Ethnobotanical Survey of Medicinal Plants Used in the Treatment of Diabetes in Irepodun Local Government Area of Osun State , Nigeria

An ethnobotanical survey of medicinal plants used for the treatment diabetes in Irepodun Local Government Area of Osun State, Nigeria was conducted between March and June, 2013. Ethnobotanical data were collected by oral interview and semi-structured questionnaire administered to fifty (50) respondents made up of traditional medical practitioners (TMPs), herb sellers, civil servants and farmers. From the survey, a total of 45 plant species belonging to 29 families were found to be useful in the treatment of diabetes. Recipes used in the treatment of this disease were documented. Prominent among them are Rauvolfia vomitoria, Aframomum meleguata, Momordica charantia, Xylopia aethiopica, Senna spp. and Vernonia amygdalina. These species were found to be very important and useful in the treatment of diabetes based on their frequency of occurrence in the recipes obtained. Herbal remedies were either prepared from dried or freshly collected plants while traditional solvent of choice included water, lime and aqueous extract from fermented maize. Decoction and pulverization were the main methods of preparation while mode of administration varies within 2 to 3 times daily. Survey revealed that leaves form the major part of plants for herbal preparations. Residents in the study area find traditional medicine cheaper as compared to orthodox medicine. A need for further scientific research based on the findings of this work is needed.


INTRODUCTION
Diabetes is a common and very prevalent disease affecting the citizens of both developed and developing countries.The World Health Organization estimated the disease in adults to be around 173 million in year 2000, two-thirds of which live in developing countries (Wild et al., 2004).
The prevalence of diabetes mellitus is on the increase worldwide and it is still expected to increase by 5.4% in 2025 (Moller and Flier, 1991).Increase in sedentary lifestyle, consumption of energy-rich diet and obesity are some of the factor causing the rise in the number of diabetics.According to American Diabetes Association, Asia, and Africa are regions with greatest potential where diabetics could rise to two or threefold above the present level (WHO, 1994).In the last few years there has been an exponential growth in the field of herbal medicine and these drugs are gaining popularity both in developing and developed countries because of their natural origin and less side effects (Modak et al., 2007).Herbal medicines continue to play an important role in diabetic therapy, particularly in the developing countries where most people have limited resources and do not have access to modern treatment (Ajaiyeoba et al., 2006).The use of herbal remedies for the treatment of diabetes has also been authenticated by WHO (Bailey and Day, 1989).The increase in demand for the use of plant based medicines to treat diabetes may be due to the side effects associated with the use of orthodox drugs such as insulin and oral hypoglycemic agents (Marles and Farnsworth, 1994).Another important factor that strengthens the use of plant materials as anti diabetics could be attributed to the belief that herbs do provide some benefits over and above allopathic medicine and allow the users to feel that they have some control in their choice of medication (Johshi and Kaul, 2001).Thus, the aim of this study was to document the medicinal plants used for the treatment of diabetes from Nigeria flora.

MATERIALS AND METHODS
The study was conducted in Irepodun Local Government Area in Osun State.The local government was created in September, 1991.There is a projected population of 119,496 people according to the 2 0 0 6 census figure .Oral interviews and structured questionnaire methods were employed.Traditional Medical Practitioners, herb sellers, farmers, the aged and civil servants were targeted audience.The questionnaire had three sections.Section 'I' requested for bio-data of the respondents for information on demographic characteristics, while section 'II' was used to identify the forest plants used for treating diabetic patients.Section 'III' was used for information on the recipe preparation and administration.A total of 50 questionnaires were administered to the respondent randomly.
Identification of specimen was done using illustrations and descriptions from a Flora (Vernacular Names of Nigerian Plants) by Gbile (2002) after collection while the authenticity was confirmed by Prof. D.A. Agboola of the Department of Biological Sciences, Federal University of Agriculture, Abeokuta, Ogun state.Pictures of the fresh specimens were also taken with the use of Sony Digital Camera.
Descriptive statistics such as frequency distribution, pie chart, and percentages were used in the analysis of the data.

RESULTS
The demographic characteristics of the respondents is as shown in Table 1, Fifty (50%) of the respondents are between the age of 51-60, 20% between age of 41-50, 16% of age greater than 60, 10% between age of 31-40 and 4% between the ages of 21-30 years.The educated among the respondents were 60%.It was observed that most of the respondents were married (70%) followed by the widow(er) (16%), single (10%) and finally the divorced (4%).Result showed that 60% of the respondents are females while 40% are males.Result also showed that most of the respondents in Irepodun Local Government Area of Osun State are herb sellers (60%), farmers (20%) and Traditional Medical Practitioners and civil servants (10%).The plant parts used mostly from the identified plants include mostly the leaves, fruits and roots.Figure 1 shows species distribution according to their families.Plant parts used in the treatment of diabetes and their frequencies are as shown in Figure 2. Table 3 shows the enumeration of anti-diabetics recipes, solvent used, preparation and the mode of administration.It was observed that recipes are made from combination of different parts from more than one plant species including fruits, leaves mostly.The preferred solvents in most preparation are water and liquid from fermented maize.Preparations mostly preferred are by decoction and powdered forms.Some of these plants used in the treatment of diabetes are shown in Plate 1. Half glass cup full of the extract is taken twice daily.
Half a glass cup is taken every morning One glass cup is taken every morning until the ailments disappear.
The patient takes one glass cup of the extract daily.Small quantity of the powder is taken on the palm with water, in the morning and late at night.Small quantity of the material is taken with hot pap in the morning and evening.
One glass cup of the extract is taken daily until ailments disappear.
Small quantity of the material is taken with hot pap once in the morning.
One tablespoon is taken in the morning and evening.
Half glass cup is taken in the morning and evening.
One tablespoon of the extract is taken in the morning and afternoon.

DISCUSSION
The result showed that 50% of the respondents in Irepodun Local Government fall under age 51-60 and 4% fall under age 21-30 ages.This implies that practices of traditional medicine in the study area are actively involved by old people.This was in support of the result of Faleyimu and Oluwalana (2008) who reported that, the older the people, the more active and experienced they are in the use and sourcing of medicinal plants.
Most of the respondents in Irepodun Local Government Area are Herb sellers (60%), Traditional Medical Practitioners, Civil Servants (10%) and farmers (20%).This could be as a result of high involvement in traditional medicine as a primary occupation by the respondent.All other economics activities are additional source of income.The various plant parts mentioned include leaves, fruits, roots, seeds, stem bark, bulb, tuber, stem and rhizome.It was observed that leaves formed the most frequently used part for diabetes (44%), followed by fruits (24%), root (11%), seeds (5%), bulb, tubers, stem bark (4%) and rhizome (2%).The plant leaves are important ingredient in traditional treatment of various diseases as it occurred as a component in many herbal preparations.This finding was in line with other studies such as Adekunle (2008) andAyodele (2005).
The families with the highest occurrence of species include Leguminosae with 4 species, followed by Euphorbiaceae, Apocynaceae, Curcubitaceae and Poaceae (3 each), which is an indicative of their importance in the treatment of diabetes.The frequent occurrence of these families was supported by Soladoye et al. (2012) who reported that antidiabetics medicinal plants suggests their importance as repository of useful plants which may be explored for diabetes treating drugs.However, Agavaceae, Araceae, Amaryllidaceae, Bromeliaceae, Bignoniaceae, Solanaceae, Tiliaceae, Piperaceae among others had the least number of species (1 each) as shown in the result, these call for urgent attention on these families before they go into extinction.Some of the recipes were prepared from single plant source, for example, Corchorous olitorus, Euphorbia hirta, and Rauvolfia vomitoria while some others are in combinations with other common plants.Method of preparation varies while decoction and grinding are the most frequently used methods.

CONCLUSION
The practice of traditional medicine has been with us from time immemorial and it is upon it that the rural population depends.The study has shown that some forest plants could be used for the treatment of diabetes in Irepodun Local Government Area of Osun State.

Figure 1 :Fermented
Figure 1: Species distribution according to families of plants used for the treatment of diabetes.
It constitutes one of the 31 local government areas in Osun State and is in the southern part of the state, sharing boundary with Ifon-osun in the north and south with Osogbo Local Government, and in the East by Oba and in the West by Erin-osun.Irepodun Local government is made up of sparsely forested area and is watered by Ojutu river, Elentere river, Konda river and a few other streams.The main ethnic group is Yoruba, with subordinate of other ethnic through trading such as Hausa, Igbira, Fulanis and Igbo.

Table 2 : Enumeration of plants used for the treatment of Diabetes by the people of Irepodun Local Government Area
The entire survey from the respondents yielded 45 plant species used as anti-diabetics from 29 different families.Botanical names, local names, common names, family habit/life form, plant parts used and distribution to their habitat (Cultivated/ Wild) are represented in Table2.Plant forms include the climbers, herbs, shrubs and trees.