Any plant or part of the plant which contains active medicinal chemical constituents and gives a definite physiological response in the treatments of diseases in humans and other animals is called medicinal plant. Many people particularly in rural areas often rely on plant resources for their domestic and primary health care needs. Indigenous people living in resources rich areas learned to collect the useful plants and their parts from various habitats such as forests, scrubs, grasslands, cultivated fields, wetlands and riverbanks and use it for various purposes following traditional practices. Medicinal plants are, therefore getting wide attention and recognition throughout global markets. It is estimated that (worldwide) some 35000 plant species are used for medicinal purposes in most traditional system of medicine. The herbal or ‘Unani’ or Greco–arab system of medicine is a growing industry worldwide. Global sales of herbal products now exceed a staggering US$ 40 billion a year as more than 70% of the developing world’s population depends on the traditional systems of medicine. Nearly 80% of the world populations rely on traditional medicines for primary health care, most of which involve the use of plant extracts. Several reports about usage of medicinal plants suggest that greater than 90% of raw material for pharmaceutical companies is drawn from natural habitats in India, and China, 25% in USA, and 25% in Pakistan.
Medicinal plants is a major source of income for many people around the world and is also extensively used as a source of drugs for the treatment of many ailments. A number of allopathic drugs are comprised of medicinal plants in the industrialized countries so themedicinal plants are important for pharmacological research and drug development. Medicinal values of forest plants were given a special attention because traditional medicines are often cheaper and easier to access for the local people, than allopathic medicine.
The supply of medicinal plants come from two sources i.e. form wild and cultivated. Although there is growing interest in the cultivation of some Non Timber Forest Products and medicinal plants, the majority will probably continue to be harvested in the wild. Major part of the wild harvested material come from developing countries, a significant amount is also collected form developed countries. For example in the United States an estimated 200 tonnes of Echinacea angustifolia is harvested from wild annually. At one time, nearly all medicines were derived from biological resources. Even today they remain vital and as much as 67%-70% of modern medicines are derived from natural products.