Common Name : Pudina / Corn Mint
Plant Parts Used : Parts Used. Leaves, flowering tops, stems, extract
Description :
A small herb of erect habit. Stem short, branched, square and creeping rhizomes. Leaves narrow below stalked, oblong, lanceolate toothed, 3-6 cm long. Small lilac flowers are in whorls.
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Characteristics and Constituents :
The main constituents of oil are 4.5-10% esters- Menthyl acetate, not less than 44% free alcohols calculated as menthol and 15-20% of ketones calculated as methonic. M. arvensis yields 70-90% of menthol. A key intermediate (+) pulegone that appears to be either oxidised to mentho-furane or reduced to (+) isomethone or (-) menthone, which are further reduced and converted to esters, menthone giving menthol and menthyl acetate. The other component found are œ - pipene, œ -thujene, -Iimonine, ß-phellandrene, cineol piperitone, caryophyllene and unidentified sesquiterpene.
Actions and Uses :
The antheimin.tic, antifungal and antibacterial actions of menthol have been studied extensively. Menthol paralyses nematode muscles, and depresses isolated rabbit intestine. Menthol has a weak to moderate local anaesthetic activity. A study of the effect of menthol on sensory receptors in the skin, and on the spinal monosynaptic reflex in the cat, showed that nerve discharge in the saphenous nerve was promoted by external application of 0.01-0.12% menthol.
In urethane-anaesthetized rabbits, menthol lowered the blood pressure slightly, but had no effect on respiration, heart rate and arterial blood flow. It has a vasodilating action on rabbit car on direct application. An increase(approx.40%) in gastro-enemus blood flow was induced on external application of a plaster containing menthol to rabbit hind limb. Local anaesthetic activity has been shown. Mentha Arvensis is widely used in many parts of the world, as a home remedy and in medical practice. Its use is as an expectorant, urinary tonic, in diseases of the liver and spleen, asthma and for pain in the joints. In India and China, the leaves and stem are made into an infusion, as a carminative and antispasmodic. It is used as a diaphoretic in fevers, indigestion, and cephalgia. An infusion with tea and lemon grass is used for general well being, carminative action and in fever.
An adverse effect reported on exposure to large doses of menthol, is the degradation of biological membranes. Menthol and pulegone from Mentha arvensis were administered to rats by gavage for 28 days at several dose levels. At the two highest (80 and 160 mg/kg) doses, pulegone induced atonia, lowered blood creatinine level, and caused histopathological changes in the liver and white matter of the cerebellum. Menthol exposure ( 200 mg/kg) induced weight reduction and hepatocyte vacuolation at all dose levels.
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