MEDICINAL AND AROMATIC CROPS (2+1)

Introduction

 
Plants have been one of the important sources of medicines even since the dawn of human civilization. In spite of tremendous developments in the field of allopathy during the 20th century, plants still remain one of the major sources of drugs in modern as well as traditional system of medicine throughout the world. Approximately one-third of all pharmaceuticals are of plant origin, wherein fungi and bacteria are also included. Over 60% of all pharmaceuticals are plant-based.





Plants may have bioactive constituents like alkaloids, glycosides, steroids, phenols, tannin, antioxidants and other groups of compounds which may have marked pharmaceutical actions as anti-cancerous, anti-malarial, anti-helminthic or anti-dysentric, etc. Many of the essential oils, dyes, latex and even vegetable oils are also widely used as medicines. Many substances that go into making up medicines are frequently products of living cells, although seemingly ‘waste’ or intermediate, metabolic compounds and not an integral part of the protoplasm and may have no obvious utility to the plants.

Out of nearly 4, 50,000 species of higher plants available, only a small proportion have been investigated for medicinal properties and still a smaller number of plants yield well defined drugs. The same is the case with lower plants and with plants of the sea origin. Thus, the knowledge of plant constituents gained so far is still meager, considering the huge number of species available in the world. Approximately, only 10% of the organic constituents of plants are reported to be known and the remaining 90% are yet to be explored.

A very small proportion of Indian medicinal plants are lower plants like lichens, ferns, algae, etc. The majority of medicinal plants are higher plants. The major families in which medicinal plants occur are Fabaceae, Euphorbiaceae, Asteraceae, Poaceae, Rubiaceae, Cucurbitaceae, Apiaceae, Convolvulaceae, Malvaceae and Solanaceae.

Drugs are derived from trees, shrubs, herbs and even from primitive kinds of plants which do not fall into the above categories. They are made from fruits (Senna, Solanum viarum, Datura, etc.), flowers (Butea monosperma, Bauhinia variegata), leaves (Senna, Datura, Periwinkle, Tylophora, etc.,), stems (Liquorice, Ginger, Dioscorea, Costus, Garlic), roots (Rauvolfia, Periwinkle, Ginseng, etc.,), seeds (Isabgol, Abrus, Nux vomica) and even bark (Cinchona).