The Wonder Herb: Mentha x piperita

Mentha x Piperita or peppermint is part of the Lamiaceae plant family and is a low-growing, perennial aromatic within the mint family (Herbal Gram Peppermint , 2006) . The aerial parts (stem or leaf) of the plant are used medicinally for distilling essential oils (Braun & Cohen, 2018).  The leaves and the stem contain volatile oils which provide the plant with its strong fragrance and taste. The major constituents for M. x piperita are menthol (40.7%) and menthone (23.4%), further components include menthyl acetate, 1,8-cineole, limonene, beta-pinene and beta-caryophyllene. Mentha x piperita leaves contain about 2.5% essential oil, 19% total polyphenolic compounds, 12% total flavonoid compounds (eriocitrin, luteolin-7-O-rutinoside and hesperidoside) and 7% total hydroxyl-cinnamic compounds (including rosemarinic acid) (Duband et al, 1992). Mentha x piperita as a medicinal herb has many actions that treat different ailments within the body. For example, it works as an antispasmodic, carminative, a Choleretic, has antimicrobial properties, antiviral properties, is an antioxidant and a stimulant as well as a coolant and an analgesic (Braun & Cohen, 2018).
 
Irritable bowel syndrome (IBS) is characterised by bloating, abdominal pain and constipation or diarrhoea. Mentha x piperita has direct antispasmodic action on the smooth muscles of the digestive tract. The continuous use of the herb as a remedy for IBS is proven through its use as a powerful diffusible stimulant, carminative, antispasmodic, stomachic working to correct spasm and irritability whilst improving tone and function of the digestive process (Ellingwood, 1919). Trials performed with enteric-coated peppermint oil capsules proved to treat IBS and found a success rate of 58% compared to 28% for the placebo (Balch, 2012). The use of this herb in capsules is highly successful for IBS patients that have minor constipation and is successful in alleviating such symptoms of IBS, improving quality of life due to a reduction in pain or bloating in the abdomen as well as relief of flatulence (Thompson, Meah & Ahmed, 2013). The flavonoids within Mentha x piperita as an essential oil may have a cholagogic effect and stimulate bile secretion which in turn sooths digestion (Rotblatt, 2002).
 
Dyspepsia or indigestion occurs when there is  acid reflex and eructation after the consumption of food. Dyspepsia is defined as a persistent pain and discomfort in the upper abdomen and can lead to bloating, belching and gas, and a burning sensation within this region of the digestive tract (WebMD. N.d). Peppermint oil acts on the smooth muscle of the bowel, it works to relax the gastrointestinal sphincter and serves as a carminative and soothes eructation that can occur during dyspepsia (Henkel, 1869). It provides release of spasm in the intestinal muscle. The use of peppermint leaves in a carminative tea infusion creates a spasmolytic action that reduces acidic reflex and indigestion as it soothes the digestive tract (Weiss, 1988). Carminatives reduce muscle spasm in the digestive tract and aid in expelling gas that occurs due to dyspepsia. Peppermint has been used for a lengthy period to sooth complaints of the stomach and has a warm bitter taste working as an astringent which causes constriction of the digestive tract and creates short term barrier for inflammation and irritation (Culpepper, 1880).
 
Headaches and migraines have a debilitating effect on patients as they are neurological disorders that can be very painful and distressing. Both conditions can lead to nausea, sharp pain in the forehead and temples and increased sensitivity to light and sounds. Migraine headaches can occur due to a reduction in blood flow to areas of the cerebral cortex. The nauseous component of migraines has been scientifically proven to be relieved from the inhalation of vapour from Mentha x piperita whilst significantly reducing the necessity of anti-emetic consumption during times of nausea (Lua and Zakaria, 2012). Tension headaches occur due to muscular strains in the head and neck or due to emotional strain. Thus, treatment of headaches aims to improve blood flow and reduce strain on the upper sections of the body. Menthol receptors on sensory nerves have been identified to be able to modulate the cool sensation on strained nerves (Mills, 2005). Topical application of Mentha x piperita as an essential oil onto the temples and forehead creates this cooling sensation on peripheral circulation, dilating muscles and constricted blood vessels around the inflicted area that make tension headaches worsen (Gobel, 1996). Thus, Mentha x piperita has peripheral vasodilatory actions. Peppermint oil has been shown to significantly increase the level of skin blood flow to the head after local application to relieve a migraine. Thus, a clinical analgesic and coolant actions exists through the use of Mentha x piperita as there is a reduction in sensitivity to a headache and its symptoms due to the alteration of sensations of the nerves, spinal cord and brain affected by headaches (Gobel et al, 1995). 
 
Respiratory tract infections (RTI) are infectious diseases which affect the upper and lower respiratory systems. These RTIs affect the sinuses, throat, airways and the lungs making them a threat to health especially to those who may have already weakened immunity. Mentha x piperita as a medicinal herb can be used to soothe infections within both respiratory tracts, the upper being related to the common cold and the lower to more serious diseases such as pneumonia (Burt, 1876). Inhalation of this antiseptic and anti-inflammatory essential oil has traditionally been used to treat respiratory tract infections such as bronchitis (Braun & Cohen, 2018). The use of chest rubs containing Mentha x piperita for its menthol properties is frequently used to treat coughs and bronchitis. The inhalation of peppermint oil proves to decrease inflammation and provides antimicrobial properties that soothe respiratory tract infections (Bone, 2003). The use of the oil as a respiratory anti-inflammatory after using aerosolized mixture can significantly reduce ozone-induced nasal and respiratory inflammation (Respiratory Research, 2011). The menthol constituents in Mentha x piperita act as mucous membrane trophorestorative as it improves mucociliary clearance, reduces coughs, controls an excessive cough and improves airway calibre in vitro (Explore: The Journal of Science and Healing, 2008). Further, peppermint oil has been found to have antimycobacterial effects to help treat those with tuberculosis. (Shkuru et al, 2002).
 
Reduced cognitive performance due to lifestyle and environmental factors can lead to lessened concentration, lowered vitality and affect mood. Random testing of essential oils including peppermint has proven that mood scales after inhalation of peppermint oil improves cognition. Mentha x piperita has stimulatory actions and beneficially modulates performance during cognitive assignments and reduced overall mental fatigue associated with lengthy cognitive functioning and concentration in adults. (Kennedy et al, 2018). Peppermint was shown to enhance memory and alertness as well as positively affecting cholinergic and GABAergic neurotransmission (The International Journal of Neuroscience, 2008). The use of Mentha x piperita works to exhilarate the mind and clear it from fogginess, overbearing thoughts and headaches when breathed in (Culpepper, n.d)
 
The use of Mentha x piperita comes with some side effects such as it may lower oesophageal sphincter pressure, affect those with hypersensitivity (salicylate sensitivity), affect those with gallbladder inflammation and gallstones (MediHerb, 2018). The consumption of Mentha x Piperita in extreme cases has been shown to slightly decrease iron absorption when consumed with meals. Mentha x Piperita has been shown to not cause toxicity and is well tolerated at the recommended dosage. The safe usage of Mentha x piperita internally during pregnancy and lactation has not been determined, although external usage of the herb and inhalation is safe (WHO, 2018). It is recommended to avoid the use of peppermint oil on the face of children and infant as it is likely to affect their sensitive skin and cause a burning sensation. Allergic reactions may also occur in hypersensitive patients (Braun & Cohen, 2018). Within the elderly age group, no cautions for the use of Mentha x piperita have been highlighted. Significant interactions with drugs involve peppermint slowing the breaking down of certain medications by the liver, for example, cyclosporine, as peppermint increases the bioavailability of cyclosporine and slows the breaking down of its compounds, therefore increasing the risk of side effects for cyclosporine, thus patients should avoid concurrent usage. The use of Mentha x piperita internally may be prematurely dissolved due to the usage of antacids which reduced the stomach acids and increase gastric pH (Journal of Herbal Pharmacotherapy, 2008). The topical and internal use of Mentha x piperita as a medicinal herb comes with come contraindications and warnings, however, it is quite safe for general use within healthy individuals.
 
Ingesting Mentha x Piperita as an oral medication can occur via an infusion, tincture or liquid extract. An infusion is an herbal tea that contains aqueous extracts from steeping dried or fresh herbal material in boiling water. It is recommended that an infusion of 3-6 grams of Mentha x piperita is infused into 150mL of water and consumed three times a day is sufficient (Blumenthal et al, 2000). A tincture is a medicine made by dissolving an herb in alcohol, it is recommended that a tincture of 5-15 grams of peppermint (1:5) is consumed 2-3 times daily. A peppermint liquid extract (1:2) containing 1.5-4.5 mL of peppermint can be consumed three times daily. The oral consumption of peppermint can be taken on an empty or full stomach, depending on iron needs (i.e. those who are post-menopausal or male and don’t need an excess of iron can consume any time of day), as those with lower levels of iron should take away from meals to maximise iron absorption.
 
External topical dosing of Mentha x Piperita as an essential oil can be used to treat headaches or migraines. Topical application around the temples and forehead, of 10% peppermint oil in ethanol has been shown to alleviate tension headaches (Gobel et al, 1996). Peppermint oil can also be used as a heating ointment for arthritis, fibromyositis, tendonitis and other musculoskeletal conditions (Pizzorno & Murray, 2013) when used a rub on affected areas as many times a day as a rubefacient balm, especially after a warm bath.
 
Mentha x piperita is a medicinal herb that has been used for an extended period of time to treat certain ailments such as irritable bowel syndrome, dyspepsia, respiratory tract infections, headaches and migraines and low cognitive function. It proves some interactions with other drug use, however, is safe to use in most conditions, therefore making it a versatile herbal medicine.

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