Rosemary Essential Oil is Best Known for Memory Support, But Find Out Why There is Much More to This Powerful Aromatic Substance
Last week, I sent an E-blast about rosemary essential oil to my essential oils subscribers. It was meant to be a little bit of a brain teaser to prelude this blog. I wanted to give a small taste of what rosemary essential oil can do for our health and was eager to get out some information I remembered on its role in cognitive health. (Catch the pun?)
After last week’s blog, “5+ Proven Reasons Clove Essential Oil Has Amazing Health Properties,” I seem to be on a role of adding more solo essential oils to my database, but that is really not by an intended choice. Both topics were spurred by the serendipitous timing of each subject brought to my attention more than several times. This occurs in various ways, usually when I am reading through articles, blogs, or journals, or listening to a podcast or seminar. I’m convinced that these themes repeat themselves on the day of my allotted writing time in order to cue me to more fully explore, research, expand on, and share in my articles what I discover with others. In fact, it seems to happen like clockwork. Click here to read this revised sneak peek introductory blog that was spurred by serendipity. Then, come back to the main course on this page.
A Little Background on Rosemary’s Makeup and Why We Care
A Microscopic View of Biochemical Constituents
One method science uses to obtain an understanding of a substance is by breaking it down to its composite parts and analyzing the mechanisms of each one. This can be helpful to determine if an isolated constituent affects a specific condition. For example, citrus oils are high in the substance limonene. This substance has been solely studied for many beneficial effects relating to immune, gastrointestinal, and gallbladder health.
Several studies provide evidence that that citrus preparations can raise the levels of d-limonene in subject’s bloodstream and that this essential oil compound can produce similar responses as d-limonene in vitro and in vivo. In fact, a wonderful review from 2014 in BioMed Research International provided a vast compilation of essential oils, their active constituents, and their mechanisms related to tumor modulation. Therefore, this scientific process is indeed providing insight into what biochemical responses can occur with the use of essential oils and their vast constituents.
However, there’s some pitfalls to this approach when studying essential oils, and for evaluating natural compounds, in general. This is related to the concept of synergism. This means that compounds can work together for combined effects greater than the sum of their separate effects. In other words, not only is synergism related to the fact that essential oils have profound psychological and physiological effects, beyond biochemical (which I discuss ad nauseam and you can read more about in detail here), but there is synergism in the biochemistry of the oils themselves. For example, this blog takes a look at all lavender can do, and at the same time, how constituents that differ can produce different results.
In a 2014 study of essential oils in The Open Microbiology Journal explained the microbe-inhibiting effect of essential oils may be due to more than its “active constituent”:
It has also been postulated that the function of the main components is regulated by other minor molecules which help in potentiating synergistic effect . It is likely that several components in essential oils play a role in characterizing the fragrance, the density, the texture, the color, ability in cell penetration, lipophilicity, fixation on cell walls, and most importantly the bioavailability. Considering that a vast range of different groups of chemical compounds are present in one essential oil, it is most likely that antibacterial activities cannot be attributed to one specific mechanism or component; and hence, there may be several targets in a cell which result in the potentiating influence. Thus, it is more meaningful and rational to study the whole essential oil rather than some of its components as to whether the concept of synergism truly exists between the components in essential oils .
Back to Rosemary
One 2013 article in Scientia Pharmaceutica reported on the power of synergism in specific regards to rosemary. The authors felt that the combination of 1,8-cineole and the monoterpenes (a-pinene) where what could have accounted for its stimulating effect on the nervous system and an enzyme involved in muscle contraction:
Our results demonstrate significant changes in ANS parameters after exposure to sweet almond oil and rosemary oil. The data of various ANS parameters were compared during rest (control), sweet almond oil inhalation, and rosemary oil inhalation as shown in Table 1. The heart rate of subjects was significantly reduced during sweet almond oil inhalation as compared with the resting condition (p < 0.05). However, after being exposed to rosemary oil, heart rate, blood pressure, and respiratory rate had significantly increased (p < 0.01). In contrast, skin temperature had decreased significantly. The results have shown consistency with a previous rosemary oil massage study which found that rosemary oil increased blood pressure and respiratory rates . The stimulatory effects on the autonomic nervous system may be explained through the abundance of oxides (1,8-cineole) and monoterpenes (a-pinene) that are present in rosemary oil. Both of these components have stimulating effects on the nervous system through sympathetic activity [12, 13]. Heuberger et al. found that the respiratory rate increased after the administration of 1,8-cineole , while Orhan et al. found that 1,8-cineole and a-pinene moderately inhibited acetylcholinesterase , an acetylcholine degradation enzyme which results in prolonged muscle contraction, and might be responsible for the reductions in skin temperatures.
That being said, let’s explore rosemary some more.
The Biochemical Composition Craziness of Essential Oils and Pinning Down Rosmarinus officinalis
Is a Rose of the Same Name Still a Rose? Yes…but it May Not Really Be the Same
Of course, before we dive into the constituents, I have to make another major point on the variations of compositions in essential oils, even within the same species. For those of you who are newbies to essential oils, I reviewed that several aspects of essential oils will effect composition and secondary metabolites present in essential oils. These include ensuring quality aspects such as ensuring no contamination, testing for active constituents, distillation techniques, plant species used, harvesting methods and growing conditions, manufacturing, finished product shipping, and more. (You can read more on all these factors here).
I discussed the details of this more in a previous blog and below is an excerpt:
A 2012 article in Alternative Medicine stated the following (bold highlighting is me):
Chemical constituents of Boswellia sacra essential oil fractions were dependent on duration and temperature of hydrodistillation. For example, when essential oils collected from 0–2 h (Fraction I), 8–10 h (Fraction II), and 11–12 h (Fraction III) at 78°C were compared, longer distillation produced higher percentages of sesquiterpenes, between alpha-copaene and caryophyllene oxide (Table? 1). All three fractions were primarily composed of monoterpenes (82.77-90.67%), including alpha-thujene, beta-pinene, and myrcene. Among the monoterpenes, alpha-pinene was the major compound present in all essential oil fractions, ranging from 65.49% to 78.45%. As anticipated, the abundance of alpha-pinene decreased with longer and higher temperature distillation due to its highly volatile nature. Compounds such as borneol, dimethyl ether orcinol, allo-aromadendrene, gamma-cadinene, and caryophyllene oxide were only present in Fraction III essential oil…
We found that boswellic acids contents depended on hydrodistillation duration and temperature (Table? 2). Essential oils prepared from longer distillation time and higher distillation temperature contained greater amounts of boswellic acids. For example, boswellic acids contents in Fractions III (19.6%) and IV (30.1%) were higher than those detected in Fraction I (0.9%) or II (0.8%) essential oil.
If you want to find some other cool references on how distillation, harvesting, farming, genetics, social forces, and location affect essential oil quality, along with reinforcing the factors above, this is a great article to dive into.
Back to Rosemary… Again
In an article abstract with the composition of rosemary found in Algerian Sahara reported:
Thirty compounds were characterized representing 98.2% of the essential oil with 1,8-cineole (29.5%), 2-ethyl-4,5-dimethylphenol (12.0%) and camphor (11.5%) as the major components.
However, rosemary from Brazil is a bit different, with camphor being the predominant constituent:
The essential oil from fresh leaves of Rosmarinus officinalis L. from Rio de Janeiro, Brazil, was isolated by hydrodistillation and analyzed through a combination of GC and GC/MS. Compounds representing 98.3% of the oil were identified. Forty-five constituents were identified according to their chromatographic retention indices and mass spectra. The major constituents of the oil were camphor (26.0%), 1,8-cineole (22.1%), myrcene (12.4%) and ?-pinene (11.5%).
Now, taking into account what was discussed down the composition craziness section and the differences found above, an abstract from a seminar from the ISHS Acta Horticulturae 925: XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010) summarized nicely the specifics on how the composition of Rosmarinus officinals L. was dependent on the origin of the species and altitude which is was grown. The authors reported that there were 31 wild rosemary populations out of 152 plants analyzed and 3 different major and minor chemotypes highlighted below:
The quantitative chemical composition of Rosmarinus officinalis L. essential oil depends, as has been reported in several publications, on the geographical origin of the species. Major components identified in the essential oil, which define the chemotype of these plants, are camphor, 1,8-cineol and ?-pinene. However, the intraspecific variability detected among plants belonging to a reduced geographical area, as occurs in the Region of Murcia (11,313 km2), implies the necessity of establishing the existence of different chemotypes in the growing area, and defining these chemotypes and their relation to the specific climatic conditions.
On these bases, 31 wild rosemary populations (a total of 152 individual plants) were prospected and analyzed. Chromatographic analysis allowed for the detection of 3 different major chemotypes, including: 1,8-cineol-?-pinene-camphor (representing a 18.42% of the total plants analyzed); camphor-1,8-cineole-?-pinene (17.76%); and 1,8-cineol-camphor-?-pinene (13.82%). Minor chemotypes characterized correspond to: ?-pinene-1,8-cineol-camphor (4.61%); ?-pinene-camphor-1,8-cineol (3.95%); and camphor-?-pinene-1,8-cineol (3.95%). It is interesting to note the existence of some plants with an essential oil rich in components such as verbenone (13% of the oil), borneol (11%) and camphene (10%). For these shrubs, the essential oil chemotype is defined by the major components mentioned above plus these minor components.
The effect of altitude of the growing area on the essential oil chemotype definition was also determined. In areas located from sea level to 1000 m a.s.l., the major component identified in the oil was 1,8 cineol (representing 49% of the plants analyzed), followed by camphor (27%). However, this situation changes in areas located between 1000 and 1500 m a.s.l., where the percentage of shrubs with camphor-1,8-cineol, and 1,8-cineol-camphor chemotypes was similar (40 and 38.5% respectively).
Perhaps, the most famous chemotype is 1,8-cineol, which I go into detail when discussing eucalyptus here. Basically, it’s a great component that modulates respiratory and immune health, microbes, inflammatory pathways, and acts as an antioxidant. Therefore, rosemary with this component will most likely have similar, yet synergistic, effects.
Side Note- The Reason Why Not to Buy “Local” with Essential Oils
Recently, I listed to a podcast with Dr. Z on using essential oils and I have to agree on his non-interest in most “local, organic essential oils”- the reason is stated well above regarding the oils makeup. Another example is when you want the therapeutic chemotypes of Boswellia, a frankincense oil from Oman is a lot different from California.
Not to say that sometimes due to ecological reasons, finding new sources and distilling and modulating harvesting as a result are necessary at times, but that takes expert precision and I ensure the oils I use are top quality.
Five of My Favorite Uses for Rosemary Essential Oil
Now, the fun part. The application and uses of rosemary essential oil. Before you dive into the use essential oils, make sure you are aware of the safety data and using them responsibly. There are five articles listed on my essential oils database here to help you in doing this. You may also want to check out this article on carrier oils if you are interested in topical applications. After all, a new study this month reported that we may have smell sensors in our skin! Wild, huh!?
1. Brain Health
As noted above, rosemary is most famous for its support in cognition. I discussed essential oils, including rosemary, and their positive role in brain health in this blog. There was a great study done that I reviewed on 20 subjects entitled, “Plasma 1,8-cineole correlates with cognitive performance following exposure to rosemary essential oil aroma.”
In the original E-blast teaser, I also discuss the use of aromatherapy on 28 dementia patients. The authors found positive benefits with the use of rosemary and lemon essential oils in the morning, and lavender and orange in the evening.
Furthermore, a review in The Journal of Quality Research in Dementia the use of aromatherapy, including rosemary, for those diagnosed with Alzheimer’s goes into further details on the impact oils have on brain health. You can read this one here.
2. Mood & Test Taking Jitters
It makes sense that rosemary would help with mood if it helps with supporting the brain, right? Well, it does, but it tends to be stimulatory. This study reports it even shows changes on EEG readings with alpha waves shifting to beta waves in the anterior region of the brain. This is associated with more wakefulness. Rosemary also has evidence for improving tasks related with cognition. which is what I discussed in the above section and in my blog with lavender here.
Whereas, lavender may not be the best oil to use alone for cognitive stimulation, if nervousness for test taking is present, the combination of it with rosemary may help. For example, one study found, “the use of lavender and rosemary essential oil sachets reduced test-taking stress in graduate nursing students as evidenced by lower scores on test anxiety measure, personal statements, and pulse rates.”
Another study in Korean (I don’t speak Korean, but the abstract was translated) validated that the synergistic use of aromatherapy, including this highlighted oil, was helpful for symptoms related to arthritis:
PURPOSE: The purpose of this study was to investigate the effect of aromatherapy on pain, depression, and feelings of satisfaction in life of arthritis patients.
METHOD: This study used a quasi-experimental design with a non-equivalent control group, pre-and post-test. The sample consisted of 40 patients, enrolled in the Rheumatics Center, Kangnam St. Mary’s Hospital, South Korea. The essential oils used were lavender, marjoram, eucalyptus, rosemary, and peppermint blended in proportions of 2:1:2:1:1. They were mixed with a carrier oil composed of almond (45%), apricot(45%), and jojoba oil(10%) and they were diluted to 1.5% after blending. The data were analyzed using an 2-test, Fisher’s exact test, t-test and paired t-test.
RESULT: Aromatherapy significantly decreased both the pain score and the depression score of the experimental group compared with the control group. However, aromatherapy didn’t increase the feeling of satisfaction in life of the experimental group compared with the control group.
CONCLUSION: The result of this study clearly shows that aromatherapy has major effects on decreasing pain and depression levels. Based on our experiment’s findings, we suggest that aromatherapy can be a useful nursing intervention for arthritis patients.
3. Hair Health
Rosemary has been touted for hair health and regrowth. There is an actual patent for a product containing this oil in a combination blend that can be found here.
4. Microbe & Mouth Effects
Rosemary has been shown to have microbe-inhibiting effects, which may be in part to its 1,8-cineole content. There are also certain antibiotics that rosemary has been shown to modulate in vitro regarding synergism or antagonistic effects, displaying its impact on critters. A review of mostly in vitro trials reported that rosemary was a very good candidate for decreasing bacteria that cause cavities as well.
A somewhat gross study with dirty dentures found rosemary inhibited “germ tube formation by Candida albicans isolated from denture wearers.”
If you want more, feel free to dive into these 287 articles that I found in PubMed when searching “rosemary and antimicrobial.l”
5. Antioxidant Protection
Rosemary essential oil has several in vitro and in vivo trials on its antioxidant powers. Here are some studies in various categories:
Reproductive Health: one trial found that rosemary and a species of lavender modulated antioxidants in vitro and protected diabetic rats from reproductive damage.
Liver Health: In another study in BMC Complementary and Alternative Medicine, rats were again divided up, this time there were several conditions including a control, a control with saline, lucky rats just given rosemary oil (good comparison), and then the toxic testing of rats who were exposed to a toxic compound to induce oxidative and liver stress and given either saline or rosemary. The authors measured various biochemical markers and reported, “Our results demonstrate that rosemary essential oil, beside exhibiting free radical scavenging activity determined by DPPH assay, mediates its hepatoprotective effects also through activation of physiological defense mechanisms.”
The information on essential oils is exploding. I am so excited. After using them personally and with wellness clients for 15 years, the momentum has hit!! Now, stay tuned, because in a few months, I’m going to do a mighty blog on another site regarding a strong combo of essential oils that contains rosemary. Hint: it’s one of my favorite oil blends!
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