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Tocotrienol
From Wikipedia, the free encyclopedia
Tocotrienols are members of the vitamin E family:[1] four tocotrienols (alpha, beta, gamma, delta) and four tocopherols (alpha, beta, gamma, delta).[2] The critical chemical structura difference between tocotrienols and tocopherols is in that tocopherols have saturated side chains, whereas tocotrienols have unsaturated isoprenoid side chains (farnesyl isoprenoid tails) with three double bonds (see Figure).[3][4]
Tocotrienols are compounds naturally occurring at higher levels in select vegetable oils, including palm oil, rice bran oil wheat germ, barley, saw palmetto, anatto, and certain other types of seeds, nuts, grains, and the oils derived from them.[5][6]
Chemically, different analogues of vitamin E all show some activity as a chemical antioxidant,[7] but do not all have the same vitamin E equivalence. Alpha-Tocopherol is the form of vitamin E that has the highest biological activity and is preferentially absorbed and accumulated in humans.[2] Like tocopherols, individual tocotrienol isomers demonstrate different bioavailability[8] and efficacy depending on the type of antioxidant performance being measured. All tocotrienol and tocopherol isomers have some physical antioxidant activity due to an ability to donate a hydrogen atom (a proton plus electron) from the hydroxyl group on the chromanol ring, to free radical and reactive oxygen species. Historically studies of tocotrienols account for less than 1% of all research into vitamin E.[9] A scientific compilation of tocotrienol research, Tocotrienols: Vitamin E Beyond Tocopherols, was published in 2013.[5]
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[hide]Health effects[edit]
A number of health benefits have been proposed included decreased risk of heart disease and cancer.[10] The Food and Nutrition Board of the Institute of Medicine of the United States National Academy of Sciences does not define a Recommended Dietary Allowance or Adequate Intake or Tolerable Upper Intake Level for tocotrienols, only for alpha tocopherol.[11]
Stroke[edit]
There are no human trials of tocotrienols for prevention or treatment of stroke. Use in animal models show promising results.[12]
Cancer[edit]
There is promising early stage research.[10] One trial small trial of women with breast cancer found a non significant trend of outcomes.[10]
Heart disease[edit]
Tocotrienols have been linked to improved markers of heart disease.[13]
Diabetes[edit]
Animal models and observational studies in humans have shown potential benefit.[10] Benefit; however, does not appear to occur from supplementation but only dietary sources.[10]
Radiation countermeasures[edit]
No human trials. Following exposure to gamma radiation, hematopoietic stem cells (HSCs) in the bone marrow, which are important for producing blood cells, rapidly undergo apoptosis (cell death). There are no known treatments for this acute effect of radiation.[14] Two studies conducted by the U.S. Armed Forces Radiobiology Research Institute (AFRRI) found that treatment with γ-tocotrienol or δ-tocotrienol enhanced survival of hematopoietic stem cells, which are essential for renewing the body's supply of blood cells.[14][15] Based on these successful results of studies in mice, γ-tocotrienol is being studied for its safety and efficacy as a radioprotective measure in nonhuman primates.[16]
Side effects[edit]
Tocotrienols are generally well tolerated and without significant side effects.[10]
History[edit]
The discovery of tocotrienols was first reported by Pennock and Whittle in 1964, describing the isolation of tocotrienols from rubber.[17] The biological significance of tocotrienols was clearly delineated in the early 1980s, when its ability to lower cholesterol was first reported by Qureshi and Elson in the Journal of Medicinal Chemistry.[18] During the 1990s, the anti-cancer properties of tocopherols and tocotrienols began to be delineated.[19] The current commercial sources of tocotrienol are rice and palm.[20] Other natural tocotrienol sources include rice bran oil, coconut oil, cocoa butter, barley, and wheat germ.[21] Tocotrienols are safe and human studies show no adverse effects with consumption of 240 mg/day for 48 months.[22] Tocotrienol rich fractions from rice, palm, or annatto, used in nutritional supplements, functional foods, and anti-aging cosmetics, are available in the market at 20%, 35%, 50%, and 70% total vitamin E content. Molecular distillation occurs at lower temperatures and reduces the problem of thermal decomposition. High vacuum also eliminates oxidation that might occur in the presence of air.[23] Annatto tocotrienol has the highest tocotrienol concentration and is tocopherol-free.
Etymology[edit]
Tocotrienols are named by analogy to tocopherols (from Greek words meaning to bear a pregnancy (see tocopherol); but with this word changed to include the chemical difference that tocotrienols are trienes, meaning that they share identical structure with the tocopherols except for the addition of the three double bonds to their side chains.
Comparison of tocotrienol and tocopherol[edit]
Tocotrienols have only a single chiral center, which exists at the 2' chromanol ring carbon, at the point where the isoprenoid tail joins the ring. The other two corresponding centers in the phytyl tail of the corresponding tocopherols do not exist due to tocotrienol's unsaturation at these sites. Tocotrienols extracted from natural sources always consist of the dextrorotatory enantiomers only. These naturally occurring, dextrorotatory stereoisomers are generally abbreviated as the "d-" forms, for example, "d-tocotrienol" or "d-alpha-tocotrienol". In theory, the unnatural "l-tocotrienol" (levorotatory) forms of tocotrienols could exist as well, which would have a 2S (rather than 2R) configuration at the molecules' single chiral center. In practice, however, tocotrienols are only produced in the d-form i.e. from natural sources. The synthetic mixed stereoisomer ("dl-tocotrienol") and its acetate are available as dietary supplements. Tocopherols and tocotrienolss have different antioxidant activities when measured in human plasma [24]
Tocotrienol studies confirm anti-oxidation[25] and suggest anti-cancer effects[26][27] than the common forms of tocopherol due to their chemical structure. The unsaturated side-chain in tocotrienols causes them to penetrate tissues with saturated fatty layers more efficiently.[28]
Lipid ORAC values are highest for δ-tocotrienol.[29] However that study also says: "Regarding α-tocopherol equivalent antioxidant capacity no significant differences in the antioxidant activity of all vitamin E isoforms were found." Scientists have suggested tocotrienols are better antioxidants than tocopherols[30][31] at preventing cardiovascular diseases[32] and cancer.[33] From the pharmacological standpoint, current formulation of vitamin E supplements, composed mainly of alpha- tocopherol, seems questionable.[34]
Metabolism and bioavailability[edit]
The metabolism and thus the bioavailability of tocotrienols are not well understood and simply increasing the intake of tocotrienols might not increase tocotrienol levels in the body.[35]
α-Tocopherol interference[edit]
Various studies have shown that alpha-tocopherol interferes with tocotrienol benefits.[35] High levels of α-tocopherol increase cholesterol production.[36] α-Tocopherol interference with tocotrienol absorption was described previously by Ikeda, who showed that α-tococopherol interfered with absorption of α-tocotrienol, but not γ-tocotrienol.[37] Finally, α-tocopherol was shown to interfere with tocotrienols by increasing catabolism.[38]
Sources[edit]
In nature, tocotrienols are present in many plants and fruits. The palm fruit (Elaeis guineensis) is particularly high in tocotrienols, primarily gamma-tocotrienol, alpha-tocotrienol and delta-tocotrienol. Other cultivated plants high in tocotrienols includes rice, wheat, barley, rye and oat.[39] In anatto however, tocotrienols are relatively abundant (only delta- and gamma-tocotrienol) and it contains no tocopherols.[40]
Annatto
From Wikipedia, the free encyclopedia
Annatto (/əˈnætoʊ/ or /əˈnɑːtoʊ/) is an orange-red condiment and food coloring derived from the seeds of the achiote tree (Bixa orellana). It is often used to impart a yellow or orange color to foods, but sometimes also for its flavor and aroma. Its scent is described as "slightly peppery with a hint of nutmeg" and flavor as "slightly nutty, sweet and peppery".[1]
The color of annatto comes from various carotenoid pigments, mainly bixin and norbixin, found in the reddish waxy coating of the seeds. The condiment is typically prepared by grinding the seeds to a powder or paste. Similar effects can be obtained by extracting some of the color and flavor principles from the seeds with hot water, oil, or lard, which are then added to the food.[2]
Annatto and its extracts are now widely used in an artisanal or industrial scale as a coloring agent in many processed food products, such as cheeses, dairy spreads, butter and margarine, custards, cakes and other baked goods, potatoes, snack foods, breakfast cereals, smoked fish, sausages, and more. In these uses, annatto is a natural alternative to synthetic food coloring compounds, but it has been linked to cases of food-related allergies. Annatto is of particular commercial value in the United States because the Food and Drug Administration considers colorants derived from it to be "exempt of certification".
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[hide]History[edit]
The annatto tree B. orellana is believed to originate from Brazil.[3] It was probably not initially used as a food additive, but for other purposes such as ritual and decorative body painting (still an important tradition in many Brazilian native tribes), sunscreen, and insect repellent, and for medical purposes.[4][5][6] It was used for Mexican manuscript painting in the 16th century.[7]
Annatto has been traditionally used as both a coloring and flavoring agent in Latin America, the Caribbean, and other countries where it was taken by Spanish and Portuguese explorers in the 16th century. It is also called by local names such as achiote, bija, roucou (Peru, French Guyana), koesoewe or kusuwe (Suriname), onoto (Venezuela),[8] atsuete (Philippines), or colorau (Brazil).[3] Its use has spread in historic times to other parts of the world, and it was incorporated in local culinary traditions of many countries outside the Americas.[8][9]
Culinary uses[edit]
Traditional cuisine[edit]
Ground annatto seeds, often mixed with other seeds or spices, are used in form of paste or powder for culinary use, especially in Latin American, Jamaican, Chamorro, and Filipino cuisines. Many cuisines traditionally use annatto in recipes of Spanish origin that originally call for saffron; for example, in arroz con pollo, to give the rice a yellow color. In Venezuela, annatto is used in the preparation of hallacas, perico, and other traditional dishes. Annatto seeds are also a component of some local sauces and condiments, such as recado rojo in Yucatán and sazón in Puerto Rico. Annatto paste is an important ingredient of cochinita pibil, the spicy pork dish popular in Mexico. It is also a key ingredient in the drink tascalate from Chiapas, Mexico. In the Philippines it is used for the sauce of pancit.
Industrial food coloring[edit]
Annatto is used currently to impart a yellow or orange color to many industrialized and semi-industrialized foods. In the European Union, it is identified by the E number E160b.
Annatto has been a traditional colorant for Gloucester cheese since the 16th century. During the summer, the high levels of carotene in the grass would have given the milk an orange tint which was carried through into the cheese. This orange hue came to be regarded as an indicator of the best cheese, spurring producers of inferior cheese to use annatto in order to replicate it. The custom of adding annatto then spread to other parts of the UK, for cheeses such as Chesire and Red Leicester, as well as colored cheddar made in Scotland.[10][11] Many cheddars are produced in both white and red (orange) varieties, with the latter being more popular despite the only difference between the two being the presence of annatto as a coloring.[12] That practice has extended to many modern processed cheese products, such as American cheese and Velveeta.
Chemical composition[edit]
The yellow to orange color is produced by the chemical compounds bixin and norbixin, which are classified as carotenoids. The fat-soluble color in the crude extract is called bixin, which can then be saponified into water-soluble norbixin. This dual solubility property of annatto is rare for carotenoids.[14] The seeds contain 4.5–5.5% pigment, which consists of 70–80% bixin.[13] Unlike beta-carotene, another well-known carotenoid, annatto-based pigments are not vitamin A precursors.[15] The more norbixin in an annatto color, the more yellow it is; a higher level of bixin gives it a more orange shade.
Safety[edit]
In the United States, annatto extract is listed as a color additive "exempt from certification" and is informally considered to be a natural coloring.[16][17] Foods colored with annatto may declare the coloring in the statement of ingredients as "colored with annatto" or "annatto color."[18]
Annatto condiments and colorants are safe for most people when used in food amounts, but they may cause allergic reactions in those who are sensitive.[19][20] In one 1978 study of 61 patients suffering from chronic hives or angioedema, 56 patients were orally provoked by annatto extract during an elimination diet. A challenge was performed with a dose equivalent to the amount used in 25 grams (0.88 oz) of butter. Twenty-six percent of the patients reacted to this color four hours after intake, worse than amaranth (9%) or synthetic dyes such as tartrazine (11%), Sunset Yellow FCF (17%), Food Red 17 (16%), Ponceau 4R (15%), erythrosine (12%) and Brilliant Blue FCF (14%).[21]
Annatto is not among the "Big Eight" substances causing hypersensitivity reactions (cow's milk, egg, peanuts, tree nuts, fish, shellfish, soy, and wheat), which are responsible for more than 90% of allergic food reactions.[22] The Food and Drug Administration and experts at the Food Allergy Research and Resource Program (FARRP) at the University of Nebraska do not include annatto in the list of major food allergens.[23]
Human research[edit]
As annatto is a source of tocotrienols, such as geranylgeraniol—compounds similar in structure and function to vitamin E—its extracts were under preliminary research as of 2015 to determine their potential biological properties in humans. In one such application, annatto geranylgeraniol is an ingredient in an experimental medical foodbeing investigated for its effect on blood lipoproteins.[24]
