Rosemary officinalis

Rosemary (Rosmarinus officinalis)

Description

It is an evergreen shrub that grows wild mainly in the Mediterranean region, especially in dry areas near the sea coast, but also in sub-Himalayan areas. Its Latin name Rosmarinus, from which the Czech name is derived, means ‘rose of the sea’. It is then cultivated in many parts of the world, from many European countries to Central America (especially Mexico), Venezuela and the Philippines. It can also be grown in our conditions, but as it does not tolerate hard frosts, the plant needs to be protected by wrapping or moved to a greenhouse for the winter.

It grows up to 2 m tall, the branches are densely covered with narrow, sessile leaves that are glossy and dark green on top and greyish underneath. It flowers with small blue or purple flowers, the fruit is a brownish drupe (20, 21).

Active ingredients

The leaf is used for treatment, both for the preparation of the infusion and for the production of the extract or oils. It is characterised by its high content of flavonoids with antioxidant effects, tannins, organic acids, triterpenes, bitter substances and substances with phytoncidal effects (i.e. capable of killing bacteria). In terms of health benefits, the most important substances are carnosol, rosmanol, carnosic, rosmarinic or ursolic acid and cineole (20, 21).

History

Rosemary is a traditional plant used since ancient times as a spice, but also for medicinal and magical purposes. It has been associated with love, marriage, and even births and deaths. In England and Germany it is also considered a symbol of remembrance and in the past it was also placed in the cradle of newborn babies to protect them from evil forces.

It has also been used in the kitchen since ancient times, both on its own (especially in meat preparation) and as part of mixtures – perhaps the most famous of which is the so-called Provençal spice.

Healing effects

In traditional phytotherapy, rosemary is used as a general tonic, as well as to aid digestion (improving digestive enzymes and bile production), eliminate bloating, increase mental and physical fitness, promote fertility (improving blood circulation to the small pelvis), treat arthritis and relieve joint pain.(21) Many of these effects have been confirmed by scientific research. In particular, rosemary has come to the attention of scientists due to its epigenetic effects. Some of the compounds it contains (carnosol, caronosalic acid, ursolic acid, rosmarinic acid) can influence which of our genetic predispositions for health actually manifest themselves and which do not.

Memory and concentration

Rosemary is one of the traditional herbs that has been shown to improve brain function and prevent dementia.(30) Its positive effect on cognitive abilities, especially memory and concentration, is so pronounced that it has even been observed in people who only inhaled rosemary aroma as part of aromatherapy. The beneficial effect on brain functioning is due to a substance called cineol, which is contained in rosemary essential oil, and it is the increase in its concentration in the blood plasma that has been observed even in people who have only inhaled rosemary essence.

The effect on memory is particularly pronounced. For example, a study conducted on university student volunteers showed that taking rosemary extract improved tests of retrospective memory (i.e. past-focused) by 14% compared to placebo. (43)

The secret of rosemary’s extraordinary effect on brain function is probably its ability to promote the production of a substance called BDNF (brain-derived neurotrophy factor). This is a protein that functions as a growth factor, which has a particular effect on nerve cells – it promotes their proliferation, growth and differentiation, and also increases the likelihood of survival of existing ones. BDNF also promotes the formation of synapses, i.e. new neural connections, a process that also takes place in the brain when we learn new knowledge and skills. In addition, BDNF deficiency is also typical of Alzeimer’s disease. In one study, 6 weeks of rosemary improved BDNF production by 27% in subjects (47).

Alzheimer’s and Parkinson’s disease

Carnelic acid protects nerve cells in a part of the brain called the hippocampus from damage leading to cell death, and also activates the antioxidant enzyme phase 2, which is important in preventing and slowing the progression of Alzheimer’s and Parkinson’s disease.(15, 16) Research has also shown that it prevents the development of the so-called “Alzheimer’s disease”. (17) In addition, a study by Japanese researchers has suggested that regular use of rosemary extract may also help individuals with advanced symptoms of Alzheimer’s disease, particularly cognitive dysfunction related to the existence of amyloid plaques – i.e. memory impairment in particular. In experiments on rats artificially induced to develop Alzheimer’s disease, scientists saw significant improvements in memory test scores after just a few doses (26).

Tumour diseases

The research on the anti-cancer effects of rosemary extract, especially the carnosol and carnosolic acid it contains, looks very promising. These, through epigenetic action, limit the so-called proliferation (i.e. uncontrolled rapid multiplication, typical for cancer cells) and promote the expression (i.e. transcription) of the GCNT3 gene, which acts against tumour formation.

Scientific studies have confirmed the effectiveness of rosemary extract in the prevention and treatment of bowel and pancreatic cancer (1), breast (3), lung and liver (4), skin, prostate and also leukaemia (7).

Anti-inflammatory action

The anti-inflammatory action of carnosol and carnosolic acid is also important, as it is also based on the epigenetic principle. It is inflammatory processes that are involved in the development of a number of problems and diseases, be they cancer, cardiovascular disease, diabetes or even psychological problems.

For example, carnosol and carnosic acid block the binding of the NF-kB transactivator (5) and also suppress the activity of the gene for the formation and activation of cyclooxygenase COX2, which promotes the production of inflammatory prostaglandins. The advantage of carnosol and carnosic acid is that, although they suppress the production of COX2, they have no effect on the production of another member of the cyclooxygenase family, COX1. Anti-inflammatory drugs such as aspirin cannot do this, leading, for example, to gastric irritation. (12, 13) In addition, rosemary extract is also anti-inflammatory by suppressing the production of nitric oxide. (8) Furthermore, carnosol and carnosic acid are more effective when they act together, making the use of rosemary extract a better choice than treatment with individual compounds.

Oxidative stress

Rosemary is one of the very powerful antioxidants that protect body tissues and cells from the damaging effects of free radicals. (2) It acts mainly against peroxide and oxygen radicals, preventing lipid peroxidation, which is one of the risk factors for cardiovascular disease. (9) It also protects cell membranes from oxidative damage. (14) Up to 90 % of the antioxidant effect of rosemary extract is provided by carnosol and carnosolic acid.

Immunity, antimicrobial and antifungal action

Rosemary stimulates the cells of the spleen, an organ that produces a number of cells and substances essential for our immunity, in addition to red blood cells. In experiments on mice, for example, adding rosemary extract to the diet caused a significant increase in the production of IgM and IgG antibodies (42).

Rosemary is also characterised by its strong antifungal action, i.e. its ability to destroy moulds and yeasts. Significant success has been recorded, for example, in the treatment of people with the yeast infection Candida albicans. This is often found in the oral cavity of cancer patients or those taking broad-spectrum antibiotics or corticosteroids, and is very resistant to conventional drugs.

Rosemary also has an antibacterial effect that works even on bacteria resistant to conventional antibiotic treatment.(20, 53, 54) It has also been shown to have an effect against some viruses – for example, HSV-1 (the causative agent of cold sores) and HSV-2, which causes genital herpes.(55, 58) Some research has even suggested that rosemary might have an inhibitory effect on HIV.(59)

Arthritis

Prostaglandins, especially prostaglandin E2 (PGE2), are key substances in the development of rheumatoid arthritis, which trigger inflammatory processes in the joints. PGE2 is produced in the human body from arachidonic acid by the enzyme mPGES-1 (microsomal prostaglandin E synthase). Carnosol and carnosic acid are very effective in suppressing the activity of this enzyme and thus preventing the formation of inflammatory prostaglandins, and these processes are mainly due to the epigenetic action of these substances. The activity of mPGES-1 is also suppressed, albeit to a lesser extent, by another substance contained in rosemary, ursolic acid (40).

An important aspect in the prevention and treatment of rheumatoid arthritis is the antioxidant action of the components of rosemary extract, especially its ability to destroy oxygen free radicals and superoxide radicals. These, in certain circumstances (e.g. in people prone to rheumatoid arthritis), intensely damage collagen molecules and other joint structures and cause denaturation of immune cells (18).

Allergies and asthma

Rosemary is a very effective substance in the treatment of allergies, especially allergic rhinitis. Allergy is basically an inappropriate reaction of the immune system to a certain stimulus in the form of an allergen (pollen grain, mite, etc.). When the mucous membrane of the respiratory tract comes into contact with the allergen, it activates and rapidly multiplies (proliferates) immune cells, especially T-lymphocytes, neutrophils or eosinophils. These cells, together with mast cells, then produce a substance called histamine, which causes allergic symptoms such as swelling, inflammation, fluid production (rhinitis, tearing), irritation, etc. The drugs used for allergies, the so-called antihistamines, have one basic shortcoming: They prevent the release of histamine or block histamine receptors, so they suppress allergic symptoms, but they do not affect the actual cause of the allergy, i.e. the activation of immune cells (31).

On the other hand, rosemary, specifically rosmarinic acid, alleviates allergic symptoms by acting directly on activated immune cells, especially T-lymphocytes, causing their apoptosis or programmed cell death. This is because it inhibits interleukin IL-2, which is responsible for activating T-lymphocytes. (32, 33) This is very important, because according to some scientific theories, immune cells activated by an allergic reaction can cause oxidative tissue damage and even increase the risk of cardiovascular disease. (35) Moreover, it is important that rosmarinic acid causes death only in activated immune cells – it leaves the non-activated ones unnoticed, so it does not limit the body’s ability to effectively defend itself against infections, for example.

In one Japanese study (10), for example, patients experienced a significant reduction in most allergic symptoms, especially rhinitis, watery and burning eyes, after 21 days of taking rosemary extract.

A reduction in inflammatory reactions in allergic reactions to dust mites has also been demonstrated, as well as relief of asthma (25). For example, in experiments on mice, it has been shown that a daily dose of 1.5 mg of rosemary extract can prevent the development of allergic asthma in contact with dust mites. (34) Its ability to relax the muscles of the respiratory tube, whose spasmodic contraction is characteristic of asthma, also plays an important role.(36)

Liver protection

Protecting the liver against the action of toxic substances is one of the best known effects of rosemary in traditional natural medicine. (20) Protection against inflammatory processes and necrosis caused by toxic chemicals, as well as the promotion of detoxification, has been shown to be the most popular of all rosemary’s properties (28, 38).

Cardiovascular disease

In traditional natural medicine, rosemary is often used as a remedy for raising morbidly low blood pressure. From this perspective, it is interesting that it can also reduce excessively high blood pressure, which is one of the main risk factors for cardiovascular disease. In Moroccan natural medicine, it is even successfully used for this purpose in diabetics (22).

Scientific studies have also confirmed that the antioxidant substances in rosemary extract, particularly the phenolic diterpenes and carnosic acid, can effectively lower blood cholesterol levels and reduce the formation of atherosclerotic plaques (23, 24).

Psychological difficulties

Rosemary has a beneficial effect on mood, in particular promoting calming, relieving anxiety and stress, and even works in this regard for patients affected by dementia. (27) Its beneficial effects on depression and anxiety have also been demonstrated after only 30 days of taking the extract (43, 44).

This herb also has a general tonic effect and helps to alleviate fatigue and lack of energy (61).

Sleep disorders

Rosemary can also be an effective aid for those suffering from sleep disorders. For example, when researchers gave it to university students in a study, after 30 days the number of those reporting good sleep rose from 47% at the start of the study to 62%, and the number of volunteers reporting poor sleep rose from 53% to 38%. (43) However, rosemary also works for sleep disorders in the elderly, even in the form of aromatherapy. (46)

Macular degeneration

This disease is one of the most serious eye diseases, often resulting in complete blindness. It causes damage to the light-forming cells of the retina, especially at the point of sharpest vision, the so-called yellow spot. Affected individuals therefore experience a loss of central vision (i.e. of the objects on which they focus), while peripheral vision is preserved. Rosemary extract, specifically the carnosol it contains, has been shown to protect retinal cells from degeneration (29).

Migraine

This herb is characterized by its strong anti-inflammatory effect and ability to relieve pain, which works effectively even in the case of migraine. In the case of an acute attack, even aromatherapy can have a positive effect. (41)

Diabetes and obesity

An interesting study, although so far only conducted on mice, has suggested the possible potential of rosemary in the treatment of diabetes. Mice that were artificially induced to develop diabetes were given rosemary for six weeks, during which time the ability of the pancreatic beta-cells to produce insulin was significantly improved. One possible reason for this was that rosemary stimulated the production of betatrophin. Betatrophin is a relatively recently discovered hormone produced in the liver that promotes the formation of new insulin-producing cells in the pancreas. A positive ‘side effect’ was weight loss in the mice studied, with rosemary acting as a protective factor to prevent muscle degradation. (48)

Another mechanism by which rosemary acts in diabetics is by activating the enzyme AMPK. This is an enzyme that is essential for the use of glucose by working muscles, which consume most of the glucose. When its production is increased, it both improves the absorption of glucose from the blood into the muscles and makes glucose metabolism more efficient within the muscle cells. (50) This effect may also contribute to weight loss, as high blood glucose levels increase the likelihood of fat storage.

However, the ability to lower blood glucose levels (especially fasting) has also been confirmed by research conducted on human volunteers. In addition, one of them found that taking rosemary (500 mg capsules 3 times a day) increased the blood levels of vitamin B12 in the test subjects by an average of 29%. This is very important because diabetics have significantly lower levels of this vitamin, which is essential for, for example, blood formation or memory functioning, compared to the general population (by an average of 40%) (49, 52).

Skin problems

Rosemary effectively destroys many skin-infecting bacteria and yeasts.(51) It also promotes skin protection against UV rays.(57)

Baldness in men

A recent study has shown that rosemary has similar effects to the drug minoxidil, which is used to suppress male pattern baldness. One study group took rosemary, the other minoxidil. After three months, neither group had yet experienced significant changes, but after six months, both groups had increased their hair counts in a roughly comparable manner (62).

Tinnitus

Tinnitus is a term referring to a variety of whistling and ringing in the ears. It is a very bothersome problem that often makes it difficult for the affected person to function normally, and in some cases it can even become a reason for suicide. The efficacy of rosemary for this problem has not yet been reliably proven scientifically, but experience with its use suggests that it may be a substance that can bring at least some relief to some sufferers.

Use and contraindications

High doses of rosemary can cause miscarriage, so taking rosemary extract or infusion is not advisable in pregnancy. However, it is not dangerous to use in quantities that are common, for example, in flavouring food. It is also not recommended for use during breastfeeding and in the case of children (there are not enough studies to prove its safety, but no harmful effects have been demonstrated).

Rosemary can also interact with some chemical drugs. It is therefore not suitable to combine it with drugs that affect blood clotting (Aspirin, Walfarin), drugs to reduce high blood pressure (so-called ACE inhibitors), diuretics and antidiabetics.