Ethnopharmacologic survey of medicinal plants used to treat human diseases by traditional medical practitioners in Dega Damot district, Amhara, Northwestern Ethiopia

Background One of the services that plants provide for human beings is their wider medicinal application. Although it is not fully assessed, the practice and wider use of traditional medicine is frequent in Ethiopia. Studies conducted previously are confined to the perceptions of modern and traditional health practitioners about traditional medicine. A total of 45 informants were selected purposefully from the study area. For collecting the data, semi-structured interviewees, observation and field walks were employed from August 10 to September 30/2014. To summarize the information, descriptive statistical methods were applied. Results Sixty species of medicinal plants distributed in 42 families were collected and identified applied locally for the treatment of 55 human disorders. The most commonly treated ones were evil eye, malaria, wound, peptic ulcer disease and rabies. According to this study, leaves were the commonly used plant parts (36.5%) and 39% of the preparations were decoctions. Oral route, 43 (44%) was the commonly used route of application whereas most (54.8%) remedies were administered only once. Fourteen percent of preparations caused vomiting in addition most (40.4%) of the formulations was contraindicated for pregnant patients. Only seventeen percent of the formulations possessed drug food interactions. Most preparations were stored within clothes, 31 (29.8%). There exists a high (ICF = 0.8) evenness of plant use among healers for treating respiratory problems. Alliumsativum (FI = 0.75) for evil eye, Phytolacca dodecandra (FI = 0.8) for rabies and Croton macrostachyus (FI = 0.78) for treating malaria were medicinal plants with highest fidelity levels showing consistency of knowledge on species best treating power. This study also documented that drought, overgrazing and firewood collection are major threats. Conclusion Dega Damot district is loaded in its medicinal plant diversity and indigenous knowledge though plants are highly affected by drought, overgrazing and firewood collection. Therefore awareness activities must be created among the district’s population by concerned governmental and nongovernmental organizations about the value of medicinal plants and conservation of these plants. The healing potential and associated adverse issues of the claimed medicinal plants should be assessed before proposing for a broader utilization. Electronic supplementary material The online version of this article (doi:10.1186/s13104-017-2482-3) contains supplementary material, which is available to authorized users.


Background
According to world health organization, traditional medicine (TM) is the sum total of the knowledge, skills and practices based on the theories, beliefs and experiences indigenous to different cultures and nations. It is used in the maintenance of health, prevention, diagnosis, or treatment of disorders [1,2]. Under TM, health practices, remedies, approaches, and beliefs incorporating plant, animal and mineral products, spiritual therapies are all included [3]. Traditional medicine is popular in the developing world and its use is rapidly spreading in the developed nations. In China, traditional herbal preparations account for 30-50% of the total drug consumption. In Ghana, Mali, Nigeria and Zambia, the first choice for 60% of children with high fever resulting from malaria is the use of herbal medicines. In Ethiopia up to 80% of the population uses TM due to the cultural acceptability of healers and local pharmacopeias, the relatively low cost of TM and difficult access to modern health facilities [4].
In Ethiopia, TM plays both preventive and curative roles. Vegetables are the abundant sources of traditional remedies. Various parts of plants like leaves, flowers, seeds, bark, sap and roots are used. Honey, butter, and sheep fat are TM sources from animals. In Ethiopia, traditional medical practitioners put much emphasis on the supernatural force as a source of wisdom for healing various illnesses. Even though practitioners practically deal with tangible problems like bone setting, simple traditional surgery, historical evidence shows that there were many prayers for the prevention and cure of various ailments [1,[5][6][7][8]. Despite its continued use over many countries, its popularity and extensive use, TM has not been officially recognized in most countries. As a result, training and research in this area have not been conducted intensively on the various aspects of TM. The safety and efficacy of data on TM are not sufficient to meet the criteria required to support its worldwide use [4,5,9,10].
In Dega Damot district about 90% of the population relies on traditional health products (unpublished data from the district) for primary health care aspects. There have been no studies conducted in the study area on the use and practice of TM. For policies regarding TM ultimately geared towards integration of TM into the national health service to be formed and implemented, results of this study will be able to protect the interest of those making use of this health care option.

Description of the study district
This study involved traditional medical practitioners residing in Dega Damot district, Northwestern Ethiopia. It shares borders with the districts of Bibugn in the north, Dembecha in the east, Kuarit and Hulet eju enesie in the west and Jabitehnan in the South (Fig. 1). The district's administrative town, Feres Bet, is located at about 400 km north western of the capital, Addis Ababa. According to 2013 data, the population of the district is about 170, 575. The district is administratively divided into 32 kebeles and Amharic which belongs to the Semitic language family is the language of the population. In Ethiopia, Kebele is the smallest administrative unit. In the district, barley, maize, potato and wheat are the main crops cultivated, off which, potato is exported to neighboring towns of the Amhara region like Burie, Bahirdar and Gondar.
According to 2004-2013 rainfall data, the District has a high rainfall distribution between July and August and a smaller rainfall between January and May. The mean monthly rainfall and mean annual rainfall of the District are 60.24 and 708.54 mm, respectively (National Metrological Service Agency, Bahirdar Branch Office, unpublished data). According to data from the health personnel of the district, the top ten diseases in 2014 are malaria, diarrhea, helmenthiasis, pneumonia, acute upper respiratory diseases, dyspepsia, typhoid, eye infection, urinary tract infection and skin infection respectively.

Selection of study subjects
Data were collected from the traditional medical practitioners (TMPs) who were purposively chosen with the help of community leaders and local authorities. The informants selected were the most knowledgeable ones as recommended by community leaders and local authorities who involved in the selection process. The ages of the TMPs ranged between 22 and 80 years. A total of 45 (40 male and 5 female) TMPs were included in this study from August 10 to September 30/2014.

Data collection techniques
Semi-structured interviews, observation and field walks were used to collect the research data. To collect information about local names of plants used, their threats, part(s) used, preparations methods, routes of remedy administration and diseases treated, individual interviews were conducted (Additional file 1). Interviews were carried out in Amharic, language that is spoken by the practitioners. For claimed plant, specimen was collected, and identified and voucher was reserved at University of Gondar. Field observations were performed to document habitat of each medicinal plant. As this study has been conducted on wild plants, permission was mandatory to perform the survey. Hence, Dega Damot district agricultural office was informed and asked permission to conduct the study and collect the medicinal plants. The study was also ethically approved by the Graduate Program Evaluation Committee of the College of medicine and health sciences, University of Gondar. Prior to the initiation of the data collection, the objective of the survey was clarified to the TMPs, verbal consent was obtained from them. Letter of collaboration was sent to district officials of the study area and biology department at University of Gondar.

Data analysis
Descriptive statistic procedures like percentage and frequency distribution were applied for analyzing and summarizing the data. To check the level of homogeneity among information provided by traditional practitioners, the informants' consensus factor, ICF [11] was computed where, Nur = number of use reports from informants for a particular plant-use category; Nt = number of taxa or species that are used for that plant use category for all informants. ICF Values vary between 0 and 1, where '1' represents the highest level of consensus. The fidelity level (FL), which shows for the percentage of informants claiming the use of a certain plant species for the same major purpose, was calculated for the commonly reported disorders as: where: Np = number of traditional practitioners that claim a use of a plant to treat a certain disease; N = number of informants that use the plants as a remedy to treat an ailment [12].

Socio-demographic data of the informants
Totally, 45 TMPs out of which 40 (88.8%) and 5 (11.2%) males and females, respectively, were involved in this study and 55.6% were illiterate. Most of them were married (86.7%) and 37.8% were older than 56 years. Thirtyone (68.9%) were farmers and all TMPs were Ethiopian orthodox tewahido Christian followers.
Forty percent of healers indicated that they acquired their healing wisdom from their family, whereas 26.6% assumed it as a gift from God. Other sources of wisdom are religious Institutions (22.2%) and preceding sickness and corresponding use (11.2%). About 67% of the practitioners had practiced their healing activities for more than 25 years.

Diseases treated and medicinal Plants used
About 55 human diseases are treated by TMPs of the district. The most commonly treated ones being evil eye, malaria, wound; peptic ulcer disease and rabies (Table 1). This study revealed that about 60 plant species find Most of the plants collected and identified from the study area were trees (40%), followed by herbs (30%) and shrubs (25%) and (Fig. 2).

Plant parts used
According to this survey, the commonly used plant part was leaf (36.5%), followed by seed (21.2%) (Fig. 3).

Method of preparation, routes of administration and dose
Traditional medical practitioners used simpler techniques like crushing and powdering with the help of easily available materials like water, honey and milk for preparation of remedies to treat various human ailments as shown in Table 1. This survey also documented that most of the remedies were given orally, (44%). Topical (26.5%), nasal (25.5%), rectal (2%), vaginal (1%) and subcutaneous (1%) routes are also used. This study showed that TMPs in the district were not aware of the exact dose of remedies to be administered. They easily determined the dose depending on mainly age. The doses of 24 preparations were not determined. Healers expressed doses as a glass of, half a cup of or a teaspoon full of.

Dosage forms and frequency of administration
The documented 60 species of medicinal plants were reported to be formulated in various forms. Majority of dosage forms were decoctions 35 (38.9%) followed by liquid preparations 18 (20%) as shown in Fig. 4. Most of the preparations were given only once (Fig. 5).

Solvents and additives
Forty-three percent of the formulations did not require any additive or solvent. Of the formulations that involve the use of solvents, water accounted 25 (42.4%) followed   Table 2).

Contraindications and side effects
According to TMPs of the area, 42 (40.4%) of the formulations were contraindicated for pregnant patients. No contraindication was indicated for 35 (33.6% of the formulations (Table 3). Twelve (11.5%) of the preparations were free from any side effect (Table 4).

Drug food interactions
According to this study, only 17% of the formulations possessed drug food interactions, of which 12 (66.7%) were exhibited by preparations for gastrointestinal problems. Synergistic reactions were observed in poly herbal preparations like in the case of remedies for evil eye.

Storage
Asked on how they store plant remedies, healers responded that they don't normally store plant preparations; rather they collect fresh material and formulate remedies. For those medicinal plants which are not easily available and which are seasonal, they collect and store in papers, horns or and with in bottles. Only three percent of the total preparations were stored in cool and dry places (Fig. 6).

Informant's consensus
Depending on the data obtained, seven use-categories (Table 5) were set in which 127 use reports were documented. As depicted below, informant consensus factor values and the mean ICF are close to 1. There is high uniformity in plant consumption for respiratory diseases.

Fidelity level
In the survey, the FL values were analyzed for seven plants in treating three medical conditions (Table 6).    Abdominal cramp 9 8.7 Free from any side effect 12 11.5

Threats to medicinal plants
As shown in Table 7 below, drought, overgrazing and firewood collection are the major threats of medicinal plants. Practitioners leveled drought as the most serious threat.

Discussion
This study revealed that about 60 plant species find applications by the TMPs of the woreda. Those plants were identified and distributed in 42 families. Families, Graminae and Solanaceae each accounts 4 (9.5%) medicinal plants followed by Fabaceae and Leguminosae, 3 (7%). But Fabaceae was the dominant family according to the conducted in Hawasa [13], Wayu Tuka District of Oromiya region [14] and Benshangul-Gumuz [15]. In addition a study done in Spain [16], Korea [17] and Loma and Gena Bosa Districts [18] showed that Asteraceae has the highest number of medicinal plants. Caesalpiniaceae was the family with higher number of plants according to the study in Nigeria [19].
The ailments reported to be handled by the TMPs of the district are those disorders most prevalent in the district. According to the result of this study, the majority of plants were reported to treat wound followed by malaria, evil eye and anthrax. However, a study done in Hawasa [13] showed that stomach ache is the disease treated by large number of medicinal plants. In addition a study done in Sheko ethinic group of Ethiopia [8] showed that skin and gastrointestinal problems were the commonly treated diseases. According to a study in Lebanon [20], most medicinal plants were used to treat gastrointestinal disorders, kidney and urinary diseases as well as blood and cardiovascular diseases. Diarrhea was the commonly treated disease in Benshangul-Gumuz [15].This discrepancy may be the result of the difference in the climatic, ethnic, and hygienic conditions the areas. The current study is also unlike the one done in Israel [21]. Mental illnesses were commonly treated according to the study in Kenya [22].
The most commonly used plant part was leaf in this study area which is in agreement with other studies. [8,13,15,18,19,21,[23][24][25][26]. Considerable threat to the mother plant radiates to the various parts of the plant. However, root was the commonly used plant part according to a study done in Benshangul-Gumuz [15]. Medicinal plants were formulated in various forms using various solvents and additives. They were formulated as decoctions, liquid preparations and pastes. This is supported by a study done in Korea [17], Israel [21], Gondar zuria woreda [24] and Hawasa [13]. However, in a study done in Chencha [18] and Tewledere districts [27], the majority of remedies were formulated as concoctions. Practitioners prepare remedies in such a simple manner without further processing which may be due to lack of education and processing instruments. TMPs of the current study area used butter, charcoal, sugar, milk and salt as additives to increase the efficacy and potency of the remedies. The rationale behind the use of honey and sugar is just to make the formulation palatable. This is supported by a study done in Israel [17] and Hawasa [13].   This study showed that there was no harmony in measurement or unit used among practitioners. Most informants stated measuring units like cup, spoon, bottle and handful which lack accuracy. This problem was also observed in studies done elsewhere which may be due to lack of education [13,14,19,28].
This study revealed that higher sizes of preparations were given orally which agrees with results of other studies [11-13, 15, 17, 22-25, 27-29]. Practitioners prefer simple routes like topical and oral due to their inability to administer remedies in other routes like intravenous. Oral administration allows relatively fast physiological action of remedies on pathogens and enhance its efficacy. However, studies conducted in Sheko ethnic group in Southwest Ethiopia [8] revealed that most preparations were prescribed for administration to the cutaneous route. According to the result of the current study, most formulations were given only once. This may be due to the fact that most practitioners do not know the actual dose to be given and fear the risk that comes at the end of the treatment due to over dose and continuous administration.
One-third of the medicinal plants recorded were trees. However, other research works indicate the abundant use of herbs [8,22,24,25,27,30]. The availability of most woody plants in the area might have enforced the local inhabitants to rely on tress.
Most of the formulations were contraindicated for pregnant patients. This is due to the healers' belief that it may harm the fetus. No contraindication is indicated for onethird of the formulations. Most preparations taken orally cause nausea, vomiting and abdominal cramp whereas, some of the preparations are free from any side effect which may be due to the lack of follow up of patients by healers once they gave remedies and due to illiteracy of the patients.
This study revealed that, only some of the formulations possessed drug food and drug-drug interactions, this may be because most practitioners are illiterate, they do not know about the interaction of their remedies with modern medicines. In addition practitioners do not follow the progress of their patients, hence have little information on drug food interaction. Synergistic reactions were observed in poly herbal preparations like in the case of remedies for evil eye.
According to this study, practitioners do not normally store remedies which is in contrast to the study done in Addis Ababa [28]. For those medicinal plants which are not easily available and which are seasonal, practitioners collect and store in papers, horns and with in bottles. Only three percent of the total preparations are stored in cool and dry places. This may be due to the lack of modern education about drug storage and other health related issues.
A total of 127 URs from 60 species of plants were recorded which were assigned to seven use categories. Analysis of ICF shows that there exists a high evenness of plant consumption among the population which is in harmony with the study in Chencha [18]. The low ICF for skin problems may because of a multifaceted preparation of plants required to treat disease. Majority of plant species have a number of medicinal values, which result in higher variety of use reports.
Croton macrostachyus (FL = 0.78) is reported by high number of informants (36%), hence more preferable than Euphorbia abyssinica (0.42) and Urtica simensis (0.67) in treating malaria. However, despite Allium sativum (FL = 0.75) is reported by less figures of informants (30%), than Echinops kebericho (FL = 0.64) which is mentionedd by relatively higher percentage of practitioners (34%), it seems that Allium sativum is more preferable than Echinops kebericho in treating evil eye. But a study done in Sheko [8] indicated that Ocimum lamiifolium, Phytolacca dodecandra, Amaranthus dubius and Amaranthus graecizans were the medicinal plants assigned with the highest FL values. This discrepancy may be the result of the differences in the type of diseases dominating the areas, and the level of availability of the medicinal plants.
According to the results of this study, drought is the most serious threat to medicinal plants followed by overgrazing. This is in conformity with the survey conducted in Gemad district [25] and Kilte Awulalo [27], but according to a study done in Loma and Gena Bosa [26], agricultural expansion was the major threat followed by timber and other demands. This is probably due to the increasing number of population. However, study done in Hawasa city [13] indicated urbanization as the most serious threat for medicinal plants.

Conclusion
Dega Damot district is loaded in its medicinal plant diversity and indigenous knowledge though plants are highly affected by drought, overgrazing and firewood collection. Therefore awareness activities must be created among the district's population by concerned governmental and nongovernmental organizations about the value of medicinal plants and conservation of these plants. The healing potential and associated adverse issues of the claimed medicinal plants should be assessed before proposing for a broader utilization.

Additional file
Additional file 1. Semi-structured interview questions.