A Bioactivity Versus Ethnobotanical Survey of Medicinal Plants from Nigeria, West Africa

Lydia L. Lifongo 0 1 2 Conrad V. Simoben 0 1 2 Fidele Ntie-Kang 0 1 2 Smith B. Babiaka 0 1 2 Philip N. Judson 0 1 2 0 P. N. Judson Chemical and Bioactivity Information Centre , Granary Wharf House, 2 Canal Wharf, Leeds LS11 5PY, UK 1 P. N. Judson Chemical and Bioactivity Information Centre , 22-23 Blenheim Terrace, Woodhouse Lane, Leeds LS2 9HD, UK 2 L. L. Lifongo C. V. Simoben F. Ntie-Kang (&) S. B. Babiaka Chemical and Bioactivity Information Centre, Department of Chemistry, Faculty of Science, University of Buea , Buea, Cameroon Traditional medicinal practices play a key role in health care systems in countries with developing economies. The aim of this survey was to validate the use of traditional medicine within local Nigerian communities. In this review, we examine the ethnobotanical uses of selected plant species from the Nigerian flora and attempt to correlate the activities of the isolated bioactive principles with known uses of the plant species in African traditional medicine. Thirty-three (33) plant species were identified and about 100 out of the 120 compounds identified with these plants matched with the ethnobotanical uses of the plants. - Medicinal plants 1 Introduction It is estimated that 6685 % of the worlds population depends directly on plants as medicines [13]. Since the existence of human civilization, plants and their by-products have been used by a large proportion of the population living in rural and urban areas for various purposes such as medicine, healthcare, food, clothing, shelter, agriculture, agrochemicals, pharmaceuticals, narcotics, etc. The sum total of this is referred to as ethnobotany [4]. Medicinal plants are defined as plants having one or more organs containing substances that can be used for therapeutic purposes or which are precursors for the synthesis of useful drugs [5]. Thus, medicinal plants represent, for the local population, a possibility of simple and cheap treatment. In addition, they represent sources of potentially important new pharmaceutical substances since all parts of a plant, from roots to seed heads and flowers, are employed in traditional remedies and can therefore act as sources of lead compounds [6]. More than 80 % of the worlds populations, especially in developing countries, depend on traditional systems of medicine for the treatment of a variety of diseases. This observation could be attributed to two main factors; inaccessibility of modern drugs and the low purchasing power within the populations living in the rural areas [7]. Moreover, some of the local remedies work and so the populations have no need for anything different. From antiquity, mankind has been developing a traditional medicinal system, based on the knowledge of medicinal plants throughout the world [8]. Africans, in particular, have used medicinal plants and animal-derived remedies in their struggle for survival and in their quest for religious experiences. The World Health Organization (WHO) defines traditional medicine as practices, knowledge and belief systems which use minerals, plants and animal based remedies, spiritual therapies and exercises to prevent, treat and maintain wellbeing [9]. This knowledge became enriched over numerous generations due to experimentation but also through observations of animal behaviour [10]. Most often, knowledge of traditional medicine is only inherited orally, thereby facing the danger of being lost in favor of Western medicine (WM). Many Africans believe in the manifestation of life forces or spirits in every creation, and that these spirits constitute the heart of all life forms, natural events or non-living things. This gives herbal medicine a vital role in health care delivery systems especially in remote areas where clinics and hospitals are sparsely located [8, 11]. Despite the advances in WM, African traditional medicine (ATM) has gained renewed interest in the health care services throughout the continent. This could probably be due to the rapidly increasing awareness of the potential and curative abilities of alternative medicines, especially from the use of medicinal plants, as well as the inadequate access to WM and physicians and the high cost for Western drugs [12]. The argument for the local African populations resorting to traditional remedies could also be partly justified by the fact that natural product inspired molecules represented about 80 % of drugs that had been put into the market [1, 13]. Previous ethnobotanical studies of medicinal plants confirm the rational use of recipes by different people or groups from different communities [14]. Numerous varieties of medicinal plants growing in Africa are widely used against many diseases ranging from endemic tropical diseases like malaria [15] and leishmaniasis [16] to complex illnesses such as asthma [17], psychosis [18], hepatitis [19] and even cancer [20]. Searching for new lead compounds to be developed as drugs or as templates for analogue synthesis and the evaluation of traditional medicine and herbal medicinal products, are the two basic reasons for the advancement of work on medicinal plants [21]. The use of plant preparations can be supported if it is safe and if their biological activity can be scientifically confirmed. This calls for quality control and standardization. If the activity cannot be confirmed, and certainly if there is a risk of toxicity, the use of herbal medicinal products should be discouraged [21]. The study of plants used traditionally as medicines is therefore an interesting discipline because of the possibility to find new drugs and also because of the strong adhesion of local populations, for the aforementioned reasons [1113, 22, 23]. This has prompted many research teams to carry out studies on plants used in Africa by traditional healers against diseases. The United Nations definition of Western Africa includes the following 16 countries: Benin, Burkina Faso, Cape Verde, Ivory Coast, the Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone and Togo. These countries occupy an area of over 6,140,000 km2 and the natural environment in this area consists of subtropical and tropical regions with semi-arid and humid climates [14]. In these communities, traditional herbalists operate closer to the people, taking advantage of the biodiversity of plant species in such areas to cure various diseases and ailments. Nigeria is located in West Africa on the Gulf of Guinea and shares borders with Cameroon (1,690 km) in the East, Chad (87 km) in the Northeast, Niger (1,497 km) in the North, Benin (773 km) in the West and the Atlantic Ocean in the South (Fig. 1) [24]. The country is divided administratively into the Federal Capital Territory (Abuja) and 36 states [25]. As a result of the large surface area occupied by Nigeria, the national territory covers different climatic and ecological zones. Nigeria is rich in biodiversity, with an array of fauna an (...truncated)