Rosemary
StarRosmarinus officinalis
Western Herbalism Properties
Botanical Description
Rosmarinus officinalis (now often placed in Salvia as S. rosmarinus), rosemary, is a dense, evergreen, aromatic shrub of the mint family, usually 0.5 to 1.5 m tall, with woody, branching stems. The leaves are crowded, narrow, and needle-like, leathery, dark green and glossy above and white-woolly beneath, with inrolled margins, and intensely fragrant from their abundant essential oil. The small two-lipped flowers, pale blue to violet (occasionally pink or white), are clustered in the upper leaf axils and bloom over a long season. The fruit consists of four small smooth nutlets enclosed in the persistent calyx. Native to the dry, rocky scrublands and coasts of the Mediterranean region, rosemary is cultivated worldwide as a culinary herb and ornamental and has a long history of medicinal use.
Active Constituents
Rosmarinic acid
Phenolic acid (caffeic acid ester)Concentration: Leaf ~1-2% dry weight (variable)
A water-soluble caffeic acid ester and one of the principal polyphenols of rosemary leaf. It is a strong free-radical scavenger and contributes to the herb's documented antioxidant and anti-inflammatory activity.
Carnosic acid
Phenolic abietane diterpeneConcentration: Leaf ~1.5-4.6% dry weight (declines on oxidation/storage)
The dominant lipophilic diterpene antioxidant of rosemary. It protects membranes from lipid peroxidation and has been studied for neuroprotective and anti-inflammatory effects; it degrades to carnosol and rosmanol on exposure to heat and oxygen.
Carnosol
Phenolic diterpene (oxidation product of carnosic acid)Concentration: Present in leaf and standardized extracts
An oxidation product of carnosic acid with anti-inflammatory and anticancer activity in preclinical models, acting partly through NF-kB and Nrf2 pathway modulation.
1,8-Cineole (eucalyptol)
Monoterpene oxideConcentration: Essential oil ~15-55% depending on chemotype
A major volatile constituent of rosemary essential oil, contributing the camphoraceous aroma. It has mucolytic and antimicrobial properties and is one of the volatiles implicated in the cognition effects of inhaled rosemary oil.
Camphor
Bicyclic monoterpene ketoneConcentration: Essential oil ~5-25% (chemotype-dependent)
A stimulant, rubefacient volatile. It contributes to the warming topical effect of rosemary oil but is neurotoxic in high internal doses, which is why the essential oil is not taken internally in significant amounts.
alpha-Pinene
Bicyclic monoterpeneConcentration: Essential oil ~10-25%
A pine-scented monoterpene with reported bronchodilatory, anti-inflammatory and acetylcholinesterase-inhibiting activity; contributes to the volatile fraction studied for memory effects.
Ursolic acid
Pentacyclic triterpenoidConcentration: Leaf surface waxes (minor)
A triterpenoid found in the leaf cuticle with anti-inflammatory, antimicrobial and skin-conditioning properties; used as a marker of triterpene content.
Caffeic acid
Hydroxycinnamic (phenolic) acidConcentration: Minor free phenolic
A phenolic precursor of rosmarinic acid contributing to the overall antioxidant capacity of aqueous rosemary preparations.
⚠ Drug Interactions
Warfarin and other anticoagulants
In vitro and animal data indicate rosemary can induce CYP1A2 (a warfarin-metabolizing enzyme) and that its constituents inhibit platelet aggregation. Concurrent use could theoretically alter INR or increase bleeding risk, though robust clinical case reports are lacking.
Clinical note: Monitor INR/coagulation if concentrated rosemary extracts are used with warfarin or other anticoagulants; culinary amounts are not a concern.
Antiplatelet drugs (aspirin, clopidogrel)
Rosemary polyphenols inhibit platelet aggregation in laboratory studies, which could be additive with antiplatelet medication.
Clinical note: Clinically significant only at high supplemental doses; advise caution before surgery.
Oral iron salts (non-heme iron)
Rosemary is rich in polyphenols that chelate non-heme iron in the gut lumen, reducing its absorption when consumed together in large amounts.
Clinical note: Separate iron supplements from large quantities of polyphenol-rich rosemary extract or tea by a couple of hours.
Preparation Methods
Infusion (herbal tea)
Parts: Leaves
Steep 1-2 g of dried rosemary leaf in a cup of just-boiled water, covered, for 10-15 minutes. Traditionally taken up to three times daily as a digestive and mild carminative.
Tincture
Parts: Leaves
An alcoholic extract (commonly 1:5 in 45% ethanol) captures both the volatile oil and diterpene fraction; typical traditional dose is 2-4 mL up to three times daily.
Essential oil (steam distilled)
Parts: Leaves, Flowering tops
Used diluted in a carrier oil (1-3%) as a rubefacient for muscle and joint aches, or diffused/inhaled in aromatherapy for concentration. Warning: the essential oil is for external or inhalation use only. Because of its camphor and 1,8-cineole content it should not be ingested, and concentrated oil should be avoided in pregnancy and in people with epilepsy or seizure disorders.
Culinary use / standardized antioxidant extract
Parts: Leaves
Fresh or dried leaves are used as a culinary herb; carnosic-acid-standardized rosemary extract (E392) is also used as a food antioxidant. Culinary quantities are recognized as safe.
Clinical Studies
Effects of Rosmarinus officinalis L. on memory performance, anxiety, depression, and sleep quality in university students: A randomized clinical trial
Sixty-eight university students received 500 mg dried rosemary powder or placebo twice daily for one month. The rosemary group showed significantly improved prospective and retrospective memory scores and reduced anxiety and depression scores versus placebo.
Short-term study on the effects of rosemary on cognitive function in an elderly population
In 28 older adults, dried rosemary leaf powder produced a biphasic dose-dependent effect on cognition: the lowest dose (750 mg) significantly improved speed of memory versus placebo, whereas the highest dose (6000 mg) impaired it, indicating a therapeutic window.
Historical Texts
Dioscorides, De Materia Medica
1st century CEBanckes' Herball
1525 (Tudor England)Culpeper, The Complete Herbal
1653References
- de Oliveira JR, Camargo SEA, de Oliveira LD. Rosmarinus officinalis L. (rosemary) as therapeutic and prophylactic agent . Journal of Biomedical Science (2019) [DOI]
- Andrade JM, Faustino C, Garcia C, Ladeiras D, Reis CP, Rijo P. Rosmarinus officinalis L.: an update review of its phytochemistry and biological activity . Future Science OA (2018) [DOI]
- Nematolahi P, Mehrabani M, Karami-Mohajeri S, Dabaghzadeh F. Effects of Rosmarinus officinalis L. on memory performance, anxiety, depression, and sleep quality in university students . Complementary Therapies in Clinical Practice (2018) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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