Ethnobotanical study of medicinal plants in Ganta Afeshum District, Eastern Zone of Tigray, Northern Ethiopia

Humans began to employ plants for the intention of health a long time ago, maybe at the first moment when they suffered from diseases [1]. Since the antique time plants have been an essential supply for deterrent and healing for humans and livestock [2]. The population living in Sub-Saharan Africa continues to suffer from infectious as well as noninfectious and deficiency diseases [3]. Because of these and other problems, a large number of people of Africa die daily of preventable and curable diseases due to the lack of simple primary health care [4].

The ailment saddle is provoked by the limitation of the medical personnel and medical provisions such as remedial devices and access to fundamental medicine. The ratio of medical doctors to patients in Africa is not fair; in Ethiopia, for example, there is one doctor to 33,000 patients and in Malawi one doctor to 50,000 patients [5]. Because of this, human beings use different plant species known in ancient traditional medicine instead. Traditional medicine has been applied by humans for the healing of different diseases since a long time before the beginning of conventional medicine and up to this time serve the health care needs of the majority of the people of Africa [3, 5‐7].

Thus, traditional medicine remains popular for both historical and cultural reasons. It is estimated that 80% of the African people depend on traditional medicine to meet up their care needs [8].

Like other parts of sub-Saharan countries, 70% of human and 90% of livestock population of Ethiopia rely on traditional medicine for primary health care [9]. In addition to the lack of availability of modern medicine, there are also culturally linked traditions. The communities have trust in the medicinal values of traditional medicine which can also be obtained at a relatively low cost as compared to the modern ones [10].

Ethiopia is exceptionally rich in history, culture, and biological diversity. It is the origin of the early of hominine species of which Lucy was a member. Around 80 languages are spoken by various ethnic groups. The country is also recognized for its diverse habitats, vegetation, and faith which results in a high diversity of traditional medicinal knowledge and practices of the people in using medicinal plants [11]. However, this rich cultural heritage is threatened, especially in the form of deforestation, fuelwood collection, illegal logging, overgrazing by stock animals, and agricultural expansion [11‐13]. Such problems include the Tigray Region where the study was conducted.

Although the literature on ethnobotany in Ethiopia is increasing, there is still a limited ethnobotanical documentation on medicinal plants and minimum phytomedicine preparation of crude extracts and isolation of active ingredients [14]. Besides, the rural population of Tigray in general and the people of Ganta Afeshum District in particular greatly depend on medicinal plants because of their acceptability, availability, affordability, and efficacy to treat human and livestock health problem and due to lack of certain infrastructure like roads, ambulance, hospital, and health center. However, these important medicinal plants become exhausted mainly due to agricultural and urban expansion as well as deforestation and heavy livestock grazing pressure.

Available reports show that limited ethnobotanical studies have been conducted in Tigray to document the use of medicinal plants [14‐20]. The studies conducted in the districts of Alamata [14], Enderta [15], Hawzen [16], LaelayAdi-yabo [17], Asgede Tsimbela [18], Ofla [19], and Kilte Awulaelo [20] documented 25, 27, 33, 37, 68, 113, and 114 medicinal plants, respectively. However, no such study has so far been conducted in Ganta Afeshum District. Therefore, the protection of these resources and documentation of related traditional knowledge are needed, and it is on the basis of this gap that the present study was undertaken. The study examined and documented the diverse medicinal plant species which are used by the people of Ganta Afeshum District, Eastern Tigray Regional State Northern Ethiopia to treat different human and livestock ailments.

The informants involved in the present study were 17–79 years old with an average age of 47 years. From the total informants, 45 (57.7%) were in the age range of 38–58, while 17 of the informants were 59–79 years old and 16 were in the age range of 17–37 years old (see Additional file 1: Table S1).

More than half of the informants (43, 55.1%) were illiterate, and 21 (26.6%) of the informants had been in school for 1–8 years, 12 (15%) of the informants finished school in grade 9–12, and the remaining 2 had schooling above grade 12. From the 54 men informants, 47 were married while 7 men informants were single. From the total of 24 women informants, 11 were married whereas 13 women informants were single.

One hundred seventy-three medicinal plant species were identified for the treatment of human and livestock ailments that distributed across 77 families and 156 genera. From the 77 plant families, Fabaceae stood first by contributing 17 (9.82%) species followed by Lamiaceae and Solanaceae that contain 9 (5.2%) species. Similarly, various studies in Ethiopia [2, 11, 37, 38] showed that Fabaceae was the dominant family among the others, whereas other studies [19, 39‐44] noted that Asteraceae was the dominant one among others.

The result indicates that medicinal plants are unevenly distributed in the four study sites. More of the medicinal plants were found in Tsaedat-Hamlo and Hagereselam due to certain reasons. Tsaedat-Hamlo is a remote part of Ganta Afeshum District about 100 km from Adigrat. This has caused insufficient coverage of modern medicine, unaffordable as well as inadequate health facilities, and medical personnel. Instead, many people there use the accessible, inexpensive, and locally available traditional medicinal plants. The kebeles Hagerselam and Tsaedat-Hamlo also had a better vegetation cover and more traditional healers than Sasun-Bethaweryat and Dbla-Siet. Also, the far remote kebeles were less influenced by modernization and urbanization. Generally, urbanization and modernization negatively affect the knowledge of traditional medicinal plants. There is also a public health concern as modernization alters the practice of traditional medicine. The loss of traditional medicinal plant knowledge of these kebeles’ people alters health care-seeking behavior. The residents of Sasun-Bethaweryat and Dbla-Siet were more educated and engaged in commercial activities; as a result, they were seeking modern medication. Less educated people tend to be less acculturated and know more medicinal plants while educated people tend to be more acculturated, know few medicinal plants, and seek Western medical treatment [45].

From the total of 173 medicinal plant species, 116 (67.44%) plants were gathered from the natural vegetation followed by 34 (19.65%) from home gardens. This indicates that the communities of the study area highly depend on the wild source to obtain the medicinal plants; in other words, the habit of cultivating medicinal plants in home gardens was not much developed. Similar studies conducted elsewhere in different parts of Ethiopia [10, 45‐49] also reported that most of the medicinal plants were collected from natural vegetation.

The medicinal plants in the study area had diverse growth form: herbs 69 (39.88%), shrubs 58 (33.52%), trees 37 (21.39), and climbers 5 (2.89). The dominance of herbs and shrubs is in agreement with several studies conducted in Ethiopia [45, 48, 50‐52]. In contrast, Lulekal et al. [2] reported from Mana Angetu District, southeastern Ethiopia, that shrubs there made up the highest proportion of the medicinal plants; the finding of Regassa [38] in Hawassa city, southern Ethiopia, showed that the majority of the collected medicinal plants there were trees, followed by shrubs, herbs, and climbers.

The results showed that the local people of the Ganta Afeshum District use different parts of medicinal plants to prepare remedies. Leaves were the most widely used part, which is an important finding because harvesting leaves does not have detrimental effects on the survival of the medicinal plants, whereas harvesting roots and whole plants has a negative impact on the survival. In the same way, several studies [45, 47, 53‐56] have revealed that the leaves of the medicinal plants were repeatedly used for the treatment of human and livestock ailments. On the other hand, Mesfin et al. [48] and Assefa and Abebe [57] reported that the roots were a widely utilized medicinal plant part to treat different ailments.

Most of the medicinal plants (212, 64%) were prepared to be used in the fresh form, and this indicates that fresh medicinal plants are much easier and quicker to prepare for remedy than the other forms. Abebe [11], Gebeyehu [42], and Chekole [45] reported similar results.

In Ganta Afeshum District, the common method of traditional medicine preparation is direct and immediate/unprocessed use of the medicinal plants followed by grinding and boiling in water. Elsewhere in Ethiopia, similar findings were reported [11, 37, 39, 47, 57, 58], and grinding, pounding, smoking, squeezing, burning, roasting, and powdering are common the methods of preparations of traditional medicines.

Oral administration was the most common way for traditional medicine followed by dermal, nasal, and anal. This discovery is in line with many findings of researchers [2, 16, 19, 39, 43, 58, 59] who reported that the major way of administration was oral. In contrast, Teklay et al. [20] reported that dermal was a common way of administration. Many of the prepared traditional medicines were taken by drinking followed by smearing, eating, fumigation, and chewing. This finding is concurrent with the discoveries of Gebeyehu [42] who reported that prepared remedies were applied by drinking, dropping, creaming (ointment), eating, inhaling/sniffing, and sucking. Similarly, Tamene [53] revealed that the medicinal plants prepared by traditional healers were applied by different methods such as drinking, painting, chewing, swallowing, put on, smelling, and smoking. In addition, traditional medicines of the study area were prepared with solvents and ingredients, such as water, honey, butter, cereal oils like sesame oil, teji/tella (local beer), milk/ergo (yoghurt), and tea/coffee. A similar study was carried out in Chifra District, Afar Region, Northeastern Ethiopia, by Seifu [50] who reported the Afar people and their traditional healers used solvents and additives like water, honey, sugar, and milk of goat and camels during the preparation of traditional medicines.

In Ganta Afeshum District, 74 human, 23 livestock, and15 both human and livestock ailments were recognized. This indicated that the people of the district were suffering from many ailments as compared to other areas such as in Gimbi District, western Wellega, where Tolasa [58] identified 49 human and 19 livestock ailments. In Minjar-Shenkora District, North Shewa Zone of Amhara Region, Alemayehu [43] reported 45 human ailments; in Seru District, Arsi Zone of Oromia Region, Gebrehiwot [39] reported 53 human and 17 livestock ailments; and in Wondo Genet natural forest and adjacent kebeles, Sidama Zone, SNNP Region, Tamene [53] recognized 40 human and 17 livestock ailments. Because of this burden of health problem, the people of Ganta Afeshum District widely used many medicinal plants, and that is why such a large number of medicinal plants were identified. Moreover, a single human ailment was found to be treated by several medicinal plants. This is in agreement with the findings of different scholars [40, 41, 43] who have reported wounds, headache, febrile illness, evil eye, tonsillitis, evil spirit, hemorrhoids, toothache, earache, and cough to be treated by several medicinal plants.

Men and women informants had equal traditional medicinal plant knowledge in the study area. This result is in line with the findings of Asnake et al. [55] but disagrees with the discoveries of Teklehaymanot and Giday [59] who showed the presence of a significant difference in traditional medicinal plant knowledge between men and women. On the other hand, married informants reported significantly more medicinal plants than single informants. This is because most of the married informants were adults and more experienced with plant contact. They also possess children and livestock, they lead a family, and they are responsible for the family health care and are also the major players in using medicinal plants. Similarly, Beyene [33] reported that married informants had a better knowledge of traditional medicinal plants than single informants.

Key informants cited significantly more medicinal plants than the general informants. This is because the key informants were traditional herbalists with broad, empirical traditional medicinal plant knowledge. They cultivate, collect, process, prepare, administer, and treat patients by using medicinal plants. General informants cited fewer medicinal plants; even though they perform self-medication (homemade remedies), they are not knowledgeable about medicinal plants. Beyene [33] got similar results.

There was a significant negative correlation between the informants’ educational level and their knowledge of traditional medicinal plants. This means that with a higher level of education, the knowledge of traditional medicinal plants decreases. Thus, modern education weakens the traditional medicinal knowledge of the young generation. This discovery agrees with the research carried out in Dire Dawa city, eastern Ethiopia, by Kebede et al. [47].

The more aged informants were, the more they were knowledgeable about traditional medicinal plants. Similar results were reported by Kebede et al. [47], Kefalew et al. [60], and Birhanu [61]. In the exercise of preference ranking, Cordia africana scored first rank, and Vernonia amygdalina, Medicago polymorpha, Laggera tomentosa, and Schinus molle scored second to the fifth rank, respectively, for the efficient treatment of febrile illness. In a study from Ofla wereda, the southern zone of Tigray Region [19], Cynoglossum lanceolatum was ranked first. Similarly, a study conducted by Chekole [45] in Gubalafto District showed that Cynoglossum coeruleum and Ocimum latifolium were preferred by the community to treat febrile illness. On the other hand, Momordica foetida was ranked first as the most effective for the treatment of rabies among Guji agro-pastoralists, Bule Hora District of Borana Zone, Oromia Region [54], and Nicotiana tabacum was ranked first for the treatment of snake bite in Gimbi woreda, western Wellega [58].

Furthermore, in direct matrix ranking, Carissa spinarum, Acacia etbaica, and Juniperus procera were ranked first, second, and third, respectively, showing multipurpose roles and the most preferred and extensively exploited by the local community. For this reason, they were the most threatened plant species in the study area and need conservation priority for their sustainability. Conversely, Cordia africana, Olea europaea, Mimusops kummel, Ziziphus spina-christi, and Acacia albida were the least preferred multipurpose medicinal plants and less threatened since they are not widely exploited by local communities. Similar studies were carried out elsewhere in other parts of Ethiopia like in Goma Wereda, Jima Zone of Oromia Region, Ethiopia, by Etana [40]. He used the method of direct matrix ranking and revealed that Cordia africana was the most preferred and first ranked multipurpose plant species. In another study in Seru wereda, Arsi Zone, Oromia Region, Ethiopia, Gebrehiwot [39] indicated that Acacia abyssinica was the most preferred multipurpose plant. A related study by Teklay et al. [20] indicated Cordia africana, Eucalyptus globules, Opuntia ficus-indica, and Dodonia angustifolia as the most preferred multipurpose plants by the local people in Kilte Awulaelo District which is from the same zone of the study area demonstrating the presence of cultural use difference of community.

In paired comparison, Rhamnus prinoides and Achyranthes aspera were ranked first and second indicating being the most preferred and effective for treatment of tonsillitis as compared to Rumex nepalensis and Lycopersicon esculentum. Similarly, Teklay et al. [20] and Chekole [45] showed Rhamnus prinoides and Achyranthes aspera were used for the same purpose to treat tonsillitis. Moreover, ten medicinal plant species have the highest use values in the study area, indicating that they are more effective to treat ailments. Among the total documented medicinal plant species, Rhamnus prinoides followed by Cordia africana and Ruta chalepensis were used to treat the highest number of diseases. In this sense, a plant with a high use value would theoretically have a correspondingly high cultural consensus [35]. Therefore, to maintain the continuous use of plant resources in the study area, conservation priorities should be given for those multipurpose and more threatened ones.

Ganta Afeshum District is relatively rich in medicinal plant species. One hundred seventy-three medicinal plant species were collected and identified. These medicinal plants were used by the inhabitants to treat 112 human and livestock ailments. Wounds, febrile illness, abdominal pain, headache, cough, evil eye, evil spirit, men impotence, and tonsillitis were frequently occurring human ailments, whereas, leech, bloating, Newcastle, and bone fracture were common livestock ailments. This indicated that the local community depends on using medicinal plant species and the associated indigenous knowledge to prevent diverse human and livestock ailments, although modern health services are expanding.

In the study area, there was no knowledge difference between men and women informants on traditional medicinal plant knowledge, whereas, educational level and knowledge of medicinal plants of informants were negatively correlated. Thus, the age and medicinal plant knowledge of the informants were positively correlated, by which the younger informants showed less concern in sharing, recording, and examining processes of traditional medication. Greater preference ranking, use value scores, and fidelity level values of the documented medicinal plant species would enable the forthcoming phytochemical and pharmaceutical studies and conservation activities.

Natural vegetation was the main source of medicinal plants in Ganta Afeshum District followed by home gardens and farmlands. But nowadays, deforestation, agricultural expansion, overgrazing, drought, and overexploitation are threatening these plant resources and their habitat. Therefore, people of the study area should apply complementary conservation approaches (in situ and ex situ) for sustainable use of these resources and prevent species extinction.