- Bay laurel's symbolism decorates many pages of Roman and Greek mythologies. Many version of the Bay Laurel legend are profusely colored with name-dropping of Apollo, Cupid, Daphne,
Laurel wreath: Bay laurel was used to fashion the laurel wreath of ancient Greece, a symbol of highest status. A wreath of bay laurel was used as the prize at the Pythian Games in honor of Apollo.
- Pythia the priestess of Apollo was reputed to chew laurel leaves from a sacred tree to induce a trance from which she uttered oracular prophecies.
- In Roman culture, the laurel was a symbol of victory and immortality.
- In the language of achievement, it provided roots to words like baccalaureate and poet laureate, along with expressions like "assuming the laurel"and resting on one's laurels."
Laurus nobilis is an evergreen shrub or small tree, variable in size, growing 7 to 18 meters high. Leaves are glabrous, 6 to 12 centimeters long and 2 to 4 centimeters wide, with entire margins, some with undulate. Flowers are dioecious. Each flower is pale yellow-green, about 1 centimeters in diameter, born in pairs beside a leaf. Fruit is a small, shiny berry-like drupe, about 1 centimeter long and containing one seed. (7)
- GC and GC-MS study of leaves for essential oil yielded29 compounds representing 99.18% of total oil. The three main components were 1,8-cineole (68.82%), 1-(S)-α-pinene (6.94%) and R-(+)-limonene (3.04%). (see study below) (2)
- GC and GC-MS study of leaves collected in Southern Italy for essential oil
identified 55 compounds, accounting for 91.6% of total EO. Main components were 1-8-cineole (31.9%), sabinene 12.2%), and linalool (102%). (see study below) (4)
- Phytochemical screening of leaves yielded: (water extract) tannins+++, alkaloids_, saponins++; (ethanol) anthracenosides+, flavonoids+++;
(ether diethylique) alkaloids+, volatile oil++; (petroleum ether) sterols and steroids+. free quinones++. (10)
- Semipreparative HPLC from laurel leaf infusion isolated 10 flavonoid O-glycosides, one flavonoid C- glycoside, catechin, and cinnamtannin B1. (see study below)
- Whole bay leaves have a shelf-life of abut a year, under normal temperature and humidity.
- Considered carminative, stomachic.
- Studies have suggested antioxidant,, antimicrobial, anti-inflammatory, anticancer, antidiabetic, antidyslipidemic, alpha-glucosidase inhibitory properties.
Edibility / Culinary
- A source of a spice used in a wide variety of recipes.
- Whole bay leaves used as flavoring agent in food preparation. Aromatic leaves are a popular spice of pasta sauces. (7)
- Ground bay leaves used for soups, stews, and stocks; used as additive to a Bloody Mary. Dried berries and pressed leaf oil used as spices. (7)
- Dried leaves used for brewing herbal tea.
- Essential oils used in the flavoring industry.
- In Iranian folk medicine, leaves used to treat epilepsy, neuralgia and Parkinsonism. (4)
- Leaves used to treat stomach bloating and flaturlence.
- Used as salve for open wounds.
- Used to treat muscle and joint pains.
- Poultice of boiled bay leaves used as remedy for rashes of poison ivy, poison oak, and stinging nettle.
- Leaf oil used in preparation of anti dandruff lotion; oil used externally for treatment of psoriasis.
- Wood as flavoring: Wood burned for strong smoke flavoring. (7)
- Ornamental: Cultivated as an ornamental plant.
- Aromatherapy: Used in massage therapy and aromatherapy.
- Oil: Fruit essential oil used in soap making.
- Repellent: Aromatic leaves can be used as insect repellent. (8)
• Antidiabetic / Antioxidant / α-Glucosidase Inhibition / Essential Oil / Leaves: Study of essential oil yielded 29 compounds, with three main constituents consisting of 1,8-cineole (68.82%), 1-(S)-α-pinene (6.94%) and R-(+)-limonene (3.04%). On antioxidant evaluation using DPPH, hydroxyl, superoxide radicals, H2O2 scavenging assays, the EO exhibited greater activities than the positive control and three main components when tested independently. On a-glucosidase inhibition assay to evaluated for in-vitro antidiabetic activity, laurel essential oil and 1,8-cineole inhibited α-glucosidase competitively while (S)-α-pinene and R-(+)-limonene were uncompetitive inhibitors. Results suggest potential for treatment of diabetes by scavenging reactive oxygen species and inhibiting α-glucosidase. (see constituents above) (2)
• Antimicrobial / Cytotoxicity / Possible CNS Effects / Essential Oil of Leaves: Study of leaves for essential oil
identified 55 compounds, accounting for 91.6% of total EO. Main components were 1-8-cineole (31.9%), sabinene 12.2%), and linalool (102%). Tested against Gram-positive (S. aureus, B. cereus) and gram-negative (E. coli, P. aeruginosa) bacteria, the EO showed significant antimicrobial activity against all microorganisms tested. The EO and various components also exhibited activity against A. niger, A. versicolor, P. citrinum and P. expansum. IC50s against human neuroblastoma cell line (SH-SY5Y) were ≥400 µg/mL indicating substances were non-cytotoxic. Study investigated the influence of EO and its components on ADCY1 expression. Treatment reduced ADCY! expression in SHSY5Y cells and intracellular production of cAMP. The EO effect may be due to the presence of linalool (10.2%). Study has shown linalool possesses dose-dependent sedative effects in the CNS. (4)
• Antibacterial / Toxicity / Toxicity / Oxidative Stress Effects: Study evaluated the antimicrobial activist and toxicity on Swiss albino mice. Plasmatic markers and enzymes were assessed and histological alterations were evaluated. Study also investigated the effect of the spice on metabolic markers, stress biomarkers and clinical parameters. The study confirmed the antibacterial effect and the toxicity of laurel at 0.3 mg/g, which induced inflammation in the liver, oxidative stress and cell necrosis in the heart. Results suggest the use of L. nobilis as spice should not exceed 0.003 mg/g as not negative effects were observed at this amount. (5)
• Cytotoxic / No Genotoxic Potential: Study evaluated the genotoxic potential of an aqueous extract of leaves using the Allium cepa assay and mouse peripheral blood cell micronucleus test. Results showed no genotoxicity, but cytotoxic activity was observed in two experimental models used. The extract exhibited an antiproliferative effect, suggested by reduction of mitotic index and the polychromatic/ normochromatic erythrocyte (PCE/NCE) ratio. Tests also showed large number of cells undergoing apoptosis with nuclear abnormalities related to cell death processes. Results may be attributed to phenolic compounds, saponins, flavonoids, and alkaloids in the extract. Results suggest L. nobilis used by the general population does not have genotoxic potential. and contains components with apoptotic and antigenotoxic potential. (6)
• Anti-Inflammatory / Leaves: Study evaluated the anti-inflammatory of bay leaf. Studies have previously documented its ability to inhibit protein denaturation. The anti-inflammatory effect was comparable to reference analgesics and non-steroidal anti-inflammatory drugs. (9)
• Herb-Drug Interactions: Major interaction: (1) Narcotic drugs- sweet bay may decrease how fast the body gets rid of pain medications, thereby potentially increasing effects and side effects; for ex: demerol, morphine, hydrocodone, etc; (2) Sedatives/CNS depressants: Sweet bay may cause sleepiness and drowsiness, and taking it with sedating medications may cause too much sleepiness; for ex: Klonopin, Ativan, Ambien, etc. (11)
• Antioxidant / Antimicrobial / Essential Oil / Leaves: Study evaluated leaf essential oils for antioxidant and antimicrobial activity obtained by hydrodistillation and SFME (solvent-free microwave extraction). The EO exhibited antimicrobial activity against S. aureus, E. coli, S. typhimurium. Antioxidant activity was assessed various assays. Strongest antioxidant activity against DPPH radical was found in EO obtained by SFME at 100% power level. Antioxidant activity obtained by HD showed greatest TEAC value which indicated strongest antioxidant activity. (13)
• Cytotoxic Effect Against Different Cancer Cell Lines: Study evaluated the effect of L. nobilis on three different cancer cell lines. Cell viability and proliferation were assessed against different concentrations of a hexane extract and showed remarkable inhibition of AMN (mouse mammary adenocarcinoma), REF (rat embryo fibroblast) and HeLa (cervical human carcinoma cell line in a dose dependent manner. (14)
• Effect of Post Harvest Storage on Oil Constituents: Study evaluated the best ways to store essential oil. The EO was analyzed by GC/MS every four months for one year. Fresh EO yielded approximately 56.83% 1,8-cineole, 13.47% α-terpenyl acetate, 4.96% trans-beta-terpineol, and 3.19 terpinen-4-ol, 4.09% α-pinene, and 6.94% sabinene. Changes in EO content depended on storage conditions. Largest change in EO constituents of the dry herb was observed after storage of one year., with less change after four months of storage. Oil compounds were more stable during the first eight months of herb storage. (15)
• Antidiabetic Effect / Leaves / Trial: Study evaluated the preventive or alleviative effect of bay leaves on 65 patients with type 2 diabetes, 50 given capsules containing 2 g of bay leaves per day for 30 days and 15 given placebo capsules. All patients who consumed bay leaves reduced plasma glucose with significant decreases of 30% after 30 days. Lipid profile showed decreases in TC, LDL, and triglycerides, with increase in HDL. No change was seen in the placebo group. Results suggest potential for decreasing risk factors for diabetes and cardiovascular diseases, and benefits for T2DM. (16)
• Quality Control Study / Bay Leaf Substitutes: Bay leaf is a name applied to several species of aromatic plants. True "bay leaf," also known as "bay laurel," is from Laurus nobilis. In herbal commerce, bay leaf may refer to other species viz., Cinnamomum tamala, Litsea glaucescens, Pimenta racemosa, Syzygium polyanthum, and Umbellularia californica, often substituted or mistaken for true bay leaf because of similarity in leaf morphology, aroma, and flavor. Some of these substitutes can cause potential health problems. Correct identification is important. The study provides a detailed comparative study. (List of plants substituted or confused with bay leaves) (17)
• Wound Healing: Study evaluated aqueous extracts of Allamanda cathartica and Laurus nobilis for wound healing activity using excision and incision wound models in Sprague Dawley rats. Wile A. cathartica showed better wound healing, in Laurus nobilis treated animals, the rate of wound contraction, weight of granulation tissue and hydroxyproline content were moderately high (p<0.05). Histological study of granulation tissue showed larger number of inflammatory cells and lesser collagen than Allamanda but better than the control group of animals. (18)
• Sesquiterpene Lactones / Leaves and Fruits: The plant fruit and leaves contain more than 30 sesquiterpene lactones (SL), including eudesmanolides, germacranolides, guaianolides. Sesquiterpene lactones possess antimicrobial, anti-diabetic, anti-inflammatory, hepatoprotective, neuroprotective and cytotoxic activities. SL inhibit the absorption of alcohol, increases activity of hepatic glutathione-S-transferase. These SL are an important source of raw materials for creation of new medicines. (20)
• Antiviral / Anti-SARS-CoV / Essential Oils: Study evaluated the chemical composition of essential oils of seven plants viz., Laurus nobilis, J. oxycedrus, T. orientalis, C. sempervirens, P. palaestina, S. officinalis, and S. thymbra. The oils were evaluated for their inhibitory activity against SARS-CoV and HSV-1 replication in vitro by visual scoring of the virus-induced cytopathogenic effect post-infection. Laurus nobilis exhibited interesting activity against SARS-CoV with IC50 of 120 µg/ml and a selectivity index (SI) of 4.16. The oil was characterized by the presence of ß-ocimene, 1,8-cineole, α-pinene, and ß-pinene as main constituents. (21)
• Insecticidal / Essential Oil: Study evaluated the insecticidal activity of bay leaf oil fractions, and isolated compounds against stored grain pest of wheat i.e., Tribolium castaneum. Extensive column chromatography of polar fraction yielded eugenol and 7,7 dimethyl-3--methylene bicyclo[2.2.1]heptan-4-ol. Results showed the EO may have potential to control grain pest, T. castaneum. Adults were more susceptible to eugenol. (22)
- Herbal products, leaf extracts essential oils in the cybermarket.