WordNet

first in order of importance; "the alpha male in the group of chimpanzees"; "the alpha star in a constellation is the brightest or main star"
the 1st letter of the Greek alphabet
the beginning of a series or sequence; "the Alpha and Omega, the first and the last, the beginning and the end"--Revelations
early testing stage of a software or hardware product; "alpha version"
any high mountain

PrepTutorEJDIC

アルファ(ギリシア語アルファベットの第1字A,α;英語のA,aに相当) / アルファ星(星座の主星)
高山,高峰

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/05/18 23:00:36」(JST)

wiki en

alpha-Cyclodextrin (α-dextrin, α-cyclodextrin, α-CD, alphadextrin, alpha cyclodextrin (dietary fiber)) is a polysaccharide of six glucose units that are covalently attached end to end via α-1, 4 linkages. This fiber is sold under the brand names, "Alpha-Fibe" and "Calorease". Alpha-Fibe is the original product that contains this unique fiber, introduced to the worldwide nutritional supplement market by Bio-Form Essentials in 2007. Soho Flordis International became the patent Assignee as of March 30th, 2012^[1]^[2] and launched the brand Calorease in 2013.

FBCx is not an ingredient, only an abbreviation, and is not part of the scientific name. The abbreviation FBCx, stands for "Fat Binding Complexer" and can be associated with the brand names, "Alpha-Fibe" and "Calorease". There are two other naturally occurring cyclodextrins, β (beta) - and γ (gamma) -, which contain seven and eight glucose units respectively. In water, these fibers take on a toroid or truncated cone configuration. In aqueous medium, the exterior surface of cyclodextrins is hydrophilic while the interior core is hydrophobic. This allows for the formation of guest-host relationships with small hydrophobic molecules. McGowan et al., for example, demonstrated that α-cyclodextrin was very effective at solubilizing the free fatty acids that are generated in the colorimetric determination of triglycerides.^[3]^{[full citation needed]} Shimada et al. have demonstrated that at an oil:water interface α-cyclodextrin “threads” onto fatty acids in a manner analogous to threading beads onto a string.^[4]^{[full citation needed]} According to these authors, the number of cyclodextrin molecules per fatty acid appears to be dependent upon the length of the fatty acids that are involved. Due to the small pore size it was generally believed that α-cyclodextrin could not form a complex with triglyceride. However, Artiss et al. demonstrated that α-cyclodextrin could complex triglyceride and at ratios that are significantly different from the 1:1 that is typical for dietary fibers.^[5] The ratio for α-cyclodextrin is actually closer to 1:9 (fiber:fat ratio). Trichard et al. have demonstrated that α-cyclodextrin and soybean oil can form porous beads that may find utility in delivering water insoluble pharmaceuticals.^[6]^{[full citation needed]}^[7]^{[full citation needed]}

Applications

α-Cyclodextrin is a multifunctional, soluble dietary fiber marketed for use as a fiber ingredient, an odor or flavor masking agent as well as for emulsification applications. It is registered as a dietary fiber in the European Union since 2008.^[8]

α-Cyclodextrin is marketed for a range of medical, healthcare and food and beverage applications which rely on its ability to bind to fats and reduce their bioavailability both in the body and in food and beverage products. As a fiber dietary supplement,α-cyclodextrin binds to fat when taken with a meal and is a natural alternative to other synthetic anti-obesity medications. α-Cyclodextrin has the unique ability among known fibers to bind nine times its own weight in fat. Although many dietary fibers appear to bind fat on a 1:1 ratio α-cyclodextrin is the only one that binds on a 1:9 (fiber:fat) ratio.As the molecular weight of the fiber and triglycerides are about the same, it would appear to follow that the cyclodextrin is actually forming a layer on the surface of the fat droplets. Bochot et al..^[9] have lent evidence to this theory by demonstrating that it is possible to produce “beads” with oily compartments by mixing an aqueous solution of the fiber with soybean oil albeit under somewhat more vigorous conditions than occur in the human stomach. This high ratio of binding makes α-cyclodextrin practical as a weight loss supplement.^{[medical citation needed]}

In order for fat or triglyceride to be absorbed it must first be digested by the pancreatic enzyme lipase. If the lipase activity is decreased then the dietary triglyceride passes through to the large bowel without being absorbed. There are, however, side effects to the use of lipase inhibitors: if dietary fat is not restricted, the free fat that passes into the large bowel will precipitate side effects. Unlike lipase inhibitors alpha-cyclodextrin forms a stable complex with the dietary fat which prevents lipase from digesting the triglyceride and the normal gut flora from using it as a carbon source, thus preventing the side effects of the lipase inhibitors.

There are no known negative side effects except for gas since it is a dietary fiber, if you take it without having fat in your meal.^{[medical citation needed]}

Animal and human studies are consistent with each other in demonstrating the positive benefits of taking alpha-cyclodextrin fiber.

Lower blood (LDL or bad) low-density lipoprotein cholesterol levels^[10]
Lower blood triglyceride levels
Preferentially lowers blood saturated fat and trans fat levels
Increased insulin sensitivity
Increased leptin sensitivity – increased satiety^[11]^{[full citation needed]}
Improved glycemic index of foods and improved glycemic control^[12]
Resolves chronic diarrhea and constipation immediately (anecdotal evidence)^{[citation needed]}

Due to its surface active properties, α-cyclodextrin can also be used as an emulsifying fiber, for example in mayonnaise. It stabilizes oil-in-water emulsions very efficiently. The three-dimensional, donut-shaped cyclodextrins have a hydrophobic cavity inside and a hydrophilic cover on the outside. A fatty acid tail of triglycerides is attracted by the cavity and encapsulated there. This leads to the build-up of a surfactant-like structure which has emulsion-stabilizing properties. Depending on the oil-to-water ratio and the amount of α-cyclodextrin used, the viscosity, and therefore the organoleptic properties, of the emulsion are altered. From ketchup-like viscosity to icing-like viscosity, all grades can be adjusted. Often with significant less fat content and thus reduced calories. Furthermore, stable emulsions are feasible even at elevated temperatures.

α-Cyclodextrin can also be used as whipping fiber, for example in desserts and confectionary applications. Tests showed that alpha cyclodextrins can cause a volume effect in various different food compositions with or without fat and at a very broad pH range. This can be used for fat free or fat containing dessert compositions and for the reduction or the replacement of egg white in confectionary and bakery applications.

Structure

α-Cyclodextrin is a naturally occurring, cyclic oligosaccharide, enzymatically produced from starch. It is a well-defined, chemically pure substance consisting of six linked glucose units.

Synthesis

Cyclodextrins are natural starch-conversion products. For industrial use, they are manufactured by enzymatic degradation from vegetable raw materials, such as corn or potatoes. First the starch is liquified either by heat treatment or using α-amylase. Then cyclodextrin glycosyltransferase (CGTase) is added for enzymatic conversion. CGTases can synthesize all forms of cyclodextrins, thus for the production of the α-cyclodextrin, one specific enzyme must be used.

References

^ "Compositions comprising dietary fat complexer and methods for their use US 8101201 B2".
^ "Compositions comprising dietary fat complexer and methods for their use US 6890549 B2".
^ McGowan MW, 1983
^ Shimada K, 1992
^ Artiss, J.D.; Brogan, K.; Brucal, M.; Moghaddam, M.; Jen, K.L.C. (2006). "The effects of a new soluble dietary fiber on weight gain and selected blood parameters in rats". Metabolism 55 (2): 195–202. doi:10.1016/j.metabol.2005.08.012. PMID 16423626
^ Trichard L D.-C. B., 2007
^ Trichard L F. E.-L., 2008
^ COMMISSION DECISION of 26 May 2008 authorizing the placing on the market of α-cyclodextrin as a novel food ingredient under Regulation (EC) No 258/97 of the European Parliament and of the Council
^ Bochot, A.; Trichard, L.; Le Bas, G.; Alphandary, H.; Grossiord, J.L.; Duchêne, D.; Fattal, E. (2007). "Α-Cyclodextrin/oil beads: An innovative self-assembling system". International J of Pharmaceutics 339 (1–2): 121–129. doi:10.1016/j.ijpharm.2007.02.034.
^ Wagner, E.; Jen, J.D.; Artiss, K.L.C.; Remaley, A.T. (2008). "Dietary α-cyclodextrin lowers low-density lipoprotein cholesterol and alters plasma fatty acid profile in low-density lipoprotein receptor knockout mice on a high-fat diet". Metabolism 57 (8): 1046–51. doi:10.1016/j.metabol.2008.02.020. PMC 2597477. PMID 18640380
^ FASEB Journal 21: A730. 2007. CS1 maint: Untitled periodical (link)
^ Buckley, JD; Thorp, AA; Murphy, KJ; Howe, PR (2006). "Dose-dependent inhibition of the post-prandial glycaemic response to a standard carbohydrate meal following incorporation of alpha-cyclodextrin". Annals of Nutrition and Metabolism 50 (2): 108–114. doi:10.1159/000090498. PMID 16373993.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 米国における真菌による中枢神経系感染症および化膿性関節炎のアウトブレイク：治療 outbreak of fungal central nervous system infection and septic arthritis in the united states treatment
2. アゾールの薬理学 pharmacology of azoles
3. 成人における侵襲性メチシリン耐性黄色ブドウ球菌感染症の治療 treatment of invasive methicillin resistant staphylococcus aureus infections in adults
4. 発作性片側頭痛：治療および予後 paroxysmal hemicrania treatment and prognosis
5. 原発性肝細胞癌の臨床的特徴および診断 clinical features and diagnosis of primary hepatocellular carcinoma

English Journal

Performance of a portable biosensor for the analysis of ethion residues.

Khaled E1, Kamel MS2, Hassan HN2, Abdel-Gawad H3, Aboul-Enein HY4.Author information 1Microanalysis Laboratory, National Research Centre, Dokki, Giza 12622, Egypt. Electronic address: elmorsykhaled@yahoo.com.2Microanalysis Laboratory, National Research Centre, Dokki, Giza 12622, Egypt.3Applied Organic Chemistry Department, National Research Centre, Dokki, Giza 12622, Egypt.4Pharmaceutical and Medicinal Chemistry Department, National Research Centre, Dokki, Giza 12622, Egypt.AbstractSensitive disposable potentiometric sensors for determination of the organophosphorus pesticide (OPs), ethion and its degradation residues have been constructed. The fabricated screen printed sensors are based on multi-walled carbon nanotube-polyvinyl chloride (MWNT-PVC) composite incorporated with α-cyclodextrin (α-CD) ionophore for butyrylcholine (BuCh) determination. Butyrylcholinesterase (BuChE) activity was measured through monitoring the BuCh hydrolysis using the fabricated sensors. The electrode potential changes linearly with BuChE concentration over the range from 0.04 to 0.4U in phosphate buffer solution. This approach can also be used to analyze ethion and its degradation products in the concentration range from 0 to 330ngmL(-1) by measuring the relative inhibition percentage of BuChE. From different ethion degradation products, inhibition by dioxon and monooxon were more potent than the parent pesticide. The proposed method was applied for determination of ethion in different samples with good accuracy and precision. The relative simple fabrication protocol of biosensor, high sensitivity and stability represents a promising approach for determination of environmental pollutants in field conditions.
Talanta.Talanta.2014 Feb 15;119:467-72. doi: 10.1016/j.talanta.2013.11.001. Epub 2013 Nov 11.
Sensitive disposable potentiometric sensors for determination of the organophosphorus pesticide (OPs), ethion and its degradation residues have been constructed. The fabricated screen printed sensors are based on multi-walled carbon nanotube-polyvinyl chloride (MWNT-PVC) composite incorporated with
PMID 24401442

A reversible light-operated nanovalve on mesoporous silica nanoparticles.

Tarn D, Ferris DP, Barnes JC, Ambrogio MW, Stoddart JF, Zink JI.Author information Department of Chemistry and Biochemistry, California NanoSystems Institute, University of California, Los Angeles, California 90095, USA.AbstractTwo azobenzene α-cyclodextrin based nanovalves are designed, synthesized and assembled on mesoporous silica nanoparticles. Under aqueous conditions, the cyclodextrin cap is tightly bound to the azobenzene moiety and capable of holding back loaded cargo molecules. Upon irradiation with a near-UV light laser, trans to cis-photoisomerization of azobenzene initiates a dethreading process, which causes the cyclodextrin cap to unbind followed by the release of cargo. The addition of a bulky stopper to the end of the stalk allows this design to be reversible; complete dethreading of cyclodextrin as a result of unbinding with azobenzene is prevented as a consequence of steric interference. As a result, thermal relaxation of cis- to trans-azobenzene allows for the rebinding of cyclodextrin and resealing of the nanopores, a process which entraps the remaining cargo. Two stalks were designed with different lengths and tested with alizarin red S and propidium iodide. No cargo release was observed prior to light irradiation, and the system was capable of multiuse. On/off control was also demonstrated by monitoring the release of cargo when the light stimulus was applied and removed, respectively.
Nanoscale.Nanoscale.2014 Feb 12. [Epub ahead of print]
Two azobenzene α-cyclodextrin based nanovalves are designed, synthesized and assembled on mesoporous silica nanoparticles. Under aqueous conditions, the cyclodextrin cap is tightly bound to the azobenzene moiety and capable of holding back loaded cargo molecules. Upon irradiation with a near-UV lig
PMID 24519642

Rheoreversible hydrogels in paper restoration processes: a versatile tool.

Mazzuca C, Micheli L, Marini F, Bevilacqua M, Bocchinfuso G, Palleschi G, Palleschi A.AbstractBACKGROUND: Paper based artworks are probably ones of the most difficult materials to restore, because of their complexity and fragile structure. Cleaning of paper artifacts, one of the process commonly carried out during restoration, usually involves the use of solvents (organic or not), that may cause several troubles, like swelling and dissolution of some components, and may also be harmful to the users.
Chemistry Central journal.Chem Cent J.2014 Feb 10;8(1):10. [Epub ahead of print]
BACKGROUND: Paper based artworks are probably ones of the most difficult materials to restore, because of their complexity and fragile structure. Cleaning of paper artifacts, one of the process commonly carried out during restoration, usually involves the use of solvents (organic or not), that may c
PMID 24513147