San: Yashtimadhu Hin: Jathimadh Mal: Irattimadhuram Tam:Athimadhuram
Ben: Yashtomadhu Pun:Muleti
Importance: Liquorice or Muleti is a perennial herb or undershrub about 1m high. Its dried peeled or unpeeled underground stems and roots constitute the drug which is an important constituent of all cough and catarrh syrups, throat lozenges and pastilles. This has been used in medicine for more than 4000 years. Hippocrates (400 BC) mentioned its use as a remedy for ulcers and quenching of thirst. Dioscorides, the father of Greek medicine described this drug in detail and considered it useful for maintaining shape of arteries and in burning stomach, trouble of liver and kidney, scabies, healing of wounds and as a remedy for eye diseases. It has been used in Arab system of medicine for more than 600 years from where it has been adopted to modern medicine (Gibson, 1978).
The commercial name of the dried rhizome and root of the plant is liquorice which is used as flavouring agent and the taste coorigent in pharmaceutical and confectionery industries and its products are widely reported to be useful in ulcer therapy. Glycyrrhizin, a triterpene glucoside, is the principal constituent of G. glabra which is 50 times sweeter than sugar.
Distribution: Liquorice is native to Mediterranean region, South Europe and Middle East. It is widely distributed in Spain, Italy, Greece, Syria, Iraq, Afghanistan, Turkey, parts of USSR and China. However its cultivation is limited to small areas in USSR, UK, and USA. In India, it grows in Punjab and Jammu and Kashmir. Semi arid areas of Haryana, Rajasthan and Gujarath states are suitable for the cultivation of Liquorice. However, its commercial cultivation has not yet been possible and the domestic requirement is largely met through imports.
Botany: Glycyrrhiza glabra Linn. belongs to the family Papilionaceae. The word Glycyrrhiza is of Greek origin meaning ‘sweet’ and glabra means ‘smooth’ which refers to smooth fruit of the species. This is a tall perennial, self pollinated herb or undershrub about 1m high with long cylindrical burrowing rootstock and horizontal creeping stolons which reach 1.5-1.8m in length. Leaves are alternate, pinnate with 9-17 leaflets. Leaflets are yellowish-green, 2.5-5cm long, ovate and obtuse. Flowers are pale blue arranged in a raceme and 1.25cm long. Calyx is glandular and pubescent. The pods are glabrous, red to brown having 3-4 seeds. Rhizome is soft, flexible and fibrous with light yellow colour and a characteristic sweet taste.
Agrotechnology: This plant thrives well in subtropical areas with very warm summers and cool winters with a rainfall not exceeding 500mm. Semi -arid and arid areas in subtropical zones are not suitable for the cultivation of this crop. It does not tolerate high humidity and waterlogged conditions. Well drained light loam soils which are rich in calcium and magnesium with slightly alkaline pH and free from stones are ideal for this crop. There are a number of varieties of this crop among which Spanish, Russian and Persian liquorice are quite common. Commercial varieties are Typica, Regel and Herd. This is propagated by seed, but usually multiplied vegetatively either through crown cuttings or stolon pieces. In the case of crown cuttings, 10-15cm long crown pieces with 2-3 buds are planted vertically at a distance of 0.6-0.7m in rows 1-1.5m apart. However, most of the liquorice is propagated through stolon pieces of the above size planted horizontally, preferably on ridges during spring at the same distance as above. Rapid clonal propagation is also possible by tissue culture technique. Murashige and Skoog’s medium supplemented with 6-benzylaminopurine and indole-3-acetic acid favoured multiple shoot production without any intervening callus phase. These regenerated plantlets can be transferred to earthen pots in the glass house and after a brief hardening phase, these are transplanted in the field with a high rate (90-95%) of survival. This plant normally does not require much fertilizers but in deficient soils, it is better to apply 10-15 tonnes FYM per hectare before planting. The field should be immediately irrigated after planting in spring and after the crop has sprouted, it requires very little irrigation. Space between the rows should be kept free from weeds. Short term vegetables like carrot or cabbage can be planted between the rows for additional income. In order to produce good rhizome, flowering shoots are clipped. No serious disease except leaf spot caused by Cercospora cavarae has been reported in this crop. Roots are ready for harvesting after 3-4 years. The root is dug when the top has dried during autumn (November- December). A trench 60cm deep is dug along the ridges and the entire root is lifted. Broken parts of the root left in the soil, sprout again and give another crop after 2-3 years. Thus liquorice once planted properly can be harvested for 10-15 years.
Postharvest technology: Harvested roots are cut into pieces of 15-20cm long and 1-2cm in diameter. They are washed and dried upto 6-8% moisture in the sun and shade alternately which reduces the weight by 50%. The average yield of dried roots varies from 1-3 tonnes per hectare depending on the variety, soil and climatic conditions.
Properties and activity: Roots gave a number of compounds the most important bieng a glucoside, glycyrrhizin which gave glycyrrhetinic acid on enzyme hydrolysis. Root also contains flavans, flavones, iso-flavanoes and coumarins including a 4-methyl coumarin, liqcoumarin, glabridin, glabrene, 4’-0-methyl and 3’-methoxyglabridin, formononetin, salicylic acid, 0-acetyl salicylic acid which has been isolated first time from nature, hispaglabridins A and B and 4’0- methylglabridin.On hydrolysis it also gave two molecules of d-glucuronic acid, each linked with 1-2 linkage to 3-hydroxyl of the sapogenin (Elgamal et al, 1969) Glycyrrhizin is antidiuretic, antiinflammatory, expectorant, antiulcerous, antihistamine. Glycyrrhizic acid is antiviral. The roots are emetic, tonic, diuretic, demulcent, mild laxative, aphrodisiac, trichogenous, expectorant, emmenagogue, alexipharmic, alterant and intellect promoting.