Importance Of Medicinal Plants

Medicinal plants are plants or plant parts, which contains chemicals that yield medicinal properties. Medicinal plants gain significance because of their contribution to local health support systems, generation of local income, foreign exchange earnings and contribution to bio-diversity. They also have expanding economic opportunities through trade, and commercial development of medicines derived from natural resources, and increased production through cultivation, particularly in developing countries. Medicinal plants are the local heritage with global importance. Humans are endowed with a rich wealth of medicinal plants. In India herbs are the principal form of medicine. The history of medicine in India can be traced to the Vedic period. The Rig Veda, perhaps the oldest repository of human knowledge, written about 4500-1600 BC claims about 99 medicinal plants, the Yajur Veda, 82 plants and Sama

(b) Vacuum dryer and (c) spray dryers

Tray-Dryers

The drugs which do not contain volatile oils and are quite stable to heat or which need deactivation of enzymes are dried in tray dryers. In this process, hot air of the desired temperature is circulated through the dryers and this facilities the removal of water contents of the drugs (e.g. belladonna roots, tea leaves)

Vacuum Dryers

It is used for the drugs which are sensitive to higher temperature. e.g. tannic acid and digitalis leaves.

Spray Dryers

Drugs which are highly sensitive to atmospheric conditions and also to temperature of vacuum-drying are dried by this method. This technique is followed for quick drying of economically important plant or animal constituents, rather than the crude drugs. E.g. tannin, pectin etc.

Garbling (Dressing)

The next step in preparation of crude for market after drying is garbling. In this process dirt and other undesirable particles of the plant, which do not constitute drug are removed.