Depleting forests endanger pharmacological progress

by Miran PERERA

The disappearance of plant species from depleting forests is most damaging to the pharmacological progress and the pharmaceutical industry, which annually spends vast amounts of funds and energy to discover plant based drugs. Though we live in an era of synthetics our dependence on nature for medicinal properties has not diminished to any extent.

It has been found that more than half of the prescriptions doled out by physicians the world over for various ailments contain properties derived from plants. From very remote times the study of nature was chiefly concerned with the utilisation of plants as sources of food and drugs.

The relationship between Botany and Pharmacology has been so close that out of ten books that Pliny (23 - 79 AD) wrote on natural history, eight were on the subject of medicinal plants. The folklore of native tribes in many parts of the world has been ever rich in knowledge about medicinal plants and floral pharmacopoeias are said to have been used by almost all ancient civilizations.

Sri Lanka is one of the world's biodiversity hot spots. This means that we have a wide range of biological species, fauna and flora in a variety of habitats. This article deals with the different dangers that are encountered by destroying forests cover specially its effects on pharmacology. Our forests are among the most floristically rich forests in Asia and are quite unique for a small country.

Diversity

The diversity while enhancing pharmacological progress, comes as a result of the wide variations in rainfall altitude and soil within the country. Our unique geological formation also plays a major role in the diversity of our vegetation. Vegetation reflects the combined effect of topography, climate and soils and destroying of such vegetation, results in grave repercussions on animal and human species. Climate is the main factor that determines the distribution and type of forests.

In the past, except for a few areas because of their soil, the whole island was covered in forests. With the increase in population and the demand for more and more land, forests were destroyed to cater to these growing need. This changed the forest landscape of the island and depleted the progress of Ayurvedic pharmaceutical industry.

It was further altered when during the British period large extends of highland forests were cleared for the cultivation of coffee and later tea. The primitive man's knowledge about various medicinal plants was so vast that the World Health Organization (WHO) has computerise 3000 plant species which have been used by him for population control alone.

To utilise these pharmaceutical data it is felt that we should endeavour to preserve all the native plants.

It is a tragedy therefore to note that irresponsible forest clearing and destruction of forests for various other purposes, chiefly in the tropics, has endangered the survival of many of these species of plants. The Forest Ordinance of 1885 was the first item of legislation which enabled the proclamation of forest reserves for conservation purposes.

At that time the crown or the state owned 95% of the forests in the island. Many areas were placed with the Forest Department as proposed forest reserves since the process of establishing reserves was time consuming. Village forests were placed under the district government agents, and other crown forests were at various times transferred from the forest department to the respective government agents. In addition the department of Wild Life Conservation had certain forest areas established for the protection of wild life in five categories under the Fauna and Flora Protection Ordinance. Till 1944, all forest and wildlife conservation came under the purview of the Forest Department. The Department of Wild Life Conservation was formed that year and took over; the function of protecting the island's wild life.

Synthetics

Though we live in an era of synthetics our dependence on nature for medicinal properties has not diminished to any extent.

It has been found that more than half of the prescriptions doled out by physicians the world over for various ailments contain properties derived from plants. The alkaloid called Ephedrine now used as a nasal decongestant or a nervous stimulant is a derivative of Ephedrine, a shrub known in China for more than 5,000 years.

Ergotrine is an alkaloid widely administered today to contract uterine muscles during childbirth. This is derived from Ergot, a poisonous substance found on a fungus of the genus Claviceps which affects rye and other serials. Dioxin, a heart stimulant is a compound extracted from Spanish Fox, a common weed in Europe.

Between 70-90% of the plant species known to science are found in the tropical rain forests. Notwithstanding, this it is, in these that the greatest damage is seen today and species are becoming extinct even before they are discovered. The rate of destruction of the tropical forests is estimated to be an incredible 20 hectares a minute. In Malaya, 350,000 hectares of valuable forest cover are being indiscriminately cleared annually.

It is said that among the 25,000 species of flowering plants found in South East Asia there are thousands which are economically vital to agricultural improvements and as pest control or sources of new drugs.

A great percentage of the 50,000 plant species at present listed as endangered are those found on island habitats such as Sri Lanka. Generally such plant and animal species having a very susceptible ecological balance in restricted habitats are the most commonly denuded by man's inroads. Considering Sri Lanka's natural vegetation there is a striking variety of forest types brought about by spatial variations in rainfall, altitude and soil.

The forests have been categorised broadly as tropical wet low land evergreen forests (at elevations between 0-1000m); wet sub montane forests (at elevations between 1000-1500m in the wet zone); wet montane forests (at elevations of 1,500-2500m); tropical dry mixed evergreen forests in the dry low lands, with riverine vegetation along riverbanks; tropical moist evergreen forests in the intermediate zone and thorny scrub in the arid areas.

In Sri Lanka and other countries many names are applied to the same forest type making it rather confusing for anyone first interested in forestry. One of the major problems faced in the management of various forest types are the invasive species that have now proliferated. There are also such invasive plants with medicinal properties. Invasive species are those species that have come in from elsewhere and take over the habitats and other resources of native species.

Invasive species increase their populations drastically at the expense of the existing flora. They are of two categories. The native and the alien - native plants or animals become invasive, then a change of environmental conditions or some other factor causes their ordinary population to multiply drastically suffocating the other species. Aliens are those species that have been introduced deliberately or accidentally from outside.

Devastation

During the last 300 years or so, man has almost annihilated many species from existence. By the devastation of forest cover and the introduction of alien plants and animals pharmaceutical progress has been impeded. Because of this, man has brought about a complete vegetative upheaval in many areas of the world.

The best way to encourage the survival potential of an endangered species is to protect it in its own natural habitat. But for many species this is not possible since their habitats have been so much disturbed and altered. In the modern world botanical gardens and horticultural centres go along way in fulfilling the requirements of displaced species.

The planting of special reserves of forests with plants having large medicinal properties is a serious priority amidst the destruction of forests in a large scale.

The future of the pharmaceutical industry depends on large scale thriving forests. At this juncture global human health is at risk for the want of new effective medication and advanced medical practices. There is advanced research being made to prepare new medicines which are more effective.

If our own Ayurvedic system is to be protected and preserved for the future generations we have to protect our medicinal plants in a large scale as most Ayurvedic pharmaceuticals are made from plants.