Research Article
Medicinal Plants of Edo State, Nigeria
Department Botany, University of Benin, PJ1B 1154, Benin City, Nigeria
H.I. Onyibe
Department Botany, Ambrose Alli University, PJ1B 14, Ekpoma, Nigeria
Medicinal plants, since times immemorial, have been used in virtually all cultures as a source of medicine. The widespread use of herbal remedies and healthcare preparations, as those described in ancient texts such as the Vedas and medicinal plants has been traced to the occurrence of natural products with medicinal properties.
Traditional medicinal practices are an important part of the primary health care delivery system in most of the developing world (Akerele, 1998; Bodeker, 1994; Sheldon et al., 1997). According to the World Health Organization, an estimated 3.5 billion people in the developing world depend on medicinal plants as part of their primary health care (Balick and Cox, 1996).
The use of traditional medicine and medicinal plants in most developing countries, as a normative basis for the maintenance of good health, has been widely observed (UNESCO, 1996). Furthermore, an increasing reliance on the use of medicinal plants in the industrialized societies has been traced to the extraction and development of several drugs and chemotherapeutics from these plants as well as from traditionally used rural herbal remedies (UNESCO, 1998). Moreover, in these societies, herbal remedies have become more popular in the treatment of minor ailments and because of the increasing costs of personal health maintenance. Indeed, the market and public demand has been so great that there is a great risk that many medicinal plants today, face either extinction or loss of genetic diversity.
Edo state is rich in medical lore. The use of plants in religious ceremonies as well as for magic and medicinal purposes is common and widespread. Based upon strong primitive roots. The art of native medicine is still widely practiced and much of this is indigenous. Among natives of various communities, knowledge of medicine has been passed by oral tradition from one generation to the next by the elderly, priests, witchdoctors or medicine men as written records in this field are almost non existent. The method is crude and highly subjective to distortion in an area where much accuracy is needed.
Traditional and folklore medicine bequeathed from generation is rich in domestic recipes and communal practice. Encompassing concepts and methods for the protection and restoration of health, traditional medicine has served as a fount of alternative medicine, new pharmaceuticals and healthcare products. The best-known examples are in China and India.
Despite the increasing use of medicinal plants, their future, seemingly, is being threatened by complacency concerning their conservation. Reserves of herbs and stocks of medicinal plants in developing countries are diminishing and in danger of extinction as a result of growing trade demands for cheaper healthcare products and new plant-based therapeutic markets in preference to more expensive target-specific drugs and biopharmaceuticals. Such concerns have stimulated positive legal and economic interest.
Genetic biodiversity of traditional medicinal herbs and plants is continuously under the threat of extinction because of growth-exploitation, environment-unfriendly harvesting techniques, loss of growth habitats and unmonitored trade of medicinal plants.
Of the estimated 250,000 to 500,000 plant species in the world, more than 85% are in environments that are the traditional homes of indigenous people. Nearly 75% of 121 plant-derived prescription drugs used worldwide were discovered following leads from indigenous medicine. Globally, indigenous peoples use 3000 different species of plant to control fertility alone. Almost all trees and many plants have a place in medicinal folk lore.
Indigenous people work on body and mind together to help cure illness. Medicinal plants are used to treat the spiritual origins of disease as well as the physical symptoms. The vast knowledge of such plants is now beginning to be acknowledged by the rest of the world. So is the role-played by indigenous people as custodians of the worlds genetic heritage. Other studies presented in this field includes (Ijomah et al., 1997; Idu and Olurunfemi, 2000; Idu et al., 1999; Gill et al., 1997).
An ethno-medical field survey was carried in the major communities spanning the three vegetation (Fresh Water Swamp in the distal south, Lowland Rain Forest and Derived Savanna in the northern part) zones of Edo State, Nigeria ( Fig. 1).
Fifty informants were interviewed regarding the type of medicinal plants used by them; they include full time/part-time herbalists, old ladies, family heads and village heads. Each interviewee was brought to the nearby forest and garden to collect plants. Interviews were conducted for periods ranging from Two hours to six hours. Herbalists were given enough time to express themselves freely during the interview. The medicinal property of each species, medical symptoms and illness was recorded. The people interviewed, were active, within the age bracket of between 40 and 80 years and were cooperative. Identification of plant species was done using standard monographs and their local flora (Keay, 1989; Akobundu and Agyakwa, 1998 ).The survey of these sites was carried out between September and October 2006.
Observation
Three hundred (300) plant species belonging to 77 families and 247 genera, used in the treatment of various diseases were encountered during the study.The plant species were collected from different parts of the state viz:
Fig. 1: | Map of the study area showing Nigeria and Edo State |
Derived Savanna: Auchi (102), Agbede (112), Igara (71), Okpella (101), Agenebode (101; Lowland Forest: Afuze (88), Ehor (105), Irua (56) ; Fresh Water (Swamp): Sakponba (94), Ologbo (99). The plants which are best known and most highly regarded in local medicine are enumerated in alphabetical order of family name; botanical name, local name and their medicinal usage are presented in Table 1.
Table 1: | Check list of medicinal plants used in Edo State, Nigeria. |
This report is based on the survey of medicinal plants from different communities in Edo State, Nigeria. The present study documents data regarding the availability of ethnomedicinal plant resources, which have various potential uses. Three hundred (300) species of herbal medicines in 77 families and 247 genera have been recorded in the course of this study. Fabaceae, Poaceae and Euphorbiaceae families are the most used medicinal plants in Edo State followed by Asteraceae, Rutaceae, Amaranthaceae, Cyperaceae, Arecaceae, Malvaceae. The dominant plant species widely used among the various communities surveyed include : Ageratum conyzoides, Asystasia gangetica, Azadirachta indica, Calopogonium muconoides, Carica papaya, Chromolaena odorata, Citrus aurantifolia, Citrus sinensis, Cocos nucifera, Colocasia esculenta, Commelina erecta, Elaeis guineensis, Eleusine indica, Ficus benghalensis, Gmelina arborea, Hura crepitans, Irvingia gabonensis, Mangifera indica, Manihot esculenta, Musa paradisiacal, Musa sapientum, Nauclea pobeguinii, Newbouldia laevis, Phyllanthus amarus, Psidium guajava, Sida acuta, Spondias mombin and Synedrella nodiflora.
All the plants mentioned in this paper are very popular among the communities of Edo state and enjoys a good reputation in Trado-medicinal practice in the areas. From this study, it was found that plants are used to treat mostly for malaria, stomach disorder, fever, cut, wounds, ulcer, sexual problems and diabetes.
The idea of having many plants for a single treatment of ailment (i.e., in the case of treatment of Cough, sour throat, cramps and gastroenteritis) is firstly, if a patient does not get relief from one remedy (plant) during a specified period of time, generally another remedy is tried and secondly if the plant cannot be found on specified time, another plant is taken as a substitute.
We suggest a detail assessment of resource quantities productivity potential, sustainable harvesting methods, domestication possibilities, market value of potentially promising species and importantly, equitable benefit sharing regimens, this view is also shared by Shrestha and Dhillion (2003) and a detailed investigation on the molecular and genetic characterization of these plants is necessary to have gene pool conservation.
Recent and renewed interest in medicinal plants coupled to developments in information technology has fuelled an explosion in the range and content of electronic information concerning medicinal plants as a re-emergent health aid. Bhat (1997) recently reviewed diverse sources of such information in traditional abstracting services as well as in a variety of online electronic databases. As a result of such developments access to indigenous peoples and cultures concerning medicinal plants are greatly facilitated. Furthermore, the active participation of such natural custodians and practitioners of valuable knowledge is guaranteed in bioactive principles and the development of new drugs.
The Edo State study concludes that traditional health practices can provide up to half of local primary health needs. Enlightened health-care workers are beginning to re-introduce traditional plant remedies where allopathic drugs have become commonplace. Properly studied and recorded, this traditional knowledge could revolutionize the world of medicine.