CHAPTER ONE
1.0 INTRODUCTION
Many cultures throughout the world still rely on traditional medicinal plants for their primary health care. Almost all the modern medicines are derived from plant with medicinal values. It is a fact that traditional medicine has become an important means of healing various ailments [Farnsworth N, 1985]. Although modern means may be available in many developed countries, people are still turning to alternative or complimentary therapist by using medicinal herbs yet few plant species that have been scientifically analysed for the possible medical applications. Documentaries are available for some of these medicinal plants. Tropical and sub tropical Africa contains between 40-45000 species of plant with a lot potential for the development of modern medicine but out of which only about 5000 species have just been harnessed [Rukangira E, 2004].
1.1 HISTORY OF MEDICINAL PLANTS.
Plants had been used for medicinal purposes long before they were recorded in history .Ancient Chinese and Egyptian papyrus writings describe medicinal uses for plant as early 3000BC [Farnsworth N, 1985]. Indigenous culture [such as Africa and native American] used plants in their healing rituals, while other developed traditional medicinal system [such as Ayurcela and traditional Chinese medicine] in which herbal therapies were used, [Farnsworth N,1985] .
In the early 19th century, when chemical analysis first become available scientist began to extract and modify the active ingredients from plants. Later, chemists began making their own version of plant compounds and overtime the use of herbal medicine declined in favour of drugs. Almost one forth a pharmaceutical drugs are derived from plants [Abbiw D, 1990].
Recently, the world health organisation estimated that 80% of people worldwide rely on herbal medicine for some part of their primary health care [Abbiw D, 1990]. In Germany about 600-700 plant based medicines are available and are prescribed by some 70% of Germany physicians. In the past 20years in the United States public dissatisfaction with the cause of prescription medications, combined with an interest in returning to natural or organic remedies as lead to an increase in herbal medicine use, [Abbiw D, 1990].
1.2 USES OF HERBAL MEDICINE
The use of herbal supplements has increased dramatically over the past 30years. Herbal supplement are classified as dietary supplement by the United States dietary supplement Health and education act [DSHEA] of 1994 [R.N. Okigbo, 2009]. That means herbal supplement unlike modern medicine can be sold in large quantity without any prescribed dosage.
However, herbal supplement must be made according to good manufacturing practices. Some examples of herbal supplements include Echinacea (Echinacea purperea and related species) ,St John’s Wort (Hypericum Perforalium) ,Ginkgo (Gingkobiloba), Garlic (Allium sativum), saw palmelto ( seronoa repens), Ginserg (panaxainseng or Asian ginseng), Goldenseal (Hydrastis canadesis ) ,valerian (valeriana officinale) , chamomile (matricaria reticutita) Evening primsrose (Oenother biennis), and milk thistle (silybum marianum) [Abbiw D, 1990].
Often, herbs may be used together because the combination is more effective and may have fewer side effects Health care provider must take many factors in account when recommending herbs, including the species and variety of the plant, plants habitat how it was stored and processed and whether or not these are contaminated by some other compounds like heavy metals and pesticides.
Herbal medicines is also used to treat may conditions such as asthma , eczema, pre menstrual syndrome ,rheumatoid arthritis, migraine, menopausal symptoms , chronic fatigues, and cancer among others. Herbal supplement are best taken under guidance of a trained health care provider. Some common herbs and their uses are discussed below:
– Alstonia (Alstonia boonei) the bark contains echitamine ( main alkaloid), two echitemidine derivatives and a lactone boonein. The two alkaloids have diuretic , spasmolytic and hypotensive properties heumatism and [Kade Sidiyasa, 1998].
– The bark of the Alstonia contricta and the Alstonia scholaris is a source of remedy against malaria, toothache, rheumatism and snake bite [John H.Wiersema, 2007]
– Alstonia scholaris is used solely for curing malaria , epilepsy, skin conditions and asthma. It is also used as an astringent herb for treating urticaria, chronic dysentery, diarrhea, snake bite and for upper purification process of Panchakarma. The milky juice of the tree is applied to ulcers. The bark contains the alkaloids ditamine, echitanine and echitamine and used to serve as alternative to quinine [John H.Wiersema, 2007]
1.3 AIMS AND OBJECTIVE
· The study is aimed at studying the medicinal components of Alstonia boonei root bark.
· To gain insight into the therapeutic properties of the plant.
· To investigate into the secondary metabolites present in the plant.