INTRODUCTION AND LITERATURE REVIEW
BACKGROUND OF STUDY
Plants are important in our everyday existence. They provide our foods, produce the oxygen we breathe, and serve as raw materials for many industrial products such as clothes, foot wears and so many others. Plants also provide raw materials for our buildings and in the manufacture of biofuels, dyes, perfumes, pesticides and drugs.
Historically, plants have always provided a source of inspiration for novel drug compounds as plant derived medicines have made large contributions to human health and well being. Medicinal plants which produce and accumulate constituents have medical properties (Adedeji et al., 2006). The use of plants in traditional medical practice has a long drawn history, and remains the mainstay of primary health care in most of the third world. Traditional medicines are used by about 60% of the world population; in both developing and developed countries where modern medicines are predominantly used (Mythilypriya et al., 2007). While an estimated 60-80% Africa’s population depends solely on herbal remedies for its primary health care needs. In diversity, plants are thought to be between 250,000 to 400,000 species spread across all continents from the Antarctic to the Arctic. They thrive in all environments from the flooded planes to the deserts, and from those who live on the seas and oceans to others that thrive on fresh water and ponds.
For classification and easy identifications, plants were divided into different taxonomical groups known as kingdoms; these are further streamlined into phylum, class, order, family genus and species. Within the family of the Clusiacea is found an amazing plant called the bitter kola (Garcinia kola).
Garcinia kola (Heckel) is an angiospermae, belonging to the family Guttiferae and is known in commerce as bitter cola. On chewing, G. kola seed has a bitter astringent and resinous taste, somewhat resembling that of raw coffee, followed by a slight sweetness. Bitter cola is a highly valued ingredient in African ethno medicine because of its varied and numerous uses which are social and medicinal; thus making the plant an essential ingredient in folk medicine. Medicinal plants such as G. kola are believed to be an important source of new chemical substances with potential therapeutic benefits (Eisner, 1990).
Bitter Kola (Garcinia Kola) is popular in Southern Nigeria. The plant is extensively used in herbal medicine and as food. It prevails as a multipurpose tree crop in the home gardens of Southern Nigeria.
Traditionally, the plant is used as a natural antimicrobial. Other medicinal properties of the plant include its usage in the treatment of skin infections in Liberia and Congo Democratic Republic. The powdered bark of the plant is applied to malignant tumors, cancers etc. The plants latex is taken internally for gonorrhea and externally to seal new wounds and prevent sepsis.
World Health Organization (1999) estimated that there were 135 million people in the world with diabetes and that this would rise to 380 million by 2025, this report also highlighted the fact that low and middle income countries will bear the brunt of the increase with Africa contributing significantly to this rise (King et al., 1998). In Nigeria, World Health Organization has disclosed that more than 1.71 million citizens above 15 years are diabetic, 70, 000 children under 15 years develop insulin dependent diabetes each year, if nothing is done, diabetes sufferers will grow to about 484 million by 2030 (Winifred, 2008). Diabetes mellitus and other numerous pathological events such as atherosclerosis and inflammatory processes are associated with the generation of Reactive Oxygen Species (ROS) and consequently the induction of several chain reactions among them, lipid peroxidation (Grober, 2010). Evidence suggests that oxidative cellular injury caused by free radicals contributes to the complications of diabetes mellitus (Baimbolkar and Sainani, 1995). Some of these radicals are extremely reactive and therefore interact with some vital macromolecules including lipids, nucleic acids and protein (Nia et al., 2003).
Before the introduction of insulin in 1922, the treatment of diabetes mellitus relied heavily on the use of traditional plant therapies (Gray and Flatt, 1999). In Africa and beyond, application of traditional medical practices to the treatment of diabetes is quite popular; several plant species have been used for this purpose (Nwaegerue et al., 2007). Active components of these plants are now being investigated and their extract are developed into drugs and little or no negative effects as contraindications, one of such plants is Garcinia kola (Adedeji et al., 2006).