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Bay leaf (Laurus nobilis)

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Also listed as: Laurus nobilis, Laurel
Related terms
Background
Evidencetable
Tradition
Dosing
Safety
Interactions
Attribution
Bibliography

Related Terms
  • 1,8-Cineole, alpha-methylene-gamma-butyrolactone moiety, bay laurel, bay tree, costunolide, daphne, dehydrocostus lactone, Grecian laurel, guaianolides, Lauraceae (family), laurel, laurel oil, laurus, Laurus nobilis L., Laurus nobilis var. angustifolia, Laurus azorica, Mediterranean bay, Mediterranean laurel, noble laurel, p-menthane hydroperoxide, reynosin, Roman laurel, santamarine, sclerophyllous shrubs, sesquiterpenes, sweet bay, sweet laurel, true bay, trypanocidal terpenoids, zaluzanin D.
  • Note: Bay leaf (Laurus nobilis) may be confused with California bay leaf (Umbellularia californica), also known as "California laurel" or "Oregon myrtle," or Indian bay leaf (Cinnamoma tamala). California bay leaf (Umbellularia californica), Indian bay leaf (Cinnamoma tamala), cherry laurel (Prunus laurocerasus), and laurel (Ocotea puberula) are not covered in this monograph, which covers bay leaf (Laurus nobilis), as well as the closely related Laurus azorica.

Background
  • Bay leaf has been used since ancient Greece as a symbol of praise or scholarship for heroes and poets. Bay leaf is primarily used to flavor foods, and it is used by chefs of ethnic cuisines, from Italian to Thai. It is also frequently used in salt-free seasonings.
  • Bay leaf is thought to be useful for gastric ulcers, high blood sugar, migraines, and infections. Bay leaves and berries have been used as astringents, to promote sweating and relief of intestinal gas, and to tone and strengthen the stomach. In the Middle Ages, bay leaf was believed to induce abortion. Traditionally, the berries of the bay tree were used to treat boils. The leaf essential oil of Laurus nobilis has been used as an antiepileptic remedy in Iranian traditional medicine.
  • Bay leaf may have beneficial effects on glucose, total cholesterol, LDL cholesterol ("bad cholesterol"), HDL cholesterol ("good cholesterol"), and triglyceride levels in patients with type 2 diabetes.
  • Currently, scientific evidence supporting the use of bay leaf to treat any condition in humans is lacking.

Evidence Table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *


Bay leaf may have beneficial effects on glucose, total cholesterol, LDL cholesterol ("bad cholesterol"), HDL cholesterol ("good cholesterol"), and triglyceride levels in patients with type 2 diabetes. Additional research is needed in this area.

C


Bay leaf may have beneficial effects on glucose, total cholesterol, LDL cholesterol ("bad cholesterol"), HDL cholesterol ("good cholesterol"), and triglyceride levels in patients with type 2 diabetes. Additional research is needed in this area.

C
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)


Tradition / Theory

The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

  • Abortifacient (inducing abortion), alcoholism (damaging effects), amenorrhea (absence of menstruation), analgesic (pain reliever), antibacterial, anticonvulsant, antifungal, anti-inflammatory, antimicrobial, antioxidant, antiseptic, antiviral, appetite stimulant, arthritis, astringent, bile flow stimulant, blood-clotting disorders, breast cancer, bronchitis, cancer, carminative (relieves gas), circulation, CNS stimulant, colic, dandruff, detoxification, diaphoretic (promotes sweating), digestive, diuretic, ear pain, emetic (induces vomiting), emmenagogue (promotes menstruation), epilepsy (seizures), food uses, furuncles (skin boils), galactagogue (promotes flow of breast milk), gastrointestinal disorders, hepatitis, herpes simplex-1 virus, hyperglycemia (high blood sugar levels), hysteria, immune system modulation, influenza, insect repellant (mosquitoes), insecticide, leukemia, methicillin-resistant (MRSA), migraine headaches, narcotic, nightmares, parasite infection, preservative, rheumatism, SARS (severe acute respiratory syndrome), sprains, stimulant, stomach ulcers, tuberculosis, wound healing.

Dosing

Adults (18 years and older)

  • For diabetes, 1-3 grams of bay leaves has been used daily for 30 days.
  • For high cholesterol, 1-3 grams of bay leaves has been used daily for 30 days.

Children (younger than 18 years)

  • There is no proven safe or effective dose for bay leaf in children.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

  • Avoid in patients with known allergy to bay leaf, its constituents, or plants in the Lauraceae or Compositae/Asteraceae families. Contact dermatitis (including airborne contact dermatitis), hand and face eczema, occupational asthma, perioral dermatitis with eczematous stomatitis, and cross-sensitization to Frullania have been reported.

Side Effects and Warnings

  • Overall, bay leaf has very few adverse effects and is likely safe when consumed in amounts normally used in foods.
  • Use caution when whole bay leaves are ingested with food. Leaves may become lodged in the gastrointestinal tract, causing tears or blockages, and they may also block breathing.
  • Use caution in patients using central nervous system (CNS) depressants. Drowsiness or sedation may occur. Use caution if driving or operating heavy machinery.
  • Bay leaf may increase the risk of bleeding. Caution is advised in patients with bleeding disorders or those taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.
  • Bay leaf may lower blood sugar levels. Caution is advised in patients with diabetes or hypoglycemia and in those taking drugs, herbs, or supplements that affect blood sugar. Blood glucose levels may need to be monitored by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.
  • Use cautiously in pregnant or breastfeeding women, as bay leaf was historically used to induce abortions.
  • Avoid in patients with known allergy to bay leaf, its constituents, or plants in the Lauraceae or Compositae/Asteraceae families. Contact dermatitis (including airborne contact dermatitis), hand and face eczema, occupational asthma, perioral dermatitis with eczematous stomatitis, and cross-sensitization to Frullania have been reported.

Pregnancy and Breastfeeding

  • Use cautiously in pregnant or breastfeeding women due to lack of available scientific evidence. Bay leaf has been used historically to induce abortion. In Italian folk medicine, bay leaf has been used to promote the flow of breast milk.

Interactions

Interactions with Drugs

  • Bay leaf may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants (blood thinners) such as warfarin (Coumadin®) or heparin, antiplatelet drugs such as clopidogrel (Plavix®), and nonsteroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).
  • Bay leaf may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. Patients taking insulin or drugs for diabetes by mouth should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.
  • Bay leaf essential oil may have anticonvulsant (anti-epilepsy) effects. Individuals using bay leaf with other medications with anticonvulsant effects should consult with a qualified healthcare professional, including a pharmacist.
  • Use caution in patients taking central nervous system (CNS) depressants. Bay leaf essential oil may increase the amount of drowsiness caused by some drugs. Examples include benzodiazepines such as lorazepam (Ativan®) or diazepam (Valium®), barbiturates such as phenobarbital, narcotics such as codeine, some antidepressants, and alcohol. Caution is advised while driving or operating machinery.
  • Bay leaf may also interact with alcohol, angiotensin-converting-enzyme (ACE) inhibitors, antibiotics, anticancer drugs, antifungals, antivirals, gastrointestinal agents, lipid-lowering drugs, and quinolones, due to possible additive effects with bay leaf.

Interactions with Herbs and Dietary Supplements

  • Bay leaf may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.
  • Bay leaf may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.
  • Bay leaf essential oil may have anticonvulsant (anti-epilepsy) effects. Individuals using bay leaf with other herbs and supplements with anticonvulsant effects should consult with a qualified healthcare professional, including a pharmacist.
  • Bay leaf may increase the amount of drowsiness caused by some herbs or supplements.
  • Bay leaf may also interact with alcohol, antibacterials, anticancer herbs, antifungals, antioxidants, antivirals, coriander, gastrointestinal herbs, insect repellants, and lipid-lowering herbs.

Attribution
  • This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography
  1. Ferreira A, Proenca C, Serralheiro ML, et al. The in vitro screening for acetylcholinesterase inhibition and antioxidant activity of medicinal plants from Portugal. J Ethnopharmacol 2006; 108(1):31-7.
  2. Hibasami H, Yamada Y, Moteki H, et al. Sesquiterpenes (costunolide and zaluzanin D) isolated from laurel (Laurus nobilis L.) induce cell death and morphological change indicative of apoptotic chromatin condensation in leukemia HL-60 cells. Int J Mol Med 2003;12(2):147-151.
  3. Khan A, Zaman G, Anderson RA. Bay leaves improve glucose and lipid profile of people with type 2 diabetes. J Clin Biochem Nutr 2009;44(1):52-56.
  4. Komiya T, Yamada Y, Moteki H, et al. Hot water soluble sesquiterpenes [anhydroperoxy-costunolide and 3-oxoeudesma-1,4(15),11(13)triene-12,6alpha-olide] isolated from laurel (Laurus nobilis L.) induce cell death and morphological change indicative of apoptotic chromatin condensation in leukemia cells. Oncol Rep 2004;11(1):85-88.
  5. Matsuda H, Shimoda H, Uemura T, et al. Preventive effect of sesquiterpenes from bay leaf on blood ethanol elevation in ethanol-loaded rat: structure requirement and suppression of gastric emptying. Bioorg Med Chem Lett 1999;9(18):2647-2652.
  6. Moteki H, Hibasami H, Yamada Y, et al. Specific induction of apoptosis by 1,8-cineole in two human leukemia cell lines, but not a in human stomach cancer cell line. Oncol Rep 2002;9(4):757-760.
  7. Nayak S, Nalabothu P, Sandiford S, et al. Evaluation of wound healing activity of . L. and . L. extracts on rats. BMC Complement Altern Med 2006;6:12.
  8. Sayyah M, Saroukhani G, Peirovi A, et al. Analgesic and anti-inflammatory activity of the leaf essential oil of Laurus nobilis Linn. Phytother Res 2003;17(7):733-736.
  9. Sayyah M, Valizadeh J, Kamalinejad M. Anticonvulsant activity of the leaf essential oil of against pentylenetetrazole- and maximal electroshock-induced seizures. Phytomedicine 2002;9(3):212-216.
  10. Simic A, Sokovic MD, Ristic M, et al. The chemical composition of some Lauraceae essential oils and their antifungal activities. Phytother Res 2004;18(9):713-717.
  11. Simic M, Kundakovic T, Kovacevic N. Preliminary assay on the antioxidative activity of extracts. Fitoterapia 2003;74(6):613-616.
  12. Soylu EM, Soylu S, Kurt S. Antimicrobial activities of the essential oils of various plants against tomato late blight disease agent . Mycopathologia 2006;161(2):119-128.
  13. Tsang TK, Flais MJ, Hsin G. Duodenal obstruction secondary to bay leaf impaction. Ann Intern Med 1999;130(8):701-702.
  14. Uchiyama N, Matsunaga K, Kiuchi F, et al. Trypanocidal terpenoids from L. Chem Pharm Bull (Tokyo) 2002;50(11):1514-1516.
  15. Van der Veen JE, De Graaf C, Van Dis SJ, et al. Determinants of salt use in cooked meals in The Netherlands: attitudes and practices of food preparers. Eur J Clin Nutr 1999;53(5):388-394.

Copyright © 2011 Natural Standard (www.naturalstandard.com)


The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.