Medicinal plants diversity
A total of 98 medicinal plant species belonging to 87 genera and 48 families were reported to be used for treating human ailments in Suro Barguda District (Appendix 1). Family Fabaceae was represented by the highest number of species (10 species, 10.2%), followed by Lamiaceae (seven species, 7.1%). Four of the medicinal plants which were used to treat human ailments were endemic to Ethiopia. Identified growth forms of medicinal plants indicated that shrubs (36; 36.7%) were more dominant than trees (30; 30.6%) and herbs (14; 14.3%). Other forms such as lianas, climbing herbs, epiphytes and succulent were 11 species (11.2%), three species (3.1%), three species (3.1%), and one species (1.0%) respectively.
Medicinal plant parts used
Even though about eight different plant parts were reported to be used for remedy preparation in different ways, a larger proportion (36.2%) of the preparations were obtained from leaves followed by roots (23.8%) and barks (18.6%). In addition to this, the stem was used for 5.7% preparations, whereas the latex alone and the leaves in mixture with other plant parts 5.2% respectively (Figure 3). Most of the remedy preparations (93.7%) were reported as they were prepared from freshly collected plant parts, 5.8% from dried parts and the remaining (0.5%) were prepared either from the fresh or dried plant parts.
Ways of herbal medicine preparation
As herbalists reported in the study area, ways of preparing remedies vary based on the type of ailment which they identified regarding symptoms observed on patients. The major way of herbal medicine preparation was through chopping or pounding the plant parts and homogenizing it with cold and clean water (35.6%) followed by crushing and put on the preparation (16.7%) and chopping, homogenizing, and boiling the preparation (15%) (Figure 4).
Route of remedy administration
Results of analysis of route of administration of medicinal preparations revealed that oral application was the most common route of administration (159 preparations, 70.4%) followed by dermal administration (49 preparations, 21.7%) and nasal administration (12 preparations, 5.3%). Other remedies were reported to be administered through a deep opening on the body formed due to infection "Luxaa - in local Oromo language or tissue cancer" (three preparations, 1.3%); aural (two preparations; 0.9%), or ocular (one preparation; 0.4%) concerning the type of ailment reported by diagnosing the patient.
Major types of diseases occurred in the study area with their clinical explanation
Out of the fifty-nine mentioned human diseases, thirty-one were considered for their traditional versus clinical explanations as indicated in Table 2.
The most preferred medicinal plants for treating human ailments
Preference ranking exercise on medicinal plant species that were reported to be used against toothache, which was one of the gastrointestinal diseases common to the study area, showed the most effective medicinal plants (Table3).
Table 3. Results of preference ranking of ten medicinal plants reported for treating toothache
Medicinal plants used for tooth ache
|
Informants designated A to J
|
Total
|
Rank
|
A
|
B
|
C
|
D
|
E
|
F
|
G
|
H
|
I
|
J
|
Acmella caulirhiza
|
8
|
5
|
6
|
7
|
4
|
2
|
3
|
1
|
8
|
1
|
45
|
10th
|
Capparis tomentosa
|
8
|
9
|
7
|
6
|
4
|
5
|
3
|
8
|
1
|
2
|
53
|
7th
|
Carissa spinarum
|
8
|
9
|
7
|
10
|
6
|
4
|
5
|
3
|
1
|
7
|
60
|
3rd
|
Clerodendrum myricoides
|
10
|
8
|
9
|
7
|
10
|
10
|
3
|
1
|
10
|
2
|
70
|
1st
|
Fagaropsis angolensis
|
8
|
6
|
7
|
9
|
10
|
5
|
3
|
4
|
4
|
3
|
59
|
4th
|
Pappea capensis
|
7
|
6
|
5
|
8
|
4
|
8
|
3
|
1
|
3
|
2
|
47
|
9th
|
Pittosporum viridiflorum
|
8
|
7
|
9
|
6
|
4
|
5
|
9
|
1
|
4
|
3
|
56
|
5th
|
Premna schimperi
|
7
|
8
|
6
|
4
|
5
|
3
|
1
|
8
|
3
|
4
|
49
|
8th
|
Rhoicissus revoilii
|
9
|
7
|
6
|
8
|
5
|
4
|
2
|
9
|
3
|
1
|
54
|
6th
|
Scherebra alata
|
9
|
10
|
8
|
7
|
5
|
6
|
10
|
4
|
2
|
3
|
64
|
2nd
|
N.B. Scores in the table indicate ranks given to medicinal plants based on their efficacy. The highest number (10) given for the medicinal plant which informants thought was most effective in treating toothache and the lowest number (1) for the least effective plant selected currently for this ranking purpose from numerous medicinal plants used to treat this disease.
Consensuses on the most frequently used medicinal plants used for treating human ailments in the study area
This study clarified that some medicinal plants were well known in the study area than others. As a result, all key informants cited such plants repeatedly as a remedy for various diseases of humans. For example, Justicia schimperiana and Warburgia ugandensis were cited by all key informants (100%) as sources of remedy for hepatitis and internal organ cancer respectively. Carissa spinarum, Ocimum urticifolium and Schrebera alata were also cited by 23 (95.8%) key informants as sources of remedy for breast disease, febrile illness, and tooth cancer respectively (Table 4).
Table 4. Key informants consensus on most commonly used medicinal plants
The botanical name of medicinal plants
|
Disease treated
|
No. of key informants
|
%
|
Carissa spinarum
|
Breast disease
|
23
|
95.8
|
Clerodendrum myricoides
|
Gonorrhea
|
22
|
91.7
|
Haplocoelum foliolosum
|
Parasitic worms
|
21
|
87.5
|
Fagaropsis angolensis
|
Coughing
|
20
|
83.3
|
Ocimum urticifolium
|
Febrile illness
|
23
|
95.8
|
Justicia schimperiana
|
Hepatitis
|
24
|
100
|
Rhus vulgaris
|
Itching
|
19
|
79.2
|
Schrebera alata
|
Tooth cancer
|
23
|
95.8
|
Warburgia ugandensis
|
Internal organ cancer
|
24
|
100
|
Withania somnifera
|
Snake venom
|
20
|
83.3
|
Effectiveness of medicinal plants
Informant consensus was used to evaluate the reliability of the data. To simplify the analysis, twelve disease categories were designated from the total 59 human ailments reported in the district and ICF values were computed based on the reported medicinal plant species and their use citations for each disease category, and the following results were obtained (Table 5).
Table 5. ICF values of traditional medicinal plants used for treating human ailments
No
|
Disease category
|
No. of spp.
|
% all spp.
|
Use citation
|
% all use citation
|
ICF
|
1
|
Dental, oral and pharyngeal diseases
|
15
|
35.5
|
76
|
38.8
|
0.81
|
2
|
Dermatological diseases
|
14
|
21.1
|
136
|
69.4
|
0.90
|
3
|
Diabetics, hepatitis, and hypertension
|
12
|
15.8
|
39
|
19.9
|
0.71
|
4
|
Evil spirit diseases
|
7
|
9.2
|
24
|
12.2
|
0.73
|
5
|
External injuries and snake bite
|
13
|
30.3
|
72
|
36.7
|
0.83
|
6
|
Febrile diseases
|
5
|
6.6
|
58
|
29.6
|
0.90
|
7
|
Gastrointestinal diseases
|
16
|
6.6
|
194
|
99.0
|
0.92
|
8
|
Musculoskeletal and nervous system
|
13
|
56.6
|
68
|
34.7
|
0.82
|
9
|
Breathing system diseases
|
15
|
7.9
|
160
|
81.6
|
0.91
|
10
|
Sensorial diseases
|
13
|
17.1
|
42
|
21.4
|
0.70
|
11
|
Tissue cancer and cold disease
|
12
|
38.2
|
40
|
20.4
|
0.72
|
12
|
Urogenital and venereal diseases
|
9
|
25.0
|
33
|
16.8
|
0.75
|
The relative healing potential of medicinal plants used for treating human ailments
Fidelity level values of medicinal plants commonly reported against a given human ailment category were computed to know the healing potential of the reported medicinal plants against the corresponding diseases and the following results were obtained (Table 6).
Table 6. Fidelity level values of medicinal plants commonly reported against a given human ailment category
No |
Medicinal plant
|
Therapeutic category
|
Np
|
N
|
FL (%)
|
1
|
Combretum molle
|
Gastro - intestinal parasites
|
28
|
29
|
97
|
2
|
Fagaropsis angolensis
|
Breathing system diseases
|
23
|
24
|
96
|
3
|
Ocimum urticifolium
|
Febrile diseases
|
14
|
15
|
93
|
4
|
Momordica foetida
|
Rabies &Gonorrhea
|
11
|
12
|
92
|
5
|
Pappea capensis
|
External injuries and snake bite
|
16
|
19
|
84
|
6
|
Rhus vulgaris
|
Dermatological diseases
|
18
|
19
|
95
|
7
|
Schrebera alata
|
Dental, oral and pharyngeal
|
13
|
15
|
87
|
8
|
Solanum incanum
|
Hepatitis and stomach ache
|
17
|
20
|
85
|
9
|
Warburgia ugandensis
|
Tissue cancer and cold disease
|
12
|
14
|
85
|
10
|
Withania somnifera
|
Evil spirit diseases
|
10
|
12
|
83
|
Legend: FL= Fidelity Level, Np = number of informants who independently cited the importance of a species for treating a particular disease, N = total number of informants who reported the plant for any given disease
Medicinal use values of selected plant species
Traditional medicinal uses of different medicinal plant species against several human ailments were compiled. Investigation of their use-value indicated that some of these plants show high medicinal use-value (UVmed) as indicated in Table 7.
Table 7. Medicinal use values (UVmed) of most-cited human medicinal plants in Suro Barguda District
Medicinal plant species
|
No. informants citing the species
|
Total citations
|
No. of ailments treated with
|
UVmed.
|
Asparagus africanus
|
81
|
605
|
4
|
7.4
|
Capparis tomentosa
|
118
|
980
|
5
|
8.3
|
Cucumis pustulatus
|
92
|
589
|
5
|
6.4
|
Euclea divinorum
|
60
|
402
|
4
|
6.7
|
Ehretia cymosa
|
120
|
912
|
7
|
7.6
|
Pappea capensis
|
140
|
1232
|
8
|
8.8
|
Premna schimperi
|
104
|
676
|
6
|
6.5
|
Identification of multipurpose medicinal plants for their conservation priority
The result of the direct matrix ranking exercise on the selected medicinal plants used for treating human ailments enabled us to identify which of the multipurpose plants was under greater pressure than other species in the area besides the respective factors that threaten the plants (Table 8).
Table 8. Average direct matrix ranking score of ten key informants for ten medicinal plant species with additional uses
Medicinal plant species
|
Use categories
|
Total
|
Rank
|
Ch
|
Co
|
Fr &Tl
|
Fw
|
Md
|
Allophylus abyssinicus
|
5
|
3
|
2
|
3
|
2
|
15
|
4th
|
Combretum molle
|
1
|
3
|
3
|
4
|
3
|
14
|
5th
|
Ehretia cymosa
|
2
|
1
|
2
|
3
|
1
|
9
|
10th
|
Fagaropsis angolensis
|
3
|
3
|
4
|
5
|
3
|
18
|
2nd
|
Olea europaea subsp. cuspidata
|
3
|
5
|
2
|
4
|
2
|
16
|
3rd
|
Pappea capensis
|
3
|
3
|
2
|
2
|
1
|
11
|
8th
|
Podocarpus falcatus
|
1
|
2
|
1
|
4
|
2
|
10
|
9th
|
Schrebera alata
|
1
|
3
|
3
|
3
|
2
|
12
|
7th
|
Terminalia brownii
|
3
|
2
|
2
|
4
|
2
|
13
|
6th
|
Warburgia ugandensis
|
4
|
5
|
4
|
3
|
4
|
20
|
1st
|
Total
|
26
|
30
|
25
|
35
|
22
|
138
|
|
Rank
|
3rd
|
2nd
|
4th
|
1st
|
5th
|
|
Where, Ch = Charcoal, Co = Construction, Fr & Tl = Furniture and Tools, Fw = Firewood and
Md = Medicinal.
N.B. Scores in the table indicate ranks given to medicinal plants based on their use diversity. The highest number (5) given for the medicinal plant which informants thought was used commonly for the mentioned purpose and the lowest number (1) for the least needed for that purpose.
Use diversity of medicinal plants
All the 98 medicinal plant species recorded for human ailments treatment in the district were cited for one or more uses other than their medicinal role. The proportion of medicinal plant species over different use categories was summarized in Figure 5.
Figure 5. The proportion of human medicinal plants over different use categories
Solvent and additives used in traditional herbal medicines prepared in the study area
Almost in all ethno formulations of traditional medicines, water served as ‘solvent’ whenever dilution is required. Different additives were incorporated in 23.4% of the whole ethno formulations and “Magado” salt (locally produced salt) was the most commonly used additive (Figure 6).
Distribution of indigenous knowledge on medicinal plants among different social groups in the community of the study area
The difference in naming medicinal plants between different social groups (elders, youngsters, male, female, literate, illiterate, key informants, randomly taken informants, etc.) was analyzed by using a statistical test as follows (Table 9).
Table 9. Statistical test of significance on the average number of medicinal plants among different informant groups in Suro Barguda District
Considerations
|
Informant groups
|
N
|
Average ± SD
|
t -value**
|
p –value
|
Gender
|
Males
|
290
|
6.62 ± 2.65
|
1.97
|
0.97
|
Females
|
102
|
6.05 ± 2.18
|
Age
|
Youngsters
|
208
|
5.16 ± 2.07
|
-12.87
|
0.00*
|
Elders
|
184
|
7.96 ± 2.19
|
Literacy
|
Illiterates
|
292
|
7.22 ± 2.31
|
12.92
|
0.00*
|
Literates
|
100
|
4.28 ± 1.82
|
Proximity to the health center
|
Near to health center
|
22
|
6.00 ± 2.37
|
-0.94
|
0.36
|
Far away from the health center
|
370
|
6.5 ± 2.57
|
Informant
category
|
Key informants
|
50
|
10.76 ± 1.09
|
25.75
|
0.00*
|
Randomly taken informants
|
342
|
5.85 ± 2.04
|
*Significant difference (p<0.05); ** t(0.05) (two tailed), degree of freedom (df) = 223,
N= number of respondents
Market survey of medicinal plants
A market survey was done in the biggest market of the district (Suro Market) to observe and collect data on the marketability and trade of medicinal plants. The researchers observed as some medicinal plants were sold for other purposes than their medicinal use?