Herb of the month: Rosmarinus officinalis
Rosmarinus officinalis (Rosemary) is an evergreen shrub from the Laminacae family of plants. It has a pungent aroma with dark green elongated leaves and white or purple flowers. Rosemary is a well-known culinary herb from the Mediterranean region and has been used as both a food seasoning, preservative and medicinal herb for thousands of years.
Historical uses:
Rosemary has a long history of use as both a culinary and medicinal herb and as a symbol of remembrance. It has been found in the tombs of the pharaohs in Ancient Egypt where it is thought it was used to embalm the dead and honour their memory. The Greeks and Romans scholars used the herb to enhance their memory and placed the herb under their pillows to prevent nightmares. The beneficial effects of rosemary on the brain, liver, heart and eyes were recognised by many of the ancient healers including the Greek physician Dioscorides. In the France during medieval times, rosemary was burned to purify the air in hospitals and used as incense in religious ceremonies.
Fun Fact: The name Rosmarinus derives from the Latin term that translates to ‘dew of the sea’. It is often found growing naturally along cliffs surrounding the Mediterranean Sea.
Part Used:
- Aerial parts (Dry leaves, branches and flowers)
Major Chemical Constituents:
Essential oil (cineole, alpha-pinene, camphor) phenolic diterpenes (carnosol, carnosic acid), rosmarinic acids, flavonoids, triterpenoids.
Therapeutic actions:
Anti-inflammatory, antioxidant, antimicrobial, circulatory stimulant, enhance memory and cognitive function, hepatoprotective.
Clinical Uses:
Rosemary is versatile in its usage and can be either ingested orally as an herbal extract or tea, and the essential oil applied topically or inhaled via aromatherapy.
Memory and cognitive function: True to its historical reference as a memory tonic, rosemary has been studied for benefits in improving cognitive function and memory. Small scale human studies have demonstrated inhalation of rosemary essential oil had a positive effect on cognitive performance and mood (Moss & Oliver, 2012). A 2018 clinical trial of university students taking rosemary 500 mg orally twice daily for one month, showed improvement in memory by approximately 14% when compared with placebo (Nematolahi et. al, 2018). Research suggests that a possible mechanism for enhanced cognitive function is due to rosemary’s action on preventing the breakdown of acetylcholine, a neurotransmitter responsible for cognition and memory (de Oliveira et. al, 2019).
Hair growth – Rosemary essential oil is commonly used topically for hair loss conditions including androgenic alopecia and alopecia areata. Although clinical evidence is lacking, preliminary research shows that applying 1ml rosemary essential oil to the scalp twice daily for 6 months is as effective as hair loss medication minoxidil 2% for increasing hair count in patients with androgenic alopecia (Panahi et. al, 2015).
Pain and inflammation: Research is primarily limited to in-vitro and animal studies. A small pilot trial relating showed that a combination of rosemary, oleanolic acid from olive leaf, and rho iso-alpha acids from hops (440mg Meta-050) taken three times daily for 4 weeks, resulted in a significant reduction of pain for arthritis patients (Lukaczer, et. al, 2005).
Reduction of oxidative stress: several in-vitro, in-vivo and animal studies have been conducted regarding the antioxidant properties of the chemical constituents contained in rosemary and their benefits in reducing the impact free radicals and oxidative stress. In rats with induced liver damage, rosemary essential oil was found to decrease ALT and AST enzyme levels, exert free radical scavenging activity and demonstrate hepatoprotective effects (Rašković et. al, 2014).
Cautions/Contraindications:
- Theoretically rosemary has anti-platelets effects. Caution in patients taking antiplatelet and anticoagulant drugs.
- Rosemary contains salicylates – use with caution in salicylate allergy
- Seizure disorders: use with caution due to cineole and camphor content which may potentiate seizures.
- Ingestion of essential oils can be harmful and cause serious side effects. Seek the advice of a qualified naturopath or herbalist prior to supplementation.
References
Bone, K 2007, The Ultimate Herbal Compendium, Phytotherapy Press, Australia
de Oliveira, J. R., Camargo, S. E. A., & de Oliveira, L. D. (2019). Rosmarinus officinalis L. (rosemary) as therapeutic and prophylactic agent. Journal of biomedical science, 26(1), 5. https://doi.org/10.1186/s12929-019-0499-8
Ghasemzadeh Rahbardar, M., & Hosseinzadeh, H. (2020). Therapeutic effects of rosemary (Rosmarinus officinalis L.) and its active constituents on nervous system disorders. Iranian journal of basic medical sciences, 23(9), 1100–1112. https://doi.org/10.22038/ijbms.2020.45269.10541
Lukaczer, D., Darland, G., Tripp, M., Liska, D., Lerman, R. H., Schiltz, B., & Bland, J. S. (2005). A pilot trial evaluating Meta050, a proprietary combination of reduced iso-alpha acids, rosemary extract and oleanolic acid in patients with arthritis and fibromyalgia. Phytotherapy research : PTR, 19(10), 864–869. https://doi.org/10.1002/ptr.1709
Moss, M., & Oliver, L. (2012). Plasma 1,8-cineole correlates with cognitive performance following exposure to rosemary essential oil aroma. Therapeutic advances in psychopharmacology, 2(3), 103–113.https://doi.org/10.1177/2045125312436573
Nematolahi, P., Mehrabani, M., Karami-Mohajeri, S., & Dabaghzadeh, F. (2018). Effects of Rosmarinus officinalis L. on memory performance, anxiety, depression, and sleep quality in university students: A randomized clinical trial. Complementary therapies in clinical practice, 30, 24–28. https://doi.org/10.1016/j.ctcp.2017.11.004
Panahi Y, Taghizadeh M, Marzony T, Sahebkar A. Rosemary oil vs minoxidil 2% for the treatment of androgenic alopecia: a randomized comparative trial. Skinmed. 2015;13(1):15-21.
Rašković, A., Milanović, I., Pavlović, N., Ćebović, T., Vukmirović, S., & Mikov, M. (2014). Antioxidant activity of rosemary (Rosmarinus officinalis L.) essential oil and its hepatoprotective potential. BMC complementary and alternative medicine, 14, 225. https://doi.org/10.1186/1472-6882-14-225
