Brown alga - Properties of the Fucus in Phytotherapy

By Dr. Rita Fabbri

Fucus vesiculosus is commonly called brown alga but may have other names, such as Ascophyllum nodoso, Quercus Marina, bladder ruin, bladder fire, sea ruin, Bladderwrack, Black tang or more generally Kelp.

Fucus vesiculosus was first described by Pliny, who called it "marine oak" in allusion to its certain similarity to oak leaves. Also the name Fucus derives from the Latin and we can translate it as tongues of fire.

In English bladder is bladder, while wrack is the marine vegetation, but also the rejection of the sea (sometimes the algae are harvested and used in the countryside as fertilizer); tang etymologically means snake tongue, then alga with serrated edges; Kelp is a term that is generally associated with different algae belonging to the genus Fucus and Laminaria, with biological properties similar to those of Fucus vesiculosus .

The brown alga is easily recognized because along the flattened fronds it is sprinkled with globular vesicles full of air, which make it float keeping it in a vertical position. If you squeeze the blisters between your fingers they will make a noise. In the extremities of some laminae, the brown alga also presents ovoid sacks containing an orange or green gelatinous substance.

Nicandro di Colofone, a Greek didactic poet, used Fucus vesiculosus as an antidote against the bite of poisonous snakes. Pliny advised him to treat goiter.

In 1791, in the "Experimental History of Materia Medica" with regard to the Brown Alga, we write: "... a mixture of two pounds of juicy vesicles, harvested in July, with a liter of sea water, stored in a container of glass for ten or fifteen days, it will reach the consistency of honey: it is an excellent remedy to cure the laxity of the gums and for the cleaning of the teeth, it cleans like a soap solution and is the best cure for the hardness and above all the decline of the glandular swellings ... ".

In 1862 the doctor Duchesne-Duparc - using Fucus vesiculosus to cure psoriasis - noticed that this algae acted on the metabolism of fats, so he began to use it successfully in the treatment of obesity. Indeed, the rich iodine content of brown algae promotes thyroid activity, so this plant is currently used to control body weight.

Botanical name : Fucus vesicolosus L. Family : Fucaceae Used parts : Tallo

Botanical description

Brown alga lives along the cliffs of the mid-temperate and arctic areas (coasts of the North Sea, the Baltic Sea, the Atlantic and the Pacific). In low tide, an expanse of yellow-brown color appears.

Brown alga does not survive more than 5 or 6 hours out of the water, which is why it only grows on submerged rocks.

The fronds of Fucus vesiculosus have a median vein, almost spherical vesicles full of air and reproductive swellings. The margin is smooth and the structure is dichotomous branched. Thin filaments are visible that do not have an absorbing function but are anchored to the reef.

Brown algae contains brown pigments and green pigments (chlorophyll).

Exposed to light, thanks to chlorophyll, it transforms the carbon dioxide dissolved in water into organic substances necessary for the life of the plant.

The breeding bulges are characterized by numerous protrusions; dissecting these swellings we note that in each protrusion there is a spherical cavity equipped with small ovoid sacks containing an orange or green gelatinous substance. In spring and at low tide, the gelatinous substance covers reproductive swellings. During high tide the ovoid sacks absorb water until they "explode", releasing flagellated spermatozoids (from orange sacks) and oosphere (from green sacks). After fertilization, the zygote is formed which subsequently becomes a new sporophyte.

Chemical composition

Iodine (in mineral and organic form), mucopolysaccharides (such as alginic acid, fucoidan and laminarin), polyphenols including floroglucinol, sterols including fucosterol, tetraterpene fucoxanthin, polar lipids, mineral salts and trace elements.

Therapeutic indications

Brown alga is commonly used in cases of obesity and overweight: its main constituent is in fact iodine, therefore it acts by stimulating the basal metabolism. Brown alga can also be used as an iodine supplement and other trace elements.

In common preparations, mainly the dry titrated extract is used, whose dosage varies from 500 to 900 mg per day.

Basal metabolism is linked to thyroid function: thyroid hormones, in fact, thyroxine (T4) and triiodothyronine (T3), intervene in the "matching" phase of mitochondrial oxidative phosphorylation, which consists in "matching" the energy released by glycolysis aerobic and anaerobic with the production of high-energy compounds (Adenosine triphosphate, Guanosine triphosphate, etc.). The greater the combination of metabolic processes and phosphorylation, the more numerous are the high-energy compounds that are formed and which will then be used for the synthesis of fats. The smaller the combination, the greater the energy that is dissipated as heat and which is subtracted from the synthesis of lipids, especially in the adipose tissue. The iodinated hormones synthesized by the thyroid speed up the basal metabolism, prevent the combination of oxidative phosphorylation, therefore increase energy expenditure and reduce lipid synthesis. This is why the brown alga, thanks to its mineral and organic iodine content, is commonly used to stimulate the basal metabolism in the reduction of body weight in obese subjects (1), overweight or in cases of slowed basal metabolism.

We have already said that brown alga can also be used as an iodine supplement and other trace elements.

The recommended daily dose of iodine is 150 µg / day. In addition to a particularly high content of iodine, brown alga is rich in trace elements that can vary substantially even as the marine ecosystem varies where the alga is lived; generally the most representative ions are Na, Mg, K, Ca and only in traces Zn, Pb, Ni, Mn, Hg, Cu, Co, Cd, As (2).

Brown alga has other pharmacological activities:

• Gastro-protective and antiulcer activity

the alginates present in the brown Alga (from 15 to 45%) form a dense viscous gel that covers and protects the mucous membrane of the stomach and reduces its acid secretion (3). The efficacy against gastro-oesophageal reflux is also documented.

• Antidiabetic activity

brown alga significantly reduces the glycemic index and the level of triglycerides in guinea pigs; this action is more evident in the diabetic animal (4).

• Anticoagulant activity

The fucoidan, contained in considerable quantities in the brown Alga, has a chemical structure correlated to that of heparin and has an important anticoagulant activity. Fucoidan however, administered orally, has a low systemic bioavailability (5).

• Antibacterial activity

Evaluated the effectiveness of brown alga in fighting infections with Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli. The antimicrobial action is due to some marine bacteria isolated on the surface of the brown Alga and capable of synthesizing completely innovative antibiotics as a chemical structure (6).

• Antiviral activity

The antiviral action is linked in particular to a series of polysaccharides and polyphenols present in the brown Alga.

• Anti-inflammatory activity

Fucoidan has an anti-inflammatory action even in the acute phase.

• Collagenase activity

Alginates activate a glycoprotein present on the fibroblast surface and involved in collagen synthesis (7). Furthermore, according to a recent study, an aqueous extract of 1% brown alga applied locally would have demonstrated anti-aging activity that could be exploited in numerous cosmetic formulations (8).

• Antioxidant activity

Some polysaccharides have an antioxidant action in vitro that could be exploited in the food industry (9).

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Contraindications, special warnings and appropriate precautions for use, undesirable effects

Preparations based on brown algae are contraindicated in case of hyperthyroidism and should be taken with caution even in cases of alleged altered thyroid function or during drug treatment with thyroid hormones. It is also advised not to take products containing brown alga continuously, but to carry out periodic cycles of about two months, interspersed with a temporary suspension of the treatment.

There are no known clinical studies conducted in pregnant and lactating women, however the use of brown alga is contraindicated in these cases. In the presence of cardiovascular disease and / or hypertension it is advisable to consult a doctor before use. Cases of allergic reactions are very rare. Overdosage can cause tremors, tachycardia, arterial hypertension.

Brown alga can have a slight laxative action due to the presence of alginates.

BIBLIOGRAPHICAL NOTES

1. "... Iodine is the most important active principle in F.vesiculosus. "The use of iodine in a population is taken into account" can ensure the intake of the total daily requirement, consequently, optimal thyroid function ... Moro CO Basile G.Obesity and medicinal plants. Phytotherapy 2000; 71: s73-s82.
2. Romaris-Hortas V, Garcia-Sartal C, Barciela-Alonso MC, Moreda-Pineiro A, Bermejo-Barrera P. Characterization of edible seaweed harvested on the Galician coast (northwesterrn Spain) using pattern recognition techniques and major and trace element data. J.Agric.Food Chem. 2010 Feb10; 58 (3): 1986-92.
3. Nagaoka M, Shibata H, Kimura- Takagi I, Hashimoto S, Aiyama R, Ueyama S, Yokokura T. Anti-ulcer effects and biological activities of polysaccharides from marine algae. Biofactors. 2000; 12 (1-4): 267-74.
4. Hypoglycemic activity of several seaweed extracts. Lamela M, Anca J, Villar R, Otero J, Calleja JM. Journal of Ethnopharmacology 1989; 27: 35-43.
5. De Azevedo TC, Bezerra ME, Santos Mda G, Souza LA, Marques CT, Benevides NM, Leite EL. Heparinoids algal and their anticoagulant, hemorrhagic activities and platelet aggregation. Biomed Pharmacother. 2009 Aug; 63 (7): 477-83.
6. Lachnit T, Wahl M, Harder T. Isolated thallus-associated compounds from the macroalga Fucus vesiculosus mediated bacterial surface colonization in the field similar to that on the natural alga. Biofouling. 2010; 26 (3): 247-55.
7. Fujimura T, Shibuya Y, Mariwaki S, Tsukahara K, Kitahara T, Healthy T, Nishizawa Y, Takema Y. Fucoidan is the active component of Fucus Vesiculosus that promotes contraction of fibroblast-populated collagen gels. Biol Pharm. 2000 Oct; 23 (10): 1180-4.
8. Fujimura T, Shibuya Y, Mariwaki S, Tsukahara K, Kitahara T, Healthy T, Nishizawa Y, Takema Y. Treatment of human skin with an extract of Fucus Vesiculosus changes its thickness and mechanical properties. J Cosmet Sci. 2002 Jan-Feb; 53 (1): 1-9.
9. Rocha de Souza MC, CT Marques, Guerra Dore C, Ferreira da Silva FR, Oliveira Rocha HA, Leite EL. Antioxidant activities of sulfated polysaccharides from brown and red seaweeds. J Appl Phycol. 2007 Apr; 19 (2): 153-160.