Lemongrass Oil

LEMONGRASS OIL

Synonyms

East India lemongrass, Malabar, or Cochin Lemongrass.

Biological Source

Lemongrass oil is obtained form Cymbopogon flexuosus Stapf. (syn. Andropogon nardus var. flexuosus Hack.), belonging to family Poaceae. It contains not less than 75% of aldehydes calculated as citral.

Geographical Source

Lemongrass is indigenous to India and is found in Tin-nevelli, Travancore, and Cochin. Two principal varieties of Lemongrass are recognized as the red-stemmed variety, the true C. flexuosus, which is a source of East Indian Lemongrass oil and the white-stemmed variety which is designated as C. flexuosus var. albescens. The oil from the latter is low in aldehyde content and is slightly soluble in 70% alcohol.

Cultivation

Lemongrass grows best in well-drained sandy loam or in light sandy soil. Dark, heavy, rich soil, gives a higher yield of grass, but the oil obtained from it has lower citral content. Warmth and sunshine favour oil development. The grass grown on lower slopes, less exposed to heavy rains, is rich in oil content. The grass is cultivated in forest clearings or on hill slopes at an altitude of about 700 m. The ground is ploughed in March–April and seeds are sown at random. The grasses come up with the first shower of the monsoon. Weeding is carried out systematically in the plantation. Protection against grazing is necessary. The grass is ready for cutting at the end of May or early in June and may be harvested every 35–40 days till November or December. The citral content of the oil is high (83%) when it is obtained from grass harvested during September–December. After cutting, the stubbles are burnt before the sporadic April monsoon shower. Fresh shoots come up from the roots with the start of regular monsoon, and the grass is ready for harvesting by the end of May. Plantations are renewed every six to eight years.

Characteristics

A light-coloured oil, rich in citral content, is obtained by steam distillation. The yield varies form 0.25 to 0.5% per acre.

                   Cymbopogon flexuosus

Chemical Constituents

Lemongrass oil is the principal source of citral (68–85%) from which ionone is derived. The oil also contains methyl heptanone, decyl aldehyde, geraniol, linalool, limonene, dipentene, citronellal, triacontane, triacontanol, intermedeol, isointermedeol, α- and β-pinene, car-3-ene, myrcene, ocimene, β-phellandrene, α-terpinene, p-cymene, terpi-nolene, methyl heptenone, geranyl acetate, β-caryophyllene, β-selinene, β-, γ- and δ-elemenes, α- and β-bisabolene, α-curcumene, γ- and δ-cadinene, methyl eugenol, elemol, β -caryophyllene oxide, eugenol, β-eudesmol, elemicin, farnesol, juniper-camphor, geraniol, anisaldehyde, terpinen-4-ol, α - and β-terpineol, and borneol.

Uses

The oil is used in perfumery, soaps, and cosmetics and as a mosquito repellent. Lonones obtained from citral are required for synthetic violet perfumes.

Marketed Products

It is one of the ingredients of the preparation known as Sage lion balm (Sage Herbals).