Open Access

An ethnobotanical study of medicinal plants in Wayu Tuka District, East Welega Zone of Oromia Regional State, West Ethiopia

  • Moa Megersa1Email author,
  • Zemede Asfaw2,
  • Ensermu Kelbessa2,
  • Abebe Beyene3 and
  • Bizuneh Woldeab1
Journal of Ethnobiology and Ethnomedicine20139:68

https://doi.org/10.1186/1746-4269-9-68

Received: 11 February 2013

Accepted: 22 September 2013

Published: 25 September 2013

Abstract

Background

This paper reports an ethnobotanical study that focused on the traditional medicinal plants used by local communities to treat human and livestock ailments. A cross-sectional study was undertaken from September 2009 to June 2010 in Wayu Tuka District of Oromia Region, Ethiopia. The aim of the study is to document medicinal plants used by local people of the study area and the threats currently affecting medicinal plants.

Methods

Ethnobotanical data were collected using semi-structured interviews, field observations and group discussion in which 63 (41 men & 22 women) randomly selected informants participated. Of which, 11 (10 male and 1 female) were local healers. Paired comparison method, direct matrix ranking and Informant consensus factors (ICF) were used to analyze the importance of some plant species.

Results

A total of 126 medicinal plant species, distributed in 108 genera and 56 families, were collected together with their medicinal uses. Of the 126 species of medicinal plants collected from the study area, eighty six (68%) were obtained from the wild whereas thirty three (26%) were from homegardens. The Fabaceae came out as a leading family with 15 medicinal species while the Solanaceae followed with eight species. Seventy eight (62%) of the medicinal plants were reported as being used for treating human ailments, 23 (18.2%) for the treatment of livestock ailments and 25 (20%) for both. The most frequently used plant parts were leaves (43%), followed by roots (18.5%) while crushing, which accounted for (29%) and powdering (28%) were the widely used methods of preparation of traditional herbal medicines.

Conclusion

The number of reported medicinal plants and their uses by the local people of the District indicate the depth of the local indigenous knowledge on medicinal plants and their application. The documented medicinal plants can serve as a basis for future investigation of modern drug.

Background

Since time immemorial, people have used plants as medicine. The investigation of plants and their uses is one of the most primary human concerns and has been practiced by all cultures for tens, if not hundreds, of thousands of years, though it wasn’t called ‘Ethnobotany’ [1]. Perhaps as early as Neanderthal humans, plants were believed to have healing powers [2]. The earliest recorded uses are found in Babylon about 1770 BC and in the code of Hamurabian ancient Egypt about 1550 BC. In the early 1500 s, Indian fever bark was one of the first medicinal plants to find appreciative consumers in Europe, which was taken from the cinchona tree (Cinchona officinalis), the bark of which was used as an infusion by native people of the Andes and Amazon highlands to treat fevers. Jesuit missionaries brought the bark to Europe and by the early 16th century the name of this medicine was transformed to “Jesuit fever bark” [2].

Traditional medicine comprises of therapeutic practices that have been in existence, for hundreds of years, before the development and spread of modern medicine and are in use today [3]. These practices vary widely, in keeping with the social and cultural heritage of different countries. Traditional medicine includes a diversity of health practices, approaches, knowledge, and beliefs incorporating plant, animal, and/or mineral-based medicines; spiritual therapies; manual techniques; and exercises, applied singly or in combination to maintain well-being, as well as to treat, diagnose, or prevent illness [4]. Traditional medicine was once again redefined in 2008 as the sum total of knowledge, skills and practices based on the theories, beliefs and experiences indigenous to different cultures that are used to maintain health, as well as to prevent, diagnose, improve or treat physical and mental illnesses [5].

A major component of traditional medicine is that which uses medicinal plants. Plant-based traditional medicine plays a key role in the development and advancement of modern studies by serving as a starting point for the development of novelties in drug discovery [6]. Various modern drugs were extracted from traditional medicinal plants through the use of plant material following the ethnobotanical leads from indigenous cures used by traditional medical systems [7]. On top of their use in fighting various ailments at local level, different medicinal plants are used as export commodities, which generate considerable income [8]. China takes the lead (45%) by importing the highest number of herbal medicines for preparation of drugs and this is followed by the United States of America (15.6%) and Australia (10.5%) [9].

In Ethiopia, the use of traditional medicinal plants is widely practiced. The wide spread use of traditional medicine in Ethiopia could be attributed to cultural acceptability, efficacy against certain type of diseases, physical accessibility and economic affordability as compared to modern medicine [10]. The size of the Ethiopian flora is estimated at 6,000 species of vascular plants of which about 10% are believed to be endemic [1118]. Traditional remedies are the most important and sometimes the only source of therapeutics for nearly 80% of the Ethiopian population and 95% of the preparations are of plant origin [10]. Due to various reasons, such as knowledgeable people in the society, the knowledge on medicinal plants of the country is getting lost. Since the knowledge of traditional medicine is transferred orally from generation to generation, basic information on the use of the plants and the part used, drug preparation methods, the diseases treated and others may be lost and discarded in the knowledge transfer process. Therefore, documentation of medicinal plants and the indigenous wisdom associated with them is important in order to pass the knowledge to the next generation since the plant materials and the indigenous knowledge can be the basis for the invention of modern drugs on top of the heritage values of the resource. In addition, such studies are vital in order to identify threatened medicinal plant species to give due attention for proper management and conservation. Thus, this study was initiated to document the traditional medicinal plant knowledge of the people and the threats currently affecting medicinal plants in Wayu Tuka District.

Materials and methods

Study area and the people

Wayu Tuka District is situated at (8° 56′N and 9° 7′N) and (36° 32′E and 36° 48′E). It is located at about 322 km west of Addis Ababa, in the East Welega Zone of the Oromia National Regional State. The District covers an area of 28,952.795 ha and comprises 12 kebeles (smallest administrative unit) belonging to ten rural areas and two urban centers namely ‘Boneya Molo’, ‘Gara Hudha’, ‘Gute Badya’, ‘Kichi’, ‘Komto’, ‘Migna Kura’, ‘Haro Chalchis’, ‘Gida Abalo’, ‘Gida Basaka’, ‘Wara Babo Miya’, ‘Gaba Jimata’ and ‘Gute’ (Figure 1).
Figure 1

Location of Wayu Tuka District in East Welega Zone; Oromia Regional State.

According to Wayu Tuka District Agricultural Office [19], the altitude of the study area ranges from 1300–3140 m.a.s.l, and the District has various topographic features. About 17,950.8445 ha (62%) of the land area is plain, 4,922.00575 ha (17%) hilly, and mountains and clifts account for 3,763.88675 ha (13%) and 2,316.238 ha (8%) respectively. The major soil types are clay loom, covering about 17371.68 ha (60%), sandy soil that stretches over an area of 10133.49 (35%) and clay constitutes 1447.64 ha (5%). The latter two soil types are suitable for agriculture including for cultivation of cereal crops including maize (Zea mays), sorghum (Sorghum bicolor) and ‘teff’ (Eragrostis tef) [19].

Based on the metrological data recorded at Nekemte station for 10 years (1998–2007), the rainfall distribution of the district is unimodial. The rainy season is locally called ‘Ganna’ and it extends from May to August with the highest peak in June and August. The highest average monthly rainfall was recorded in June (4,026.7 mm) and the lowest in January (99.9 mm), with the hottest months from March to October. The maximum mean temperature was recorded in February and March (27.9°C) and the coldest months of the year stretch from November to January, the lowest temperature having been recorded in December and January (12.2°C). In general, the mean annual temperature and mean annual rainfall of the District are 18.8°C and 2,067 mm, respectively (Figure 2).
Figure 2

Climadiagram of the study area from 1998–2007 at Nekemte Weather Station, East Welega Zone. Data source: National Meteorological Service Agency.

The vegetation of the area belongs to the moist evergreen montane forest and this type of forest is known to occur in southwest Ethiopia, particularly in parts of Welega, Ilubabor and Kefa [20]. The common species in the area include Poutenia adolfi-friederici, Trilepisium madagascariense, Morus mesozygia, Mimusops kummel, Podocarpus falcatus, Coffea arabica and Galiniera saxifraga.

Based on the 2007 population and housing census, the population of Wayu Tuka District is projected to be 66394, with 63325 (95.4%) in the rural, directly living on agriculture and assocciated activities also by supplying its produce to the neighboring urban dwellers. The people of the District belong to the Oromo ethnic community. Afaan Oromo (the Oromo language) is the widely spoken language in the area.

The District has three governmental clinics, four governmental health posts and one non-governmental health post. In the District, the leading ten human diseases are internal parasites (intestinal), rheumatism, upper respiratory diseases, skin diseases, diarrhea, malaria, gastritis, and fever of unknown causes, ear diseases and anemia [Wayu Tuqa Wereda Health Office: Report on diseases found in the Wereda, Unpublished].

There are two veterinary clinics in the District where the number of cattle and the number of clinics are not balanced. The ten most serious livestock diseases in the District are trypanasomiasis, internal parasites, external parasites, pasteurollosis (ovine and bovine), blackleg, anthrax, African horse sickness, sheep and goat pox, New Castle disease, babeosis and mastits [19].

Methods

A reconnaissance survey of the study area was carried out from September 15 to 30, 2009 and resulted in the identification of nine study sites, namely Boneya Molo, Gaba Jimata, Gara Hudha, Gute, Gute Badya, Kichi, Komto, Migna Kura and Wara Babo Miya. The study sites were selected based on the availability of practice of traditional medicine, and on the recommendations of elders and local authorities in Wayu Tuka District. Moreover, the three agro-climatic zones were also considered to select the study sites (kebeles).

Ethnobotanical data collection

A total of 63 (41 males and 22 females) informants were selected out of 66394 population following [21]; 43 were selected randomly and 20 key informants were selected purposively and systematically based on the recommendations of knowledgeable elders, local authorities and development agents by taking 2–3 individuals from each study site. Out of which 11 were traditional healers (10 males and 1 female). The informants were local inhabitants aged between 19–102 years. The selection of key informants was also based on the quality of explanations that particular informants gave during an interview. Local healers automatically qualified as key informants being traditional experts who are custodians of indigenous knowledge on medicinal plants.

Ethnobotanical investigations were carried out to collect data on medicinal plants used to treat human and livestock ailments in Wayu Tuka District following standard methods [21, 22]. The techniques used were semi-structured interviews, field observations, group discussion and guided field walk. The data were collected from October 1, 2009 to December 15, 2009 and March 26, 2010 to April 06, 2010. Interviews and discussions were undertaken based on checklist of questions prepared in English and translated to ‘Afaan Oromo’. Information was carefully recorded during an interview with an informant as well the knowledge of vegetation categorization was asked and recorded. Field observations were performed with the help of local guides on the morphological features and habitats of each medicinal plant species in the field.

Discussions were conducted on threats to medicinal plants, conservation of the medicinal plants and transferability of knowledge in the community. Before collecting the data, written permission was secured from the office of the District and permission was obtained from the administrator of each selected kebele. Following this, the purpose of the study was explained to each informant and verbal prior consent was obtained.

Specimen collection and identification

The reported medicinal plants were collected from natural vegetation and homegardens during the field walks and habits of the plants were listed. Preliminary identification was done at the site (field) and the collected voucher specimens were taken to the National Herbarium of Ethiopia (Addis Ababa University). Specimen identification and confirmation was undertaken by using taxonomic keys and various volumes of the Flora of Ethiopia and Eritrea [1118]. Finally, the identified specimens were reconfirmed by a taxonomic expert and the specimens with their label stored at the National Herbarium.

Data analysis

The collected ethnobotanical data were entered into Excel spreadsheet 2007 and summarized using descriptive statistical methods such as frequency and percentages. Paired comparison method [21] was used to determine the relative importance of plant species, which are used in the treatment of blackleg. In paired comparison, 9 informants were selected and asked to choose the best item from every pair according to personal perception in treating Blackleg. The total number of possible pairs (21) was obtained by applying the formula n (n-1)/2, where n is the number of medicinal plants being compared. A total rank of paired comparison was obtained by summing the number of times each item was chosen. An item with highest frequency of choices had the highest score.

Direct matrix ranking [21, 22] exercises were employed in order to compare the multiple uses of a given plant species based on information gathered from informants. The multipurpose species were selected out of the total medicinal plants and the uses of these plants were listed and 8 randomly selected key informants were asked to assign use values to each species. Each chosen key informant was asked to assign use values (5 = best, 4 = very good, 3 = good, 2 = less used, 1 = least used and 0 = not used). The values (average scores) of each species were summed up and ranked.

The Informant consensus factor (ICF) was calculated for each category to identify the agreements of the informants on reported cures for the group of ailments. The ICF [23] was calculated as follows
ICF = nur nt / nur 1
Where,
ICF = Informants Consensus Factor
nur = number of use citation in each category
nt = number of species used

Results

Indigenous knowledge and local vegetation categories

People of the study area classify vegetation of their surroundings mainly based on density of plant species that cover the land. The following four categories of vegetation were used by the community to distinguish one vegetation type from another. They then describe the location of a medicinal or other useful plant distribution in terms of these categories.

Caffee’ is marshy vegetation where mostly plant species of the families Poaceae and Cyperaceae grew. The place is generally considered unsuitable for ploughing and crop cultivation but is suitable for grazing.

Luugoo-lagaa’ is equivalent to reverine vegetation which is found at the banks of rivers, mostly composed of Syzygium guineense subsp. guineense and Ficus sycomorus.

‘Bosona’ is a type of forest with densely populated plant species with many tall trees, making the home of wild animals. An example of such vegetation in the study area is ‘Bosona Komto’ (Komto Forest), which is found in Komto Kebele.

‘Daggala’ is the term used to refer to seasonal plants.

Medicinal plants of the study area

One hundred twenty six species, belonging to 108 genera and 56 families, were used by local people of the District to treat various human and livestock ailments (Tables 1, 2 and 3). There were seven endemic species of Ethiopia found among the reported traditional medicinal plants (Albizia malacophylla, Coccinia abyssinica, Impatiens tinctoria subsp. abyssinica, Lippia adoensis, Pycnostachys abyssinica and Saturegia paradoxa). Among the families that contributed more medicinal species were the Fabaceae, represented by 15 species (12%), Solanaceae with 8 (6.3%) species, Asteraceae with 7 (5.6%), and other 44 families contributing 57 (45%) species are represented by 1 or 2 species (Table 4). Of the 126 species of medicinal plants collected from the study area, most of them (86, 68%) were obtained from the wild whereas 33 (26%) were from homegardens, and only 7 (5.5%) species were from both homegardens and wild habitats (Tables 1, 2 and 3).
Table 1

List of medicinal plants for treating human diseases in the study area, Wayu Tuka District

Scientific name

Local Oromo name

Family

Hab

Ha

Plant part, preparation and application

Disease treated

V. No.

Acacia abyssinica Hochst. ex Benth.

Laaftoo

Fabaceae

T

W

Juvenile leaves crushed and sniffed

Bat urine

MM072

Acmella caulirhiza Del.

Guutichaa

Asteraceae

H

Hg

Fresh flowers chewed and swallowed

Tonsillitis

MM038

Albizia gummiffera (J. F. Gmel.) C.A. Sm.

Muka arbaa

Fabaceae

T

W

Leaves crushed, mixed in water. Put in cotton and rubbed on affected teeth.

Toothache

MM068

    

Bark chewed in order to get relief from Rheumatism

Rheumatism

 

Albizia sp.

Ambaltaa

Fabaceae

T

W

Dried bark powdered and applied on affected part

Wound

 

MM077

Allium sativum L.

Qullubbii adii

Alliaceae

H

Hg

The bulb taken with ‘injera’ and Capsicum annuum L. for 5 days before eating breakfast

Malaria

MM013

Asparagus africanus Lam.

Sariitii

Asparagaceae

Sh

W

Fresh leaves crushed and applied on the affected part

Spider poison

MM092

Bidens macroptera (Sch. Bip. ex Chiov.) Mesfin

Keelloo

Asteraceae

H

W

Fresh leaves put on fire and rubbed on affected part

Athletes foot

MM037

Brassica carinata A. Br.

Goommana

Brassicaceae

H

Hg

Dried seed Powdered and mixed with water then drunk.

Common cold

MM002

Brucea antidysentrica J.F. Mill.

Qomanyoo

Simaroubaceae

T

B

Fresh leaves crushed and mixed with Leaves of Bersema abyssinica Fresen. and cooked With porridge and given for a person in need

Ascaris

MM028

Root powdered and mixed in water and drunk

Diarrhea

 

Croton macrostachyus Del.

Bakkanisa

Euphorbiaceae

T

W

Exudates put on the cut skin to stop bleeding

Skin cut

MM080

Bark of croton put on fire and the smoke used as to protect mosquito bite

Mosquito repellant

 

Juvenile leaves smashed and rubbed on affected part

Ring worm

 

Dried root powdered and given to Dog with ‘injera’ which suffered by Rabies

Rabies

 

Catha edulis (Vahl) Forssk ex Endl.

Caatii

Celastraceae

T

Hg

Fresh leaves crushed and boiled in water with leaves of Ruta chalepensis L., fresh leaves of Periploca linearifolia Quart. –Dill. & A. Rich. and fresh leaves of Englerina woodfordioides Gilbert then sugar added while it is boiling, put off from the fire and make to cool finally a cup of tea will be taken for four days.

Cough

MM020

Carissa spinarum L.

Agamsa

Apocynaceae

Sh

W

Fresh bark chewed early before having breakfast

Stomach ache

MM103

The bark Chewed or hold in teeth for 5-10 min.

Toothache

 

Canarina eminii Aschers ex Schweinf.

Maaracaa

Campanulaceae

Cl

W

The whole plant crushed together, chewed and swallowed

Headache

MM154

Whole plants crushed and rubbed on affected part

Scabies

 

Capparis tomentosa Lam.

H.gurraacha

Capparidaceae

Sh

W

Roots crushed and sniffed

Fibril illness

MM101

Carica papaya L.

Paappaayyaa

Caricaceae

T

Hg

When the leaves become yellow, that means getting to dry, powdered and boiled in water and a cup of tea will be taken for 5 days.

Malaria

MM085

The steam crushed and tied on affected part

Wound

 

Seed chewed and swallowed

Internal parasite

 

Caylusea abyssinica (Fresen.) Fisch. and Mey.

Illancoo

Residaceae

H

W

Fresh leaves cooked and eaten with ‘injera’ /bread

Amoeba

MM110

Centella asiatica (L.) Urban

Baala buqqee

Apiaceae

H

W

Leaves crushed and rubbed

Tinea corporis

MM058

Citrus limon (L.) Burn.f.

Loomii

Rutaceae

T

Hg

Squiz the fruit and massage on bleeding gum

Gum bleeding

MM022

Crush the fruit and apply its content on skin burn.

Skinburn

 

Citrus aurantium L.

Qomxaaxxee

Rutaceae

T

Hg

Suck the content of the fruit when suffered by hypertension

Hypertension

MM021

Clausena anisata (Wild.) Benth

Ulmaayii

Rutaceae

Sh

W

Leaves powdered and mixed with water and given immediately for the victimed

Snake bite

MM090

Bark of Clausena anisata, leaves of Sida rhombifolia, root of Cucumis ficifolius, bark root of Brucea antidysentrica powdered together and mixed in milk then drunk a cup of tea for three days in order to get cured from Rabies disease

Rabies

 

Clematis simensis Fresen.

Hidda fiitii

Ranunculaceae

Cl

W

Fresh root chewed

Stomach ache

MM198

Clutia abyssinica Joub. & Spach.

Ulee foonii

Euphorbiaceae

Sh

W

Fresh leaves hold in teeth for 20–30 minutes

Toothache

MM098

Coffea arabica L.

Buna

Rubiaceae

Sh

Hg

The dried coffee bean roasted and powdered then given to the patient by mixing with honey.

Diarrhea

MM017

Coccinia abyssinica (Lam.) Cogn.

Ancootee

Cucurbitaceae

H

Hg

The root Cooked with leaves of Croton macrostachyus and eaten with ‘injera’ for four days.

Tuber closes

MM100

Cordia africana Lam.

Waddeessa

Boraginaceae

T

W

Leaves of Cordia africana, leaves of Acanthus polystachius crushed together with Feces of goat then put on fire the ash mixed with butter and creamed on affected part.

Spider poison

MM091

Crotalaria spinosa Hochst. ex. Benth.

Shumburaa gugee

Fabaceae

H

W

Root crushed, mixed with water and drunk

Rabies

MM067

Cymbopogon citratus (DC.) Stapf

Marga citaa

Poaceae

H

Hg

Fresh root chewed with salt to get relief from stomach ache

Stomach ache

MM173

Cynoglossum lanceolatum Forssk.

Maxxannee

Boraginaceae

H

W

Fresh leaves smashed and the exudates dropped in ear

Ear disease

MM124

Fresh Leaves crushed and sniffed

Headache

 

Leaves smashed and the extracts dropped in eye

Eye disease

 

Leaves powdered with leaves of Croton macrostachyus and creamed on the affected part by mixing with butter

Homeroide

 

Datura strumanium L.

Asaangira

Solanaceae

Sh

W

Fresh leaves smashed and smelled

Nasal bleeding

MM084

Seed put on fire and the smoke inhaled

Tooth ache

 

Drynaria volkensii Heiron.

Baala balleessaa

Polypodiaceae

Ep

B

Fresh root put on fire and until get hot and then bite by affected teeth for an hour

Tooth ache

MM059

Echinops hispidus Fresen.

Keberchoo

Asteraceae

H

W

Dried bark put on fire and the smoke inhaled

Evil eye

MM034

Ehretia cymosa Thonn.

Ulaagaa

Boraginaceae

T

W

Fresh leaves chewed

Toothache

MM009

Embelia schimperi Vatke

Hanquu

Myrsinaceae

Li

W

Fruit eaten early in the morning

Tape worm

MM047

Ensete ventricossum Cheesman

Baala warqee

Musaceae

H

Hg

The latex half cup of tea taken to get relief from stomach ache

Stomach ache

MM012

Eucalyptus globulus Labill

Akaakltii adii

Myrtaceae

T

B

Fresh leaves boiled in water and then the patient laid down in it in order to inhale the smoke

Common cold

MM087

Euphorbia tirucalli L.

Cadaa

Euphorbiaceae

Sh

Hg

The milky latex dropped on affected part

Homeroide

MM005

Gardenia ternifolia Schumach.

Gambeela

Rubiaceae

T

W

Fresh seed put in fire ad when it gets hot put on affected part

Homeroide

MM019

Grewia ferruginea Hochst. ex A. Rich.

Dhoqonuu

Tiliaceae

T

W

The hair washed by leaves of Grewia ferruginea and used as a soap

Dandruff

MM048

Hagenia abyssinica (Brace) J.F.Gmel.

Heexoo

Rosaceae

T

W

The dried or fresh floral part powdered soaked in water and left for four days and taken with coffee before having break fast

Tape worm

MM089

Indigofera arrecta Hochst. ex A.Rich

Heennaa

Fabaceae

Sh

W

Leaves powdered and mixed with butter and applied on the affected part for five days

Spider poison

MM078

Indigofera spicata Forssk.

Reencii

Fabaceae

H

W

Leaves powdered and mixed in water and taken when need arise.

Diabetics

MM203

Lagenaria siceraria (Molina) Standl.

Buqqee seexanaa

Cucurbitaceae

H

W

Put on fire and burn the affected part

Dandruff

MM099

Leucas martinicensis (Jacq) R.Br.

Fidoo

Lamiaceae

H

W

Steam put on fire and let the patient laid in it for smoke

Eye disease

MM065

Lippia adoensis Hochst. ex Walp

Kusaayee

Verbenaceae

H

B

Fresh leaves chewed

Burn on chest

MM109

Mirabilis jalapa L.

Ababa diimaa

Nyctagnaceae

Sh

W

Creamy powder of the fruit will be rubbed on affected part.

Homeroide

MM111

Momordica foetida Schumach.

Humbaawoo

Cucurbitaceae

H

W

Root washed, crushed and mixed with water and the exudates taken for five days one liter per a day.

Kidney problem

MM029

Ocimum urticifolium Roth

Ancabbii

Lamiaceae

Sh

Hg

Fresh leaves crushed and smashed then the extracts rubbed on affected part

Fibril illness

MM133

Olea europaea L. subsp. cuspidata (Wall. ex G. Don) Cif.

Ejersa

Oleaceae

T

W

Fresh root chewed

Stomach ache

MM041

Panicum hochstetteri Steud.

Marga gogorrii

Poaceae

H

W

Fresh leaves chewed

Kidney problem

MM127

Pavonia urens Cav.

Hincinnii

Malvaceae

H

W

Powdered leaves tied on affected part

Wound

MM062

Phytolacca dodecandra L’ Herit.

Andoodee

Phytolaccaceae

Li.

Hg

Few root powdered and mixed with water and drunk for two days

Gonorrhea

MM088

Root of Phytolacca dodecandra, juvenile leaves of Momordica foetida leaves of Justicia schimperiana and juvenile leaves of Croton macrostachyus powdered together and very few given with tea before having breakfast for three days. One cup of tea is given for man whereas half cup of tea for children

Liver disease

 

Plantago lanceolata L.

Qorxobbii

Plantaginaceae

H

W

Fresh leaves crushed and tied

Skin cut

MM044

Plectranthus edulis (Vatke) Agnew

Dinnicha oromoo

Solanaceae

Sh

W

Root cooked and eaten

Loss of appetite

MM108

Prunus africana (Hook. f.) Kalkm.

Hoomii

Rosaceae

T

W

Powdered and tied for five days

Wound

MM016

Prunus persica (L.) Batsch

Kookii

Rosaceae

T

Hg

Juvenile leaves dried and powdered then mixed with butter and creamed on affected part in Wednesday and Friday

Tinea corporis

MM007

Pycnostachys abyssinica Fresen.

Yeeroo

Lamiaceae

H

W

Fresh leaves crushed, smashed and the extracts dropped in the eye

Eye disease

MM129

Rhamnus prinoides L Herit.

Geeshoo

Rhamnaceae

Sh

Hg

Fresh leaves chewed

Tonsillitis

MM081

Ricinus communis L.

Qobboo

Euphorbiaceae

H

B

Fresh leaves crushed and mixed with water and taken one cup of tea for 3 consecutive days.

Rabies

MM006

Fresh root crushed and mixed with root of Justicia schimperiana and put in cup of tea and mixed with water and drunk

Liver disease

 

Rumex abyssinicus Jacq.

Dhangaggoo

Polygonaceae

H

W

Leaves crushed and smashed then applied on affected part

Scabies

MM053

Ruta chalepensis L.

Ciraaddama

Rutaceae

H

Hg

Fresh leaves and roots chewed

S.ache

MM083

Rytigynia neglecta (Hiern) Robyns

Mixoo

Rubiaceae

T

H

Leaves powdered and sniffed

Bat urine

MM056

Saccharum officinarum L.

Shankora

Poaceae

Sh

W

Steam put in fire and eaten when get hot in order to get relief from common cold

Common cold

MM093

Schinus molle L.

Qundoobarbaree

Anacardaceae

T

W

Fresh seed chewed

Tonsillitis

MM023

Saturega paradoxa (Vatke) Engl. ex Seybold

Kefo sa’aa

Lamiaceae

H

W

Fresh leaves crushed and sniffed

Bat urine

MM200

Securidaca longepedunculata Fresen.

Xamanaayii

Polygalaceae

T

W

Dried roots crushed and put on fire then the smoke sniffed

Evil eye

MM112

Dried bark powdered and taken with local alcohol for 5 days

Liver disease

 

Senna septemtrionalis (Viv) Irwin & Barneby

Samamakii

Fabaceae

Sh

W

Fresh leaves smashed and mixed with water then one cup of tea taken.

Snake bite

MM145

Stephania abyssinica (Dillon & A. Rich.) Walp.

Hidda kalaalaa

Mensipermaceae

H

W

The whole part of Stephania abyssinica crushed and boiled in water then the smoke will be inhaled until the patient getting sweat

Common cold

MM040

Solanum gigantum Jacq.

Hiddii saree

Solanaceae

Sh

W

Root crushed and taken with coffee

Rabies

MM202

Solanum incanum L.

Hidi lonii

Solanaceae

Sh

W

Break the fruit and drop its content on wound to stop bleeding

Wound

MM118

Vernonia auriculifera Hiern

Reejii

Asteraceae

Sh

W

Fresh leaves smashed and the extracts dropped on the cut skin

Skin cut

MM033

Vicia faba L.

Baaqelaa

Fabaceae

H

Hg

Dried seed chewed

Gastric

MM003

Vigna unguiculata (L.) Walp.

Hiphoo

Fabaceae

Cl

Hg

Fresh leaves smashed and rubbed on affected part

Tinea corporis

MM063

Vigna vexillata L. A. Rich.

Gurra hantuutaa

Fabaceae

Cl

W

Leaves crushed with leaves of Cucumis ficifolius A. Rich. and rubbed on affected part

Spider poison

MM066

Oliverella hildebrandtii (Engl.) Tieghem

Dheertuu dhumugaa

Loranthaceae

Ep

Hg

Fresh leaves crushed and rubbed on hair

Dandruff

MM 031

Ximenia americana L.

Hudhaa

Olacaceae

Sh

W

Crushed and mixed with water and one cup of tea taken for 1–5 days until the blood stop

Menstruation

MM152

Exudates drunk for five days 2 cup per a day.

Contraceptive

 

Zingiber officinale Roscoe

Jinjibila

Zingebraceae

H

Hg

Chewed and swallowed

Tonsillitis

MM011

Key: Hab Habit: H Herb, Sh Shrub, T Tree, Cl Climber and Li Liana; Ha habitat: W Wild, Hg Homegarden, B Both, V. No. Voucher number.

Table 2

List of medicinal plants for treating livestock diseases in the study area, Wayu Tuka District

Scientific name

Local Oromo name

Family

Hab

Ha

Plant part, preparation and application

Disease treated

V. No.

Acacia persiciflora Pax

Garbii

Fabaceae

T

W

The powdered bark mixed in water and given for the cattle forcefully

Stomach ache

MMO64

Acanthus polystachius Delile

Kosorruu

Achantaceae

Sh

W

Fresh leaves crushed and rubbed on affected part (wound)

‘Madaa gatiittii’

MM106

Albizia malcophylla (A. Rich.) Walp.

Arganboobee

Fabaceae

T

W

Bark powdered and given for treatment of Blackleg

Blackleg

MM070

Buddleja polystachya Fresen.

Hanfaarree

Loganaceae

Sh

W

Fresh leaves smashed and the extracts dropped in the eyes of affected cattle

Eye disease

MM024

Colocasia esculenta (L.) Schott

Goodarree

Araceae

H

B

Tuber crushed and mixed with water then given to the cow

Delayed placenta

MM027

Combretum collinum Fresen.

Unuunuu

Combretaceae

T

W

A bottle of mixed fresh crushed bark given for cattle by one bottle forcefully

Breast ulcer

MM102

Combretum molle R. Br. ex. G. Don

Dabaqqaa

Combretaceae

T

W

Steam put on the fire and rubbed the affected tongue

Tongue infection

MM149

Girardinia bullosa (Steud.) Wedd.

Gurgubbee

Urticaceae

Sh

W

Root powdered and mixed in water and applied orally

Blackleg

MM046

Grewia bicolor Juss.

Harooressa

Tiliaceae

T

W

Bark of Grewia bicolor grinded and mixed in water and salt added finally given for the cattle which placenta is delayed during delivery

Delayed placenta

MM151

Guizotia scabra (Vios.) Chiov.

Tuufoo

Asteraceae

H

W

Fresh leaves of Guizotia scabra and leaves of Calpurnia aurea crushed and rubbed

External Parasite/silmii

MM191

Helinus mystacinus (Ait.) E. Mey. ex Steud.

Hidda hoomoo

Euphorbiaceae

Cl

W

Leaves crushed and smashed and rubbed for external parasite

External parasite

MM097

Hymenodictyon floribundum (Hochst. & Steud.) Robinson

Altadhahaa

Rubiaceae

T

W

Fresh leaves smashed and the exudates dropped in the eyes of affected cattle

Eye disease

MM156

Impatiens tinctoria A. Rich. subsp. abyssinica (Hook. f. ) Grey Wilson

Qicuu

Balsaminaceae

H

W

Powdered root taken

Blackleg

MM153

Rhus ruspolii Engl.

Xaaxessaa

Anacardaceae

T

W

Fresh leaves crushed and rubbed on affected part

External parasite

MM051

Root of Rhus ruspolii Engl. powdered and mixed with water and drunk

Hyena bite

 

Solanum anguivi Lam.

Hidii seexanaa

Solanaceae

Sh

W

Fresh fruit boiled in water and dropped in the eyes of affected cattle

Eye disease

MM120

Root grinded and mixed with water and given One bottle for three days

Trypanosomiasis

Sorghum bicolor (L.) Moench

Bisingaa caabbii

Poaceae

H

Hg

Seed mixed in remnants of local beer and given

Delayed placenta

MM094

Thalictrum rhynchocarpum Dill. & A. Rich.

Mararree

Rananculaceae

H

W

The whole part crushed and given

Blackleg

MM045

Teclea nobilis Del.

Hadheessa

Rutaceae

Sh

W

Leaves crushed and mixed with water and given for the thin cattle

Thinness

MM025

Steam powdered and mixed with water and given forcefully by beer bottle

Anthrax

Verbascum sinaiticum Benth.

Gurra harree

Scrophulariaceae

H

W

Fresh leaves powdered and mixed in water then given orally for external parasite

External parasite

MM125

Key: Hab Habit: H Herb, Sh Shrub, T Tree, Cl Climber and Li Liana, Ha habitat, W Wild, Hg Homegarden, B Both, V. No. Voucher number.

Table 3

List of medicinal plants for treating both human and livestock diseases in the study area, Wayu Tuka District

Scientific name

Local Oromo name

Family

Hab

Ha

Plant part, preparation and application

Disease treated

V. No.

Calpurnia aurea (Ait.) Benth.

Ceekaa

Fabaceae

Sh

W

Fresh leaves soaked in water and wash the body of calf

External parasite

MM074

9 juvenile leaves of Calpurnia aurea, 9 leaves of Senna occidentalis and 9 juvenile leaves of Clausena anisata smashed and the extracts taken. One cup of tea is given for man and half cup for Children

Ascaris

 

Leaves crushed and mixed in water given by bottle forcefully

Snake bite

 

Cucurbita pepo L.

Buqqee

Cucurbitaceae

H

Hg

The dried seed roasted and eaten

Tape worm

MM018

Fruit cooked and rubbed on affected part

External parasite

 

Cucumis ficifolius A. Rich.

Faca’aa

Cucurbitaceae

H

W

Very few fresh root chewed with salt

Gonorrhea

MM026

Very few root powdered and mixed with one litter of water then given to the cattle forcefully

Blackleg

 

Guizotia abyssinica (L.f.) Cass.

Nuugii

Asteraceae

H

Hg

Seed roasted powdered and the decoction drunk

Swelling

MM036

Seed powdered and rubbed on madaa gatiitii of oxen

Madaa gatiittii

 

Hordeum vulgare L.

Garbuu

Poaceae

H

Hg

Seed of Hordeum vulgare powdered with seed of Brassica carinata and drunk

Swelling

MM082

Seed covered and left to let germinate then grinded and mixed with remnants of local beer or ‘tella’ and given orally

Blotting

 

Justicia schimperiana (Hochst. ex Nees) T. Anders.

Dhummuugaa

Acanthaceae

Sh

Hg

Fresh leaves crushed and given for hen or cock

Coccidiosis

MM008

Leaves put on fire with leaves of Brucea antidysentrica and rubbed on head

Headache

 

Lepidium sativum L.

Shinfaa

Brassicaceae

H

Hg

Dried seed powdered and eaten with injera to get cure from malaria or rubbed the body for protection from mosquito bite

Malaria

MM015

Seed powdered in water and given by the bottle forcefully

Blackleg

Linum usitatissimum L.

Talbaa

Linaceae

H

Hg

The hair washed by seeds of Linum usitatissimum and used as a soap

Dandruff

MM096

Seed powdered and given by mixing in water

Breast ulcer

Lotus corniculatus L.

Abbaa qiddii

Fabaceae

H

W

Powdered root taken with tea

Snake bite

MM065

Kalanchoe laciniata (L.) DC.

Bosoqqee

Crassulaceae

H

W

Fresh or dried root of Kalanchoe laciniata, seed of Capsicum frutescens, Allium sativum and leaves of Croton macrostachyus Powdered together and given for affected cattle

Blackleg

MM158

Malva verticillata L.

Karfichoo

Malvaceae

H

W

Leaves cooked and the smoke inhaled to get relief from ‘Mich’

Fibril illness

MM150

Maesa lanceolata Forssk.

Abbayyii

Myrsinaceae

Sh

W

Fresh leaves crushed and rubbed on the body

External parasite

MM079

Nicotiana tabacum L.

Tamboo

Solanaceae

H

Hg

Leaves crushed and mixed with water and drunk

Snake bite

MM004

Leaves crushed and tied on affected part

Snake poison

 

Leaves crushed and put in the mouth then the cow will not drink water or feed for certain minutes until the leech come out

Leeching

 

Rumex nepalensis Spreng.

Timijjii

Polygonaceae

H

W

Few root chewed and swallowed

Gastric

MM055

Fresh leaves crushed and mixed with Leaves of Acanthus polystachius By mixing with butter creamed on affected part

Spider poison

 

Root powdered and mixed in water then mixed in water and given for the cattle forcefully(waga’uu)

Blackleg

 

Stereospermum kunthianum Cham.

Botoroo

Bignoniaceae

T

W

Fresh/ Dried bark of Stereospermum kunthianum Cham., bark of Croton macrostachyus, Root of Cucumis ficifolius, bulb of Allium sativum L. and seed of Capsicum frutescens powdered together and half of a bottle given for three days

‘Kaashmeer’

MM176

Dried bark put on fire and the smoke inhaled

Evil eye

 
     

Powdered and mixed with water and one cup of tea taken for three days

S.ache

 
     

Leaves crushed and rubbed

Spider poison

 

Vernonia amygdalina Del.

Eebicha

Asteraceae

Sh

Hg

Leaves crushed and mixed with remnants of local beer(‘Tella’)and given for the cow

Delayed placenta

MM010

     

Leaves crushed and soak in water and the exudates drunk orally for five days

Malaria

 

Key: Hab Habit, H Herb, Sh Shrub, T Tree, Cl Climber and Li Liana, Ha habitat, W Wild, Hg Homegarden, B Both, V. No. Voucher number.

Table 4

Taxonomic diversity of medicinal plants in the study area

Family

Number of genera

Percentage

Number of species

Percentage of species

Fabaceae

11

10.0

15

12.0

Solanaceae

4

3.7

8

6.3

Asteraceae

5

4.6

7

5.6

Lamiaceae

5

4.6

6

4.7

Poaceae

6

5.5

6

4.7

Cucurbitaceae

5

4.6

5

4.0

Rutaceae

4

3.7

5

4.0

Euphorbiaceae

5

4.6

4

3.0

Rubiaceae

3

2.7

4

3.0

Boraginaceae

3

2.7

3

2.3

Malvaceae

3

2.7

3

2.3

Rosaceae

2

2.0

3

2.3

Other 44 families

52

48.0

57

45.0

Total

108

100

126

100

The result of growth form analysis of medicinal plants showed that herbs constituted the highest proportion being represented by 55 (43.6%) species, while there were 34 (27%) tree species, 26 (20.6%) shrubs and 3 (2%) lianas (Figure 3).
Figure 3

Growth forms (habits) of medicinal plants in the study area.

Informants of the study area harvest different plant parts for preparation of traditional drugs (e.g. leaves, roots, seeds, barks and fruit). In the study area, the informants reported that more species (70, 43%) of medicinal plants were harvested for their leaves and these were followed by roots (30, 18.5%), seed and bark (18, 22.2%) each and 26 others (bulb, tuber, stem, fruit and flower) covered 16% (Figure 4).
Figure 4

Plant parts used for the treatment of human and livestock ailments.

Among the collected 126 medicinal plant species, 78 (62%) were claimed to treat human health problems (Table 1), 23 (18.2%) were claimed to treat livestock ailments (Table 2) and 25 (20%) were for both human and livestock ailments (Table 3).

People of the study area mostly administer traditional medicine orally. This accounted for 64%, followed by dermal administration (27.3%) and others (nasal, anal, optical, ear) accounting to 8.3%. Local people also reported that various additives were given during administration of traditional medicine.

Condition, dosage and effectiveness of traditional medicine in the study area

The majority of the remedies (74.2%) in the study area were prepared from fresh parts of medicinal plants followed by dried form (20.7%) and (5%) prepared either from dry or fresh plant parts. Most of the medicinal plant preparations involved the use of single plant species or a single plant part (85%) while those mixing different plants or plant parts (15%) were rarely encountered in the study area. Healers, usually prepare remedies by mixing various plants or plant parts. Lack of consistency regarding amount of medicines to be used was observed among informants during the interview.

Local people of the study area used various ways of measuring dosage which were generally categorized under three major classes. One is dosage used for those medicinal plants which are expected to be highly toxic. For such medicines the measurement was undertaken by little finger index and very few amounts of the prepared medicine taken by a cup of coffee (Locally known as ‘Sinii’). For example, medicines prepared from Phytolacca dodecandra, Cucumis ficifolius, Carissa spinarum and Securidaca longepedunculata are toxic if overdosed. The second is the dosage used for medicinal plants which can have little effect. The dosage is measured by hand palm and taken by bottle or locally made material from Lagenaria siceraria known as ‘Hullee’. E.g., traditional medicines prepared from Vernonia amygdalina. In the third case there are medicinal plants that do not have any observable side effect. Medicines prepared from Allium sativum, Citrus limon, and Citrus aurantium can be taken according to personal preference of the patient. Moreover, informants indicated the effectiveness of traditional medicines to get relief from certain diseases including rabies and health problems associated with the liver, spider poisoning and those caused by bat urine.

Methods of preparation of traditional medicine

In the study area, the most common methods of preparation of traditional medicine from plant material was crushing (29%), followed by powdering (28%) and others (Table 5).
Table 5

Method of preparation of traditional medicine in the study area

Method of preparation

Number of preparations

Percentage

Crushing

39

29.0

Powdering

38

28.0

Chewing

19

14.0

Concoction

17

12.6

Decoction

11

8.0

Others

13

10.0

Importance of medicinal plants in the study area

Paired comparison ranking of 7 medicinal plants that were reported as effective for treating blackleg, was conducted after selecting 9 informants. The informants were asked to compare the given medicinal plants based on their efficacy. The results showed that Cucumis ficifolius scored the highest mark and ranked first indicating that it was the most effective in treating blackleg and followed by Lepidium sativum (Table 6).
Table 6

Paired comparison of medicinal plants used to treat blackleg in the study area

Medicinal plants used

Respondents (R1-R9)

 

R1

R2

R3

R4

R5

R6

R7

R8

R9

Total

Rank

Clematis simensis

1

1

1

1

1

0

1

0

1

7

6th

Cucumis ficifolius

5

5

5

4

6

4

6

4

5

44

1st

Cyphostemma cyphopetalum

0

1

1

0

0

2

0

1

0

5

7th

Kalanchoe laciniata

3

4

2

2

4

3

2

5

2

27

5th

Lepidium sativum

3

4

5

5

3

4

5

4

5

38

2nd

Rumex nepalensis

3

3

4

4

4

4

4

5

4

35

3rd

Thalictrum rhynchocarpum

6

3

3

5

3

4

3

2

4

33

4th

Direct matrix ranking of multipurpose medicinal plants

Among the medicinal plants reported by the informants, there were those that were used for other purposes and thus grouped as multipurpose species. Key informants first identified eight medicinal plant species that were used by the community for additional purpose including fire wood, charcoal making, construction purposes, food, fencing and forage. Application of direct matrix ranking to these species showed that Cordia africana was the best, followed by Eucalyptus globulus and Crotom macrostachyus (Table 7).
Table 7

Direct matrix ranking of eight multipurpose medicinal plants (Average score of 8 key informants)

Plant species

Use categories

Total

Rank

Medicine

Fire wood

Charcoal

Construction

Food

Fence

Forage

Acacia abyssinica

2

4

5

4

0

2

0

17

4th

Cordia africana

3

4

5

5

3

2

0

22

1st

Croton macrostachyus

5

4

3

4

0

2

0

18

3rd

Eucalyptus globulus

4

5

3

5

0

2

0

19

2nd

Justicia schimperiana

5

2

0

1

0

4

3

15

6th

Prunus africana

2

3

4

4

0

3

0

16

5th

Rhamnus prinoides

4

1

1

0

0

3

3

12

7th

Ricinus communis

3

1

0

0

2

3

1

10

8th

Informant consensus factor (ICF)

The result showed that, diseases that were frequent in the study area have higher Informant Consensus Factor. Medicinal plants that are effective in treating certain disease and well known by community members also have higher ICF. Malaria and headache had the highest ICF value (0.85) whereas, Rabies had the lowest ICF value (0.25) (Table 8).
Table 8

Informant consensus factor by categories of diseases in the study area, Wayu Tuka District

Category

No. of spp.

Total % of spp.

No. of use citation

% of use citation

ICF

Malaria and headache

7

5.5

42

13.0

0.85

Fibril illness, swelling and evil eye

9

7.0

40

12.4

0.79

Intestinal parasite, diarrhea, amoeba and stomach ache

17

13.5

60

19.0

0.72

Ear, eye and tooth ache (Organ)

7

5.5

23

7.5

0.71

Cattle ailments (Blackleg, Anthrax, Leech and External parasite)

14

11.0

30

10.0

0.55

Common cold and cough

8

6.0

16

5.0

0.53

Snake bite, spider poison and bat poison

16

12.6

28

9.0

0.44

Skin diseases, skin cut and wound

25

20.0

41

13.0

0.40

Lung, kidney and liver diseases (Organ)

8

6.0

12

4.0

0.36

Gonorrhea and menstruation

3

2.0

4

2.0

0.33

Rabies

7

5.5

9

3.0

0.25

Threats to medicinal plants and conservation practices in the study area

In Wayu Tuka District various factors that were considered as main threats for medicinal plants were recorded by discussion with the informants. Accordingly, the major factors reported were deforestation for the purpose of agricultural expansion (75%), overgrazing (10%), collection of plant material for construction (10%) and fire wood (5%).

People of the study area know the benefits of conserving medicinal plants. However, the effort of conserving medicinal plants is very limited (minimal). That is an evident for being only 26% of medicinal plants were collected from homegarden. Local healers who frequently make use of medicinal plants for a living do not conserve medicinal plants very well, and they preferred to collect them from wild stands when patients visit them. It was explained by informants that local healers do this in order not to let the other community members know the identity of the medicinal plants they are using. Informants further explained that if healers planted the species in their homegardens, they suspect that somebody else might see them while they are preparing the medicine from the plants and start to prepare them and reduce the income which could have gone to the healer. Further observations showed some medicinal plants frequently growing in homegardens, including Ocimum urticifolium and Ruta chalepensis, the medicinal plant knowledge of which is in the public domain. Beliefs have reported to have some contributions to conservation of medicinal plants. It was reported that medicinal plants collected during ‘Chegino’ (that means Monday, Wednesday and Friday) are not used, and limitation of days for collecting medicinal plants reduces the effect of over-harvesting.

Discussion

Medicinal plants used to treat human and livestock ailments in the study area

A considerable number (126) of medicinal plants have been documented in this study. The number of reported medicinal plants and their uses by the local people of the District indicates the depth of the local indigenous knowledge on the medicinal plants and their applications. Out of the collected medicinal plants, 78 species were reported for use in the treatment of human diseases, whereas 23 species were used to treat livestock ailments and 25 species were used to treat both human and livestock ailments. Similar findings were reported by other studies [2427] in other parts of Ethiopia where local people use more medicinal plants to treat human diseases than livestock ailments.

Various studies [2729] conducted in Ethiopia as well as in other countries of the world reported that the majority of medicinal plants are being harvested from non-cultivated areas. This observation is a good indication of the fact that the local people have not yet started cultivating the majority of the plant species they are using as medicines. Some medicinal plants recorded in Wayu Tuka District were also used as remedies in other parts of Ethiopia. Accordingly, 51 medicinal plants were documented in [28]; 47 species in [30]; 41 species in [24]; 36 species in [25]; 33 species in [31]; 30 species in [26] and 15 species in [32, 33]. The fact that some of the reported plants are having similar uses elsewhere can be considered as indication of their pharmacological effectiveness [31].

Among the families, Fabaceae was represented by 15 species (12%) followed by Solanaceae which had 8 species. The finding of the family Fabaceae as the contributor of higher number of plant species used for medicinal purposes than other families is in line with similar studies elsewhere in Ethiopia [30, 31, 3436], whereas other researchers reported that Asteraceae is the leading family with highest number of medicinal plants [24, 25, 32]. Both findings are reasonable since the two families are both represented by higher number of species in the Ethiopian Flora.

The most widely used plant remedies by people of Wayu Tuka District were obtained from herbs which constituted the highest category of 55 species (43.6%). This finding is in line with other results [24, 26, 30, 33, 37]. Moreover, Giday et al. [33] reported that Zay people derive their medicine from herbs partly because of the fact that forests have been degraded and it takes much time and effort to harvest plant material from medicinal trees. It is true that herbs can grow everywhere (roadside, homegarden, farmland and in wild habitats) and common in the study area compared with other species such as trees, shrubs and climbers. However, other findings [25, 27, 3436, 38] indicated that shrubs were the most frequently used plant categories.

People of the study area, prepare remedies for human or livestock ailments, either from single plant or plant parts or by mixing them. Most of medicinal plants reported from the study area were claimed to be prepared from a single plant or plant part. Similar findings were also reported for use of multiple plants or plant parts for a single health problem [35, 39, 40] and use of single species was rare. This finding deviated from that reported by another researcher [30] who reported that 78% of the preparations of traditional medicine by people of Chelya Wereda were drawn from mixtures of different plants or plant parts and another work [36] also reported that local healers of Sokoru mostly used more than one plant species to prepare remedy for an ailment. In the present study, it was observed that healers mostly used multiple plants or plant parts in order to increase the strength and efficacy of the drug as they reported during the interview. For example, rabies was treated by mixing the bark of Clausena anisata, leaves of Sida rhombifolia, root of Cucumis ficifolius, and root bark of Brucea antidysentrica. They used different additives like soil, ash, honey, salt, sugar, local beer, milk and butter in order to increase the flavor, taste and general acceptability of certain orally administered remedies. This means that since traditional medicines could have sour or bitter tastes in most cases the additives reduce such tastes and may even improve the efficacy of the medicine.

The finding of leaves to be the most widely harvested plant parts is inline with other results [24, 3032]. However, other findings [25, 26, 35] indicated that roots were mostly utilized plant part. It was reported that collection of root, bark and whole plants might kill plants in harvest [41]. The same document also reported that root, which accounts for 58.3% is the most extensively used plant part in Ethiopia. Utilization of leaves may not cause detrimental effect on the plants compared with plant species in which root is utilized. However, this has to be seen on a case by case basis.

Mode of preparation, condition and route of application

Crushing was the most widely used method of preparation of remedy in the area. This finding agrees with the findings of Getaneh [24], Yineger and Yehuwalaw [36] and Yirga [42]. However, the finding of Mesfin et al. [25] and Amenu [30] shows that powdering and pounding are the dominant method of preparation in Wonago and Chelya Woreda respectively.

The majority of the medicines (74%) were prepared from fresh plant materials in the study area. Different studies from other parts of Ethiopia also reported similar results [2426, 28, 31, 32, 42, 43]. Preference of application of fresh plant parts is related to the efficiency of the medicines in curing diseases compared with the dried parts. This is because of the fact that most important chemical may be changed upon drying [44]. On the other hand, utilization of fresh plant parts may threaten the plants through frequent collection including in dry seasons since local people made minimal efforts in storing dried plant material for later use.

About 64% of the medicines in the area were administered orally and 27.3% used as dermal applications. In similar studies, other researchers reported oral administration of medicine as the leading route of application, in particular the results from Chelya Wereda [30] and Fentalle area [35], which accounted for 60.3% and 54.7% respectively. Similarity among those results showed that internal diseases are more prevalent in Ethiopia.

Effectiveness and dosage of medicines

Medicinal plants are reported to be effective in certain diseases. The results from Sokoru District [36] indicated that local people visit traditional healers even in preference to modern medications. In the present study, local people indicated their preferences for traditional medicines over modern drugs to get relief from certain diseases including rabies and health problems associated with the liver, spider poisoning and those caused by bat urine.

Lack of consistency regarding amount of medicines to be used was observed among informants during the interview. It was reported that lack of precise dosage is one drawback of traditional medicinal plants [39, 45, 46].

Threats to medicinal plants and conservation practices in the study area

Medicinal plants are at increasing risk from destruction of their habitats (agricultural activities, fire wood collection, collecting plants for construction, overgrazing by domestic animals, urbanization) and over-harvesting of known medicinal species. As already indicated, most medicinal plants in the study area relied on collection of leaves and this practice helps to reduce the rate of threats on plant species compared with utilization of roots. However, there were medicinal plants in the study area in which roots were collected for treatment of ailments. As a result, over collection poses a threat to medicinal plants in the cases of harvesting the roots. This was observed in the cases of Cucumis ficifolius, Rumex nepalensis and Securidaca longepedunculata. These medicinal plant species were used to treat blackleg, evil eye and liver diseases and informants reported that it is difficult to collect them easily and they are getting lost due to over utilization for medicinal purposes.

Informants highly cited that deforestation became the most threatening factor on medicinal plants as reported by other researchers [25, 33]. In this respect, plant species with multiple uses were said to be highly affected as also witnessed during the research. For instance, local people of the area preferred Cordia africana for construction; timber production, charcoal and medicine and it is on the verge of being eliminated from the area.

The conservation of medical plants in the study area was minimal rather beliefs have some contributions to conservation of medicinal plants as also reported by another study [27, 30]. Keeping the knowledge on medicinal plants secretly can also have some contribution for their conservation. Thus, if medicinal plants are known by all people the impact could increase [25].

Conclusion

The present study records 126 reported medicinal plants and their uses and majority of traditional medicinal plants were harvested mostly from wild. In the study area herbs constituted the highest proportion of medicinal plants to be utilized. Majority of medicinal plant species were harvested for their leaves and utilization of leaves may not cause detrimental effect on the plants compared with plant species in which root is utilized. Although high numbers of medicinal plants have been reported to be used for the treatment of human and livestock health problems, they are being threatened by different human activities while conservation efforts are minimal in the area. Deforestation for agricultural purpose was the major threat reported to medicinal plants of the study area. To save medicinal plants from further loss, the District Agricultural Office needs to team up with the local people, including by providing to the community planting materials of the most threatened and preferred medicinal and multipurpose species so that they can grow them in their homegardens. Moreover, the documented medicinal plants can serve as a basis for future investigation of modern drug.

Declarations

Acknowledgments

We are very much grateful to Wayu Tuka District administration for their corporation in allowing us to carry out the study. Especially, Mr. Yadessa Abdi is heartfully acknowledged for his help in convincing the local people to participate in the study. Moreover, informants are fully acknowledged for their participation by providing relevant responses to the questions. Thus, without them the study would not have been realized. We also gratefully acknowledge the financial support provided by Addis Ababa University.

Authors’ Affiliations

(1)
Department of Biology, Medawalabu University
(2)
National Herbarium, Addis Ababa University
(3)
Department of Environmental Health Sciences and Technology, Jimma University

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