Rosemary essential oil: Health benefits and Side effects

Introduction

Rosemary plant (Rosmarinus officinalis L.; Family Lamiaceae) is most popular for its aromatic oil which is called “rosemary oil”. This oil is extracted mainly by steam distillation of the fresh leaves and flower of the plant. It is colorless or pale yellow liquid, with a characteristic flavor and camphoraceous taste. Rosemary essential oil benefits are good for skin, hair, and relief joint pain, anxiety and depression.

Uses of Rosemary essential oil 

Rosemary essential oil widely used as a food preservative, perfumery industry (fragrances, ointments, shampoos, and soaps), Eau-de-cologne, hair tonics, hair lotion, cold cream.

This oil is also used for Arthritis, bruises, eczema, gout, muscular pain, neuralgia, revitalizing paralyzed limbs, rheumatism, rheumatoid arthritis, sciatica, scrofulous sores and wounds

Geographical distribution

Rosemary plant is native to the Mediterranean region but is now cultivated in many parts of the world.

Constituents of Rosemary essential oil

Rosemary essential oil representing 97.97% of the oil in which the major constituents are 1,8-cineole, α-pinene, camphor, camphene, β-pinene and other components as follows (1).

Nutrients Percentage
Monoterpenes 95.10%
Sesquiterpenes 4.77 %
Oxygenated monoterpenes 63.88%
Monoterpene hydrocarbons 31.22%
Sesquiterpene hydrocarbons 4.77%
1,8-cineole 15-55%
Camphor 5-31%
Pinene 2.0- -9.0%
α-pinene 15–26 %
β-pinene 8.16%
Camphene 2.5-12.0%
β-caryophyllene 1.8-5.1%
Verbenone 2.2-11.1%
Limonene 1.5-5.0%
Myrcene 0.9-4.5%

  Health benefits of Rosemary essential oil

1. Prevent oxidative stress

Rosemary essential oil inhalation (5 min) decreases the stress hormone, cortisol level in saliva and increases free radical scavenging activity which protects the body from oxidative stress.

This oil (50 mg/kg) contains a high amount of antioxidants that protect against alloxan-induced male reproductive function damage and oxidative stress by improvement in body weight gain, relative reproductive organ weights, testosterone level, as well as sperm quality decline (2).

2. Rosemary essential oil treats Systemic sclerosis

Systemic sclerosis is a disease that includes tightening of the skin, joint pain, exaggerated response to cold (Raynaud’s disease) in hand and fingers. However, rosemary essential oil (10%) applied to hands for 3 hours over 3 days shows vasodilation and warming effect of the hand (3).

3. Treat nervous system disorder

Inhalation of rosemary oil (10%) increases in blood pressure, heart rate, and respiratory rate. This oil contains 1,8-cineole which shows a wonderful effect on elevation of mood, more vigor, active, fresh and increase brain wave activity (4). Rosemary oil aromatherapy may have some potential for improving cognitive function, especially in Alzheimer’s disease patients (5).

4. Anti-inflammatory properties of Rosemary essential oil

This oil contains (500 mg/kg) terpene compounds, such as 1,8-cineole and myrcene which exhibit anti-inflammatory and analgesic effects. It inhibits the leukocyte migration thus this oil is beneficial to treat inflammation and pain (6,7).

5. Treat liver injury

Studies suggest that rosemary essential oil (5 mg/kg and 10 mg/kg) for 7 days prevents lipid peroxidation and scavenge harmful free radicals. Therefore, this oil show hepatoprotective activities and prevent liver cell damage induced by CCl4 toxicity (8).

6. Healthy hair

Rosemary essential oil (2% or 3 drops, 114 mg) massage into the scalp daily showed improved hair regrowth, increase in hair count at the 6-month thus this oil is safe and effective for the treatment of androgenetic alopecia (baldness) and alopecia areata (patchy hair loss) (9).

7. Reduce pain

Rosemary essential oil (20 mg/kg) in combination with both codeine and paracetamol shows beneficial analgesic effect in the management of pain like musculoskeletal pain renal colic pain and dysmenorrhea) (10). This oil shows a wonderful effect on muscle relaxation and improves local blood circulation and alleviates pain (11).

Moreover, aromatherapy acupressures with rosemary essential oil for 20 minutes in twice-daily for 2 weeks reduce shoulder pain and improve motor power in stroke patients (12).

8. Insecticidal properties of Rosemary essential oil

It contains a good amount of limonene and camphor which show insecticide effect against two-spotted spider mite (Acari: Tetranychidae) (13), mosquitoes  (Aedes aegypti) (14), the primary vector for Lyme disease (Ixodes scapularis) (15) and cabbage looper (Trichoplusia ni) (16).

9. Treat anxiety and Depression

1,8-cineole found in rosemary oil show a wonderful effect on the treatment of depression. Furthermore, rosemary essential oil contains a bioactive compound known as α-pinene which possesses anxiolytic property (17). Thus rosemary essential oil inhalation protects against stress-related psychiatric disorders (18).

10. Healthy skin

Rosemary essential oil containing nanoparticles gel increase skin hydration, heal skin wounds, treat skin disorders, including age-related skin damages (19). Therefore, Rosemary essential oil may helpful for the treatment of cutaneous alterations involving loss of skin hydration and elasticity (20).

11. Manage diabetes

1,8 cineole, -pinene obtained from rosemary essential oil decreased blood glucose level (17%), increase the insulin levels and help in glucose utilization by cells (21).

12. Reduce the risk of atherosclerosis

Rosemary essential oil is rich source of α-pinene, Camphor, cineole, borneol which decrease total cholesterol, triglyceride level and increase serum high-density lipoprotein (good cholesterol) thus this oil preserves normal structure of liver, reduce the risk of atherosclerosis and act as a natural therapeutic agent for the protection against cardiovascular disorder (CVD) (22).

13. Antimicrobial properties of Rosemary essential oil

The oil contains antimicrobial compounds like 1,8-cineole, α-pinene, β-pinene which fight against various microbes such as Candida albicans, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Klebsiella pneumonia (23).

14. Treats colitis

Rosemary essential oil (400 μl/kg) contains a good amount of alpha-pinene and 1,8-cineole which is useful for the reduction of colon tissue lesions and colitis indices thus, reduce colon tissue injuries (24).

15. Treats hypotension

Rosemary essential oil (1 ml every 8 h) stimulates blood pressure levels both systolic and diastolic blood pressure levels. Thus this oil is responsible for its antihypotensive effect, increases blood pressure and improves patients’ quality of life (25).

Side effect of Rosemary essential oil

In the bottom rosemary oil contains multiple medicinal and cosmetic properties with less adverse side effects but please take precaution to avoid contact of eyes, pediatrics, as well as pregnant women when using this oil (26). 

Super Summary

Rosemary essential oil benefits are mainly because of terpenes, 1,8-cineole, α-pinene, camphor. This oil is beneficial for decreasing stress and joint pain, anxiety, and depression. Besides this rosemary essential oil has anti-atherosclerosis, antimicrobial and insecticidal properties. External application of rosemary essential oil is good for skin and hair.

Edited By: Dr. Asha Jyoti Bharati

References

  1.   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5368539/
  2.   https://www.liebertpub.com/doi/10.1089/jmf.2014.0040
  3.   https://www.ncbi.nlm.nih.gov/pubmed/30219447
  4.   https://www.ncbi.nlm.nih.gov/pubmed/23833718
  5.   https://www.ncbi.nlm.nih.gov/pubmed/20377818
  6.   https://www.ncbi.nlm.nih.gov/pubmed/19053868
  7.   https://www.ncbi.nlm.nih.gov/pubmed/21663474
  8.   https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4227022/
  9.   https://www.ncbi.nlm.nih.gov/pubmed/9828867/
  10. https://www.ncbi.nlm.nih.gov/pubmed/25635991
  11. https://www.sciencedirect.com/science/article/pii/S0944711309002554
  12. https://www.ncbi.nlm.nih.gov/pubmed/17388768
  13. https://www.ncbi.nlm.nih.gov/pubmed/17195668
  14. https://www.ncbi.nlm.nih.gov/pubmed/17583499
  15. https://www.ncbi.nlm.nih.gov/pubmed/20695287
  16. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4649899/
  17. https://www.ncbi.nlm.nih.gov/pubmed/23122155/
  18. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5741888/
  19. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5750654/
  20. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5747963/
  21. https://www.ncbi.nlm.nih.gov/pubmed/28928060
  22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5471466/
  23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5625792/
  24. http://europepmc.org/articles/pmc3203268
  25. https://www.ncbi.nlm.nih.gov/pubmed/24269249
  26. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5905578/

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