Synonyms: Peppermint oil, Oleum mentha piperita, Mint oil.
Biological source: Mentha oil is obtained by steam distillation of flowering tops of Mentha piperita Linn.
Family: Labiatae.
Geographical source: It is cultivated in Japan, England, France, Italy, USA, Bulgaria, USSR and India (Jammu and Uttar Pradesh).
Cultivation and Collection:
The basic requirement for the cultivation of mentha are well drained fertile sandy loam
soil (pH = 7), rainfall (95 to 105 cm), temperature (15 to 25°C), altitude (250 to 400 meter).The suckers are vegetatively propagated for cultivation purpose.
Description:
Colour: Yellowish in colour or colourless
Odour: Agreeable, pleasant and characteristic
Taste: Aromatic, Pungent (followed by cooling sensation)
Solubility: Soluble in alcohol (70 percent), alcohol, ether and chloroform insoluble in
water.
Weight per ml: 0.9 to 0.912 gm.
Optical rotation: At 25°C −16° to −30°.
Refractive index: 1.4590 to 1.4650.
Chemical nature: Neutral to litmus paper.
Chemical Constituents:
It mainly contains l-menthol (either in free form or ester form). There are three varieties of peppermint i.e. American variety (contain 80 per cent menthol), Japanese variety (contain 70 to 90 per cent menthol) and Indian variety which contain 70 per cent of menthol. Other
important constituents are menthofuran, menthone, menthyl acetate, menthyl isovalerate,
jasmone and other derivatives like cineole, l-limonene, isopulegone, camphene, pinene, jasmine and esters (possess pleasant odour). Menthofuran is responsible for bad odour due to resinification.
Chemical Test:
Take few ml of oil and mix it with 5 ml nitric acid solution. The solution should be made by adding 1 ml nitric acid into 300 ml of glacial acetic acid. Heat the solution on waterbath
for 5 to 10 minutes. The liquid develops bluish colour which gets deep in colour upon more
heating and shows copper coloured fluorescence and after few minutes it turns golden yellow.
Uses:
The oil is used as carminative, stimulant, flavouring agent and antiseptic. It is used in
pharmaceutical preparations, cosmetic industries, tooth paste, tooth powder, shaving cream,
chewing gum, candies, jellies, perfumery and essence manufacturing.