Laurel

Bay leaf/Drug Interactions:

  • ACE inhibitor drugsACE inhibitor drugs: In in vitro study, an ethanolic extract of Laurus nobilis showed a high ACE inhibition value of 64% (1mg/mL) (54).
  • AlcoholAlcohol: In animal study, several active principles of Laurus nobilis have been found to selectively inhibit ethanol absorption in oral ethanol-loaded rats (55; 56). The sesquiterpene lactone, costunolide, and its active component, alpha-methylene-gamma-butyrolactone (alpha-MGBL), have been found to have inhibitory effects on blood ethanol elevation, based on inhibition of gastric emptying and dilution of the ethanol concentration by the increased gastric fluid (57).
  • AntibioticsAntibiotics: In laboratory study, Laurus nobilis L. essential oil exhibited strong, dose-dependent antibacterial activity against various bacteria, including Staphylococcus aureus, Enterococcus faecalis, Yersinia enterocolitica, Listeria monocytogenes, Chromobacterium violaceum, methicillin-resistant Staphylococcusaureus (MRSA), vancomycin-resistant enterococci (VRE), and Mycobacterium tuberculosis (36; 58; 20; 59; 60; 61; 62; 38). Two kaempferol glycosides isolated from Laurus nobilis (kaempferol-3-O-alpha-L-(2'',4''-di-E-p-coumaroyl)-rhamnoside (C2) and kaempferol-3-O-alpha-L-(2''-E-p-coumaroyl-4''-Z-p-coumaroyl)-rhamnoside (C3)) showed strong antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (35). Synergistic effects have been noted when used with fluoroquinolones, particularly hydrophobic quinolones, norfloxacin, and ciprofloxacin (35).
  • Anticoagulants/antiplateletsAnticoagulants/antiplatelets: Cinnamtannin B-1, a constituent of Laurus nobilis, has been found to inhibit platelet aggregation (25).
  • Antidiabetic agentsAntidiabetic agents: Based on preliminary study, bay leaf (at doses of 1-3g daily) had beneficial effects on clinical parameters, including glucose, in subjects with type 2 diabetes (4). Maintenance reductions were noted in lowering glucose levels, even after therapy was discontinued, suggesting that bay leaf may have a sustaining effect (4). Based on laboratory study, bay leaves have demonstrated a positive effect on insulin activity (63). A low level of protein glycation has also been noted, which may be suggestive of the antidiabetic potential of the extract (64).
  • AntifungalsAntifungals: In laboratory study, the essential oil of Laurus nobilis was found to inhibit the growth of Phytophthora infestans, Ravensara anisata, Saccharomyces cerevisiae, Candida rugosa, and molds (Aspergillus niger and Rhizopus oryzae) in a dose-dependent manner (65; 20; 66).
  • Antilipemic agentsAntilipemic agents: Bay leaves have been found to lower total and LDL cholesterol and triglycerides and increase HDL cholesterol (4). The effects may be due to the polyphenol content (4).
  • Antineoplastic agentsAntineoplastic agents: Laurus nobilis has been found to inhibit human tumor cell growth (67; 23; 33).
  • Antiviral agentsAntiviral agents: Based on laboratory study, the essential oils of Laurus nobilis had inhibitory effects against herpes simplex virus (HSV-1) and SARS-associated coronavirus (SARS-CoV) with an IC50 value of 120mcg/mL and a selectivity index (SI) of 4.16 for SARS-CoV (22).
  • Gastrointestinal agentsGastrointestinal agents: Based on animal and laboratory study, bay leaf was found to have gastroprotective effects against ulcerogenesis (30; 31). The antiulcerogenic activity was found for 20% and 40% aqueous extracts as well as for the oily fraction of these seeds (30).
  • QuinolonesQuinolones: Two kaempferol glycosides isolated from Laurus nobilis (kaempferol-3-O-alpha-L-(2'',4''-di-E-p-coumaroyl)-rhamnoside (C2) and kaempferol-3-O-alpha-L-(2''-E-p-coumaroyl-4''-Z-p-coumaroyl)-rhamnoside (C3)) showed strong antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (35). Synergistic effects have been noted when used with fluoroquinolones, particularly hydrophobic quinolones, norfloxacin, and ciprofloxacin (35).
  • SedativesSedatives: In animal study, Laurus nobilis leaf essential oil produced sedation and motor impairment (19).

    • Bay leaf/Herb/Supplement Interactions:

  • AntibacterialsAntibacterials: In laboratory study, Laurus nobilis L. essential oil exhibited strong, dose-dependent antibacterial activity against various bacteria, including Staphylococcus aureus, Enterococcus faecalis, Yersinia enterocolitica, Listeria monocytogenes, Chromobacterium violaceum, methicillin-resistant Staphylococcusaureus (MRSA), vancomycin-resistant enterococci (VRE), and Mycobacterium tuberculosis (36) (58; 20; 59; 60; 61; 62; 38). Two kaempferol glycosides isolated from Laurus nobilis (kaempferol-3-O-alpha-L-(2'',4''-di-E-p-coumaroyl)-rhamnoside (C2) and kaempferol-3-O-alpha-L-(2''-E-p-coumaroyl-4''-Z-p-coumaroyl)-rhamnoside (C3)) showed strong antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (35). Synergistic effects have been noted when used with fluoroquinolones, particularly hydrophobic quinolones, norfloxacin, and ciprofloxacin (35).
  • Anticoagulants/antiplateletsAnticoagulants/antiplatelets: Cinnamtannin B-1, a constituent of Laurus nobilis, has been found to inhibit platelet aggregation (25).
  • AntifungalsAntifungals: In laboratory study, the essential oil of Laurus nobilis was found to inhibit the growth of Phytophthora infestans, Ravensara anisata, Saccharomyces cerevisiae, Candida rugosa, and molds (Aspergillus niger and Rhizopus oryzae) in a dose-dependent manner (65; 20; 66).
  • AntilipemicsAntilipemics: Bay leaves have been found to lower total and LDL cholesterol and triglycerides and increase HDL cholesterol (4). The effects may be due to the polyphenol content (4).
  • AntineoplasticsAntineoplastics: Laurus nobilis has been found to inhibit human tumor cell growth (67; 23; 33).
  • AntioxidantsAntioxidants: Laurus nobilis has demonstrated strong antioxidant activity in various studies (65; 20; 66; 68; 54; 25; 69; 70; 71; 72).
  • AntiviralsAntivirals: Based on laboratory study, the essential oils of Laurus nobilis have inhibitory effects against herpes simplex virus (HSV-1) and SARS-associated coronavirus (SARS-CoV) with an IC50 value of 120mcg/mL and a selectivity index (SI) of 4.16 for SARS-CoV (22).
  • CorianderCoriander: In laboratory study, a mixture of the essential oils of bay leaf and coriander resulted in stronger antioxidant activity than either herb alone (70).
  • Gastrointestinal agentsGastrointestinal agents: Based on animal and laboratory study, bay leaf was found to have gastroprotective effects against ulcerogenesis (30; 31). The antiulcerogenic activity was found for 20% and 40% aqueous extracts as well as for the oily fraction of these seeds (30).
  • HypoglycemicsHypoglycemics: Based on preliminary study, bay leaf (at doses of 1-3g daily) had beneficial effects on clinical parameters, including glucose, in subjects with type 2 diabetes (4). Maintenance reductions were noted in lowering glucose levels, even after therapy was discontinued, suggesting that bay leaf may have a sustaining effect (4). Based on laboratory study, bay leaves have demonstrated a positive effect on insulin activity (63). A low level of protein glycation has also been noted, which may be suggestive of the antidiabetic potential of the extract (64).
  • Insect repellentsInsect repellents: Laurus nobilis essential oil, particularly the 1,8-cineole constituent, have been found to be active against Culex pipiens with protection up to two hours (34; 73). Laurel leaf has also been found to have insecticidal effects against larvae of Thaumetopoeapityocampa Schiff (moth) (74).
  • SedativesSedatives: In animal study, Laurus nobilis leaf essential oil produced sedation and motor impairment (19).

    • Bay leaf/Food Interactions:

  • AlcoholAlcohol: In animal study, several active principles of Laurus nobilis have been found to selectively inhibit ethanol absorption in oral ethanol-loaded rats (55; 56). The sesquiterpene lactone, costunolide, and its active component, alpha-methylene-gamma-butyrolactone (alpha-MGBL), have been found to have inhibitory effects on blood ethanol elevation, based on inhibition of gastric emptying and dilution of the ethanol concentration by the increased gastric fluid (57).

    • Bay leaf/Lab Interactions:

  • Coagulation panelCoagulation panel: Cinnamtannin B-1, a constituent of Laurus nobilis, has been found to inhibit platelet aggregation (25).
  • Lipid profileLipid profile: In clinical study, 1-3g daily of bay leaves for 30 days reduced total cholesterol, LDL cholesterol, and triglycerides, and increased HDL cholesterol in patients with type 2 diabetes (4)
  • Serum glucoseSerum glucose: In clinical study, 1-3g daily of bay leaves for 30 days reduced fasting serum glucose in patients with type 2 diabetes (4).