What are allergies?
Allergies are also known as allergic diseases and cover a variety of conditions caused by hypersensitivity of the immune system to something in the environment. These diseases include hay fever, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. The most common allergy worldwide is hay fever, approximately 7.8% of people over the age of 18 years old in the US suffer from hay fever.
With the summer on its way and the allergies it brings now is the perfect time to explore rosmarinic acid and its potential health benefits. Today we are going to take a look at rosmarinic acid and its uses for the treatment of allergies and in particular asthma and respiratory allergies.
The anti-allergenic found in nature
Rosmarinic acid the naturally occurring plant compound is known to reduce inflammation and allergic responses and is therefore indicated in the treatment of asthma and allergies. There have been numerous antioxidant and anti-inflammatory effects reported for rosmarinic acid which likely contribute to its anti-allergenic properties (1-3).
Rosmarinic acid has a demonstrated free radical scavenging effect against both superoxide anions and hydroxyl radicals. Animal studies have also shown that rosmarinic acid can help to suppress the allergic immunoglobulin response and inflammatory response in white blood cells. Taken together these mechanisms are part of what gives rosmarinic acid its anti-inflammatory effect.
Rosmarinic acid has a demonstrated free radical scavenging effect against both superoxide anions and hydroxyl radicals. Animal studies have also shown that rosmarinic acid can help to suppress the allergic immunoglobulin response and inflammatory response in white blood cells.
The inflammatory response occurs when tissues are injured by bacteria, trauma, toxins, heat, or any other cause. The damaged cells release chemicals including histamine, bradykinin, and prostaglandins. These chemicals cause blood vessels to leak fluid into the tissues, causing inflammation.
Immunoglobulins, also known as antibodies, are glycoprotein molecules produced by white blood cells. They act as a critical part of the immune response by specifically recognizing and binding to particular antigens, such as bacteria or viruses and supporting their destruction. Inhibiting these mechanisms is part of what gives rosmarinic acid its anti-inflammatory effect.
Plants and herbs containing high levels of rosmarinic acid often have anti-allergenic as well as anti-inflammatory properties. Rosmarinus is a well known antioxidant and Perilla frutescens as well as a number of the Salvia species that also contain rosmarinic acid are antioxidants and anti-inflammatories (4-7). Whilst all these plant species vary in their medicinal effect due to their differing chemical constituents, rosmarinic acid is increasingly being considered significant for its anti-inflammatory and immune modulating potential.
Perilla frutescens also known as the beefsteak plant is a popular cooking garnish in Asia but is also part of traditional Asian herbal medicine, in particular Japan and Korea. This plant has been traditionally used for allergies and for treating allergic reactions from seafood and with its high rosmarinic acid content this comes as little surprise why. Traditional medicine has also used this particular plant for the treatment of bronchial asthma. Perilla frutescens has also be studied for its anti-inflammatory properties and has been demonstrated in an animal model where it was effective at inhibiting the passive cutaneous anaphylaxis (PCA) reaction from allergens (8). It was able to significantly reduce the inflammatory response at the injury site of the test animals compared to the untreated control animals.
Respiratory allergies and asthma
Increasing levels of airborne pollutants have been been suggested as a reason for the rising cases of allergies, asthma and lung diseases in the world population. Previous studies have demonstrated that diesel exhaust particulates can create reactive oxygen species (ROS) in the body. One study showed that oral supplementation with rosmarinic acid prevented an inflammatory response from from the diesel fumes (9). The researchers demonstrated that supplementation with rosmarinic acid reduced the level of pro-inflammatory proteins and cytokines, decreased neutrophil infiltration and lowered lung parenchymal and interstitial edema in test animals.
Dust mites are another source of allergy and asthma symptoms and has been the focus of research in relation to rosmarinic acid (10). The researchers utilized a mouse model of asthma that uses tracheal tissue sensitized to react to dust mites. This particular mouse model is able to reliably cause inflammation and changes to interleukin (glycoproteins produced by leucocytes for regulating immune responses) and eotaxin levels when exposed to dust mites. Eotaxin is found in the tissue of various mucous membranes and is a chemokine (signaling protein) that regulates and activates the eosinophils. Eosinophils are a type of white blood cell and one of the immune system components responsible for fighting parasites and some infections in vertebrates.
The mice were treated with Perilla frutescens extract, which contained a high level of rosmarinic acid, showed only a minor inflammatory response from exposure to dust mites. In addition to this reduced inflammatory response, eosinophils, interleukins, and eotaxin levels were all significantly lower in the mice given rosmarinic acid.
Human clinical trials for rosmarinic acid
Studies have also been conducted in humans, in 2004 a 21 day, randomized, double blind, clinical trial was organized by Takano et al (11). In this study various doses of rosmarinic acid-enriched Perilla extract were tested in comparison to a placebo for the treatment of seasonal allergic rhinoconjunctivitis. Study participants were given 200 mg, 50 mg or a placebo and the results were recorded for the study period. The researchers noted that there was a dose-dependent decrease in reported symptoms such as itching and watery eyes. The treatment groups both had a significantly lower levels of neutrophils and eosinophils when examined.
The same research team did another study and treated the test subjects with rosmarinic acid with seasonal allergic rhinoconjunctivitis (12). The researchers monitored inflammatory response and cytokine levels from nasal cells, as in the previous study the treatment groups had a lower level of neutrophils and eosinophils when compared to the placebo group.
The antioxidant and anti-inflammatory properties of rosmarinic acid, and indeed plants with high concentrations of it, are of potential interest for the treatment of allergies, in particular respiratory ones. The various in vitro and in vivo studies combined with clinical trial data supports the use of rosmarinic acid in the treatment and prevention of asthma and allergies. Considering the long history of safe use of plants containing rosmarinic acid in traditional medicines and more recent scientific analysis, rosmarinic acid is certainly worth considering adding to your personal supplement regimen.
(1) Van Kessel, K. P., Kalter, E. S., & Verhoef, J. (1986). Rosmarinic acid inhibits external oxidative effects of human polymorphonuclear granulocytes. Inflammation Research, 17(3), 375-376.
(2) Bakırel, T., Bakırel, U., Keleş, O. Ü., Ülgen, S. G., & Yardibi, H. (2008). In vivo assessment of antidiabetic and antioxidant activities of rosemary (Rosmarinus officinalis) in alloxan-diabetic rabbits. Journal of ethnopharmacology, 116(1), 64-73.
(3) Erkan, N., Ayranci, G., & Ayranci, E. (2008). Antioxidant activities of rosemary (Rosmarinus Officinalis L.) extract, blackseed (Nigella sativa L.) essential oil, carnosic acid, rosmarinic acid and sesamol. Food Chemistry, 110(1), 76-82.
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(6) Tepe, B., Eminagaoglu, O., Akpulat, H. A., & Aydin, E. (2007). Antioxidant potentials and rosmarinic acid levels of the methanolic extracts of Salvia verticillata (L.) subsp. verticillata and S. verticillata (L.) subsp. amasiaca (Freyn & Bornm.) Bornm. Food Chemistry, 100(3), 985-989.
(7) Mayer, B., Baggio, C. H., Freitas, C. S., dos Santos, A. C., Twardowschy, A., Horst, H., … & Otuki, M. F. (2009). Gastroprotective constituents of Salvia officinalis L. Fitoterapia, 80(7), 421-426.
(8) Makino, T., Furuta, Y., Wakushima, H., Fujii, H., Saito, K. I., & Kano, Y. (2003). Anti‐allergic effect of Perilla frutescens and its active constituents. Phytotherapy Research, 17(3), 240-243.
(9) Sanbongi, C., Takano, H., Osakabe, N., Sasa, N., Natsume, M., Yanagisawa, R., … & Yoshikawa, T. (2003). Rosmarinic acid inhibits lung injury induced by diesel exhaust particles. Free Radical Biology and Medicine, 34(8), 1060-1069.
(10) Sanbongi, C., Takano, H., Osakabe, N., Sasa, N., Natsume, M., Yanagisawa, R., … & Yoshikawa, T. (2004). Rosmarinic acid in perilla extract inhibits allergic inflammation induced by mite allergen, in a mouse model. Clinical & experimental allergy, 34(6), 971-977.
(11) Takano, H., Osakabe, N., Sanbongi, C., Yanagisawa, R., Inoue, K. I., Yasuda, A., … & Yoshikawa, T. (2004). Extract of Perilla frutescens enriched for rosmarinic acid, a polyphenolic phytochemical, inhibits seasonal allergic rhinoconjunctivitis in humans. Experimental Biology and Medicine, 229(3), 247-254.
(12) Osakabe, N., Takano, H., Sanbongi, C., Yasuda, A., Yanagisawa, R., Inoue, K. I., & Yoshikawa, T. (2004). Anti‐inflammatory and anti‐allergic effect of rosmarinic acid (RA); inhibition of seasonal allergic rhinoconjunctivitis (SAR) and its mechanism. Biofactors, 21(1‐4), 127-131.