Laminaria sp. / Zeewieren

Laminaria for cervical dilation is used in the form of “tents,” usually made of any hygroscopic (readily absorbs water) material, that are placed to maintain the opening or cause dilation. Dilators are made from the dried stems of laminaria seaweeds. When dried and rounded into a stick-like shape, the dilators are approximately 6 cm (2.5 inches) long with a diameter of 0.3 to 0.5 cm. A strong thread is attached to one end, and a collar prevents migration into the uterus. The stem is hygroscopic and can swell 3 to 5 times its original diameter within 12 to 24 hours. Other natural products used as tents for various purposes include sponges, dried corn stalks, slippery elm bark, and tupelo wood. 2 Hollow laminaria tents were developed in the 1800s to improve uterine drainage, and laminaria coated with wax was designed to release antiseptics as the wax melted.

Tents fell into disuse because of complications caused by infections. This was especially evident in tents derived from land plants because of the inability of sterilization to inactivate Clostridium spores, the causative agents of tetanus, botulism, and gas gangrene. Although laminaria from the ocean harbors relatively nonpathogenic bacteria, polluted waters and poor packaging negated the advantage. However, with the advent of ethylene oxide and gamma irradiation sterilization techniques, interest in laminaria dilators returned.

L. bracteata Ag. ( L. japonica Aresch) is commonly used in soup, candy, and sushi, or is eaten with rice or as a salad. The plant is known as kombu in the Far East and is cultivated in China, Korea, and Japan. 3

Chemistry

Laminarin (laminaran) is a polysaccharide found in laminaria sap. Soluble and insoluble forms are found in algae. 4 , 5 Kelp are rich in algin, a high molecular weight polysaccharide that forms viscous colloidal solutions or gels in water. This property has led to the use of kelp derivatives as bulk laxatives. 6 The constituents of laminaria also include iodine, potassium, magnesium, calcium, and iron. 7 , 8 , 9

Laminaria Uses and Pharmacology

Cervical ripening

Laminaria dilators have been used to dilate the cervix and to induce labor in abortions. When inserted into the cervix, laminaria dilators absorb surrounding moisture and gradually swell to a diameter of approximately one-half inch. While most of the swelling occurs in the first 4 to 6 hours, it may continue for up to 24 hours. Because this is a gradual process, the patient rarely notices pain. At the same time, the cervix is induced to ripening (becoming soft and flexible). The effect is often limited to local cervical ripening; however, stimulation of the cervix can induce labor.

The mechanism of action may be similar to that of a foreign body that, when inserted into the cervical canal, disturbs the normal chorioamniotic balance and initiates a cascade of prostaglandin synthesis. This in turn has myometrial-contracting and cervical-ripening effects. 10 Mediation by arachidonic acid has been suggested, but is not supported by evidence. 11 Cervical dilation may also be the result of partial placental detachment induced by laminaria. 12

Clinical data

A Cochrane review of mechanical methods of labor induction considered trials of laminaria versus placebo, prostaglandins, oxytocin, or extra-amniotic infusion. Most trials were small and evaluated different outcomes, making comparisons difficult. Thus, the review used risk of cesarian delivery as the comparator outcome measure. The lack of blinding in these trials must also be considered a potential source of bias. 13

In trials of laminaria versus placebo, no evidence exists of increased risk of cesarian delivery. Rates of cesarian delivery were the same for laminaria versus oxytocin and for laminaria versus extra-amniotic infusion. Likewise, in trials versus prostaglandins, the risk of cesarian delivery was the same for both groups; however, laminaria caused less hyperstimulation with fetal heart rate changes. No added benefit was found in trials of laminaria added to prostaglandins or to oxytocin. 13

Trials subsequent to the Cochrane review, which included trials up to 2001, have largely found similar results. 14 More recent trials have evaluated laminaria versus misoprostol and mifepristone, finding similar efficacy, but showing an increase in cost, induction times, and pain associated with laminaria. 15 , 16 , 17 , 18 The lack of blinding remains a methodological issue.

The potential exists for adverse outcomes with laminaria dilator use, especially infectious morbidity; endometritis, fetal sepsis, septic shock, and anaphylaxis have been reported. 10 , 19 , 20 , 21 A review of laminaria in cervical ripening found no difference in maternal infection rates for trials reporting infection-related outcomes, but the number of trials was small. 22 A further review concluded that serious infection and anaphylaxis were rare with commercial laminaria devices. 23 In a review of trials using laminaria in mid-trimester abortions, no increased risk of clinically important subsequent pregnancy complications was found. 24

Other uses

Sulfated polysaccharides from marine Laminaria cichoroides exert anticoagulant activity similar to that of heparin, but clinical relevance is unclear. 25 , 26

The basal parts of the blades of L. japonica and L. angustata have been used as a hypotensive agent (ne-kombu) in Japanese folk medicine. 27 Chemical analysis of the blades suggests that histamine and the amino acid laminine may be responsible for this hypotensive effect. 28 , 29

Alginate-containing algae reduce the absorption of radioactive strontium in animals and humans and are used in the management of radioactive intoxications. 30

Dosage

Clinical trials are lacking to provide dosing information for uses other than mechanical cervical dilation.

Pregnancy/Lactation

Laminaria dilators have been used to dilate the cervix and to induce labor in abortions. Information on the use of laminaria for other purposes during pregnancy is lacking. Avoid use.

Interactions

None well documented. Anticoagulant activity has been observed in vitro with sulfated polysaccharides from marine L. cichoroides . 25 , 26 The iodine content of kombu ( L. japonica ) may affect measurement of serum thyrotropin levels. 27

Adverse Reactions

There is a risk of laminaria dilators becoming trapped and fragmenting. 23 , 31 Synthetic laminaria dilators prepared from hydrophilic polymers provide increased levels of structural stability. 32

Increases in serum thyrotropin were observed in healthy volunteers who consumed kombu 15 g daily for 7 to 10 days. Long-term ingestion (55 to 87 days) led to abnormally elevated serum thyrotropin levels, but these returned to normal on discontinuation of consumption. The effect was attributed to the iodine content of the seaweed. Reports of hypothyroidism exist among Japanese populations, but causality has not been established. 27

Bibliography

1. Morton JF. Major Medicinal Plants: Botany, Culture, and Uses . Springfield, IL: Thomas; 1977.

2. Newton BW. Laminaria tent: relic of the past or modern medical device? Am J Obstet Gynecol . 1972;113(4):442-448.

3. Johansen HW, Akioka H. Salad from the sea. Sea Front . 1988;34:136.

4. Windholz M, Budavari S, Blumetti RF, Otterbein ES, eds. The Merck Index; An Encyclopedia of Chemicals, Drugs, and Biologicals . 10th ed. Rahway, NJ: Merck & Co; 1983.

5. Zvyagintseva TN, Shevchenko NM, Chizhou AO, Krupnova TN, Sundukova EV, Isakov VV. Water-soluble polysaccharides of some far-eastern brown seaweeds. Distribution, structure, and their dependence on the development conditions. J Exp Mar Biol Ecol . 2003;294(1):1-13.

6. Tyler VE. The New Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies . Philadelphia, PA: GF Stickley Co; 1987.

7. The Drug & Natural Medicine Advisor: The Complete Guide to Alternative & Conventional Medications . Alexandria, VA: Time-Life Books; 1997.

8. Lininger SW, Wright JV, eds. The Natural Pharmacy . Rocklin, CA: Prima Publishing; 1998.

9. van Netten C, Hoption Cann SA, Morley DR, van Netten JP. Elemental and radioactive analysis of commercially available seaweed. Sci Total Environ . 2000;255(1-3):169-175.

10. Kazzi GM, Bottoms SF, Rosen MG. Efficacy and safety of Laminaria digitata for preinduction ripening of the cervix. Obstet Gynecol . 1982;60(4):440-443.

11. Crawford MA, Casperd NM, Sinclair AJ. The long chain metabolites of linoleic avid linoleic acids in liver and brain in herbivores and carnivores. Comp Biochem Physiol B . 1976;54(3):395-401.

12. Jonasson A, Larsson B, Lecander I, Astedt B. Placental and decidual u-PA, t-PA, PAI-1, and PAI-2 concentrations, as affected by cervical dilatation with laminaria tents or Hegar dilators. Thromb Res . 1989;53(2):91-97.

13. Boulvain M, Kelly A, Lohse C, Stan C, Irion O. Mechanical methods for induction of labour. Cochrane Database Syst Rev . 2001;(4):CD001233.

14. Almog B, Levin I, Winkler N, et al. The contribution of laminaria placement for cervical ripening in second trimester termination of pregnancy induced by intra-amniotic injection of prostaglandin F(2)alpha followed by concentrated oxytocin infusion. Eur J Obstet Gynecol Reprod Biol . 2005;118(1):32-35.

15. Prairie BA, Lauria MR, Kapp N, Mackenzie T, Baker ER, George KE. Mifepristone versus laminaria: a randomized controlled trial of cervical ripening in midtrimester termination. Contraception . 2007;76(5):383-388.

16. Darwish AM, Ahmad AM, Mohammad AM. Cervical priming prior to operative hysteroscopy: a randomized comparison of laminaria versus misoprostol. Hum Reprod . 2004;19(10):2391-2394.

17. Edelman AB, Buckmaster JG, Goetsch MF, Nichols MD, Jensen JT. Cervical preparation using laminaria with adjunctive buccal misoprostol before second-trimester dilation and evacuation procedures: a randomized clinical trial. Am J Obstet Gynecol . 2006;194(2):425-430.

18. Borgatta L, Chen AY, Vragovic O, Stubblefield PG, Magloire CA. A randomized clinical trial of the addition of laminaria to misoprostol and hypertonic saline for second-trimester induction abortion. Contraception . 2005;72(5):358-361.

19. Lin SY, Cheng WF, Su YN, Chen CA, Lee CN. Septic shock after intracervical laminaria insertion. Taiwan J Obstet Gynecol . 2006;45(1):76-78.

20. Kim SH, Chang YH, Kim WK, et al. Two cases of anaphylaxis after laminaria insertion. J Korean Med Sci . 2003;18(6):886-888.

21. Knowles SR, Djordjevic K, Binkley K, Weber EA. Allergic anaphylaxis to Laminaria. Allergy . 2002;57(4):370.

22. Heinemann J, Gillen G, Sanchez-Ramos L, Kaunitz AM. Do mechanical methods of cervical ripening increase infectious morbidity? A systematic review. Am J Obstet Gynecol . 2008;199(2):177-188.

23. Lichtenberg ES. Complications of osmotic dilators. Obstet Gynecol Surv . 2004;59(7):528-536.

24. Jackson JE, Grobman WA, Haney E, Casele H. Mid-trimester dilation and evacuation with laminaria does not increase the risk for severe subsequent pregnancy complications. Int J Gynaecol Obstet . 2007;96(1):12-15.

25. Drozd NN, Tolstenkov AS, Makarov VA, et al. Pharmacodynamic parameters of anticoagulants based on sulfated polysaccharides from marine algae. Bull Exp Biol Med . 2006;142(5):591-593.

26. Yoon SJ, Pyun YR, Hwang JK, Mourao PA. A sulfated fucan from the brown alga Laminaria cichorioides has mainly heparin cofactor II-dependent anticoagulant activity. Carbohydr Res . 2007;342(15):2326-2330.

27. Miyai K, Tokushige T, Kondo M; Iodine Research Group. Suppression of thyroid function during ingestion of seaweed “Kombu” ( Laminaria japonoca ) in normal Japanese adults. Endocr J . 2008;55(6):1103-1108.

28. Funayama S, Hikino H. Hypotensive principle of Laminaria and allied seaweeds. Planta Med . 1981;41(1):29-33.

29. Chiu KW, Fung AY. The cardiovascular effects of green beans ( Phaseolus aureus ), common rue ( Ruta graveolens ), and kelp ( Laminaria japonica ) in rats. Gen Pharmacol . 1997;29(5):859-862.

30. Gong YF, Huang ZJ, Qiang MY, et al. Suppression of radioactive strontium absorption by sodium alginate in animals and human subjects. Biomed Environ Sci . 1991;4(3):273-282.

31. Borgatta L, Barad D. Prolonged retention of laminaria fragments: an unusual complication of laminaria usage. Obstet Gynecol . 1991;78(5 pt 2):988-990.

32. Chvapil M, Droegemueller W, Meyer T, Macsalka R, Stoy V, Suciu T. New synthetic laminaria. Obstet Gynecol . 1982;60(6):729-733.

Laminaria digitata

is a large, tough, glossy kelp, which can grow from 1 to 3 meters in size, and up to 4 meters in optimum conditions. Its color ranges from dark brown to golden brown to olive brown to olive green. The broad frond or blade is large, lacks a midrib, and is shaped like the palm of a hand with a number of more or less regular finger-like segments (hence the Latin name for this seaweed). The number of frond digits extend almost to the base of the frond, and vary with amount of exposure. In shelter these are few and short, but with increasing exposure, they are more numerous (up to 10 or 12). The length of the frond varies with season, age of plant and location, and can reach lengths of 1 to 1.5 meters in suitable conditions. The smooth and flexible stipe (stem, or stalk) is oval in cross-section, can be 3 to 4 centimeters in diameter, smooth, flexible, non-sticky, and is usually free of epiphytes, although old stipes which have become slightly roughened may support a few epiphytes, particularly Palmaria palmata. Laminaria digitata attaches to anchor stones and rocky substrates by freely branched haptera, which spread out to form a shallow dome-shaped, claw-like holdfast. The spreading root-like protrusions are called rhizoids.

This perennial species lives for 3 to 6 years, and in some cases reached 10 years. Laminaria digitata grows more slowly from late summer to January, and then experiences rapid growth from February through July. It is one of the more deeper growing edible seaweeds, and may only accessible a few days out of every month on the lowest new and full moon tides. Laminaria digitata is found in rock pools and attached to rocks, bedrock or other suitable hard substrata in the lower intertidal and subtidal or sublittoral fringe, down to a maximum depth of 20 meters in clear waters. It can be found higher up on the shore in areas of intense wave action. Laminaria digitata clings to the rocks as the full force of the ocean flows through its fingers in heavy waves, swells, and surf, and flourishes in moderately exposed areas or at sites with strong water currents. With its flexible stipe and deeply divided blade, it is well adapted to fast, turbulent water flow and multidirectional forces. In the upper sublittoral, Laminaria digitata grows in masses and forms extended uniform kelp beds or meadows. When it does become occasionally exposed at extreme low tide, it lies flat on the seabed with the uppermost blades covering the lower ones, protecting them against desiccation from wind and sun. The extension of Laminaria digitata beds into greater depths of the mid-sublittoral zone is restricted by the occurrence of Laminaria hyperborea, thus Laminaria digitata can often be found as a belt above Laminaria hyperborea. Its distribution is also limited by salinity, wave exposure, temperature, desiccation and general stress. Laminaria digitata may be confused with young Laminaria hyperborea plants. Laminaria digitata is darker, its stipe is oval in cross-section and is very flexible, whereas Laminaria hyperborea is lighter in color, and its stipe is circular, longer, and thicker.

Names

an choirleach, anguillier, Atlantic kombu, bezhin bleuñv, bezhin siliou, bezhin sklej, bezhin stonn, bezhin warle, Braggair, cholgorn, coirleach, coirrleach, common kelp, cupóga, feamannach dubh, fingered tangle, Fingertang, Fingertäng, Fingertare, foetoù-traezh, fouet de sorcière, gladgesteeld, vingerwier, goazle, goémon de coupe, grac'hle, gwaskle, gwrac’hle, horsetail kelp, kaol, kaolenn, kelp, kombu, Kombu Breton, konbu, korle, laminaire digitée, laminaire flexible, learach, leath, leathach fada, leathrach, liadhaig, melkern, oarweed, oarweed kelp, ouarle, red ware, red wrack, salkorn, sea girdle, sea girdles, sea tangle, sea wand, sea-girdles, silketare, taangel, tali, tali du, tali gwrac'hle, tali laezh, tali moan, tali warle, taly, tangle, Thöngull, vingerwier, warle

Geographic Distribution

Laminaria digitata is a North Atlantic Arctic-cold-temperate species which does not occur in the North Pacific. It is found along both coasts of the English Channel; the southernmost occurrence of this species in European waters is on the southern coasts of Brittany. Laminaria digitata grows along most coasts of Britain and Ireland, and along the North Sea coasts of Scandinavia. Its northerly range includes into the Barents Sea and the western shores of Novaya Zemlya, and has been reported to occur in the Svarlbard Archipelago. Laminaria digitata also grows in Iceland, the Faeroes, southern Greenland and the eastern coasts of North America, as far south as Cape Cod.

Uses

Laminaria digitata plants contain minerals, vitamins and trace elements. These include iodine, calcium, potassium, iron, carotene, alginic acid, laminaran, mannitol, protein, carotene, niacin, phosphorus, the B complex vitamins, vitamin C and many other trace elements. This species stores flavor-enhancing glutamic acid, or sodium glutamate, which imparts a mellow, silky taste to dishes. The slight sweet background is mannitol, a natural sugar. In terms of relatives, Laminaria digitata is closely related to the five species (Saccharina latissima, Saccharina japonica, Saccharina angustata, Laminaria longissima and Laminaria ochotensis) typically harvested as 'kombu' in Japan, and is frequently harvested and sold as kombu in North America. Many recipes calling for kombu could be made with this form of kelp.

Laminaria digitata, both harvested and collected from the shore, was traditionally used as an agricultural fertilizer. In the 18th century it was burned to extract the potash it contained for use in the glass industry. In the 19th and 20th centuries it was used for the extraction of iodine. It is still used as an organic fertiliser but more recently Laminaria digitata is commercially harvested in Brittany for alginate production. Its use is expanding to thalassotherapy and balneotherapy and other specialty products. The extraction of alginic acid contributes to applications such as the manufacture of toothpastes and cosmetics, and in the food industry for binding, thickening and moulding. With increased demand, harvesting became mechanised in order to be effective. In Europe, the other kelp species exploited by the hydrocolloid industry is Laminaria hyperborea. They are also utilised by the cosmetic and agrochemical industries and for biotechnological applications. Laminaria digitata is imported in Japan and China for making dashi, a soup stock, and for other culinary purposes, such as accelerating the cooking time of vegetables such as beans and lentils.

Over 40 companies from the UK, Ireland, Iceland, France, Italy, Germany, United States, Canada, and Australia are selling more than 100 different products which include Laminaria digitata as an ingredient. Some examples are listed below./p>

Personal care products:

• body wraps, cleansing muds, and bath soak products

• facial masks and toners, body scrubs and soaps

• shampoos and conditioners

• makeup removers, and cleansing milks, gels, and creams

• body lotions, shaving lotion, and indoor tanning lotion

• eye contour serum, rejeuvenating eye cream, day creams, night creams, hand creams, and repair creams

• slenderizing gels and anti-cellulite drainage serums and treatments

• skin rejeuvenators, hydrators, and moisturizers, including collagen stimulators for increasing skin elasticity and firming which helps diminish fine lines and wrinkles over time

• Laminaria digitata is known to revitalize tired looking skin and is an effective anti-oxidant helping repair damage caused by free radicals and improving dull complexions

Food and nutrition products:

• as a sea vegetable: snacks, soup mixes, flavoring and seasoning; slaw

• flakes, powder, and whole

• nutritional supplements and energy drinks

• agricultural and gardening fertilizers, and animal feeds

• alginic acid for the hydrocolloid industry

• biodegradable surface cleaners for use in home, garden, and commercial and industrial settings

Harvesting

Large scale, mechanical harvesting of Laminaria digitata takes place in Brittany, France and Iceland. Smaller scale harvesting by hand takes place in Ireland, the UK, Canada, and the United States.

France has a long history of seaweed harvesting. Kelps were traditionally harvested by hand and transported from the shore by horses. Today, there are certain ports along the coast of Brittany where the boats land their harvest. In the ports the raw material is loaded onto trucks. Each loaded truck has to drive over a balance to register the weight of the biomass harvested by the particular boats, before transporting the raw material to the processing companies. The prices for the Laminaria digitata are negotiated by the fishermen and the industry before the start of the harvesting season and are valid throughout the season. Prices are adjusted for each boat at the dockside to take into account the actual quality in terms of purity of the crop (for example, the proportion of Saccharina polyschides within the Laminaria digitata harvest, and the amount of stones pulled up with the crop). In France, about 60,000 tonnes of Laminaria digitata are harvested annually, primarily in Brittany, for the French hydrocolloid industry. Laminaria digitata was previously an important source for the Norwegian alginate industry. This was harvested in Norway by hand from the lower eulittoral, but with the advent of mechanical harvesting of Laminaria hyperborea and Ascophyllum nodosum, the use of Laminaria digitata has essentially ceased there.

Because kelp species are long-lived and are of major importance as constituents of the benthic lower intertidal and subtidal ecosystems, specific management schemes have been developed to ensure sustainable harvesting. In France, seaweed harvesting is regulated by the French Government and the National Syndicate of Marine Algae, which is a group drawn from the kelp industry (comprised of two companies), fishermen and scientific advisers. Several dozen boats are licensed for harvesting of Laminaria digitata. Landings of raw material per boat are restricted to 1,000 to 1,500 tons per year, and harvesting quotas are bound to the harvesting vessel. Only a portion of the biomass of a kelp forest is harvested. Regulations of harvesting times are imposed to make allowance for growth, reproduction and regeneration of kelp beds. These measures are thought to be sufficient to ensure sustainable harvesting. Thus, because of a relatively short regeneration time, there are no official regulations on fallow periods. Only in certain areas supporting only a small number of fishing boats, fishermen have introduced fallow periods in self-management.

Harvesting Techniques

In Iceland, the company Thorverk mechanically harvests Laminaria digitata in late autumn and winter by a coaster equipped with a dredge. In Brittany, a specialised mechanical kelp harvesting device mounted on small boats called a "scoubidou" is used. This was a further development of a tool used in the 1950s. The scoubidou is a 2 to 4 meter long steel bar with a spiral curved iron hook or sickle at the end which is suspended from a hydraulic arm mounted on the boat. This is lowered into the thickest part of the Laminaria digitata forests and then rotated or twisted, gathering up the stipes like twisting spaghetti on a fork. The hook is then winched inboard using the hydraulic arm, and whole plants of Laminaria digitata are ripped from the substratum, including blades, stipes and some holdfasts. The scoubidou can pull up about 10 kg per extraction, which takes about 30 seconds. By employing the scoubidou method, kelp plants smaller than 60 centimeters (plants younger than 2 years) are thought to be too small to be caught by the hook and remain to develop into the crop for the following year. Using this method harvests averaged 1.5 to 2 tons wet weight per boat per day. The scoubidou is operated from an 8 to 12 meter long boat manned by one or two harvesters and have a loading capacity of 10 to 20 tons raw material. The larger boats can carry two scoubidous. The scoubidou boats operate in the Laminaria digitata beds from May to October, and during the winter are used to collect scallops. Depending on the size of the boat and the equipment (one or two scoubidous), the boats are allowed to land between 12 to 18 tons of Laminaria digitata per day and 1,000 to 1,500 tons per year.

Manual harvesting is sometimes done with a small boat at low tide, and may involve stepping out of the boat in a wetsuit to cut the Laminaria digitata with a knife. In certain locations with higher tidal range, it may be possible to harvest it without a boat. Regardless of method, juvenile plants should remain uncut.