An ethnomedicinal study in tulo district, west hararghe zone, oromia region, Ethiopia

Abstract

Traditional medicinal plants used by local Oromo people of Tulo District in west Hararghe, Ethiopia, were investigated before people's medicinal knowledge vanishes. Data on medicinal plants and demography were obtained between November 2019 and October 2020 through semi-structured interviews, group discussion and direct guided onsite observation to elicit information from 376 non-traditional and 20 traditional medicine practitioners. Ethnobotanical indices including informant consensus factor (ICF), preference ranking (PR), fidelity level (FL), relative frequency of citation (RFG) and cultural importance (CI) were employed for the data analysis. Moreover; descriptive statistics, t-test, analysis of variance and linear regression were used to reveal the effects of socio-demographic factors on respondents' traditional medicinal knowledge. Totally 104 plants distributed among 98 genera and 55 families were enumerated for the treatment of 60 illnesses. Seventy-seven of these medicinal plants serve to treat human ailments, whereas 11 and 16 of them were used for livestock and for both, respectively. Asteraceae and Lamiaceae were species rich families. Leaves were the most frequently (41.53%) reported structures for the preparation of remedies. Crushing was the principal approach (34.50%) of remedy preparation. Oral administration was frequently (66.08%) used route of application. The highest ICF was observed for swelling and hemorrhoid (0.90) category. Metabolic and degenerative as well as other ailment categories had the least ICF values. About 66% of medicinal plants had FL value of 100%. In PR, G. abyssinica was ranked first to treat cough. RFC values varied from 0.03 to 0.18 with the highest record for Salvia nilotica (0.18) followed by Lepidium sativum, Rydingia integrifolia and Nigella sativa each with 0.16; Euphorbia abyssinica and Asplenium monanthes each with 0.15. Extensive use of land for agricultural purpose was key threat to medicinal plant of Tulo District. All the tested socio-demographic features except religion significantly (P < 0.05) affected the traditional knowledge on medicinal plants possessed by the study population. The results of this study reveals that the people of Tulo District rely on traditional medicine of plant origin, and their indigenous knowledge is instrumental to exploit the most potential plants for further validation. Therefore, the medicinal plant species wealth of the study site and the associated indigenous knowledge need to be preserved.

1. Introduction

Since ancient times, local communities inhabiting a given place have developed knowledge on the use and management of plants of their surroundings [1]. Around the globe, local communities possess exclusive knowledge related to plant resources that they rely on for food, medicine and other uses [2]. To explore their expertise on utilization of plants for different purposes, scientific ethnobotanical investigations are of paramount importance [3]. According to World Health Organization (WHO) nearly 60% of people in the globe utilize traditional medicine for treating illnesses, and besides modern medication, up to 80% of the population living in Africa rely on traditional medicinal plants for their healthcare [4]. Their dependence on traditional medicinal plants is mainly due to poor economic potential to afford to modern medication and limited number of modern health facilities especially in remote rural areas [5]. However, unless documented, medicinal plants and the indigenous knowledge associated to them may vanish in the future through various anthropogenic factors that are exacerbated by human population expansion. In this regard, ethnobotanical studies help to record and preserve information related to medicinal plants used traditionally by indigenous people.

The ethnic group dwelling in Tulo District is Oromo, the dominant ethnic community in Ethiopia [6]. This indigenous ethnic community has been practicing the Gada System (social institution) that sets guiding principles to help the local people preserve their socio-economic, political and cultural systems [5]. Previous studies [5,7] show Oromo people's reliance on the natural resources, in particular plant wealth; for food, shelter, ethnomedicine, firewood and religious purposes. Particularly, they have acquired a rich traditional medicinal knowledge on using plants of their vicinity to solve health problems [5]. Nevertheless, plant diversity and the local traditional knowledge related to them are generally under threat in Ethiopia [8,9]. Albeit a lot of reports on ethnomedicinal studies of Oromo people in Oromia region, Ethiopia [[10], [11], [12], [13], [14], [15], [16], [17]] are available, such studies in east and west Hararghe zones are scanty with only few available studies [18,19]. Thus, this study aimed at the identification and documentation of traditional medicinal plants and the expertise of the local people on their utilization as remedies for humans and livestock ailments in Tulo District, west Hararghe, Oromia region, Ethiopia. This study also assessed the key anthropogenic activities that put medicinal plants of the study area at risk. The novelty of this work is that the study district has never been explored from ethnobotanical point of view and the identified medicinal plant species of the study area were subjected to comprehensive quantitative analysis to figure out elite plants for medicinal purposes.

2. Materials and methods

2.1. Study site and demography

This study was carried out in Tulo District, which is found in west Hararghe zone of Oromia region at a distance of 360 km away from the capital city of Ethiopia, Addis Ababa (Fig. 1). The altitude of the district extends from 1631 to 2800 m above sea level. About 56.67% of this District is Midland (1600–2300 m above sea level), whereas 43.33% of it is Highland (>2300 m above sea level). Totally, 174,215 people (85,888 males and 88,327 females) live in the District. About 18,087 people of the District are urban dwellers, whereas 156,128 are rural dwelling [20]. The main language of the indigenous people is Afaan Oromo. In terms of religion, 90% of the people are Muslims while 10% are Christians. Under Tulo District, there are 33 Kebeles (Kebele is the lowest administration unit) of which 30 are rural and 3 are urban Kebeles. Totally, the District has 5 health centers, 1 hospital, 2 higher clinics, 30 health posts, 6 private drug vendors, 1 drug store, 5 small clinics, 42 elementary (1–8 grades) schools and 3 high schools.

Fig. 1.

Map of the study area (Source GIS Software).

The mean yearly temperature of the district is 26 °C, whereas that of rainfall is 1700 mm. (Tulo District Agricultural and Natural Resource Development Office [TDANRDO], 2018, unpublished data). In the area, most of the people engage in mixed subsistence agriculture, i.e., rearing livestock and cultivating cereals mainly maize and sorghum; tuber crops particularly sweet potato and potato; vegetables like onion and cabbage; and fruits such as lemon, banana, papaya and orange. The major income generating cultivated cash crops are coffee (Coffea arabica L.) and haricot bean (Phaseolus vulgaris L.). A large number of the populace in the District rely on traditional medicine of plant origin for treating human and livestock ailments to shun using expensive modern drugs.

2.2. Determination of sample size

Totally the number of households of the eight Kebeles considered for this study was 41,634. Hence, we used the formula of Yemane [21] defined below to get the representative sample size.

$$n=\frac{N}{1+N{\left(e\right)}^2}$$

Where ‘n’, represents the required representative sample size; ‘N’, represents the entire population of the studied Kebeles (=41,634); ‘e’, represents margin of error, which is 5%; and 1 = the probability of event occurring.

Thus, the representative sample was:

$$\frac{41634}{1+\left(41634*0.0025\right)}=396$$

Thus, preceding ethnobotanical data collection, a total of 396 informants with age range of 21–80 years were considered for this study. Among this total respondents, 376 were randomly sampled ordinary people that do not work as traditional healers. However, 20 individuals were known for their experience as traditional healers (herbalists) and selected purposively as key informants [22].

2.3. Sampling procedure and collection of data

Scouting was done between October and November 2019 to choose 8 study Kebeles. Three Kebeles: Efa Andode (2192–2700 m above sea level), Hunde Misoma (2293–2680 m above sea level) and Kare Kufa (2356–2800 m above sea level) from high-land areas and five Kebeles: Reke Tefura (1701–1987 m above sea level), Lubo Dekeb (1743–1984 m above sea level), Kufan Zik (1892–1965 m above sea level), Nejeta (1800–1902 m above sea level) and Buchesa (1631–1848 m above sea level) from mid-land areas were purposively selected to cover different agro-ecologies.

Prior to data collection, permission was obtained from Tulo District Administrative Office. Respondents were then approached and informed that the purpose of the study was only for education, but not for any other purpose. Thereafter they gave us oral consent to provide information we sought. Then after, ethnobotanical data were gathered between November 2019 and October 2020 by adapting the guidelines on ethnopharmacological studies [[23], [24], [25]]. Ethnobotanical techniques employed included interviews, group discussion and direct guided onsite observation to obtain information related to respondents' socio-demographic status, their traditional experience on utilization of medicinal plants, and factors threatening medicinal plants and conservation efforts being made to preserve medicinal plants. Interview was conducted with individuals separately to get socio-demographic (gender, educational status, age, marital status, religion and occupation) data, local names of medicinal plants, type of the disease they cure, plant part for remedy preparation, approaches to prepare remedies and modes of administration of remedies. Questions for interview were developed first using English language and later converted to native Afaan Oromo language of the indigenous people. Respondents were explained about the purpose of the survey and consent was obtained from the men to get information from female respondents too. Accordingly, females were interviewed near home gardens and the surrounding vegetation. Group discussion was carried out with traditional healers as per the arranged checklist questions and onsite field observations were made with them to observe medicinal plants' habits, their habitat and collection of medicinal plants’ specimens.

2.4. Collection and identification of ethnomedicinal plants

Voucher specimens of ethnomedicinal plants were collected, pressed, dried, mounted and identified by using Flora of Ethiopia and Eritrea [26,27], other literatures [28] and by comparing with authentic specimens found in the herbarium of Haramaya University. After identification, the specimens were kept in the Herbarium of Haramaya University.

2.5. Data analysis

Descriptive statistical method was used to analyze qualitative data. Ethnobotanical indices viz. Informant consensus factor (ICF), preference ranking (PR), fidelity level (FL), the relative frequency of citation (RFC) and cultural importance (CI) were also computed to determine the most locally important species.

Informant consensus factor is a value that shows extent of agreement between people on the medicinal values of plants for the cited illness. In order to calculate this index, we first broadly classified the reported ailments into 8 categories (Table 2). ICF value was determined as follows:

$$\mathrm{I}\mathrm{C}\mathrm{F}=\frac{\mathrm{n}\mathrm{u}\mathrm{r}-\mathrm{n}\mathrm{t}}{\mathrm{n}\mathrm{u}\mathrm{r}-1}$$

Where, ‘nur’ stands for the number of use citations for each ailment, ‘nt’ stands for the number of species used for the ailment category [29,30].

Table 2.

Informant consensus factor (ICF) for eight disease categories.

No	Ailment category	Nt	Nur	ICF
1	Body swelling and hemorrhoid	9	81	0.90
2	Gastrointestinal diseases and Parasitic infections (Stomach ache, bloating, Dyspepsia, Vomiting, Abdominal pain, Diarrhea, Gastritis, Constipation, Heart burn, Intestinal parasite including Ascariasis, Taeniasis and Amoebiasis)	21	108	0.81
3	Dermatology and Sensory organ diseases (Wound, Ringworm, Skin rash, Skin infection, Wart, Scabies, Dandruff, Eczema, Leech infestation, Eye disease, Ear disease, Nasal bleeding, Nerve problem, Toothache, Gum bleeding)	32	150	0.79
4	Febrile illness and related diseases (Febrile, Fever, Typhoid, Anemia, Headache, Evil eye, Stabbing pain)	17	72	0.77
5	Respiratory system and pharyngeal related diseases (Cough, Common cold, Asthma, Tonsillitis)	20	65	0.69
6	Urogenital related diseases (Gonorrhea, Orchitis, Impotence, Uterus problem, Urine retention, Placental retention)	8	17	0.56
7	Metabolic and degenerative diseases (Jaundice, Hypertension, Heart problem, Diabetes, Breast cancer, Malaria, Kidney disease, Gallstone, Anemia)	18	32	0.45
8	Others (Rabies, Anthrax, Black leg, Snake poisoning, Spider poisoning)	11	18	0.41

Note: ‘Nur’ denotes number of use citations for category; ‘Nt’ denotes number of medicinal plant species cited for a disease category.

Preference ranking was done to rank six plants reported as a cure for cough. For this, ten key informants who mentioned the six plants as a cure for cough were randomly picked to do the ranking exercise depending on the relative potential of medicinal plants to cure cough. Those 6 mentioned plants were then given to individual respondents so as to rank them by giving the highest value (6) to the medicinal plant they believe is most effective and lowest value (1) for least effective one, and any value between 6 and 1 for the remaining plants based on their curative potential. The assigned values of each plant species were summed and then ranked based on the total score.

Fidelity level which shows a tendency of using a certain plant for curing single disease was computed by adopting the equation used by Ref. [30] as follows:

$$\mathrm{F}\mathrm{L}(\%)=\frac{\mathrm{N}\mathrm{P}}{\mathrm{N}}*100$$

‘FL’, represents fidelity level; ‘Np’, represents the number of respondents who make use of a plant species for treating an illness; ‘N’, represents the number of respondents that use the plants as a medicine to treat any given disease.

The Relative frequency of citation was calculated by following the formula indicated by Refs. [[31], [32], [33]] as follows.

$$\mathrm{R}\mathrm{F}\mathrm{C}=\frac{\mathrm{F}\mathrm{C}}{\mathrm{N}}$$

‘FC’, represents the number of respondents who cited a plant for its medicinal value, whereas ‘N’, is the total number of respondents that took part in the study.

The cultural importance (CI) was computed following the approaches of Refs. [31,34].

In order to compare medicinal knowledge of the different socio-demographic groups, t-test and analysis of variance were done. Regression analysis was also checked to detect socio-demographic factors that predicted traditional medicinal knowledge. In all cases, SPSS version 16 statistical software was used to analyze the data and statistical significance was considered at p < 0.05.

Ranking was also made to prioritize the most important human activities that put medicinal plants in danger. For this, 10 key respondents were first requested to free list all possible anthropogenic causes that jeopardize medicinal plants and give the maximum value (5) for what they claim as the highest threatening factor and the minimum value (1) for the lowest threatening factor, and ordered the remaining ones according to their level of importance.

3. Results and discussion

3.1. Ethnomedicinal plants recorded

Totally 104 medicinal plant species that belong to 98 genera and 55 families were documented from Tulo District. These plants were reported to treat about 60 different illnesses of humans and livestock. This number implies that the study site is the abode of huge repository of flora and rich expertise of the locals on medicinal plants. This suggests the wide utilization of traditional medicine of plant origin by the local community of Tulo District. The majority (78 plant species) was enumerated to treat various human health problems, whereas 10 and 16 plant species were used to cure livestock and ailments of both (Table 1), respectively.

Table 1.

Enumeration of ethnomedicinal plants used for the treatment of ailments of humans and livestock.

										Ethnobotanical Indices
Species name	Family	V.No.	V. Name	Ht	Hbt	Part	Ailments	R	AP	FL (%)	NU	CI	FC	RFC
Acacia abyssinica Hochst. ex Benth.	Fabaceae	MB101	Laaftoo	T	W	Fruit	Orchitis	O	F	100	1	0.003	27	0.07
Acokanthera schimperi (A.DC.) Schweinf.	Apocynaceae	MB18	Qaraaru	S	W	Root	Gonorrhea	O	F	100	1	0.003	31	0.08
Afrocarpus falcatus (Thunb.)	Podocarpaceae	MB97	Birbirsa	T	W	Bark	Evil eye	N	Dr	100	1	0.003	30	0.08
C·N.Page
**Agave sisalana Perrine ex Engelm.	Agavaceae	MB52	Algee	S	W	Root	Gum bleeding	O	B	56	2	0.005	34	0.09
						Stem	Black leg		F
Allium cepa L.	Alliaceae	MB1	Shunkurtii Diimaa	H	Cu	Bulb	Heart burn	O	F	62.8	3	0.008	35	0.09
							Stabbing pain
							Impotence
**Allium sativum L.	Alliaceae	MB8	Qullubbii adii	H	Cu	Bulb	Febrile illness	O	B	54.7	4	0.010	53	0.13
							Bloating
							Malaria
							Stomach ache
Aloe trichosantha A.Berger	Aloaceae	MB56	Hargeysa	S	W	Leaf	Diabetes	O	F	56.4	6	0.010	39	0.09
							Hypertension
						Sap	Wound	D
							Heart burn	O
							Headache
							Snake poisoning
*Ampelocissus bombycina (Bak.) Planch	Vitaceae	MB103	Dubbaa jinnii	C	W	Fruit	Anthrax	O	F	100	1	0.003	33	0.08
Anthemis tigreenisJ. Gay ex A.Rich	Asteraceae	MB2	Zarnab	H	W	Seed	Cough	O	F	100	1	0.003	40	0,10
Artemisia afraJacq. ex Willd.	Asteraceae	MB98	Sakayyee adii	S	W	Leaf	Nerve problem	D	F	100	1	0.003	19	0.05
Asplenium monanthes L.	Aspleniaceae	MB46	Digaloo	M	W	Leaf	Fever	O	B	100	1	0.003	61	0.15
			makannisaa
Bersama abyssinica Fresen.	Melianthaceae	MB28	Qillisaa	T	W	Fruit	Ascariasis	O	F	63.8	2	0.005	36	0.09
							Taeniasis
Bidens pilosa L.	Asteraceae	MB48	Xiyyee	H	W	Leaf	Wound	D	F	70.5	3	0.008	51	0.13
							Nasal bleeding	N
							Febrile illness	O
Brassica carinata A.Braun	Brassicaceae	MB19	Midhaan raafuu	H	Cu	Seed	Uterus problem	O	Dr	51.7	4	0.010	29	0.07
							Dyspepsia
							Typhoid
							Malaria
Brassica nigra (L.) Koch	Brassicaceae	MB11	Sinaaficii	H	Cu	Seed	Common cold	O	Dr	55.2	5	0.013	38	0.09
							Asthma
							Stomach ache
							Intestinal parasite
							Wound	D
Caesalpinia decapetala (Roth) Alston	Fabaceae	MB58	Qajimaa	S	W	Seed	Tonsillitis	O	F	45.7	3	0.008	35	0,09
						Root	Amoebiasis
						Leaf	Body swelling	D
Calpurnia aurea (Aiton) Benth.	Fabaceae	MB15	Ceekaa	S	W	Root	Vomiting	O	F	65.7	4	0.010	35	0.09
						Leaf	Jaundice
							Snake poisoning
							Amoebiasis
**Capsicum annum L.	Solanaceae	MB37	Mixmixaa	H	Cu	Fruit	Leech infestation	D	B	70	3	0.008	50	0.13
							Malaria	O	F
						Leaf	Dyspepsia		B
Carica papaya L.	Caricaceae	MB50	Paapaayaa	T	Cu	Root	Malaria	O	F	64.1	2	0.005	39	0.09
						Seed	Intestinal parasite		Dr
Carissa spinarum L.	Apocynaceae	MB26	Hagamsa	S	W	Root	Wound	D	Dr	51.2	2	0.005	39	0.09
							Body swelling
Carthamus tinctorius L.	Asteraceae	MB51	Suufii	H	Cu	Seed	Cough	O	Dr	100	1	0.003	32	0.08
Casimiroa edulis La Llave	Rutaceae	MB29	Habuqqaa	T	Cu	Fruit	Kidney disease	O	F	100	1	0.003	40	0.10
Catha edulis (Vahl) Endl.	Celastraceae	MB6	Jimaa	S/T	Cu	Leaf	Common cold	O	B	67.3	2	0.005	46	0.12
							Asthma
Cissampelos mucronata A.Rich.	Menispermaceae	MB80	Baal-tokkee	C	W	Root	Dyspepsia	O	F	77.7	2	0.005	45	0.11
							Snake poisoning	D
Citrus limon (L.) Osbeck	Rutaceae	MB3	Xuuxxoo	S	Cu	Fruit	Abdominal pain	O	F	60.7	4	0.010	51	0.13
							Vomiting
							Gum bleeding
							Ringworm	D
Citrus paradise Macfad.	Rutaceae	MB81	Komxaaxxee	S	Cu	Fruit	Hypertension	O	F	45.4	2	0.005	33	0.08
							Ringworm
Commelina benghalensis L.	Commelinaceae	MB13	Hoolagabbis	H	W	Leaf	Ringworm	D	F	100	1	0.003	32	0.08
Coriandrum sativum L.	Apiaceae	MB5	Shukaar	H	Cu	Seed	Stomach ache	O	F	100	1	0.003	41	0.10
Cordia africana Lam.	Boraginaceae	MB41	Wadessa	T	W	Leaf	Eczema	D	Dr	100	1	0.003	32	0.08
Crinum abyssinicum Hochst. ex A.Rich.	Amaryllidaceae	MB2	Qullubbii	H	W	Bulb	Cough	O	F	100	1	0.003	39	0.09
			waraabeessaa
Croton macrostachyus Hochst. Ex Delile	Euphorbiaceae	MB17	Bakkanisaa	T	W	Leaf	Ringworm	D	F	100	1	0.003	55	0.14
Cucumis ficifolius A.Rich.	Cucurbitaceae	MB62	Yemidir imbuway	H	W	Leaf	Common cold	O	F	100	1	0.003	43	0.11
Cucurbita pepo L.	Cucurbitaceae	MB77	Dubbaa	C	Cu	Seed	Headache	O	Dr	94	2	0.005	49	0.12
						Fruit	Taeniasis
*Cussonia ostinii Chiov.	Araliaceae	MB71	Hafratu	T	W	Leaf	Leech infestation	O	F	100	1	0.003	35	0.09
Cymbopogon citratus (DC.) Stapf.	Poaceae	MB9	Xajii saar	H	W	Root	Evil eye	N	Dr	63.6	3	0.008	33	0.08
						Leaf	Gallstone	O
						Root	Diarrhea		F
**Datura stramonium L.	Solanaceae	MB73	Banjii	H	W	Leaf	Wound	O	F	36.1	4	0.010	36	0.09
						Seed	Toothache
						Leaf	Rabies
						Root	Skin rash	D
Daucus carota L.	Apiaceae	MB14	Kaaroota	H	Cu	Root	Kidney disease	O	F	100	1	0.003	30	0.08
Digitaria velutina (Forssk.) P.Beauv	Poaceae	MB104	Sarduu	H	W	Leaf	Wound	D	F	100	1	0.003	38	0.09
Dodonaea viscosa subsp. angustifolia (L.f.) J.G.West	Sapindaceae	MB89	Ittacha	S	W	Leaf	Eczema	D	Dr	35.2	3	0.008	34	0.09
						Leaf	Body swelling		F
						Stem	Gum bleeding	O
Dovyalis abyssinica (A.Rich.) Warb.	Salicaceae	MB20	Koshimoo	S	W	Leaf	Body swelling	D	F	53.3	2	0.005	30	0.08
						Seed	Hemorrhoid
Echinops kebericho Mesfin	Asteraceae	MB75	Qabarichoo	H	W	Root	Evil eye	N	Dr	100	1	0.003	30	0.08
Ehretia cymosa Thonn	Boraginaceae	MB93	Ulaagaa	T	W	Leaf	Stabbing pain	D	F	100	1	0.003	17	0.04
*Erythrina burana Chiov.	Fabaceae	MB42	Walensuu	T	W	Leaf	Wound	D	F	100	1	0.003	21	0.05
Eucalyptus globulus Labill.	Myrtaceae	MB47	Baargamoo adii	T	W	Leaf	Common cold	N	F	100	1	0.003	32	0.08
Eucalyptus camaldulensis Dehnh.	Myrtaceae	MB23	Baargamoo diimaa	T	W	Leaf	Stomach ache	O	F	100	1	0.003	29	0.07
Euphorbia abyssinica J.F.Gmel.	Euphorbiaceae	MB83	Hadaamii	T	W	Sap	Gastritis	O	F	100	1	0.003	58	0.15
Euphorbia tirucalli L.	Euphorbiaceae	MB35	Qinciba	S	W	Latex	Wart	D	F	100	1	0.003	33	0.08
Ficus vasta Forssk.	Moraceae	MB24	Qilxuu	T	W	Leaf	Ear disease	Er	F	100	1	0.003	18	0.05
**Foeniculum vulgare Mill.	Apiaceae	MB4	Kamoona	H	Cu	Root	Urine retention	O	F	72	2	0.005	43	0.11
							Placental retention
Gossypium barbadense L.	Malvaceae	MB39	Jirbbii bukkee	S	W	Seed	Skin rash	D	F	100	1	0.003	31	0.08
Guizotia abyssinica (L.f.) Cass.	Asteraceae	MB84	Nuugii	H	Cu	Seed	Cough	O	F	100	1	0.003	56	0.14
Hagenia abyssinica (Bruce ex Steud) J.F.Gmel.	Rosaceae	MB65	Heexoo	T	W	Flowers, Seed	Intestinal parasite	O	Dr	100	1	0.003	42	0.11
Juniperus procera Hochst. ex. Endl.	Cupressaceae	MB34	Gatiraa habashaa	T	W	Seed	Uterus problem	O	Dr	100	1	0.003	37	0.09
Justicia schimperiana (Hochst. Ex Nees) T. Anderson	Acanthaceae	MB85	Dhumugaa	S	W	Root	Jaundice	O	Dr	48.7	3	0.008	39	0.09
						Leaf	Intestinal parasite		B
						Root	Typhoid
Kalanchoe marmorata Baker	Crassulaceae	MB59	Phiphii	H	W	Leaf	Ear disease	Er	B	100	1	0.003	23	0.06
**Lagenaria siceraria (Molina) Standl.	Cucurbitaceae	MB67	Buqqee	C	W	Leaf	Ear disease	Er	F	100	1	0.003	36	0.09
**Lawsonia inermis L.	Lythraceae	MB82	Hinnaa	S	W	Leaf	Diarrhea	O	F	100	1	0.003
Leonotis ocymifolia (Burm.f.) Iwarsson.	Lamiaceae	MB32	Raaskimir	S	W	Leaf	Cough	O	F	100	1	0.003	56	0.14
**Lepidium sativum L.	Brassicaceae	MB43	Shifuu	H	Cu	Seed	Bloating	O	Dr	100	1	0.003	65	0.16
**Leucas stachydiformis (Benth.) Hochst. Ex Briq.	Lamiaceae	MB44	Mukaroo	H	W	Leaf	Spider poison	D	F	100	1	0.003	57	0.14
Linum usitatissimum L.	Linaceae	MB33	Talbaa	H	Cu	Seed	Constipation	O	F	65	2	0.005	43	0.11
							Gastritis		Dr
Lippia adoensis Hochst.	Verbenaceae	MB44	Sukee	S	W	Leaf	Skin infection	D	Dr	100	1	0.003	49	0.12
Lycopersicon esculentum Mill.	Solanaceae	MB12	Timaatim	H	Cu	Leaf	Skin rash	D	Dr	64.7	2	0.005	34	0.09
						Fruit	Anemia	O	F
**Melia azedarach L.	Meliaceae	MB45	Kiniinzaaf	T	W	Leaf	Intestinal parasite	O	F	100	1	0.003	42	0.10
Mentha aquatica L.	Lamiaceae	MB30	Naanaa	H	Cu	Leaf	Cough	O	F	85.9	2	0.005	57	0.14
							Common cold
**Mimusops kummel Bruce ex A.DC.	Sapotaceae	MB32	Burris	S	W	Leaf	Body swelling	O	B	100	1	0.003	30	0.08
Mirabilis jalapa L.	Nyctaginaceae	MB60	Harmal	H	W	Root	Breast cancer	O	F	100	1	0.003	42	0.10
*Momordica charantia L.	Cucurbitaceae	MB87	Mukaloonii	C	W	Leaf	Bloating	D	F	100	1	0.003	19	0.05
Moringa oleifera Lam.	Moringaceae	MB95	Shiferaaw	T	Cu	Leaf	Hypertension	O	F	45.7	2	0.005	35	0.09
							Stabbing pain
Musa paradisiaca L.	Musaceae	MB91	Muuza	H	Cu	Leaf	Snake poisoning	D	F	100	1	0.003	34	0.09
Myrtus communis L.	Myrtaceae	MB85	Adas	S	W	Leaf	Dandruff	D	F	100	1	0.003	30	0.08
Myrsine africana L.	Myrsinaceae	MB72	Qacuu/qacamoo	S	W	Fruit	Taeniasis	O	Dr	69.2	2	0.005	52	0.13
						Seed	Ascariasis		F
*Nicotiana tabacum L.	Solanaceae	MB31	Timboo	H	Cu	Leaf	Leech infestation	D	F	100	1	0.003	37	0.09
Nigella sativa L.	Ranunculaceae	MB38	Habasoodaa gurraatii	H	Cu	Seed	Common cold	O	Dr	51.6	4	0.010	62	0.16
							Asthma
							Stabbing pain
							Headache	N
Ocimum lamiifolium Hochst. ex Benth.	Lamiaceae	MB49	Daamaakasediimaa	S	Cu	Leaf	Common cold	N	Dr	89	4	0.010	54	0.14
							Febrile Illness	O	F
							Eye disease	E
							Fever	O
Olea europaea L.	Oleaceae	MB99	Ejarsa	T	W	Leaf	Asthma	N	F	100	1	0.003	11	0.03
Parthenium hysterophorusL.	Asteraceae	MB70	Faramsiis	H	W	Leaf	Hemorrhoid	D	Dr	100	1	0.003	39	0.09
*Phytolacca dodecandra L'Hér.	Phytolaccaceae	MB79	Handoode	S	W	Root	Intestinal parasite	O	F	40	2	0.005	25	0.06
							Wound	D
Plumbago zeylanica L.	Plumbaginaceae	MB79	Marxas	H	W	Leaf	Heart problem	O	F	100	1	0.003	53	0.13
Portulaca oleracea L.	Portulacaceae	MB74	Mararree	H	W	Leaf	Eczema	D	F	100	1	0.003	24	0.06
*Premna schimperi Engl.	Lamiaceae	MB94	Urgessaa	S	W	Leaf	Body swelling	D	F	100	1	0.003	41	0.10
Psidium guajava L.	Myrtaceae	MB55	Zaytuna	T	Cu	Leaf	Kidney stone	O	F	100	1	0.003	38	0.09
Punica granatum L.	Lythraceae	MB66	Rumaana	S	Cu	Leaf	Gastritis	O	F	37.9	2	0.005	29	0.07
						Fruit	Gum bleeding
Raphanus raphanistrum L.	Brassicaceae	MB86	Raafuu shimbirroo	H	W	Seed	Impotence	O	Dr	100	1	0.003	26	0.07
Rhamnus prinoides L'Hér.	Rhamnaceae	MB92	Geeshoo	S	Cu	Leaf	Tonsillitis	D	F	100	1	0.003	51	0.13
Rhus ruspoli Engl.	Anacardiaceae	MB57	Xaaxeesaa	S	W	Leaf	Body swelling	D	F	100	1	0.003	40	0.10
*Ricinus communis L.	Euphorbiaceae	MB53	Qobboo	S	W	Fruit	Anthrax	O	Dr	100	1	0.003	31	0.08
Rotheca myricoides (Hochst.) Steane & Mabb.	Lamiaceae	MB90	Misrichii	S	W	Stem	Toothache	O	F	100	1	0.003	19	0.05
**Rumex nepalensis Spreng.	Polygonaceae	MB21	Mucharraab	H	W	Leaf	Body swelling	D	F	71.4	3	0.008	42	0.11
						Root	Breast cancer
							Snake poisoning	O
Rumex nervosus Vahl	Polygonaceae	MB68	Dhangagoo	S	W	Leaf	Body swelling	D	F	100	1	0.003	38	0.09
Ruta graveolens L.	Rutaceae	MB100	Xalataam	H	Cu	Fruit	Hypertension	O	F	61.1	2	0.005	36	0.09
							Diabetes
Rydingia integrifolia (Benth.) Scheen & V.A. Albert	Lamiaceae	MB54	Xuunjitii	S	W	Leaf	Headache	N	Dr	100	1	0.003	64	0.16
**Salvia nilotica Juss. Ex Jacq.	Lamiaceae	MB27	Hulgab	S	W	Root	Wound	D	F	100	1	0.003	70	0.18
Solanum incanum L.	Solanaceae	MB76	Hiddii	S	W	Fruit	Scabies	D	F	100	1	0.003	26	0.07
*Silene macrosolen Stued. ex A.Rich	Caryophyllaceae	MB36	Liqii	H	W	Root	Rabies	O	Dr	100	1	0.003	28	0.07
Sphaeranthus suaveolens (Forssk.) DC.	Asteraceae	MB63	Raashedii	H	W	Leaf	Headache	O	F	100	1	0.003	25	0.06
**Tamarindus indicus L.	Fabaceae	MB107	Rooqaa	T	W	Root	Gastritis	O	B	100	1	0.003	35	0.09
Thymus schimperi Ronniger	Lamiaceae	MB7	Xoosinyoo	H	Cu	Leaf	Hypertension	O	B	100	1	0.003	55	0.14
Urtica simensis Hochst. Ex A.Rich	Urticaceae	MB22	Doobbii gabaabduu	H	W	Leaf	Impotence	O	F	100	1	0.003	32	0.08
*Verbascum sinaiticum Benth.	Scrophulariaceae	MB69	Gurra harree	H	W	Root	Anthrax	O	F	100	1	0.003	39	0.09
Verbena officinalis L.	Verbenaceae	MB102	Mukalaagaa	H	W	Leaf	Tonsillitis	O	F	100	1	0.003	35	0.09
**Vernonia amygdalina Del.	Asteraceae	MB10	Obichaa	T	W	Root	Intestinal parasite	O	F	100	1	0.003	43	0.11
**Withania somnifera (L.) Dunal	Solanaceae	MB40	Hidda budee	S	W	Leaf	Evil eye	N	Dr	100	1	0.003	57	0.14
Zingiber officinale Roscoe	Zingiberaceae	MB16	Zanjabil	H	Cu	Rhizome	Cough	O	Dr	100	1	0.003	37	0.09

Note: ‘*’ represents plants are used for livestock's diseases, ‘**’ is for both humans' and livestock's diseases, whereas plants with no asterisk are used to treat humans' ailments only. V. No. = Voucher Number; V. Name = Vernacular name; Ht = Habit (H=Herb, C=Climber, S=Shrub.

T = tree and M = Mistletoes); Hbt = Habitat (W =Wild, Cu=Cultivated); AP = Approaches of preparation (F=Fresh, Dr = Dried and B=Both); R = Route of Administration (O=Oral, N=Nasal, D = Dermal, Er = Ear, E = Eye).

Asteraceae and Lamiaceae, each being represented by 9 species were “the dominant families” followed by Solanaceae (6 spp); Fabaceae (5 spp); Cucurbitaceae, Brassicaceae, Rutaceae, Euphorbiaceae and Myrtaceae (4 spp each); Apiaceae (3 spp); Boraginaceae, Poaceae, Verbenaceae, Alliaceae, Polygonaceae, Apocynaceae and Lythraceae had 2 species each. The rest 38 families had one species each. The abundance of medicinal plant species under Asteraceae and Lamiaceae families may be ascribed to their cosmopolitan distribution [35]. Members of family Asteraceae and Lamiaceae were reported for their wider use in traditional medicine to treat various ailments in Tulo District, which could be ascribed to the occurrence of diverse bio-active constituents [36,37]. Species under Lamiaceae family are known to possess a wide spectrum of plants with essential oil composition that have use in cosmetic, perfume and pharmaceutical industries [38], and have pharmacologically important compounds such as terpenoids, flavonoids, phenolics and alkaloids [[39], [40], [41]]. Species under the Asteraceae family have been found to contain various components such as sesquiterpenoids, diterpenoids, phenols and flavonoids with a variety of biological activities [[42], [43], [44]]. Reports have also been found on the high medicinal usage of both families in Ethiopia [9,[45], [46], [47], [48], [49]].

3.2. Life-form, habitat and parts of ethnomedicinal plants used

Most of the documented medicinal plants were herbs followed by shrubs, trees, climbers and mistletoes (Fig. 2). This dominance of herbs and shrubs may be due to their rapid widespread growth [50]. Previous reports [16,51,52] from Ethiopia reiterated the results obtained in our study. The high usage of herbs for therapeutic purpose was also reported by Ref. [53].

Fig. 2.

Life-forms of ethnomedicinal plants.

Most (73) of the plant species were harvested from wild environment, and a few (31) of them were cultivated. Our result was validated by other similar works [[54], [55], [56]]. This infers that majority of the medicinal plants in Tulo District are not under human management and are facing any anthropogenic and natural disturbances.

People native to the current study District make use of different parts of medicinal plants to treat humans' and livestock's ailments. Nevertheless, leaf was the most widely (56.73%) reported plant organ followed by root (22.11%), seed (18.27%), fruit (13.46%), bulb (2.88%), stem (2.88%), sap (1.92%), latex (0.96%) and rhizome (0.96%). Leaves have been reported as vital reservoirs of most bioactive compounds like alkaloids, phenolics and terpenoids [57]. High reliance on leaves for remedy preparations was reported previously by different researchers in Ethiopia [8,58,59]. More use of leaves than other plant parts reduces the risk of losing medicinal plants [[60], [61], [62]].

3.3. Approaches of remedy preparation and administration

Local people of Tulo District prepare remedies from medicinal plants while in fresh or dried form or both. Most reported form, however, was fresh harvest (73.08%), whereas about 25.96% medicinal plants were used in dry form. On the other hand, for 9.61% of medicinal plant parts, either freshly harvested or in dry form is possible to prepare the remedies. Reports show that the use of fresh harvest surpasses the dried form due to its assumed greater efficacy, because of its intact and unchanged secondary metabolites [63]. Earlier, various researchers [5,56,64,65] published similar reports from other parts of Ethiopia.

Regarding to the preparation of remedies, the local ethnic people use different approaches depending on the type of diseases. The top popular approaches reported were pounding, crushing and boiling. They accounted for more than 70% of the reported preparation methods, whereas direct application, smoking, etc. accounted for 30% of the methods. Such reports have been given by other researchers including [5,52,64,65], suggesting the commonality of methods of remedy preparations by indigenous communities of different localities and ethnic groups in Ethiopia.

During field observations, we noticed that local people use two or more herbal combinations in the preparation of remedies to treat some illnesses. For example, combinations of bulbs of Allium cepa with rhizome of Zingiber officinale for impotence problem, seeds of Brassica nigra with Allium sativum bulbs for asthma, Carthamus tinctorius seeds with Allium sativum bulbs for cough, Rhamnus prinoides leaves with juice of Citrus lemon for tonsillitis and poly-herbal formulations (e.g. Leaves of Premna schimperi combined with leaves of Calpurnea aurea and Croton macrostachyus) for body swelling in livestock. Combined use of remedies has been previously reported [30,66] to cure some ailments, suggesting high synergistic effects.

The indigenous people follow various routes of remedy administration or application, which of course is based on the type of ailment and the affected body part. Mostly remedies are taken orally, but dermal and nasal were also considerable routes recorded (Fig. 3). Different investigators [56,58,[67], [68], [69], [70]] who carried out similar research in various corners of the country have also reported the same.

Fig. 3.

Routes of administration of remedies.

3.4. Ethnobotanical indices

3.4.1. Informant consensus factor

The homogeneousness of traditional medical knowledge among the informants on utilization of medicinal plants for curing particular disease categories was tested using ICF index. The values of ICF vary from 0 to 1, whereby 1 depicts highest agreement and subsequent decrease in agreement level with values decreasing from 1 [71]. In the present study, the computed values of ICF for eight category of ailments ranged from 0.50 to 0.90 (Table 2). The finding showed that Swelling and hemorrhoid had the highest ICF value with a nearly complete agreement between respondents followed by gastrointestinal diseases and parasitic infections, Dermatology and Sensory organ diseases, febrile illness and related diseases. Earlier [72], reported highest ICF value (0.99) for hemorrhoid from another District in west Hararghe zone. This implies that hemorrhoid is the most common ailment that the local community shares information on the remedy of this ailment [73]. On the other hand, lower ICF value indicates rare occurrence of the ailment in the study area for which less information is exchanged among individuals to seek for its remedy [74].

3.4.2. Preference ranking

Ranking exercise performed by 10 key traditional healers on 6 plant species that were stated to cure cough revealed that Guizotia abyssinica was the favorite medicinal plant to cure cough (Table 3). This shows that the ethnic people of the study site prefer one plant over the other to treat a given ailment for which multiple remedies are suggested. This preference could be due to the perceived effectiveness of a medicinal plant for the reported ailment and further investigations on its chemical content and pharmacology are required.

Table 3.

Ranking of favorite medicinal plant to cure cough.

No	Plant species	Respondents' (R1-R10) Scores										Total	Rank
		R1	R2	R3	R4	R5	R6	R7	R8	R9	R10
1	Guizotia abyssinica	6	5	6	5	6	4	5	6	5	6	55	1st
2	Anthemis tigreenis	5	3	6	5	6	5	6	5	6	5	52	2nd
3	Carthamus tinctorius	5	6	2	5	4	6	5	6	5	4	48	3rd
4	Mentha aquatica	4	2	5	1	6	5	3	2	4	2	34	4th
5	Zingiber officinale	2	1	3	2	1	2	1	2	3	2	19	5th
6	Crinum abyssinicum	2	1	1	2	1	3	1	2	2	1	16	6th

Note: Scores given by the informants (R_1-R₁₀) are based on the efficacy of the medicinal plant species to treat cough; where ‘6’ suggests the highest curative potential and ‘1’ suggests lowest potential to cure cough.

3.4.3. Fidelity level, RFC and CI

Ethnobotanical quantitative indices (e.g. FL, RFC and CI) were computed to determine popularity and cultural importance of medicinal plants used by the local people of the study area. Fidelity level (FL) helps to identify the most important plant used to cure a given disease. It suggests the medicinal plant that is specifically used to cure a given ailment. FL of a plant reported by many respondents for the same purpose will have the highest value, whereas plant reported for several purposes will have lowest FL [75]. In the current study, FL for all 104 plants was computed by considering the most frequently reported ailment to be treated by each medicinal plant. Results showed that the values ranged from 35.2 to 100% (Table 1). Majority (66%) of the medicinal plants had FL value of 100% (e.g., Croton macrostachyus, Hagenia abyssinica, Rydingia integrifolia, Salvia nilotica, Thymus schimperi, etc.). Cucurbita pepo had FL value of 94% followed by Mentha aquatic (84.9%), whereas the rest had below 80%. The high FL value shows that these plants were mentioned individually by several informants for the treatment of certain specific ailments. This could be a signal of their therapeutic efficiency for the reported ailments. In Ethiopia, there have been wide reports on the role of C. macrostachyus for treating ringworm [5,9,11,[76], [77], [78]]. Traditional use of H. abyssinica for the treatment of intestinal parasites (especially worms) has also been well vindicated [10,[79], [80], [81]]. Hence, the plant species with highest FL value deserve further investigations on their pharmacology and phytochemistry. The least FL index rank was reported for Dodonaea viscosa subsp. angustifolia for treating Eczema (Table 1). Although some plant species have been found with low FL index, they should not be ignored from conservation plan and pharmacological investigations for sustainable use in the future [82].

The RFC demonstrates the significance of the medicinal plants in relation to the respondents who mentioned them [83]. In our investigation, five plants having top FC values were Salvia nilotica (n = 70) followed by Lepidium sativum (n = 65), Rydingia integrifolia (n = 64), Nigella sativa (n = 62), Asplenium monanthes (n = 61) and Euphorbia abyssinica (n = 58). The RFC results of the entire medicinal plants ranged from 0.03 to 0.18 for their curative properties (Table 1). The highest RFC (0.18) was recorded for Salvia nilotica followed by Lepidium sativum, Rydingia integrifolia and Nigella sativa each 0.16; Euphorbia abyssinica and Asplenium monanthes each 0.15. Overall, 37% of the recorded plants had RFC values above 0.1 (Table 1). The high RFC values of these species depict that these plants are familiar and widely used by the locals for their medicinal property. Thus, plants with high RFC are recommended for further phytochemical and bioactivity studies. On the contrary, the lowest RFC (0.03) was recorded for Olea europaea, suggesting that this species is less known for its medicinal value. Of course, the relative frequency of citations differs from region to region and they depend on traditional medicinal knowledge of the local people [84].

The cultural importance index (CI) is used to determine the value of a particular plant that is used by the locals [84]. On analyzing the species ranking based on the CI index, Brassica nigra and Aloe trichosantha were amongst the most culturally important species with a CI index of 0.013 each followed by Aloe trichosantha, Nigella sativa and Ocimum lamiifolium with a CI index of 0.010 each (Table 1). Several plant species were found to have CI index of 0.003. The extent of information possessed by the locals, their background on local culture and the predominant situations of a given place influence CI values [84].

3.5. Socio-demographic features and knowledge on traditional medicine

A participant's level of traditional knowledge has always been associated with certain socio-demographic status including gender, age, educational level and occupation [85,86]. Thus, the above stated socio-demographic features were examined to unveil their role related to traditional medicinal knowledge based on the amount of cited medicinal plants by respondents. Results showed that male respondents cited significantly higher (t_67.174 = 2.484, P = 0.015) amount of medicinal plants when compared to female counterparts (Table 4). In Ethiopia, the traditional medical knowledge is transferred from one generation to the other through verbal communication to family members, particularly to sons [30]. The higher medicinal knowledge of males than females could therefore be attributed to the gender biased knowledge transfer. The same result was reported by various researchers who conducted ethnobotanical investigations in different regions of Ethiopia [45,82,[87], [88], [89]]. Our statistical analysis showed that age categories varied significantly (P < 0.01, df = 4, F = 26.8) in the amount of reported medicinal plants. Overall, respondents of age ≥51 years cited large amount of medicinal plants when compared to individuals of age <51 (Table 4). This suggests that the older people possess accumulated knowledge due to their long years of interaction with their environment [90,91]. Some earlier studies conducted by Refs. [45,82,89,90,92] vindicate our results. The lower medicinal knowledge possessed by younger individuals implies the probable decline in knowledge transfer between generations, which in turn can be considered as one of the factors jeopardizing indigenous knowledge. Therefore, the elderly people should be encouraged to exchange their rich expertise on traditional medicine to the young ones before they die. Moreover, analysis of multiple linear regression showed that gender (β = 1.143, P = 0.05) and age (β = 1.925, P = 0.01) of the study population were found to be determinants of respondents' knowledge on traditional medicine, and our finding is in line with that of [5,59,93].

Table 4.

Demographic features of respondents.

Demographic features	Categories	No.	No. of plants reported (mean ± SE)	P-value
Gender	Male	305	5.87 ± 0.41	0.015
	Female	91	4.34 ± 0.41
Education	Illiterate	151	7.10 ± 0.53	<0.001
	Elementary level (1–8 grade)	150	4.69 ± 0.28
	Secondary level (9–12 grade)	75	2.70 ± 0.41
	>12 grade	8	2.00 ± 0.00
	Religious study	12	8.00 ± 2.30
Age	20–30	32	1.5 ± 0.19	<0.001
	31–40	48	2.38 ± 0.18
	41–50	102	12.0 ± 0.42
	51–60	103	10 ± 0.28
	>60	111	18.0 ± 0.65
Occupation	Peasant	258	5.60 ± 0.38	<0.001
	Teacher	68	3.33 ± 1.33
	Housewives	37	5.72 ± 0.61
	Pensioners	8	11.50 ± 1.50
	Merchants	25	2.73 ± 0.45
Marital status	Married	380	5.73 ± 0.33	<0.001
	Single	16	1.0 ± 0.0
Religion	Islam	281	5.59 ± 0.40	0.802
	Christian	115	5.41 ± 0.58

Respondents’ knowledge on traditional medicines of plant origin was also significantly affected by the level of their education (P < 0.01, df = 4, F = 10.5), occupation (P < 0.01, df = 4, F = 7.89) and marital status (t_95.00 = 14.289, P < 0.001). Previous reports by Refs. [45,55,81,89,92] show that the number of reported medicinal plants, which suggests the extent of traditional knowledge, decreases with increasing level of education.

3.6. Threats to ethnomedicinal plants and conservation efforts

Respondents reported five anthropogenic factors that they consider as the key threatening factors to the availability of medicinal plants of their surroundings and ranked them according to their level of importance (Table 5). Expansion of agriculture through which natural ecosystems are exploited for farming was ranked first as the major cause of deterioration of medicinal plant resources followed by use of plant for fire wood, charcoal production, overgrazing by animals and use of plant materials for construction purposes. The livelihood of most Ethiopian population is based on agriculture, especially crop production. With increasing human population, agricultural lands are encroaching to the wilderness consistently, making agriculture as the dominant factor to convert the natural ecosystem to manmade ecosystem. Results of some previous studies also support our finding [16,52,73,93].

Table 5.

Anthropogenic factors for loss of medicinal plant species in the study site.

No.	Threatening factors	Respondents' (R1-R10) Scores										Total	Rank
		R1	R2	R3	R4	R5	R6	R7	R8	R9	R10
1	Agricultural expansion	6	5	6	6	6	5	5	6	6	6	57	1st
2	Fire wood collection	5	4	6	5	6	5	6	5	6	5	53	2nd
3	Charcoal	5	6	4	5	4	6	5	6	5	4	50	3rd
4	Overgrazing by animals	4	2	3	1	3	5	3	2	3	2	28	4th
5	House construction	2	1	2	3	1	2	1	2	2	2	18	5th

Note: Scores given by the informants (R_1-R₁₀) are based the perceived threatening levels of the factors on the medicinal plants. Score 6 stands for highest threatening factor, whereas 1 is the least and others ordered according to their relative importance.

In spite of being threatened by anthropogenic factors, from our observation in the field, we have also noticed some conservation efforts being made for some medicinal plants by growing them around home. For example, Thymus schimperi, Coriandrum sativum, Ocimum lamiifolium, Ruta graveolens, Moringa oleifera, Rhamnus prinoides, Foeniculum vulgare and Punica granatum were found to be grown in home gardens by some people. These plants are being managed by humans most probably because of their use as food and spice in addition to their medicinal value. However, most of the reported medicinal plants are from wild and were given no conservation attention. Thus, they need due attention for conservation.

4. Conclusion

In conclusion, report of high number of medicinal plants shows the occurrence of enormous knowledge on traditional medicine and reliance of the people on traditional medicine due to limited access to modern medication and for cultural reasons. Age and gender were predictors of knowledge on traditional medicine. Of all human activities, conversion of natural habitats for agricultural purposes was the major treat to medicinal plants. Therefore, appropriate conservation methods including growing of medicinal plants in home garden are recommended to preserve plants and associated indigenous knowledge. The medicinal plants, especially those with high preference ranking, ICF and FL should be screened pharmacologically for their efficacy and safety for wider usage.

Author contribution statement

Meskerem Bogale, J. M. Sasikumar, Meseret C. Egigu: Conceived and designed the experiments; Performed the experiments; Analyzed and interpreted the data; Contributed reagents, materials, analysis tools or data; Wrote the paper.

Funding statement

This work was supported by Ministry of Education, Ethiopia.

Data availability statement

Data included in article/supplementary material/referenced in article.

Declaration of interest's statement

The authors declare no conflict of interest.

Appendix A. Supplementary data

The following is the Supplementary data to this article.