Laminaria
Scientific Name(s): Laminaria bracteata Ag., Laminaria digitata (L.) Lamour.
Common Name(s): Brown algae, Devil's apron, Kelp, Kombu, Lamicel, Laminaria, Ne-kombu, Sea girdles
Medically reviewed by Drugs.com. Last updated on Jan 19, 2022.
Clinical Overview
Use
Laminaria has been used traditionally as a hygroscopic cervical dilator and inducer of labor, and commercial products are available for this purpose. The basal parts of the blades of Laminaria japonica and Laminaria angustata have been used as a hypotensive agent (ne-kombu) in Japanese folk medicine.
Dosing
Clinical trials are lacking to provide dosing information for uses other than mechanical cervical dilation.
Contraindications
Use is contraindicated during pregnancy.
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.
Adverse Reactions
There is a risk of laminaria dilators becoming trapped and fragmenting. Cases of hypersensitivity, including anaphylaxis, have also been reported.
Toxicology
Information is lacking.
Scientific Family
- Laminariaceae
Botany
Laminaria, a genus of brown algae commonly known as "kelp," is found primarily in the cold waters of the North Atlantic and North Pacific oceans.1
History
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,
