History/Traditional Use

Source: http://www.faqs.org/
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Peppermint (Mentha piperita L.) belongs to the large family Lamiaceae, which is the oldest group of traditional and medicinal herbs. Although pepper-flavoured mint was first described in England by John Ray in 1696, the use of dried peppermint leaves dates back to at least 1000 BCE in ancient Egypt (Spirling & Daniels, 2001). Since then, peppermint has been cultivated all over the world, and has been used for a wide variety of purposes. In ancient Greece, peppermint leaves were traditionally used as a digestive aid and as treatment for gallbladder disease (Kligler & Chaudhary, 2007). It was also used as an inhalant to treat upper respiratory illnesses (Kligler & Chaudhary, 2007).  In the eastern part of the world, the Japanese used peppermint oil as a component of eye wash in 984 AD (Ellis & Stevenson, 1950).

            
               By the time peppermint was first medically described, as many as 40 ailments were said to be treated with peppermint (Haas, 2010). These included flatulence, dyspepsia, headaches, biliary disorders, and GI tract problems (McKay & Blumberg, 2006). The most common method of administration of peppermint across all cultures was by ingestion in order to treat the internal problems that it was traditionally used for.  In specific instances, such as treating upper respiratory illnesses, peppermint was administered as an inhalant to provide the quickest and most efficient route through the nasal passage to the lungs. 

Active Components and Preparation

Source: http://www.food-info.net/images/menthol.jpg

            











       

              
               The active constituent of peppermint is the peppermint oil, made by the distillation of the stem and root of the peppermint plant (Kligler & Chaudhary, 2007). It has been suggested that peppermint oil is composed of over 1000 components, but the ones with the largest percent composition include “menthol (33-60%), menthone (15-32%), menthyl acetate (2-11%), iso-menthone (2-8%), menthofuran (1-10%), and limonene (1-7%)” (McKay & Blumberg, 2006). 

               Menthol not only represents the largest component in peppermint oil, but is also predominantly responsible for the oil’s therapeutic properties (Tate, 1997). Peppermint oil is often prepared in an enteric-coated standardized capsule to treat GI tract symptoms, but can also be administered topically as an anaesthetic to relieve local pain (Sustrikova & Salamon, 2004). The medicinal effects of the peppermint herb are not only limited to the oil, but also include the leaves and shoots of the herb, that can often be found used in herbal teas.

Modern Use & Current Research



               Many of the traditional uses of peppermint are still being used today, especially those to treat symptoms of the GI tract. In particular, peppermint oil is commonly used to treat digestive problems, heartburn, nausea, abdominal pains, headache, and coughs (Sustrikova & Salamon, 2004). Irritable bowel syndrome (IBS) is a relatively common condition characterized by abdominal distension and pain, bloating, flatulence, and diarrhoea. Due to the success of peppermint oil in treating traditional GI tract ailments, many recent studies have been conducted to test its efficacy in treating IBS. Cappello et al. (2007) published a study in which a double-blind placebo-controlled randomized trial was performed on fifty-seven patients with IBS ranging in age from 18 to 80 years old. Both the peppermint oil and placebo were prepared in enteric-coated capsules, containing 225mg of their respective substances, two of which were given randomly to each patient twice a day for 4 weeks. At the end of the trial, it was found that the number of patients in the peppermint oil group that had a greater than 50% reduction in total IBS symptoms were significantly larger than in the placebo group (Figure 1) (Cappello et al., 2007).

(Cappello et al., 2007)

               This finding illustrates that treating IBS patients with two enteric-coated capsules of peppermint oil twice a day for 4 weeks will significantly reduce symptoms of IBS for approximately 1 month after treatment (Cappello et al., 2007). The protocol of the study was sound in that a double-blind RCT was conducted using standardized doses of the treatments. Furthermore, the authors ensured an appropriate balance of baseline conditions between the patients in the two groups.

               Migraines affect many people all over the world and can be quite disabling when severe. Haghighi et al. (2010) conducted a study on the efficacy of peppermint oil, with particular focus on its menthol component, on the treatment of migraine without aura. A triple-blind placebo-controlled randomized trial was performed on 60 patients experiencing migraines ranging in age from 18 to 65 years old. The peppermint drug was prepared by mixing 10% menthol crystals in ethanol. One ml of either the drug or the placebo was applied twice on the forehead and temporal area with a 30 minute interval between each application and left untouched for 2 hours. At the end of the trial, it was found that 38.3% of patients in the drug group and 12.1% of patients in the placebo group were “pain free” 2 hours after treatment (Haghighi et al., 2010). Furthermore, 33.3% of the drug group and 12.1% of the placebo group maintained a pain free response during the first 24 hours after treatment (Figure 2) (Haghighi et al., 2010).

(Haghighi et al., 2010)

               The findings of this study indicate that the application of a 10% solution of menthol and ethanol is statistically significant in the treatment of migraines (Haghighi et al., 2010). The protocol of this study is sound in that a triple-blind RCT was conducted, but the solution of menthol in ethanol may have not been adequate enough to produce more favourable results.

Adverse Effects and Drug Interactions

               The use of peppermint as a medicinal herb has been generally safe and non-toxic at therapeutic doses. However, at high enough concentrations, there have been reports of adverse reactions, as well as adverse drug interactions. When peppermint is administered orally at high concentrations, mucosal tissues may become irritated to the extent that a contact dermatitis develops (Magee, 2005). Peppermint can also potentially become an irritant and provoke hypersensitivity or allergic reactions (Spirling & Daniels, 2001). If taken in the form of a non enteric-coated capsule, heartburn and oesophageal discomfort may result (Spirling & Daniels, 2001).

(Magee, 2005)

               Other common adverse reactions include blurred vision, vomiting, and nausea (Kligler & Chaudhary, 2007).  In recent studies, it has been hypothesized that peppermint oil may have an effect on the metabolism of drugs in the body by inhibiting the cytochrome P450 1A2 system (Kligler & Chaudhary, 2007). As a result, there will be increased serum levels of drugs metabolized by this system.  As with many other medicinal products, peppermint oil is not recommended for use in very young children or pregnant women (Kligler & Chaudhary, 2007).

Works Cited

Cappello, G., Spezzaferro, M., Grossi, L., Manzoli, L., & Marzio, L. (2007). Peppermint oil (Mintoil) in the treatment of irritable bowel syndrome: A prospective double blind placebo-controlled randomized trial. Digestive and Liver Disease, 39, 530-536.

Ellis, N. K. & Stevenson, E. C. (1950). Domestic production of the essential oils of peppermint and spearmint. Economic Botany, 4 (2), 139-149.

Haas, L. F. (1995). Mentha piperita (peppermint). Journal of Neurology, Neurosurgery, and Psychiatry, 59, 607. 

Haghighi, A. B., Motazedian, S., Rezaii, R., Mohammadi, F., Salarian, L., Pourmokhtari, M., et al. (2010). Cutaneous application of menthol 10% solution as an abortive treatment of migraine without aura: a randomised, double-blind, placebo-controlled, cross-over study. International Journal of Clinical Practice, 64 (4), 451-456.

Kligler, B. & Chaudhary, S. (2007). Peppermint Oil. American Family Physician, 75 (7), 1027-1030.

Magee, K. A. (2005). Herbal therapy: a review of potential health risks and medicinal interactions. Orthodontics and Craniofacial Research, 8, 60-74.

McKay, D. L. & Blumberg, J. B. (2006). A review of the bioactivity and potential health benefits of peppermint tea. Phytotherapy Research, 20, 619-633.

Spirling, L. I., & Daniels, I. R. (2001). Botanical perspectives on health – Peppermint: more than just an after-dinner mint. The Journal of the Royal Society for the Promotion of Health, 121 (1), 62-63.

Sustrikova, A. & Salamon, I. (2004). Essential oil of peppermint (mentha x piperita L.) from fields in Eastern Slovakia. Horticultural Science, 31 (1), 31-36.

Tate, S. (1997). Peppermint oil: a treatment for postoperative nausea. Journal of Advanced Nursing, 26, 543-549.