Ethno-botanical study of traditional medicinal plants used to treat human and livestock ailments in Raya Alamata District, Northern Ethiopia

Background In Ethiopia, traditional medicine based mainly on medicinal plants, has been used for centuries for the treatment of human and animal health problems. The objective of this study was to document medicinal plants used to treat human and domestic animals ailments as well as the associate indigenous knowledge and conservation methods in Raya Alamata District in Northern Ethiopia. Methods Ethno-botanical data were collected through semi-structured interviews, guided field walks, group discussions, field observations, preference ranking, paired comparison and direct matrix. The data were analyzed by descriptive statistics, informant consensus factor, and various ranking methods. Results The results showed 47 medicinal plant species belonging to 44 genera and 31 families. The plants were used to treat 27 human and 8 livestock diseases. Among others, members of Fabaceae were leading in terms of the number of medicinal plant species composition, consisting of 9 species. Of these species, the majority (53.19%) grew naturally in the wild. Herbs took the lead in terms of the number of plants used in the preparation of remedies, constituting 46.81% of the species, followed by shrubs that instituted 27.66%. Leaves were the most commonly used plant part, constituting 41.94% of the total uses, followed by roots, constituting 20.97%. Dermal route of administration was the most commonly used route of administration (43.55%), followed by oral route of administration (38.71%). Direct matrix ranking showed Balanites aegyptiaca L. as the most preferred multipurpose species in the community. Paired ranking indicated that Aloe megalacantha Bak. as the most commonly used medicinal plants for healing external wounds. Agricultural activity for new agricultural lands became seriously threatened medicinal plant resources. Many of the local communities with traditional medicinal knowledge gave priority to the immediate use of medicinal plants than to the sustainable uses. Particularly, the collection method of plants or plant parts for medicinal use is mostly destructive.


Introduction
Ethno-botany is a broad term referring to the study of the relationship between background people, plants and environment involving a wide range of disciplines [1]. Humans began to employ plants for the intention of health a long time ago, may be at the first moment when they suffered from diseases [2]. Since the antique time plants have been an essential supply for deterrent and healing for humans and livestock [3]. Traditional remedies are the most important and sometimes the only source of therapeutics for nearly 80% of the population and 95%of traditional medicinal preparations in Ethiopia is of plant origin [4].
Medicinal plants are used as a major source for health promotion, prevention and cure. At the ancient time people primarily select plants for food, in doing that they also select plants by trial and error processes for their health care [5]. In most of the developing nations, the health care need of about 80% of the population depend on traditional medicines [6]. Ethiopia is rich in its biodiversity as a result of the different ecological and climatic conditions [7]. This rich biodiversity is also favored for a wide range of disease causing agents. These diseases were tackled by herbal remedies and religious beliefs now and then [8].
The cultivation and use of the medicinal plants are not new to Ethiopians, because of their acceptability, accessibility and affordability [9]. This means that Ethiopians have a body of expertise concerned with therapeutic properties of the local flora. Many skills such as the use of plants and animal products and religious beliefs are included in Ethiopian traditional medicines [4]. Although most practices and treatments in herbal medicine require specialists or professionals which are called herbalists, self-care using plants is also common in Ethiopia. The promotion of traditional health practices alongside modern health services is the most promising means for ensuring affordable and sustainable heath care for poor communities throughout the developing countries [10].
According to AB Cunningham [11], in situ and ex situ conservations are some conservation measures that have been undertaken around the world aimed at protecting threatened medicinal plants from further destruction. Traditionally used medicinal plants and associated knowledge are disappearing at an alarming rate [4]. Natural and anthropologic factors contribute to these losses, but threatening factors may vary from one region to the other [12]. Literatures show that studies on medicinal plants were conducted in different parts of Ethiopia to document the use of medicinal plants. The studies conducted in Maale and Ari ethnic communities [13], in the environs of Tara -gedam and Amba remnant forests of Kemkem district [14], in Gubalafto district [14] and in Guduru district [15] documented 128, 163, 135 and 57 medicinal plants respectively. In this context, therefore, the present study conducted a full-scale study on the ethno-botany of the traditional medicinal plants in Raya Alamata District in Northern Ethiopia. Local communities of Raya Alamata District has their own way of perceiving nature, their environment and health problems to react to them by making use of their indigenous knowledge and practices, which have been accumulated for generations to come up with both human and livestock ailments. The traditional practices have also their own contribution to the modern ones. Despite this reality, there is lack of proper conservation and management that leads to the shrinking and finally destruction of the plant communities with negative impacts on medicinal plants and related knowledge of the local people. In addition, knowledgeable elders may die without sharing their knowledge to the younger generation. Therefore, the general objective of this research was to identify and document medicinal plant species and associated traditional knowledge in Raya Alamata District, Northern Ethiopia. This study was also conducted with the following specific objectives: (1) to identify medicinal plants species which are used to treat both human and livestock ailments, (2) to document the indigenous knowledge of the people on the preparation and use of medicinal plants to treat health problem in the study area, (3) to identify the plant parts used for medicinal purposes and (4) to find out the threats and local methods used by indigenous people to manage medicinal plants.

Description of the study area
Raya Alamata District is located in the southern zone of Tigray, bordered by Raya Azebo in the North, Ofla in the West, Amhara in the South and Afar in the East. It has latitude and longitude of 12 o 25′ N and 39 o 33′E. It is situated 600 kilometers North of Addis Ababa and about 180 kilometers south of the According to the National Meteorological Agency (NMA) [16] the District receives 600-700 mm annual rainfall and 23-27 o C annual temperature. The size of the district is 75,502.14 hectares and 23 % of the District is divided in to western highland and 73 % eastern lowland.
The study was conducted in three Kebeles in the Raya Alamata District, Northern Ethiopia. The three Kebeles -Garjalle, Selen Wuha and Merewa -were selected for ethno -botanical data collection by simple random sampling (lottery method) ( Figure 1).

Informant selection techniques
A total of 18 key informants (seven from Garjalle, five from Selen Wuha and six from Merewa kebeles) from the age of 29 to 78 were interviewed. The key informants were selected purposively following G Martin [1] with the help and recommendation of Kebele administration leaders, elders, religious leaders and others who have information about traditional healers. This technique was used to get hold of healers who had no official permission for their traditional medicinal practices as the names of non-legalized healers were not registered in the government offices.

Ethno -botanical data collection
The ethno -botanical data was collected from April to May in 2019. The techniques employed for data collection were group discussion, key informant interviews, field observations, and guided field walks.
Interview questions were prepared for the key interviews to collect data primarily on the medicinal plants used to treat different ailments, plant parts used, preparation methods of remedies, condition of preparation, administration routes and other uses than medicinal values.

Plant specimen collection and identification
Sample specimens of medicinal plant species were collected from wild and home gardens. Then they were numbered, pressed and dried for identification. The identification of plants cited for their medicinal value was made both in the field and at the National Herbarium of Addis Ababa University.
The identification of the plant specimens was done using different volumes of Flora of Ethiopia and Eritrea books, useful trees and shrubs of Ethiopia. Comparison for identification was done with authenticated specimens with the help of experts at the National Herbarium experts from Agricultural Research Office of Raya Alamata and the Institute of Biodiversity and Conservation (IBC) of Ethiopia.
Data on disease treated, plant parts used, method of preparation of remedy, details of the administration, dosage, any noticeable side effects, and preservation techniques were collected.

Data analysis
A descriptive statistical method, such as percentage and frequency, were employed to analyze and summarize the data on medicinal plants, their uses and associated knowledge. Data associated to sources of medicinal plants, method of preparation, routes of administration, conditions of preparation, and plant parts and habits used were analyzed through descriptive statistical analysis with MS Excel. According to disease categories in earlier work [17] and with some modification, the human ailments were categorized into seven categories based on the usage reports mentioned by the informants in the study area. The collected data were analyzed through the informant consensus factor and various ranking methods.

Informant Consensus Factor (ICF)
The ICF was calculated for each category to identify the agreements of the informants on the reported cures for the group of ailments. The ICF was calculated as follows: number of use citation in each category (NUR) minus the number of species used (NT), divided by the numbers of use citations in each categories minus one [18].

Where, ICF=Informant Consensus Factor
NUR=Number of Use Citation

NT=Number of Species
The informant consensus factor was calculated for each category. The informant consensus of medicinal plant usage resulted in ICF ranging from 0.36 to 0.64 per illness category. A high value of ICF (close to 1) indicates that relatively few species are used by a large proportion of people, while a low value indicates that the informants disagree on the taxa to be used in the treatment within a category of illness.

Priority ranking
It is the simplest analytical tool for ethno-botanical studies. According to G Martin [1], priority ranking involves asking people to think of five to seven items and request to arrange those items according to a given criterion. Such criteria may be personal preference, perceived importance in the communities, or the list of plants resources that people feel are becoming increasingly rare in their communal forests. Therefore, in this study the set of 5 plants were selected from the list of medicinal plants that were reported as scarce by most informants in the study area and presented to the 6 key informants to rank according to their degree of scarcity. Each rank was given a numerical value of (1, 2, 3, and so on) with the most important items (most scarce medicinal plant species) given the highest value while the least important item was assigned 1. Then, the number was summed and ranked.

Direct matrix ranking
Direct matrix ranking was done following G Martin [1] in order to compare multipurpose use of medicinal plants. Six multi -purpose medicinal plant species commonly reported by the informants were selected out of the total collected medicinal plants and use diversity of these plants would be listed for the key informants to order them by considering six attributes which included medicine, firewood, charcoal, construction, food and fence were listed and the species were provided to six key informants to give value according to the use of the species for the particular attribute. The scores which were given to each attribute were added, ranked so as to compare use values of the reported plant species. Then, each chosen key informants would be asked to assign to attribute of each species (5 = most valuable, 4 = very good, 3 = good, 2 = less used, 1 = least valuable, and 0 = not used). The values of each species were summed up and ranked.

Paired comparison
Paired comparison can be used to understand the degree of preferences or levels of importance of

Ranking of threats to medicinal plants
Ranking of threats to medicinal plants that were reported by most of the informants in the study area was conducted using six selected key informants as described by G Martin [1]. As mentioned by most of the informants' six threats were selected and the informants were asked to give six for the most threatening factor and one for the least threatening factor in the study area. This information was used to determine the highest threatened factor to traditional medicinal plants in the study area and to suggest the necessary appropriate conservation measures.

Source and willingness to share knowledge of traditional medicinal plants use
Family was the major source of ethno -medicinal knowledge in the study district. Accounting for 66.67 % of the in formants, fathers were the major source of knowledge on traditional medicinal plants (Table 1).

Composition of medicinal plant species
A total of 47 plant species, with their medicinal use value, were recorded and distributed among 31 families and 44 genera (Appendix 1). In term of species composition, the family Fabaceae, Solanaceae, Euphorbiaceae, Asteraceae, Oleaceae, Cucurbitaceae and Rhamnaceae ( Figure 5) were the most frequently cited in the study district. The rest of the species belonged to one family each.
This might be owing to the relatively higher abundance of those species in the study area. The knowledge about habits, the part used, type, dosage, administration of the medicinal plants is circulating chiefly among practitioners of traditional medicine [25]. Accordingly with regard to habits of medicinal plants herbs were found to be accounted for 19(40.43%) followed by shrubs accounted 15 (31.91%). A Teklay, B Abera and M Giday [26] found herbs to be the most utilized plants, accounted for 44% of the species, followed by shrubs 29% in Kilte Awulaelo district, Tigray Region of Ethiopia and A Enyew, Z Asfaw, E Kelbessa and R Nagappan [27] also found that herbs with 43.87% followed by shrubs accounted for 35.84% in and around Fiche district, Central Ethiopia.

Plant parts used for medicine
Results showed that leaves and roots were the most commonly used plant parts in the preparation of remedies, accounting for 26(41.94% and 13(20.97%) of the total medicinal plant parts, respectively.
This was pursued by seeds 8 (12.9%) and fruits 8(12.90%) as well as bulbs 3 (4.48%), latex 3 (4.48%) and bark 1(1.61%) ( Figure 5). The use of leaves helped sustainable harvesting of plants. The popularity of the root part next to leaves might be due to the simplicity in using and preparing remedies out of it, such as chewing or inhalation after heating with fire. Roots can be also dried and powdered or homogenized with water.

Mode of preparation, route of administration, dosage and side effects
The study revealed that the highest mode of preparation was in the form of pounding 20(32.26%) and pursued by crushing 17(27.42%), chewing 8(12.91%), powder form 7(11.29%), roasted smoke 5(8.06%), unprocessed 3(4.84%) and in the form of juice 2(3.22%) ( Figure 6). This may be due to the possibility of effective extraction of plant ingredients when pounding, crushing and chewing so that it's curative potential would increase. This result is in agreement with a result from a study conducted in Guduru district of Oromia Some 14(24.14%) of the remedies were mixed with water, butter, honey and coffee while the remaining were used without addition of any ingredients ( District. This study is in line with study made by G Chekole [29] in Gubalafto district, Northern Ethiopia who indicated that lack of precision and standardization as one of the drawbacks for the recognition traditional health care system. Although the measurement types were different, there are some common measurements like coffee cup, teaspoon, finger length and glass. Age, sex, physical condition and stage of illness were also considered in the study area by some healers to determine the amount of the remedies to be given by using their experience. Lack of precision and standardization was one of the drawbacks for the recognition of traditional   (Figure 7). Water was the most frequently used when solvents were needed. Coffee and butter were also used as solvents or additives, to some degree in the preparation of remedies. Healers stored the collected traditional plant medicines in their homes for further usage, mostly in powdered and raw dried forms. In this regard, clothes and plastic bags were used mainly to store the dried medicine. However, the preferences of fresh plant parts for medicine were higher than dried ones. Based on the information gathered from the key informants the highest method of   [32] in Debark District, Amhara Region Ethiopia and A Kefalew, Z Asfaw and E Kelbessa [31] in Ada'a district, East Shewa Zone of Oromia Regional State, Ethiopia.

Priority ranking of medicinal plants
Priority ranking of five medicinal plants based on the degree of threats (availability) in the study area was conducted using 6 key informants. The results ( Table 6) indicated Olea europea is the most threatened in the study area followed by Acacia etbaica and Calpumia aurea ( Table 6).
Priority ranking of five medicinal plants in terms of availability showed that Olea europea was the most threatened medicinal plant in the study District. The result of preference ranking showed a particular medicinal plant is more preferred by the local people based on the given criteria.
Preference ranking was made in Ethiopia by many authors to see the choice of the local people as reported by A Tora and T Heliso [33] in low land of Konta special District, in Southern Ethiopia and B

Kidane, T van Andel, LJG van der Maesen and Z Asfaw [13] in Maale and Ari ethnic communities in
Southern Ethiopia. in Guduru district of Oromia Regional State, Ethiopia and L Kidane, G Gebremedhin and T Beyene [28] in Ganta Afeshum district, Eastern Zone of Tigray, Northern Ethiopia.

Paired comparison
Paired comparison was made to determine the most preferred medicinal plants among the five species that were used to treat external wound in the study area. The responses of 6 key informants showed that Aloe megalacantha ranked first followed by Heliotropium steudneri (Table 8)  *Key: where R represented respondents

Status of medicinal plants
The   Ethno-botanical data collected from the study area by means of guided field walk indicated that most of the local people used traditional medicine prepared from plant parts during infection for both humans and livestock in different ways and dosages based on the type of ailments. The most common health problems mentioned were dermal diseases, abdominal pain, respiratory diseases, leech and many others. They also reflected that accessibility of plants decreased during the dry season when it becomes difficult to find especially the herbs.

Factors threatening medicinal plants and conservation practices
Anthropogenic factors affect the medicinal plants in the study area. The factors include drought, agricultural activities for new agricultural lands, fire wood, charcoal, construction and urbanization.
Being a wildness of the cited medicinal plants exposed to various anthropogenic factors. From these factors the main threats to medicinal plants in the study area were, agricultural activities for new agricultural lands for expansion was ranked first by the selected key informants pursued by drought and fire wood respectively (Table 9).
People need plants for their daily life activities. In Raya Alamata District, nearly all key informants and the general group discussants were familiar with one or more than one threats that cause scarcity of medicinal plants in the study area. As mentioned by most of the informants, six threats were selected in the study area. This information was used to determine the highest threats to medicinal plants in the study area and helps to suggest the necessary appropriate conservation measures. Agricultural activities for new lands and drought ranked 1 st and 2 nd , respectively, followed by fire wood collection   Figure 1 Location map of the study area Habits of medicinal plants Mode of preparation of traditional medicine Status of medicinal plants