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Algae Therapeutic Compounds – Alginic Acid and Phlorotannins
July 14, 2013
lgae have many compounds that are already used widely in the human and animal food supply as well as medicines. Alginic acid and phlorotannins will be examined here.
Alginic acid or alginates are naturally occurring hydrophilic colloidal polysaccharide, (carbohydrate) extracted from the cell wall of red and brown seaweed such as kelp. Alginic acid forms viscous fluids by absorbing 300 times its own weight in water. Many processed foods use alginic acid as a thickening agent. Food processors also use alginic acid as an emulsifier or bulking, foaming, gelling or glazing agent. The compound also provides value as a humectant, (moisturizer) and stabilizer. Alginates are commonly added to drinks, ice cream, jellies and cosmetics for thickening, smoothing and maintaining moisture.
Alginates inhibit the formation of ice crystals, which keep ice cream creamy and insure toothpaste and lipstick does not dry out before use. Alginate absorbs water quickly, which makes it useful as an additive in dehydrated foods and diet products such as slimming aids. Alginate is used in many pharmaceutical products such as anti-acids. The combination of the alginic acid and bicarbonate creates a barrier, which prevents stomach acid from refluxing back up into the esophagus. Calcium alginate is used in many types of medical products, including burn dressings that promote healing. The alginate sustains moisture so the dressing can be removed with less pain than conventional dressings.
Several lines of research have shown algae’s ability to decrease lipids and lower blood sugar, which improve diabetic symptoms. Algae polysaccharides such as carrageenan are excellent sources of dietary fiber that moderate hypoglycemic events and lower cholesterol and lipids. Algae carrageenan reduces triglycerides and low-density proteins in blood cholesterol, which helps regulate lipids.
Most algae contain low-fat proteins that often have nutrient profiles superior to land-based vegetables and grains, as well as dairy or meat. The next generation of food processing will incorporate the low fat, nutrient rich algae components throughout the food system to improve health and reduce obesity and diabetes.
Sodium alginate has been used in culinary physics or molecular gastronomy at some of the best restaurants in the world. Molecular gastronomy investigates the physical and chemical ingredient transformations that occur while cooking. The study includes the social, artistic and technical components of culinary and gastronomic phenomena such as spherification of juices and other liquids. Sodium alginate is combined with calcium lactate to create spheres of liquid surrounded by a thin jelly membrane. High-end restaurants present these spheres with different internal liquids for cocktails, appetizers, side dishes and deserts.
Alginic acids are made up of hydrophilic colloidal polysaccharides that deliver complex molecules such as peptides, proteins, nucleic acids, oligonucleotides, and plasmids across biological surfaces. The delivery capability makes alginic acids ideal carriers for obesity, diabetic and related medicines. Alginate is used in the weight loss industry as an appetite suppressant. The mechanism includes the absorption of water to create the feeling of satiety or fullness. Researchers at Newcastle University found that dietary alginates can reduce human fat uptake by more than 75%.
Sodium alginate acts as a natural chelator for metals and is sold in the nutraceutical industry as a detoxifier for removing heavy metals from the body. Research has shown that sodium alginate pulls heavy medals including radioactive toxins from the body, such as iodine-131 and strontium-90.
The effect of soluble fiber on the blood glucose response seems related to its ability to increase the viscosity of a meal. Viscous fibers slow the gastric emptying rate of a meal in subjects with and without diabetes. Alginate fibers offer a source of viscous dietary fiber in algae-based foods. The main constituents of alginates are uronic acids (mannuronic and guluronic acids), which give the alginate characteristics similar to pectin (galacturonic acid).
Alginic acid has been shown to exhibit antioxidant and angiotensin-converting enzyme, (ACE) inhibitory activities. Alginic acid reduces tension on blood vessels, lowers blood flow and causes dilation of blood vessels, which results in lower blood pressure. ACE inhibitors are used to treat hypertension, cardiac failure, diabetic nephropathy and renal failure. These soluble polysaccharides act as prebiotics, stimulating growth of beneficial bacteria in the colon.
Some algae such as the blue-green spirulina have no cell walls, which aid digestion and nutrient absorption. Studies have demonstrated digestion rates of 95% for essential amino acids. Algae provide higher quality protein than red meat. Unlike meat, algae contain all eight essential amino acids required for human body. Algae also pack a variety of essential vitamins including A, C, D, E, and b-carotene, biotin, folic acid, pantothenic acid and creatine. Vitamin E and B-carotene content is the best antioxidant and helps the body stave off free radical damage. Algae also deliver the powerful antioxidant astaxanthin, which scavenges free radicals and protects the body against oxidative damage. Astaxanthin moderates the lipids that raise LDL-cholesterol; strengthens and maintains cells and their membranes and tissues.
Phlorotannins are a type of tannins found in red, brown algae and other algae. Tannin molecules bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. Some phlorotannins have the ability to oxidize and form covalent bonds with proteins. These natural organic compounds provide integral structural components of cell walls in algae. They serve several other functions including protection from UV radiation.
Several lines of medical research indicate algae phlorotannins offer a rich source of natural health-promoting components including anti-diabetic and anti-cancer compounds. The chelating properties of phlorotannins have been demonstrated assist with metal sequestration. A team led by Graciliana Lopes tested ten different seaweeds from the coast of Portugal and found anti-oxidation, antibacterial, radioprotective and anti-HIV properties. The team noted that phlorotannins offer a novel and potent pharmacological alternative for the treatment of a wide range of microbial infections, especially inflammatory problems. Phlorotannins’ extracts may be preferred in order to avoid side effects and allergic reactions commonly associated with synthetic drugs.
The accumulation of advanced glycation end products is associated with diabetes, Alzheimer’s disease, renal failure and other maladies. Phlorotannins from brown algae inhibit the formation of advanced glycation end products by scavenging reactive carbonyls. Phlorotannins also offer therapeutic agents for diabetic complications by providing mechanisms for oxidative stress-mediated pathways.