Oil uses: Spearmint is used for its aromatic oil, called oil of spearmint. The most abundant compound in spearmint oil is R-(–)-carvone, which gives spearmint its distinctive smell. Spearmint oil also contains significant amounts of limonene, dihydrocarvone, and 1,8-cineol. Unlike oil of peppermint, oil of spearmint contains minimal amounts of menthol and menthone. It is used as a flavouring for toothpaste and confectionery, and is sometimes added to shampoos and soaps. Research and health effects of spearmint oil Spearmint has been used traditionally as medicines for minor ailments such as fevers, and digestive disorders. There is research on spearmint extracts in the treatment of gout and as an antiemetic. Spearmint oil used as insecticide and pesticideSpearmint essential oil has had success as a larvicide against mosquitoes. Using spearmint as a larvicide would be a greener alternative to synthetic insecticides due to their toxicity and negative affect to the environment. Used as a fumigant, spearmint essential oil is an effective insecticide against adult moths.
Medical uses: Antitumor The main chemical component of spearmint is the terpenoid carvone, which has been shown to aid in the inhibition of tumors. Perillyl alcohol, an additional terpenoid found in lower concentrations in spearmint, positively effects the regulation of various cell substances involved in cell growth and differentiation. Antioxidant Studies on spearmint have shown varying results on the antioxidant effects of the plant and its extracts. Results have ranged from spearmint essential oil displaying considerable free radical scavenging activity to no antioxidant activity in spearmint essential oil, but strong activity in spearmint methanolic extract. Antioxidant activity has been shown to be significantly higher in spearmint that is dried at lower temperatures rather than high. It is suggested this is due to the degradation of phenolics at high temperatures. In experiments demonstrating antioxidant properties in spearmint oil, the major component, carvone, alone showed lower antioxidant activity. Antimicrobial Spearmint has been historically used for its antimicrobial activity, which is likely due to the high concentration of carvone. Its in vitro antibacterial activity has been compared to, and is even said to surpass, that of amoxicillin, penicillin, and streptomycin. Spearmint oil is found to have higher activity against Gram-positive bacteria compared to Gram-negative bacteria, which may be due to differing sensitivities to oils. The degree of antimicrobial activity varies with the type of microorganism tested. Additional properties Studies have found significant antiandrogen effects in spearmint, specifically following routine spearmint herbal tea ingestion. Antispasmodic effects have been displayed in spearmint oil and carvone, the main chemical component of spearmint. Beverages Spearmint leaves are infused in water to make spearmint tea. Spearmint is an ingredient of Maghrebi mint tea. Grown in the mountainous regions of Morocco, this variety of mint possesses a clear, pungent, but mild aroma. Spearmint is an ingredient in several mixed drinks, such as the mojito and mint julep. Sweet tea, iced and flavoured with spearmint, is a summer tradition in the Southern United States.