water has little effect on viscosity. Aside from water content, the composition of honey also has little effect on viscosity, with the exception of a few types. At 25 °C (77 °F), honey with 14% water content generally has a viscosity around 400 poise, while a honey containing 20% water has a viscosity around 20 poise. Viscosity increase due to temperature occurs very slowly at first. A honey containing 16% water, at 70 °C (158 °F), has a viscosity around 2 poise, while at 30 °C (86 °F), the viscosity is around 70 poise. As cooling progresses, honey becomes more viscous at an increasingly rapid rate, reaching 600 poise around 14 °C (57 °F). However, while honey is very viscous, it has rather low surface tension.[6][7]

A few types of honey have unusual viscous properties. Honeys from heather or manuka display thixotropic properties. These types of honey enter a gel-like state when motionless, but then liquify when stirred.[8]

Electrical and optical properties[editar | editar código-fonte]

Because honey contains electrolytes, in the form of acids and minerals, it exhibits varying degrees of electrical conductivity. Measurements of the electrical conductivity are used to determine the quality of honey in terms of ash content.[7]

The effect honey has on light is useful for determining the type and quality. Variations in the water content alter the refractive index of honey. Water content can easily be measured with a refractometer. Typically, the refractive index for honey ranges from 1.504 at 13% water content to 1.474 at 25%. Honey also has an effect on polarized light, in that it rotates the polarization plane. The fructose gives a negative rotation, while the glucose gives a positive one. The overall rotation can be used to measure the ratio of the mixture.[7][9] Honey may vary in color between pale yellow and dark brown, but other bright colors may occasionally be found, depending on the source of the sugar harvested by the bees.[10]

Hygroscopy and fermentation[editar | editar código-fonte]

Honey has the ability to absorb moisture directly from the air, a phenomenon called hygroscopy. The amount of water the honey absorbs is dependent on the relative humidity of the air. Because honey contains yeast, this hygroscopic nature requires that honey be stored in sealed containers to prevent fermentation, which usually begins if the honey's water content rises much above 25%. Honey tends to absorb more water in this manner than the individual sugars allow on their own, which may be due to other ingredients it contains.[9]

Fermentation of honey usually occurs after crystallization, because without the glucose, the liquid portion of the honey primarily consists of a concentrated mixture of fructose, acids, and water, providing the yeast with enough of an increase in the water percentage for growth. Honey that is to be stored at room temperature for long periods of time is often pasteurized, to kill any yeast, by heating it above 70 °C (158 °F).[9]

Thermal characteristics[editar | editar código-fonte]

Creamed honey. On the left is how it appears fresh, but the honey on the right has been aged at room temperature for two years. While still edible, the Maillard reaction produces considerable differences in the color and flavor of the aged honey.

Like all sugar compounds, honey caramelizes if heated sufficiently, becoming darker in color, and eventually burns. However, honey contains fructose, which caramelizes at lower temperatures than glucose.[11] The temperature at which caramelization begins varies, depending on the composition, but is typically between Predefinição:Convert/Dual/LoffAoffDbSoffT. Honey also contains acids, which act as catalysts for caramelization. The specific types of acids and their amounts play a primary role in determining the exact temperature.[12] Of these acids, the amino acids, which occur in very small amounts, play an important role in the darkening of honey. The amino acids form darkened compounds called melanoidins, during a Maillard reaction. The Maillard reaction occurs slowly at room temperature, taking from a few to several months to show visible darkening, but speeds up dramatically with increasing temperatures. However, the reaction can also be slowed by storing the honey at colder temperatures.[13]

Unlike many other liquids, honey has very poor thermal conductivity, taking a long time to reach thermal equilibrium. Melting crystallized honey can easily result in localized caramelization if the heat source is too hot, or if it is not evenly distributed. However, honey takes substantially longer to liquify when just above the melting point than at elevated temperatures.[7] Melting 20 kg of crystallized honey, at 40 °C (104 °F), can take up to 24 hours, while 50 kg may take twice as long. These times can be cut nearly in half by heating at 50 °C (122 °F). However, many of the minor substances in honey can be affected greatly by heating, changing the flavor, aroma, or other properties, so heating is usually done at the lowest temperature possible for the shortest amount of time.[14]

Acid content and flavor effects[editar | editar código-fonte]

The average pH of honey is 3.9, but can range from 3.4 to 6.1.[15] Honey contains many kinds of acids, both organic and amino. However, the different types and their amounts vary considerably, depending on the type of honey. These acids may be aromatic or aliphatic (nonaromatic). The aliphatic acids contribute greatly to the flavor of honey by interacting with the flavors of other ingredients.[15]

Organic acids comprise most of the acids in honey, accounting for 0.17–1.17% of the mixture, with gluconic acid formed by the actions of an enzyme called glucose oxidase as the most prevalent.[15] Other organic acids are minor, consisting of formic, acetic, butyric, citric, lactic, malic, pyroglutamic, propionic, valeric, capronic, palmitic, and succinic, among many others.[15][16]


Fumagilina é uma biomolécula complexa e usada como um agente antimicrobiano. Foi isolado em 1949 a partir do microrganismo Aspergillus fumigatus.[17]

A fumagilina foi originalmente patenteado pela Upjohn, uma empresa farmacêutica, em 1953. Na corrida para encontrar novos antibióticos para substituir penicilina para os seres humanos, muitos antibióticos foram desenvolvidos e testados. Dado que a fumagilina, não ter qualquer potencial óbvio para os seres humanos, ele foi esquecido pela Upjohn. Em 1957 a Abbott Laboratories, patenteado produto Fumidil B® para o tratamento da nosemose causado pelo Nosema apis das abelhas.





Usos[editar | editar código-fonte]

Em animais[editar | editar código-fonte]

Ele foi originalmente usado contra o parasita microsporídio Nosema apis que infecciona as abelhas melíferas. Contudo em alguns países está proibido seu uso por ser um contaminante não aceitável do mel, por exemplo no Chile (ver www.sag.cl )a pesar de que no Chile esta totalmente disseminada a Nosemose.

Alguns estudos descobriram que seja eficaz contra alguns myxozoan parasitas, includindo Myxobolus cerebralis, um importante parasita dos peixes; contudo, nos testes mais rigorosos necessários para aprovação pela agência FDA (Food and Drug Administration) dos EUA, não foi efetivo.

Há relatos de que a fumagilina controla Nosema ceranae,[18] que foi recentemente implicado como uma causa possível distúrbio do colapso das colônias.[19][20] O último relatório, no entanto, tem mostrado que é ineficaz contra Nosema ceranae.[21] Fumagilina é também investigada como um inibidor do desenvolvimento do parasita da malária .[22][23]

Em humanos[editar | editar código-fonte]

Fumagilina tem sido usada no tratamento de microsporidiose.[24][25] Também como um amebicida.[26]

Fumagilina pode bloquear a formação de vasos sanguíneos através da ligação a uma enzima metionina aminopeptidase 2 [27] e, por essa razão, o composto, em conjunto com os derivados semi-sintéticos, são investigados como um inibidor de angiogênese [28] no tratamento do câncer.

Ensaios clínicos preliminares estão sendo realizadas por Zafgen em usar o análogo químico da fumagilina o beloranib para perda de peso.[29]

De acordo com Zbidah e colegas de trabalho da Alemanha fumagilina é tóxico para os eritrócitos in vitro.[30]

Síntese total[editar | editar código-fonte]

A fumagilina e o seu relacionado fumagilol (o produto hidrolisado) tem sido alvo na síntese total, com diversos relatos de estratégias bem sucedidas, racêmica, assimétrica e formal.[31][32][33][34][35][36][37][38][39]


Referências

  1. ↑ Piotr Tomasik (20 October 2003). Chemical and Functional Properties of Food Saccharides. [S.l.]: CRC Press. pp. 74–. ISBN 978-0-203-49572-8  Verifique data em: |data= (ajuda)
  2. ↑ Root, p. 355
  3. ↑ a b Tomasik, Piotr (2004) Chemical and functional properties of food saccharides, CRC Press, p. 74, ISBN 0-8493-1486-0
  4. ↑ Kántor Z, Pitsi G, Thoen J (1999). «Glass Transition Temperature of Honey as a Function of Water Content As Determined by Differential Scanning Calorimetry». Journal of Agricultural and Food Chemistry. 47 (6): 2327–2330. PMID 10794630. doi:10.1021/jf981070g 
  5. ↑ Russell EV, Israeloff NE (2000). «Direct observation of molecular cooperativity near the glass transition». Nature. 408 (6813): 695–698. PMID 11130066. doi:10.1038/35047037 
  6. ↑ Value-added products from beekeeping. [S.l.]: Food and Agriculture Organization of the United Nations. 1996. pp. 7–8. ISBN 978-92-5-103819-2. Consultado em 5 January 2016  Verifique data em: |acessodata= (ajuda)
  7. ↑ a b c d Bogdanov, Stefan (2009). «Physical Properties of Honey» (PDF). Cópia arquivada (PDF) em 20 September 2009  Verifique data em: |arquivodata= (ajuda)
  8. ↑ Krell, pp. 5–6
  9. ↑ a b c Root, p. 348
  10. ↑ «Bees 'producing M&M's coloured honey'». Telegraph.co.uk. 4 October 2012. Consultado em 30 December 2014  Verifique data em: |acessodata=, |data= (ajuda)
  11. ↑ Hans-Dieter Belitz, Werner Grosch, Peter Schieberle Food chemistry Springer Verlag, Berlin-Heidelberg 2004 p. 884 ISBN 3-540-69933-3
  12. ↑ Zdzisław E. Sikorski Chemical and functional properties of food components CRC Press 2007 p. 121 ISBN 0-8493-9675-1
  13. ↑ Root, p. 350
  14. ↑ Krell, pp. 40–43
  15. ↑ a b c d «pH and acids in honey» (PDF). National Honey Board Food Technology/Product Research Program. April 2006  Verifique data em: |data= (ajuda)
  16. ↑ Wilkins, Alistair L.; Lu, Yinrong (1995). «Extractives from New Zealand Honeys. 5. Aliphatic Dicarboxylic Acids in New Zealand Rewarewa (Knightea excelsa) Honey». J. Agric. Food Chem. 43 (12): 3021–3025. doi:10.1021/jf00060a006 
  17. ↑ F. R. Hanson, T. E. Elbe, J. Bacteriol. 1949, 58, 527
  18. ↑ Williams, G.R.; Sampson, M.A.; Shutler, D.; Rogers, R.E.L. (2008). «Does fumagillin control the recently detected invasive parasite Nosema ceranae in western honey bees (Apis mellifera)?». Journal of Invertebrate Pathology. 99 (3): 342–344. PMID 18550078. doi:10.1016/j.jip.2008.04.005 
  19. ↑ Sabin Russell (26 de abril de 2007). «UCSF scientist tracks down suspect in honeybee deaths». San Francisco Chronicle 
  20. ↑ «Scientists Identify Pathogens That May Be Causing Global Honeybee Deaths» (Portable Document Format). Edgewood Chemical Biological Center. 25 de abril de 2007 
  21. ↑ Huang, Wei-Fone; Leellen Solter; Peter Yau; Brian Imai (7 March 2013). Schneider, David S, ed. «Nosema ceranae Escapes Fumagillin Control in Honey Bees». PLoS Pathogens. 9 (3): e1003185. doi:10.1371/journal.ppat.1003185  Verifique data em: |data= (ajuda)
  22. ↑ Xiaochun Chen et al. "Fumagillin and Fumarranol Interact with P. falciparum Methionine Aminopeptidase 2 and Inhibit Malaria Parasite Growth In Vitro and In Vivo". Chemistry & Biology, Vol. 16 Nr. 2 (2009) blz. 193-202. Chen, X.; Xie, S.; Bhat, S.; Kumar, N.; Shapiro, T. A.; Liu, J. O. (2009). «Fumagillin and Fumarranol Interact with P. Falciparum Methionine Aminopeptidase 2 and Inhibit Malaria Parasite Growth in Vitro and in Vivo». Chemistry & Biology. 16 (2): 193–202. PMID 19246010. doi:10.1016/j.chembiol.2009.01.006 
  23. ↑ Christopher Arico-Muendel et al. "Antiparasitic activities of novel, orally available fumagillin analogs". Bioorganic & Medicinal Chemistry Letters Vol. 19 Nr. 17 (2009), blz. 5128-5131 Arico-Muendel, C.; Centrella, P. A.; Contonio, B. D.; Morgan, B. A.; o’Donovan, G.; Paradise, C. L.; Skinner, S. R.; Sluboski, B.; Svendsen, J. L.; White, K. F.; Debnath, A.; Gut, J.; Wilson, N.; McKerrow, J. H.; Derisi, J. L.; Rosenthal, P. J.; Chiang, P. K. (2009). «Antiparasitic activities of novel, orally available fumagillin analogs». Bioorganic & Medicinal Chemistry Letters. 19 (17): 5128–5131. PMC 2745105Acessível livremente. PMID 19648008. doi:10.1016/j.bmcl.2009.07.029 
  24. ↑ Lanternier F, Boutboul D, Menotti J, et al. (February 2009). «Microsporidiosis in solid organ transplant recipients: two Enterocytozoon bieneusi cases and review». Transpl Infect Dis. 11 (1): 83–8. PMID 18803616. doi:10.1111/j.1399-3062.2008.00347.x  Verifique data em: |data= (ajuda)
  25. ↑ Molina JM, Tourneur M, Sarfati C, et al. (June 2002). «Fumagillin treatment of intestinal microsporidiosis». N. Engl. J. Med. 346 (25): 1963–9. PMID 12075057. doi:10.1056/NEJMoa012924  Verifique data em: |data= (ajuda)
  26. ↑ Lefkove B, Govindarajan B, Arbiser JL (August 2007). «Fumagillin: an anti-infective as a parent molecule for novel angiogenesis inhibitors». Expert Rev Anti Infect Ther. 5 (4): 573–9. PMID 17678422. doi:10.1586/14787210.5.4.573  Verifique data em: |data= (ajuda)
  27. ↑ Gilbert, M. A.; Granath, W.O. Jr. (2003). «Whirling disease and salmonid fish: life cycle, biology, and disease». Journal of Parasitology. 89 (4): 658–667. PMID 14533670. doi:10.1645/GE-82R 
  28. ↑ Ingber, D.; Fujita, T.; Kishimoto, S.; Sudo, K.; Kanamaru, T.; Brem, H.; Folkman, J. (1990). «Synthetic analogues of fumagillin that inhibit angiogenesis and suppress tumour growth». Nature. 348 (6301): 555–557. Bibcode:1990Natur.348..555I. PMID 1701033. doi:10.1038/348555a0 
  29. ↑ «Zafgen Announces Positive Topline Phase 1b Data for ZGN-433 in Obesity». MedNews. Drugs.com. 5 January 2011  Verifique data em: |data= (ajuda)
  30. ↑ Zbidah, M; Lupescu, A; Jilani, K; Lang, F (2013). «Stimulation of suicidal erythrocyte death by fumagillin». Basic & Clinical Pharmacology & Toxicology. 112 (5): 346–51. PMID 23121865. doi:10.1111/bcpt.12033 
  31. ↑ Corey, E. J.; Snider, B. B. (1972). «Total synthesis of (+-)-fumagillin». Journal of the American Chemical Society. 94 (7): 2549–2550. PMID 5016935. doi:10.1021/ja00762a080 
  32. ↑ Kim, D.; Ahn, S. K.; Bae, H.; Choi, W. J.; Kim, H. S. (1997). «An asymmetric total synthesis of (−)-fumagillol». Tetrahedron Letters. 38 (25): 4437–4440. doi:10.1016/S0040-4039(97)00925-8 
  33. ↑ A Concise Synthesis of Fumagillol David A. Vosburg, Sven Weiler, Erik J. Sorensen Angewandte Chemie International Edition Volume 38, Issue 7, Date: April 1, 1999, Pages: 971-974 DOI
  34. ↑ Martin Hutchings*, D. M. (2001). «A Concise Synthesis of Fumagillol». Synlett (5): 0661–0663. doi:10.1055/s-2001-13359 
  35. ↑ Taber, D. F.; Christos, T. E. (1999). «Synthesis of (−)-Fumagillin». Journal of the American Chemical Society. 121: 5589. doi:10.1021/ja990784k 
  36. ↑ Boiteau, J. G.; Van De Weghe, P.; Eustache, J. (2001). «A New, Ring Closing Metathesis-Based Synthesis of (−)-Fumagillol». Organic Letters. 3 (17): 2737–2740. PMID 11506622. doi:10.1021/ol016343z 
  37. ↑ Bedel, O.; Haudrechy, A.; Langlois, Y. (2004). «A Stereoselective Formal Synthesis of (−)-Fumagillol». European Journal of Organic Chemistry. 2004 (18): 3813. doi:10.1002/ejoc.200400262 
  38. ↑ Yamaguchi, J.; Toyoshima, M.; Shoji, M.; Kakeya, H.; Osada, H.; Hayashi, Y. (2006). «Concise enantio- and diastereoselective total syntheses of fumagillol, RK-805, FR65814, ovalicin, and 5-demethylovalicin». Angewandte Chemie International Edition in English. 45 (5): 789–793. PMID 16365904. doi:10.1002/anie.200502826 
  39. ↑ Yamaguchi, J.; Hayashi, Y. (2010). «Syntheses of Fumagillin and Ovalicin.». Chemistry (Weinheim an der Bergstrasse, Germany). 16 (13): 3884–3901. PMID 20209516. doi:10.1002/chem.200902433 
  • Gilbert, M. A. & Granath, W.O. Jr. (2003). Whirling disease and salmonid fish: life cycle, biology, and disease. Journal of Parasitology, 89(4), pp. 658–667
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