Traditional medicinal plants used by Kunama ethnic group in Northern Ethiopia

Utilization of medicinal plants is almost as old as the history of mankind. Semi-structured interview, guided field walk, group discussion and market survey were used to collect ethnobotanical data in Tahitay Adiyabo and Kafta Humera districts in northern Ethiopia. A total of 47 informants (30 males and 17 females) were selected purposefully from three sub-districts: Lemlem (n = 27), Adi-Goshu (n = 10) and Hilet-Coca (n = 10). A total of 115 species of medicinal plants were collected and identified for treating 59 humans and livestock ailments. The most commonly used plant parts for herbal preparations were roots (35.5%) and leaves (21.74%) and were administered through oral, dermal, ocular, nasal and vaginal routes in decreasing order. Oral application (58 preparations, 50.43%) was the highest and most commonly used route of application followed by dermal application (35 preparations, 30.43%). Kunama tribes are rich in medicinal plant species and the associated indigenous knowledge. Future studies should focus on phytochemical extraction of herbal drugs for their efficacy and possible toxicity.


INTRODUCTION
Utilization of medicinal plants is almost as old as the history of mankind. More than 80% of the world's population relies on traditional medicine to meet their daily health requirements (World Health Organization (WHO), 2001). This is partly due to accessibility, efficacy on treatment and affordable cost compared to Western medication (Cunningham, 1993;Konno, 2004). Medicinal plants were regularly used by people in prehistoric times for biomedically curative and psychotherapeutic purposes (Barboza et al., 2009). Knowledge of medicinal plants has resulted from trial and error methods, and often based on speculation and superstition (Hamayun et al., 2006). Nearly 50,000 species of higher plants have been used for medicinal purposes, and are also used in food, cleaning, personal care and perfumery (Barboza et al., 2009). Traditional knowledge of medicinal plants is important for modern medicine development (WHO, 2001;Luiz and Barbosa, 2012). Major pharmaceutical drugs have been derived from biological diversity (Bisset, 1994). For example, Aspirin was discovered independently by residents of both the New and Old worlds as a remedy for aches and fevers (Raskin et al., 2002).
Despite the wide utilization of medicinal plants for healthcare (Balick and Cox, 1996), medicinal plants across Africa are poorly documented. Plant remedies are the most important source of therapeutics for nearly 80% of the population in Ethiopia (Dawit, 2001;Awas, 2007) and most of the knowledge is still in the hands of traditional healers. Ethnobotanical research to document the knowledge and practices of traditional healers is invaluable. The present study reports ethnobotanical knowledge and practices by Kunama ethnic group (hereafter called Kunama) in northern Ethiopia where they are the smallest ethnic groups. Tigray National Regional State is one of the nine regions found in northern Ethiopia. It consists approximately 95% Tigrayans, 2.6% Amhara, 0.7% Erob and 0.05% Kunama (Fosse, 2006). The Kunama are a Nilotic people living in Ethiopia and Eritrea and about 100,000 (2% of the population of Eritrea) Kunama live in Eritrea near the border with Ethiopia between the Gash and Setit rivers (Refugees International, 2004).
In Tigray Kunama life in Kafta Humera and Tahitay Adiyabo districts near the border with Eritrea and the number of Kunama has dropped to 2,976 since the remaining 2,000 have migrated into the other Regions of Ethiopia (Community Supported Agriculture, 2008). They are known for treating human and livestock ailments using herbal medicine (COR, 2007) and live in remote and isolated areas both in Ethiopia and Eritrea. Access to the Kunama is difficult, and very little first-hand information is available in relation to their indigenous knowledge and practices (Refugees International, 2004). The present study attempts to document Kunama ethnobotanical knowledge and practices in northern Ethiopia.

METHODOLOGY
All locally available traditional healers (n = 30) and elders (n = 17) were selected for the study. A semi-structured interview, guided field walk and group discussion were used to collect ethnobotanical data. Medicinal plant specimens were collected, numbered and pressed at spot, and identified at National Herbarium, Addis Ababa University, Ethiopia. Preference ranking, direct matrix ranking, ranking of threats to medicinal plants, Informant consensus, Informant consensus factor (ICF) and Fidelity level were used to quantify ethnobotanical data (Martin, 1995).
Preference ranking was made following Martin (1995) for five most cited medicinal plants that were known for the treatment of snake bite. Seven randomly selected tradtional healers were given the five most cited medicinal plants to rank based on their efficancy. Ranking was done by giving five to the most efficient plant and one to the least. Following Martin (1995) six tradtional healers were selected for direct matrix ranking of five multi purpose (medicinal, firewood, food, charcol, cash income, construction and shade) medicinal plants. Ranking was done by giving five to the most important plant and one to the least. Ranking of threats to medicinal plants was done by ranking five highly cited threats by taking six traditional healers randomly. The traditional healers valued five to the most destructive factor (threat) and one to the least. Finally ranking of threats was made by adding the value of each threat. In order to confirm the reliability of the ethnobotanical information traditional healers were visited three times (Informant consensus). Informant consensus factor (ICF) was calculated in order to identify the agreement of the informants on the reported ailments as follows: number of use citations in each category (nur) minus the number of species used (nt), divided by the number of use citations in each category minus one (Heinrich et al., 1998). The reported aliments were categorized and then the ICF were calculated using the formula; Fidelity level (FL) was calculated by taking five most cited medicinal plants in order to know the importance of the medicinal plants for a particular purpose; by dividing the number of informants who mentioned the medicinal plant for treating particular medicinal disease to the total number of informants who mentioned the plant for any use.

FL= ;
Where Ip is the number of informants who mentioned the plant for particular purpose, and Iu is the total number of informants who mentioned the plant for any use. Market survey was conducted in the administrative center of Tahitay Adiyabo district called Shirarro and Kafta Humera district called Adi-Goshu and Adebay markets on three consecutive saturdays, the market day of the local communities. It was carried out by interviewing individuals who sell and buy plants or plant products.

DISCUSSION
A Total of 115 medicinal plant species belonging to 97 genera and 47 families were used to treat 59 human and livestock ailments by Kunama in the study area. Since ancient times Kunama have used biological renounces as a source of medicine for the control of various ailments affecting humans and their livestock. This demonstrates that Kunama are remarkable in utilizing different species of medicinal plants for treating various human and livestock disease. However, such remarkable knowledge is currently being threatened elsewhere in Ethiopia due to environmental degradation and deforestation (Yirga, 2010a, b, c;Zenebe et al., 2012).
Deforestation, soil erosion, agricultural expansion and drought are threatening the medicinal plants of the study area and the associated knowledge. Documentation of traditional medical knowledge in Ethiopia still remains at minimum level (Teklay et al., 2013) suggesting urgent ethno botanical studies and subsequent conservation measures to conserve resources from further loss . The indigenous knowledge and the associated plants in Ethiopia are being depleted mainly due to deforestation and environmental degradation which results in loss of some important medicinal plants (Desissa and Binggeli, 2000;Ragunathan and Abay, 2009). Farmers in the study area also use medicinal plants for treating livestock diseases. This might be due to lack of access to modern veterinarians, price of modern medicines and ethno veterinary traditional medicinal plants are believed to be more efficacious for treatment of livestock ailments than modern medicines (Harun-or-Rashid et al., 2010). Ethno veterinary medicines are also easy to prepare and with very little or no cost to farmers (Jabber et al., 2005).
The majority of medicinal plants were collected from the wild which is consistent with many studies across Ethiopia (Cotton, 1996;Giday, 2001;Giday and Ameni, 2003;Yineger et al., 2008;Bekalo et al., 2009;Yirga, 2010b, c). Medicinal plants were also collected from caves and lakes mainly herbs and algae. This indicates that medicinal plants are collected from different habitats that might be linked with the substrate and mineral composition of the area. The natural forest resource base of Tigray region is over exploited due to human economic       activities and population pressure (Nyssen et al., 2004) and covers about 0.2% of the total area (Tesfay, 2006). Anthropogenic and natural factors such as drought cause many of the medicinal plants to be rarely encountered.
The practice of cultivating medicinal plants is quite limited in the area and across Ethiopia (Giday, 2001;Abdurhman, 2010). Measuring units such as coffee cup, bottle cup, tea spoon, drops and fingers were used for dose determination. Lack of standardization and precision of preparations are drawbacks of traditional health care system elsewhere (Getahun, 1976). Root was the most used plant part in the preparation of remedies in the area compared to other parts and this is consistent with many studies in the country (Lulekal et al., 2008;Mesfin et al., 2009;Birhane et al., 2011). In contrast to this other studies conducted elsewhere in Ethiopia reported the dominance of leaves in the preparation of remedies (Giday and Ameni, 2003;Bekalo et al., 2009;Yirga, 2010b;Abebe and Hagos, 1991). Frequently harvesting of roots causes death of the medicinal plant.
Fresh was the dominant condition of medicinal preparation in the study area. The frequent use of fresh materials might be important to reduce lose of volatile oils, the concentration of which could deteriorate on drying (Giday et al., 2009). A. oerfota, S. longepedunculata and T. capensis had highest fidelity level values suggesting good healing potential of the plants. Plants that are used in a repetitive fashion are more likely to be biologically active (Trotter and Logan, 1986). Kunama are rich in medicinal plant species and the associated indigenous knowledge. Future studies should focus on phytochemical extraction of herbal drugs for their efficacy and possible toxicity.