Peppermint as a tea has become very popular and it is thought to have a number of health benefits for variety of ailments such as biliary disorders, dyspepsia, enteritis, ﬂatulence, gastritis, intestinal colic, and spasms of the bile duct, gallbladder and gastrointestinal (GI) tract.
When the steam from the tea is inhaled it can ease sinus congestion and the inflammation of the mucous membrane in the nose and throat.
In Germany, peppermint leaf tea has been licensed for use during indigestion or dyspepsia.
The oil has been used as an herbal pain relief and is a common ingredient in products aimed at athletes to soothe sore muscles. Peppermint oil, as an external treatment, has been approved for myalgia, muscle pain, and neuralgia and nerve pain.
The essential oil of peppermint has been used as a topical application to repel insects.
In India, researchers at the Malaria Research Centre in Delhi have found that the oil repels adult mosquitoes and can kill the larvae. This, in turn, can have positive effects on diseases such as Dengue Fever and Malaria.
The camphor or menthol, derived from the peppermint oil is used as an antiseptic when treating colds, as a topical counter-irritant.
It has been shown, that peppermint oil can reduce the muscle spasms in the upper and lower gastrointestinal tract of patients undergoing endoscopies, barium enemas, and colonoscopies and also that peppermint oil in capsule form can relax the muscle in the stomach and small intestine, which would ease cramping.
It has been approved for internal use by the German Commission E, to effectively treat the gastrointestinal tract, gallbladder, and bile ducts.
It is also approved for irritable colon and as a remedy for irritable bowel syndrome, where it has been shown to provide mild relief for the symptoms of flatulence, abdominal pain and distension.
A number of studies have investigated the antioxidant effect of Mentha piperita. For example, an aqueous solution of previously frozen, yet fresh leaves were found to have the highest level of oxygen radical absorbance capacity, among a group of other popular medicinal herbs.
It was also found to have a higher free radical scavenging capacity than other species in the genus Mentha and off all tea infusions, it was the peppermint tea that was found to have the greatest antioxidant capacities.
It has been noted that peppermint may have cancer-fighting and anti-tumor abilities. It was shown to significantly suppress the effect of okadaic acid which promotes tumor formation.
A high dose of menthol derived from the herb reduces the activity of cytosolic arylamine N- acetyltransferase (NAT) activity in the human liver tumor cell, however, this effect lessens with dose, and at very low doses can promote NAT relative to other substances.
Studies have shown that the flavonoid glycoside, luteolin-7-O-rutinoside, obtained from Mentha piperita has a significant effect on the inhibition of histamine release.
Menthol was also found to suppress the production of inflammatory mediating compounds. It has therefore been suggested that peppermint can play a role as an anti-allergenic.
It has been noted that peppermint has anti-viral properties and aqueous extracts from the plant have significant effects on influenza viruses.
The herb has been shown to inhibit influenza virus reproduction, reducing the infectiousness. In 1998, a study demonstrated that Mentha piperita was highly potent against the human immunodeficiency virus-1 (HIV-1) at a dose of 16µg/mL.
Peppermint oil has been extensively researched concerning its antibacterial abilities. Its components menthol and menthene have shown a moderate inhibitory effect against human pathogens, such as Staphylococcus aureus, Listeria, Staphylococcus epidermis.
One study found peppermint oil to be effective against 22 independent bacterial strains. Menthol is the most effective of the peppermint components, shown to be quite effective for gastrointestinal bacteria.