Horticulture :: Medicinal Crops

Horticulture :: Medicinal Crops ::Gymnema

GYMNEMA

Madhunashini (Gymneme sylvestre R.Br.) is an important medicinal climber acclaimed for its anti-diabetic properties. Its preparations have profound actions on the modulating taste, particularly suppressing sweet taste sensations. For this reason gymnema sylvestre is known in Hindi as gurmar or “sugar destroyer”. It is widely found growing in the tropics of Africa, Asia and Malaysia. In India, this plant is found growing in abundance in the forests of Karnataka, Tamil Nadu and Bihar. Due to its raising demand in South East Asian countries, the plant is becoming endangered particularly in Tamil Nadu.

Uses:

Gymnema has pronounced effects on blood sugar, at least among diabetics. Within the past two decades researchers have determined that gymnema extracts mat even play a role in the treatment of Type 1 diabetics, who typically need daily injections of insulin to control the disease. Gymnema taken orally lowers blood glucose levels and improves blood fat and cholesterol profiles. This climber is extensively used in almost all the Indian system of medicine as a remedy for rheumatism, cough, ulcer and pain in eyes. It is also useful in inflammations, dyspepsia, constipation, jaundice etc., Roots have been reported as remedy for snakebite. The anti-diabetic property of the plant is attributed to the presence of mixture of triterpines and saponins in the leaves. These have been designated as gymnemic acids A,B,C and D, which have the gymnemagenin and gymnestrogenins.

Soil and Climate:

The species grows on a variety of soil in different localities. Red sandy loam or medium deep black soil is reported to be ideal for this crop. The plant is sensitive to water logging and hence its cultivation on such soil should be avoided.

Madhunashini prefers tropical and sub-tropical type of climate. It is found growing even in dry areas also. The areas with high or medium well distributed rainfall are suitable for its cultivation.

Types:

Based on the leaf size, the climber can be classified into two types.

Small leaves type: Leaves are oval measuring 1.0-3.5 cm length and 1.5-2.5 cm very soft, found in dry regions.
Broad and pubescent type: These leaves are also oval measuring 3-6 cm in length and 3.5-5.0 cm in width. Leaves are dark green compared to small leaf type and also are pubesecent.

Propagation:

The plant can be multiplied either by seeds or by stem cuttings.

Propagation by seeds

The plant bears the fruits during November-December months. Seeds are collected from freshly harvested fruits. Then they soaked overnight in water and next day the seeds are sown in the seed pan containing soil mixed with sand. The seed pans are watered daily and the seeds germinate in about 15 days. After 40-50 days they are transplanted to polythene bags containing a mixture of soil, sand and FYM mixed in equal proportion. About 2-3 kg seeds are required for raising one hectare crop.

Propagation by cuttings

This method is the commercial method. The matured stem cuttings of 15 cm length are treated with 500ppm IBA for about 18 hours. Then they are planted in the polythene bags containing equal proportions of soil, sand and well rotten FYM. Before planting in the polythene bags the cuttings are also treated with 1 percent Bavistin and have to be watered every day. Roots develop after ninety days if planting and they are transplanted in the main field.
Land preparation and planting
Gymnema is an evergreen climber and the best season for planting is june-july. After ploughing and leveling of the land, 45cm3 sized pits are made at a distance of 2.5 m between the rows and 1.75 m between plants (within the row). The pits are dug open 15 days earlier to planting and are filled with green leaves and top soil and 2 kgs of well rotten manure per pit. The pits are to be irrigated and left for one week, and then the rooted cuttings are planted in the pits.

Training:
Since gymnema is a climber, it has to be trained on trellies of “Y” shape iron structure bent at 600 to be sides. The two main stems are trained on opposite directions. Care should be taken that the climbers should not fall on to the ground. The climber can also be trained to a wire fence which will serve double purpose.

Manures and fertilizers:

5t/ha of FYM is to be applied as basal dose at the time of land preparation. The inorganic fertilizers application of 95:45:35kg/ha of NPK is recommended.

Interculture:

Irrigation is given immediately after planting and fertilizers are applied. Later on, irrigation once in 5-6 days is sufficient. During summer, depending in the weather condition irrigation frequency needs to be increased. Since, weeds compete with the plants for water and nutrients, an area of one metre around the plant needs to be kept clean by hand weeding at periodical intervals.

Plant protection:

Thrips, mites and green fly are the important insects observed, which can be controlled by spraying Dimethoate (Rogor 2ml per liter of water). Mites can be effectively controlled by any Acaricide. To control green fly, monocrotophos can be sprayed (1 ml/l).
Medicinal plants require production involving minimal or no usage of chemical pesticides. Organic practices include control measures using neem based formulations; fish oil resin soap can be used to manage such sucking pests. Botanicals viz., extracts of garlic, Vitex negundo, Lantana camera, Clerodendron inerme, Calotropis gigantean are often combined and sprayed periodically for controlling the pests.
Powdery mildew and leaf spot are the major disease and can be controlled by spraying 3g of water soluble sulphur (or) 2g of Mancozeb in one liter of water at an interval of 10-15 days.

Harvesting and yield:

The crop is ready for harvest during the second year after planting. Leaves are the economic part and the harvesting of leaves begin when plants start flowering i.e., during end of June or first week of July. Leaves can be harvested along with flowers either by hand or can be cut with sicke/knife. The harvested leaves are dried under shade by allowing sufficient air to circulate by spreading thinly on clear ground for about 7-8 days. Direct sunlight should be avoided to maintain the quality of the leaves.
An average of 5-6 kg dried leaves per plant can be obtained from at 3-4 years old plant yielding about 10,000 – 15,000 kgs of dried leaves per hectare. The crop can be cultivated for 10-15 years under good management.