Globally, there has been concerted efforts to monitor quality and regulate the growing business of phytodrugs and traditional medicine. Data analysis confirms that the phytodrugs serve as crucial sources for the new drugs which can be further modified during drug development. Health authorities and governments of various countries have taken an active interest in providing standardised phytomedications.
Studies reveal that the origin of the drugs developed in the last two decades showed that natural products or natural–derived drugs comprised of 28 per cent of all New Chemical Entities (NCEs). Not only were this 24 per cent of the NCEs synthetic or natural base compounds thus elevating the percentage of such products to nearly 52 per cent of all NCEs. This confirms the fact that the natural products including phytodrugs serve as crucial sources for the new drugs which can be further modified during drug development.
According to World Health Organisation (WHO), as much as 80 per cent of the world’s population relies on traditional medicine. With increased concerns about rising healthcare costs, some governments are encouraging the use of indigenous systems of medicine rather than expensive imported drugs. This has been a strong driver for the resuscitation of phyto products. Today's healthcare systems rely largely on plant material. Much of the world's population depends on traditional medicine to meet daily health requirements, especially within developing countries. Use of plant-based remedies is also widespread in many industrialized countries and numerous pharmaceuticals are based on or derived from plant compounds.
The pharmaceutical industry is both large and highly successful. At present, about 50 per cent of the total plant-derived drug sales come from single entities, while the remaining 50 per cent come from herbal remedies. Although the latter have greater volumes of consumption, the relatively low volumes of single entities, which are mostly prescription products, are more than compensated by their higher prices. Single entity plant drugs, which mostly treat serious medical ills, include atropine, digoxin, morphine, paclitaxel, pilocarpine, reserpine, scopolamine, topotecan and vincristine, among many others. Several of the compounds have outlived their usefulness in light of better alternatives, however, and are exhibiting decline in sales. On the other hand, as a consequence of new drug developments, single entities overall are projected to increase their market share of the combined total future dollar sales.
Sales of plant-based drugs in US
Sales of these plant-based drugs in the US amounted to some $4.5 billion in 1980 and an estimated $15.5 billion in 1990. Development of drug from plants is a long and arduous process which involves many disciplines. It has been estimated that only 5 to 15 per cent of the approximately 250,000 species of higher plants have been systematically investigated for the presence of bioactive compounds. In the industrialized countries, substances derived from plants are in everyday use digoxin, ephedrine, morphine, quinine and many more. Less often used like reserpine, guggulipid and artemisinin are equally well known. All 119 plant-derived drugs used worldwide in 1991 came from fewer than 90 of the 250,000 plant species that have been identified.
Studies reveal that natural products are used to treat 87 per cent of all categorised human diseases including infections, cancer, and above all, auto-immune. There was no introduction of any natural or phytodrug for seven drug categories (anaesthetic, anti-anginal, anti-histaminic, anxiolytic, antidote, diuretic, and hypno-sedative) during 1981 to 2002. In the case of anti-bacterial agents, natural product including phytodrugs have made significant contributions as either direct treatments or templates for synthetic modification. Of the 90 drugs of that types became commercially available in the United States or were approved worldwide from 1982 to 2002, 79 per cent can be traced to a natural product or phytodrug origin.
Traditional Medicine and Complementary/Alternative Medicine (TM/CAM), which are predominantly based on herbal and other herbal ingredients, have come to be widely and increasingly used in both developing and developed countries despite limited evidence of efficacy particularly in the last two decades. TM/CAM are used for the full spectrum of disease from self-limited to life-threatening illnesses.
The World Bank reports trade in medicinal plants, botanical drug products and raw materials is growing at an annual growth rate between 5 and 15per cent. In India the value of botanical related trade is about US$ 10 billion per annum with annual export of US$ 10 billion while China’s annual herbal drug production is worth US $ 48 billion with export of US$ .6 billion. Presently, the United states is the largest market for Indian botanical products accounting for about 50 per cent of the total exports. Japan, Hong Kong, Korea and Singapore are the major importer of Traditional Chinese Medicine (TCM) taking 66 per cent share of China’s botanical drugs export.
According to a study by Grifo and colleagues, 884 of a representative, 150 prescription of drugs in the United States fell in the category of natural products and related drugs . They are prescribed predominantly as anti-allergic/pulmonary/ respiratory agents, analgesics, cardiovascular drugs and for infectious diseases. Another study found that natural products and related drugs accounted for 40per cent, 24 per cent, and 26 per cent, respectively of the top 35 worldwide ethical drug sale from 2000 to 2002. Many European and Asian countries have taken a more holistic approach to researching the efficacy of herbal remedies. In Germany, France and Japan, the past 20 years have seen a rapid increase in research into and use of standardised, semipurifed, herbal extracts called phytomedicines.
Earlier the Traditional Systems of Medicine formed the foundation of healthcare in India and several years after attaining independence there was little capability and expertise available. It was later after establishing the Central Drug Research Institute (CDRI) that the task of developing modern drugs was initiated. Being a task which requires a lot of tie and involves immense costs, the new drug discovery thus depend on the chances of finding new lead molecules after screening a large number of potential sources. It was, therefore, thought prudent to narrow down this search to plants with known therapeutic activities used in traditional remedies.
Core of Indian medicine systems
Three major indigenous systems of medicine form the core of Indian medicine systems which include Ayurveda, Unani and Siddha. Among these, Ayurveda alone describes use of over 600 medicinal plants in some 8,000 formulations. India has one of the richest plant medical traditions in the world. It is a tradition that is of remarkable contemporary relevance for ensuring health security to the teeming millions.
In addition, the publication in 1993 of WHO research guidelines safety and efficacy studies of herbal medicines provided a major stimulus to the development of herbal remedies wherever feasible. Initially, the isolation of pure molecules from plants and their further development to “modern” drugs constituted the basic objective of such natural product research. This approach changed when a standardised extract of Commiphora mukul (gugulipid) was developed as a cholesterol-lowering drug by CDRI and approved by the the Drugs Controller General of India.
(The author is a herbal consultant, based in Mohali)