Species richness and plants use patterns for the management of hypertension and diabetes
For the management of hypertension and diabetes, the traditional healers (THs) cited thirty-six (36) species. These species belonged to thirty-two (32) genera and twenty (20) families. Among these species, Sclerocarya birrea (6.08%), Parkia biglobosa (5.41%), Khaya senegalensis (4.73%), Combretum micranthum (4.05%) and Moringa oleifera (4.05%) are the most cited for the management of hypertension. However, for the treatment of diabetes, Cassia sieberiana (8.57%) and Cassia italica (3.81%) are frequently cited by THs (Table II). The parts of the plants mentioned are practically the same for both pathologies. However, the formulation methods differ notably from one disease to another. Indeed, the decoction (51.85%) is strongly used in the case of the preparation of anti-hypertensive recipes. Calcination is used more often for the formulation of anti-diabetic recipes (16%) than for anti-hypertensive ones (7.41%). This is also the case for infusion (10%) which is only used for the formulation of some anti-diabetic recipes (Figure 2).
Table II. Species used for the management of hypertension and diabetes in the sub-sahelian area of Burkina Faso, West Africa
Species
|
Family
|
Local name (Mooré)
|
Hypertension
|
Diabetes
|
FC
|
Organs
|
Formulation
|
FC
|
Organs
|
Formulation
|
Acacia sieberiana DC
|
Fabaceae
|
Gonponsgo
|
0.68
|
TB
|
D
|
0.95
|
TB
|
D
|
Anogeissus leiocarpa (DC.) Guill. & Perr.
|
Combretaceae
|
Siiga
|
2.7
|
Lv; TB
|
D; M
|
0.95
|
Lv
|
I
|
Balanites aegyptiaca (L.) Delile
|
Zygophyllaceae
|
Kièglga
|
0.68
|
TB
|
D
|
0.95
|
TB
|
D
|
Boscia angustifolia A. Rich.
|
Capparaceae
|
Zigrezika
|
2.03
|
TB
|
D
|
0.95
|
TB
|
M
|
Boswellia dalzielii Hutch.
|
Burseraceae
|
Komdayouingo
|
1.35
|
TB
|
M
|
0.95
|
TB
|
D
|
Cadaba farinosa Forssk.
|
Capparaceae
|
Kinsga
|
2.03
|
Rt
|
D
|
0.95
|
Rt
|
Ca
|
Calotropis procera (Aiton) R.Br.
|
Apocynaceae
|
Putrepuga
|
0.68
|
Rt
|
M
|
0.95
|
Rt
|
D
|
Cassia italica (Mill.) Lam. ex F.W.Andrews
|
Fabaceae
|
Nontoulm-Songdré
|
2.03
|
Lv
|
D; M; Po
|
3.81
|
Lv
|
D; M; Po
|
Cassia sieberiana DC.
|
Fabaceae
|
Yâmtiiga
|
5.41
|
Rt
|
M; Po; D
|
8.57
|
TB; Lv
|
M; Po; D
|
Cochlospermum tinctorium Perr. ex A. Rich
|
Cochlospermaceae
|
Sonsga
|
2.03
|
Rt
|
M
|
1.9
|
Rt
|
Po
|
Combretum glutinosum Perr. ex DC.
|
Combretaceae
|
Koèguenga
|
0.68
|
Lv
|
Po
|
0.95
|
Lv
|
I
|
Combretum micranthum G. Don
|
Combretaceae
|
Kânga/Rannega
|
4.05
|
Lv
|
D;M
|
1.9
|
Lv
|
I
|
Crescentia cujete L.
|
Bignoniaceae
|
Wamde-Tiiga
|
0.68
|
Lv
|
D
|
0.95
|
Lv
|
D
|
Daniellia oliveri (Rolfe) Hutch. & Dalziel
|
Fabaceae
|
Aonga
|
2.03
|
TB
|
D
|
2.86
|
TB
|
Ca
|
Feretia apodanthera Delile
|
Rubiaceae
|
Finninga
|
1.35
|
Rt; Lv
|
D; M
|
1.9
|
Rt; Lv
|
I
|
Ficus platyphylla Delile
|
Moraceae
|
Kamsongo
|
2.03
|
TB
|
D
|
0.95
|
Lv
|
D
|
Ficus sycomorus L.
|
Moraceae
|
Kankanga
|
0.68
|
TB
|
D
|
0.95
|
TB
|
D
|
Guiera senegalensis J.F.Gmel.
|
Combretaceae
|
Wilinwiiga
|
2.03
|
Lv
|
D; M
|
0.95
|
Lv
|
I
|
Khaya senegalensis (Desr.) A Juss.
|
Meliaceae
|
Kuka
|
4.73
|
TB
|
D; Po; M
|
2.86
|
TB
|
D; Po
|
Lagenaria siceraria (Molina) Standl.
|
Cucurbitaceae
|
Kândé
|
0.68
|
Fr
|
Ca
|
0.95
|
Lv
|
Ca
|
Lannea acida A. Rich.
|
Anacardiaceae
|
Sanbtoulga
|
0.68
|
TB; Lv
|
D
|
2.86
|
TB
|
M; Po; Ca
|
Lannea microcarpa Engl. & K. Krause
|
Anacardiaceae
|
Sâbga
|
0.68
|
TB
|
D
|
1.9
|
Lv; TB
|
M; D
|
Leptadenia hastata (Pers.) Decne.
|
Apocynaceae
|
Leulongo
|
0.68
|
Wp
|
D
|
1.9
|
Rt; Lv
|
Ca
|
Mitragyna inermis (Willd.) Kuntze
|
Rubiaceae
|
Yiilga
|
0.68
|
TB
|
Ca
|
0.95
|
Lv; TB
|
D; M
|
Moringa oleifera Lam.
|
Moringaceae
|
Arzentiiga
|
4.05
|
Lv; Fr
|
Po; D
|
0.95
|
Lv
|
Po
|
Parkia biglobosa (Jacq.) R.Br. ex G. Don
|
Fabaceae
|
Roanga
|
5.41
|
TB;Rt;Se
|
D; Po
|
0.95
|
Se
|
Po
|
Pennisetum glaucum (L.) R.Br.
|
Poaceae
|
Kazui
|
1.35
|
Se
|
M; Po
|
1.9
|
Rt; Se
|
Ca
|
Piliostigma reticulatum (DC.) Hochst.
|
Fabaceae
|
Baguen-Daaga
|
0.68
|
Lv
|
D
|
1.9
|
Fr
|
Ca; M
|
Saba senegalensis (A.DC.) Pichon
|
Apocynaceae
|
Wèdga
|
2.03
|
Rt; TB
|
D; M
|
0.95
|
Lv
|
D
|
Sclerocarya birrea (A. Rich.) Hochst.
|
Anacardiaceae
|
Noabga
|
6.08
|
TB; Lv
|
M; D
|
1.9
|
TB
|
M; D
|
Securidaca longipedunculata Fresen.
|
Polygalaceae
|
Pèlga
|
1.35
|
Rt
|
D
|
0.95
|
Rt
|
Ca
|
Sterculia setigera Delile
|
Malvaceae
|
Ponsonponrgo
|
0.68
|
Lv
|
Ca
|
0.95
|
TB
|
M
|
Tamarindus indica L.
|
Fabaceae
|
Pusga
|
4.05
|
Lv; Fr
|
M; Po; Ca; D
|
2.86
|
Lv; TB
|
M; D
|
Ximenia americana L.
|
Ximeniaceae
|
Lennga
|
2.03
|
Rt; Lv
|
D
|
0.95
|
Rt; TB
|
Po
|
Xylopia aethiopica (Dunal) A. Rich.
|
Annonaceae
|
Kiparin-Sablga
|
0.68
|
Fr
|
D
|
1.9
|
Fr
|
Po
|
Ziziphus mauritiana Lam.
|
Rhamnaceae
|
Mougouniga
|
1.35
|
Lv; TB
|
D
|
0.95
|
Rt
|
M
|
FC: Frequency of Citation; TB : Trunk bark; Lv : leaves; Rt : root; Fr : fruit; Se : seeds; Wp : whole plant; Tu : tuber; D : decoction; M : maceration; I : infusion; Po : powder; Ca : calcination
Traditional healers' perceptions of the availability of antidiabetic and antihypertensive species, causes of their extinction and putative solutions
Among the 36 species cited in the management of hypertension and diabetes, the THs surveyed commented on the availability of 32 species cited in the management of hypertension and diabetes. The other plants (4) namely Lagenaria siceraria, Pennisetum glaucum and Moringa oleifera that cultivated plants and Xylopia aethiopica (whose organs are sold) were not considered. According to the THs, 21 species or 65.62 % of the woody species cited are rare or endangered; two (6.25%) species (Cochlospermum tinctorium and Daniellia oliveri) have disappeared and 9 (28.12%) species namely Balanites aegyptiaca, Combretum glutinosum, Combretum micranthum, Guiera senegalensis, Khaya senegalensis, Lannea microcarpa, Leptadenia hastata, Piliostigma reticulatum and Sterculia setigera were supposed to be readily available or still quite frequent (Table III). The THs claimed that most of the rare species were formerly available even around homes, but nowadays the minimum access distance is at least five kilometers. Many causes were mentioned by the THs to explain the rarefaction or the disappearance of the species cited. Anarchic exploitation of plant organs, drought, bush fires and abusive wood cutting are the main causes. Indeed, 23.17% of the causes named are related to the exaggerated barking of trunks and the anarchic extraction of the plant roots. Drought, bush fires and abusive wood cutting were quoted with a proportion of 41.46%. According to 35.37% of the citations, the disappearance of species is linked to the combination of all the factors mentioned. However, THs were all unanimous in recognizing that the species they use require conservation. As solutions to these various factors mentioned above, the THs proposed:
(i) the actors training involved in the exploitation of plant resources on techniques for the plant harvesting organs and the production of seedlings,
(ii) the systems reinforcement for monitoring and repression of acts of non-compliance with the relevant regulations,
(iii) the strong authorities involvement in charge of environmental and health issues,
(iv) the need for each traditional healers to domesticate the species that he frequently uses and that are in danger of extinction.
Table III. Availability of species in the sub-sahelian area according to the traditional healers
Number
|
Available species
|
Rares species
|
Extinct species
|
1
|
Balanites aegyptiaca
|
Acacia sieberiana
|
Cochlospermum tinctorium
|
2
|
Combretum glutinosum
|
Anogeissus leiocarpa
|
Daniellia oliveri
|
3
|
Combretum micranthum
|
Boscia angustifolia
|
|
4
|
Guiera senegalensis
|
Boswellia dalzielii
|
|
5
|
Khaya senegalensis
|
Cadaba farinosa
|
|
6
|
Lannea microcarpa
|
Calotropis procera
|
|
7
|
Leptadenia hastata
|
Cassia italica
|
|
8
|
Piliostigma reticulatum
|
Cassia sieberiana
|
|
9
|
Sterculia setigera
|
Crescentia cujete
|
|
10
|
|
Feretia apodanthera
|
|
11
|
|
Ficus platyphylla
|
|
12
|
|
Ficus sycomorus
|
|
13
|
|
Lannea acida
|
|
14
|
|
Mitragyna inermis
|
|
15
|
|
Parkia biglobosa
|
|
16
|
|
Saba senegalensis
|
|
17
|
|
Sclerocarya birrea
|
|
18
|
|
Securidaca longipedunculata
|
|
19
|
|
Tamarindus indica
|
|
20
|
|
Ximenia americana
|
|
21
|
|
Ziziphus mauritiana
|
|
Relative vulnerability of antidiabetic and antihypertensive species
Among the 36 species identified with traditional healers, 28 woody species were considered for the vulnerability assessment. Out of the 28 woody species assessed, 25 woody species (89.28%) exhibit a vulnerability index IV ≥ 2 and can therefore be classified as vulnerable. Among them, seventeen species are moderately vulnerable (2 ≤ IV≤ 2.43) and eight others are very vulnerable (IV ≥ 2.5). In this later category fall Cadaba farinosa, Lannea acida, Parkia biglobosa, Saba senegalensis, Sclerocarya birrea, Tamarindus indica, Ximenia americana and Ziziphus mauritiana. Only three species such as Combretum micranthum, Combretum glutinosum and Guiera senegalensis are weakly vulnerable with IV<2 (Figure 3). As the main parameters indicating vulnerability, the mode of harvesting, the nature of the organs used and the relative frequency of occurrence are generally considered. Indeed, 82.14% of the species cited for both hypertension and diabetes management are subject to intensive debarking or anarchic and exaggerated root harvesting which could lead to species extinction. This is the case for the species Khaya senegalensis, Parkia biglobosa, Anogeissus leiocarpa; Securidaca longipedunculata, Cassia sieberiana and Ximenia americana. In addition, 78.57% of the species are rated as vulnerable due to the nature of the organs used (bark, roots, leafy stems...) and 82.14% of the species are vulnerable because to their relatively low frequency of occurence (RF <.1/3 MF).
Ecological importance and rarity of antidiabetic and antihypertensive species determined by floristic surveys
The floristic surveys identified 58 woody species belonging to 42 genera and 23 families. Among the species inventoried in the plots, 21 species (36.21%) were cited by the THs for the management of hypertension and diabetes. Combretum micranthum (IVI= 107.92), Cassia sieberiana (IVI = 64.4), Piliostigma reticulatum (IVI= 60.14), Combretum glutinosum (IVI= 58.22) and Balanites aegyptiaca (IVI=50.24) can be classified as species of high ecological importance species due to their relative frequency (IVI > 50). Acacia sieberiana (IVI = 2.25), Sterculia setigera (IVI = 3.07) and Mitragyna inermis (IVI = 3.60) are the species with lowest ecological importance. According to the Rarity Index (RI), 57.14% of the plants species used for treatment of hypertension and diabetes are rare (RI ≥ 80); 23.80% are moderately frequent (60 ≤ RI < 80) and 19.05% such as C. micranthum (RI=20), C. sieberiana (RI=52), P. reticulatum (RI=52), and C. glutinosum (RI=54) are very frequent (RI < 60). Notably, most of the highly vulnerable species, namely Lannea acida, Saba senegalensis, Ziziphus mauritiana, Parkia biglobosa and Tamarindus indica are rare in the sampled localities (RI ≥ 80) (Table IV).
Table IV. Importance value and rarity indices of antihypertensive and anti-diabetic species inventoried in the plots
Species
|
RDO
|
RF
|
RDE
|
IVI
|
RI
|
Acacia sieberiana DC.
|
0.19
|
2
|
0.05
|
2.25
|
98
|
Anogeissus leiocarpa (DC) Guill. et Perr.
|
4.03
|
26
|
4.05
|
34.09
|
74
|
Balanites aegyptiaca (L.) Delile
|
6.27
|
38
|
5.97
|
50.24
|
62
|
Boscia angustifolia A. Rich.
|
0.71
|
10
|
0.44
|
11.15
|
90
|
Cassia sieberiana DC
|
5.44
|
48
|
10.96
|
64.40
|
52
|
Combretum glutinosum Per. ex DC.
|
4.17
|
46
|
8.05
|
58.22
|
54
|
Combretum micranthum G. Don.
|
6.22
|
80
|
21.70
|
107.92
|
20
|
Feretia apodanthera Delile
|
0.03
|
8
|
0.22
|
8.25
|
92
|
Guiera senegalensis J.F. Gmel.
|
0.24
|
16
|
1.26
|
17.51
|
84
|
Khaya senegalensis (Desr) A. Juss
|
1.95
|
4
|
0.22
|
6.17
|
96
|
Lannea acida (L) A. Rich.
|
0.36
|
6
|
0.16
|
6.53
|
94
|
Lannea microcarpa Engl.et K. Krause
|
8.36
|
22
|
1.21
|
31.57
|
78
|
Mitragyna inermis (Willd) O. Krze
|
1.27
|
2
|
0.33
|
3.60
|
98
|
Parkia biglobosa (Jacq.) R. Br. ex G. Don.
|
14.79
|
12
|
0.49
|
27.28
|
88
|
Piliostigma reticulatum (DC) Hochst
|
3.26
|
48
|
8.88
|
60.14
|
52
|
Saba senegalensis A. (DC) Pichon
|
0.17
|
8
|
0.66
|
8.82
|
92
|
Sclerocarya birrea (A. Rich.) Hochst.
|
6.82
|
24
|
1.59
|
32.41
|
76
|
Sterculia setigera Delile
|
1.01
|
2
|
0.05
|
3.07
|
98
|
Tamarindus indica L.
|
6.58
|
16
|
0.60
|
23.18
|
84
|
Ximenia americana L.
|
1.06
|
26
|
3.12
|
30.18
|
74
|
Ziziphus mauritiana Lam.
|
0.11
|
10
|
0.38
|
10.50
|
90
|
RDO: relative dominance; RF: relative frequency; RDE : Relative density; IVI : ecological importance value index; RI : rarity index.