A total of 100 respondents within the age range of 21-40, 41-60 and > 60 years , both women and men, who use medicinal plants to manage diabetes, were interviewed. These Traditional Medicines were used for self-medication and/or to treat patients who willingly consult the healers. The informants were made up of herb sellers (68%), Traditional Medical Practitioners (30%) and the other category (2%) who practice or reside in the study area. There were more women (90%) than men (10%) . A good number of the informants were youngsters whose age fall within 21-40 (35%) while those of middle-aged groups of 41–60 having the highest occurrence of 50%. Only 15% of the informants were above 60 years. Most of the informants have little or no basic level of education with those having at least primary education making up 32%, secondary education 7% and tertiary education forming only 1%. Informants without a formal education make up 60% of total informants who participated in the interview. In addition, the work experience of the informants’ ranges from5 years and above with few of them born into the trade while others have gone through apprenticeship training in medicinal plant trade.
Bode and Oje communities , the study areas are dominated by aborigines of the old Ibadan city, which at Nigeria’s independence in 1960 was the largest city in Sub-Saharan Africa with an estimated population of 3.5 million [53]. The study areas are among the oldest known markets reputed to have existed over 100 years and they are centrally situated in the heart of the metropolitan city, Ibadan, Oyo state, Nigeria. They have played significant roles in provision of alternative medicine for rural dwellers within the region and they are well patronized. The surrounding forests with their rich plant biodiversity has encouraged and strengthen their dependence on plants for their primary healthcare needs including the herbal treatment of diabetes. Some of the antidiabetic medicinal plants mentioned by the informants included Allium sativum, Carica papaya, Abrus precatorius which have been reported by other authors in ethnobotanical surveys conducted in South-western and South-eastern parts of the country as commonly used to treat diabetes (Abo et al., 2008; Gbolade, 2009). Also, it has been reported in a survey conducted in South-western region that the following Allium ascolanicum, Alstonia boonei, Annona senegalensis, Citrullus colocynthis, Ocimum gratissimum, Curculigo pilosa, Garcinia kola, Gladiolus psittacinus, Nauclea latifloria among others, are used in treating diabetes [5]. Another survey conducted identified the following medicinal plants has having antidiabetic properties which are Carica papaya, Musa paradisiaca, Allium sativum, Allium cepa while Tetrapleura tetraptera, Nauclea latifolia, Vernonia amygdalina, Hibiscus sabdariffa, Allium sativum, exhibit antihypertensive properties [54]. This indicated conformity of the information provided by respondent in this study with what has been reported elsewhere for the treatment of diabetes.
Educational level of informant interviewed in this study was predominantly low suggesting that the improved or advanced methods of Traditional Medical Practices are still lacking. Education has been used as one of the many social and economic indicators to ascertain the state of development and the level of advancement of the informants in traditional medicine. It inspired higher ethnical behavior; refine taste, refine the method of plants preparation and dosage regimen, cultural awareness, patriotic devotion and social responsibility [55]. There is therefore an urgent need for the sensitization of these healers in order to improve their practices and to ensure patient’s health is safeguarded.
During the survey, the informants were interviewed in their native dialect for ease of communication and to ensure clarity in obtaining appropriate information; in addition, local names of the medicinal plants used in the management of diabetes were provided and subsequently authenticated. The use of local names is in agreement with what was reported by Singh that plants are generally recognized by their local names in every part of the world [56]. Although local names are not recommended directly for scientific accounts of plants as they lack uniformity and consistency [56], yet they may certainly be considered as a useful tool for obtaining useful information on plants, discovering new useful medicinal plants as well as new uses of known plants [57]. Local names provide means of reference by local people in a particular area.
Diversity of plants used for diabetes treatment
In Table 1, the description of documented ethnomedicinal have been presented. A total of 60 medicinal plants belonging to 57 genera, from 35 families have been documented for use in the traditional management of diabetes. The most cited family is Fabaceae ranked highest (23%) with 8 plant species, followed by Apocynaceae (17%) with 6 plant Species, Annonaceae (11%) with 4 plant species, Cucurbitaceae (11%) with 4 plant species and Liliaceae (8%) with 3 plant species. Hunteria umbellata, was the most cited plant species with the highest frequency (F - 56), use mention index (UMI - 0.56) and frequency of citation (FC – 23.53) reflecting its popularity and perhaps efficacy in the management of diabetes (Table 2). Euphorbia lateriflora, Floscopa Africana, Gongronema latifolium, Allium ascalonicum, Adenopus breviflorus, had the least frequency (F - 1), use mention index (UMI - 0.01) and frequency of citation (FC – 0.04) suggesting their least popularity of use by the informants for the traditional treatment of diabetes. The plant habits include trees having the highest frequency of50%, followed by shrub (26%), climbers and herbs make up 11% (Table 1). Informants equally reported specific organs of plants frequently used part for the management of diabetes. Of these, 25% were leaves, followed by fruits (22%), Bark (13%), Root (13%), Leaves/root (8%), Bulb (5%), Stem (4%), Seeds (3%), Stem (3%), Whole Plant (3%), Leaves/Stem bark (2%) (Figure 2). Leaves appear to be the plant part most commonly used plant organ during the management of diabetes in the traditional medicine of Bode and Oje communities of Oyo state, Nigeria. In addition, informants confirmed that different organs of the plants were sometimes combined to treat diabetes.
Modes of preparation and administration
. The mode of preparation preferred were decoction, juice extract, cold maceration, drying and pulverization into powder. Informants use different solvents to adequately extract the active portion from documented plants including water, carbonated drinks, local gin (ethanol), lime and aqueous extract from fermented maize. There was generally no standardized volume of administration but the herbal recipes were administered using glass cups or tumblers with approximately 150 mLs three times daily. Plant parts commonly used by informants include the leaves, fruits, bark and roots which are preferably used when fresh (Figure 2). The most reported mode of administration of documented herbal preparation is oral while the methods of preparation include decoction, infusion, soaking, drying and pulverization into fine powder
Table 1: Documented plants used in the management of diabetes in Bode and Oje communities of Ibadan, Nigeria.
|
S/N
|
Botanical name
|
Family
|
Vernacular name (Yoruba)
|
Common name
|
Plant part used
|
Habit
|
1
|
Abrus precatorius Linn.
|
Fabaceae
|
Oju-ologbo
|
Rosary pea, Crab’s eye
|
Leaves, root
|
Herb
|
2
|
Acacia nilotica (Linn.) Wild ex.
Del.
|
Fabaceae
|
Booni, banni
|
Gum Arabic tree
|
Leaves
|
Tree
|
3
|
Adenopus breviflorus
|
Cucurbitaceae
|
Tagiri
|
Pseudo colocynth
|
Fruit
|
Creeper
|
4
|
Allium ascalonicum
|
Liliaceae
|
Alubosa elewe
|
Shallot, leafed onion (spring onion)
|
Bulb
|
Herb
|
5
|
Allium sativum
|
Liliaceae
|
Alubosa aayu
|
Garlic
|
Bulb
|
Herb
|
6
|
Aloe vera (L.) Burm.f.
|
Asphodelaceae (Liliaceae)
|
Aloe
Ahonerin
|
Aloe vera
|
Whole plant
|
Herb
|
7
|
Alstonia boonei De.Wild
|
Apocynaceae
|
Awun
|
Stool wood
|
Bark
|
Tree
|
8
|
Annona senegalensis Pers.
|
Annonaceae
|
Epo
|
Wild custard apple
|
Leaves, stem bark
|
Shrub
|
9
|
Anthocleista djalonensis A. Chew.
|
Loganiaceae
|
Sapo
|
Cabbage tree
|
Bark
|
Tree
|
10
|
Aristolochia ringens Vahl
|
Aristolochiaceae
|
Akogun
|
Dutchman’s pipe
|
Root, bark
|
Creeper
|
11
|
Bombax buonopozense P. Beauv
|
Bombacaceaea
|
Ponpola
|
Silk cotton tree
|
Leaves
|
Tree
|
12
|
Bucholzia coriacea Engl.
|
Capparaceae
|
Wonderful kola
|
Musk tree
|
Fruits
|
Shrub
|
13
|
Calliandra haematocephala
Linn.
|
Fabaceae
|
Tude
|
Snowflake acacia
|
Leaf, Root
|
Shrub
|
14
|
Carica papaya
|
Cariacaceae
|
Ibepe
|
Pawpaw
|
Fruit
|
Tree
|
15
|
Cassia fistula Linn.
|
Fabaceae
|
Aidan-toro
|
Golden shower
|
Leaves
|
Tree
|
16
|
Citrullus colocynthis
|
Cucurbitaceae
|
Baara
|
Water melon
|
Fruit
|
Creeper
|
17
|
Citrus aurantifolia (Christm.)
Swingle.
|
Rutaceae
|
Osan wewe
|
Lime
|
Fruits, juice
|
Tree
|
18
|
Clausena anisate
|
Rutaceae
|
Atari-obuko (egboagbasa)
|
Clausena
|
Roots,bark
|
Tree
|
19
|
Cocos nucifera
|
Arecaceae
|
Agbon
|
Coconut
|
Coconut water
|
Tree
|
20
|
Cucumeropsis mannii Naudin
|
Cucurbitaceae
|
OdidiItoo/ Egusi-itoo
|
White-seed melon
|
Fruits , seeds
|
Climber
|
21
|
Curculigo pilosa (Schum&
Thonn) Engl.
|
Hypoxidaceae
|
Epakun
|
Golden eye grass
|
Fruits, root
|
Tree
|
22
|
Euphorbia lateriflora Schum. & Thonn.
|
Euphorbiaceae
|
Enu opiri
|
Little cactus
|
Stem
|
Shrub
|
23
|
Ficus exasperata Vahl.
|
Moraceae
|
Ipin
|
Sound paper leaf
|
Leaves
|
Tree
|
24
|
Floscopa Africana (P.Beauv.)
|
Commelinaceae
|
Igba opolo
|
Lizard’s tail
|
Leaves
|
Herb
|
25
|
Garcinia kola
Heckel
|
Guttiferae (hypericaceae)
|
Orogbo
|
Bitter kola
|
Fruit
|
Tree
|
26
|
Gladiolus dalenii Van. Geel.
|
Iridaceae
|
Baka
|
Dragon’s –head lily
|
Bulb
|
Shrub
|
27
|
Gongronema latifolium Benth et Hook.
|
Asclepiadaceae
|
Madunmaro (arokeke)
|
Bush buck
|
Leaves
|
Shrub
|
28
|
Gossypium barbadense
|
Malvaceae
|
Owu akese
|
West Indian cotton leaves
|
Leaves
|
Tree
|
29
|
Hibiscus sabdariffa
|
Malvaceae
|
Isapa funfun
|
Bush rosette
|
Fruit
|
Herb
|
30
|
Hunteria umbellata (K. Schum)
Haller. F.
|
Apocynaceae
|
Abeere
|
Aarin
|
Fruit, seeds,
|
Tree
|
31
|
Hyptis pectinata (L.) Poit.
|
Lamiaceae
|
Jobgo
|
Bushmints
|
Leaves
|
Shrub
|
32
|
Irvinga gabonensis (Aubry-Lecomte ex O’Rorke) Baill.
|
Irvingiaceae
|
Epon (epo)
|
Bush Mango/ African mango
|
Seeds
|
Tree
|
33
|
Khaya ivorensis A. Chev.
|
Meliaceae
|
Oganwo
|
African mahogamy
|
Bark
|
Tree
|
34
|
Kigelia Africana (lam.) Benth.
|
Bignoniaceae
|
Pandoro/Amuyan
|
African Sausage tree
|
Fruits
|
Tree
|
35
|
Markhamia tomentosa (Benth.) H. Schum.
|
Bignoniaceae
|
Oruru
|
Bell bean tree
|
Bark
|
Tree
|
36
|
Mondia whitei (Hook.f.)
|
Apocynaceae
|
Isigun
|
White’s ginger
|
Root, root bark
|
Creeper
|
37
|
Morinda lucida Benth
|
Rubiaceae
|
Oruwo
|
Brimstone tree
|
Leaves
|
Tree
|
38
|
Moringa oleifera Lam.
|
Moringaceae
|
Ewe igbale
|
Moringa, miracle tree
|
Whole plant
|
Tree
|
39
|
Mormodica charantia Descourt.
|
Cucurbitaceae
|
Ejinrin
|
Africa cucumber
|
Leaves
|
Creeper
|
40
|
Musa paradisiaca
|
Musaceae
|
Ogede agbaagba
(dudu)
|
Plantain
|
Stems
|
Tree
|
41
|
Nauclea latifolia
|
Rubiaceae
|
Egbesin
|
Nauclea
|
Leaves, root
|
Tree
|
42
|
Ocimum gratissimum
|
Lamiaceae
|
Efinrin
|
Sweet basil
|
Leaf
|
Herb
|
43
|
Olax subscorpiodea Oliv.
|
Olacaceae
|
Ifon
|
Ifon
|
Leaves, root
|
Tree
|
44
|
Oxytenanthera abyssinica (A.Rich.) Munro
|
Poaceae
|
Paran pupa, funfun
|
Savannah Bamboo
|
Leaves
|
Herb
|
45
|
Parkia biglobosa Jacq
|
Fabaceae
|
Igba
|
African Locust Bean
|
Seeds, leaves
|
Tree
|
46
|
Parquetina nigrescens (Afzel)
Bullock.
|
Periplocaceae
|
Ogbo
|
African parquetina
|
Leaves
|
Creeper
|
47
|
Picralima nitida
|
Apocynaceae
|
Erin
|
Picralima
|
Bark
|
Tree
|
48
|
Psidium guajava
|
Myrtaceae
|
Guava
|
Guava
|
Fruits, Leaves
|
Tree
|
49
|
Rauwolfia vomitoria Afzel.
|
Apocynaceae
|
Asofeyeje
|
African rauwolfia
|
Stem bark,
Leaves
|
Shrub
|
50
|
Securidaca longepedunculata
|
Polygalaceae
|
Ipeta
|
Violet tree
|
Root, bark, Stem
|
Tree
|
51
|
Senna alata
|
Fabaceae
|
Asunwon oyinbo
|
Candle bush
|
Leaf
|
Shrub
|
52
|
Senna podocarpa Guil. &Perr.
|
Fabaceae
|
Asunwon ibile
|
Candle bush
|
Leaves
|
Shrub
|
53
|
Sphenocentrum jollyanum Pierre
|
Menispermaceae
|
Akerejupon
|
Sphenocentrum
|
Leaves, root,
Seed
|
Tree
|
54
|
Strophanthus hispidus D.C
|
Apocynaceae
|
Sagbere, sagere
|
Arrow poison plant
|
Root
|
Shrub
|
55
|
Tetrapleura tetraptera (Schun&Thonn) Taub.
|
Fabaceae
|
Arindan, aidan
|
Aidan tree
|
Roots
|
Tree
|
56
|
Uvaria afzelii Sc. Elliot
|
Annonaceae
|
Gbogbonise
|
Monkey finger
|
Leaves, root
|
Shrub
|
57
|
Uvaria chamae P. Beauv
|
Annonaceae
|
Eruju
|
Finger root
|
Root
|
Shrub
|
58
|
Vernonia amygdalina
|
Asteraceae
|
Ewuro
|
Bitter leaf
|
Leaf
|
Shrub
|
59
|
Xylopia aethiopica (Dunal) A.
Rich
|
Annonaceae
|
Eeru-lamo (Erualamo)
|
African pepper
|
Fruit
|
Tree
|
60
|
Zea mays
|
Poaceae
|
Omi dun (omi ogi)
|
Maize
|
Juice
|
Shrub
|
Table 2: Quantitative analysis of antidiabetic plants used in Bode and Oje communities of Ibadan city, Nigeria
S/N
|
Botanical name
|
Mode of preparation
|
Frequency
|
Use mention index (UMI)
|
Frequency of Citation (FC)
|
1
|
Abrus precatorius Linn.
|
Infusion
Decoction
|
1
|
0.01
|
0.42
|
2
|
Acacia nilotica (Linn.) Wild ex.
Del.
|
Powder
|
2
|
0.02
|
0.84
|
3
|
Adenopus breviflorus
|
Powder
Infusion
|
1
|
0.01
|
0.42
|
4
|
Allium ascalonicum
|
Powder
|
1
|
0.01
|
0.42
|
5
|
Allium sativum
|
Powder
|
1
|
0.01
|
0.42
|
6
|
Aloe vera (L.) Burm.f.
|
Maceration
|
1
|
0.01
|
0.42
|
7
|
Alstonia boonei De.Wild
|
Decoction
Infusion
|
1
|
0.01
|
0.42
|
8
|
Annona senegalensis Pers.
|
Infusion
|
1
|
0.01
|
0.42
|
9
|
Anthocleista djalonensis A. Chew.
|
Decoction
Infusion
Maceration
|
4
|
0.04
|
1.68
|
10
|
Aristolochia ringens Vahl
|
Powder
Decoction
Maceration
Infusion
|
22
|
0.22
|
9.24
|
11
|
Bombax buonopozense P. Beauv
|
Decoction
|
1
|
0.01
|
0.42
|
12
|
Bucholzia coriacea Engl.
|
Maceration
|
1
|
0.01
|
0.42
|
13
|
Calliandra haematocephala
Linn.
|
Decoction
|
4
|
0.04
|
1.68
|
14
|
Carica papaya
|
Maceration
|
1
|
0.01
|
0.42
|
15
|
Cassia fistula Linn.
|
Decoction
|
1
|
0.01
|
0.42
|
16
|
Citrullus colocynthis
|
Decoction
Infusion
|
10
|
0.10
|
4.20
|
17
|
Citrus aurantifolia (Christm.)
Swingle.
|
Juice extract
|
9
|
0.09
|
3.78
|
18
|
Clausena anisate
|
Decoction
|
1
|
0.01
|
0.42
|
19
|
Cocos nucifera
|
Juice extract
|
33
|
0.33
|
13.87
|
20
|
Cucumeropsis mannii Naudin
|
Juice extract
|
1
|
0.01
|
0.42
|
21
|
Curculigo pilosa (Schum&
Thonn) Engl.
|
Powder
Decoction
|
8
|
0.08
|
3.36
|
22
|
Euphorbia lateriflora Schum. & Thonn.
|
Maceration
|
1
|
0.01
|
0.42
|
23
|
Ficus exasperate Vahl.
|
Juice extract
|
3
|
0.03
|
1.26
|
24
|
Floscopa Africana (P.Beauv.)
|
Juice extract
|
1
|
0.01
|
0.42
|
25
|
Garcinia kola
Heckel
|
Powder
|
2
|
0.02
|
0.84
|
26
|
Gladiolus dalenii Van. Geel.
|
Powder
Maceration
|
8
|
0.08
|
3.36
|
27
|
Gongronema latifolium Benth et Hook.
|
Decoction
|
1
|
0.01
|
0.42
|
28
|
Gossypium barbadense
|
Juice extract
|
1
|
0.01
|
0.42
|
29
|
Hibiscus sabdariffa
|
Powder
|
1
|
0.01
|
0.42
|
30
|
Hunteria umbellata (K. Schum)
Haller. F.
|
Powder
Decoction
Maceration
|
56
|
0.56
|
23.53
|
31
|
Hyptis pectinata (L.) Poit.
|
Juice extract
|
1
|
0.01
|
0.42
|
32
|
Irvinga gabonensis (Aubry-Lecomte ex O’Rorke) Baill.
|
Powder
|
1
|
0.01
|
0.42
|
33
|
Khaya ivorensis A. Chev.
|
Decoction
|
1
|
0.01
|
0.42
|
34
|
Kigelia Africana (lam.) Benth.
|
Powder
|
1
|
0.01
|
0.42
|
35
|
Markhamia tomentosa (Benth.) H. Schum.
|
Decoction
|
1
|
0.01
|
0.42
|
36
|
Mondia whitei (Hook.f.)
|
Decoction
Maceration
|
1
|
0.01
|
0.42
|
37
|
Morinda lucida Benth
|
Juice extract
|
3
|
0.03
|
1.26
|
38
|
Moringa oleifera Lam.
|
Juice extract
Infusion
Decoction
|
2
|
0.02
|
0.84
|
39
|
Mormodica charantia Descourt.
|
Juice extract
|
5
|
0.05
|
2.10
|
40
|
Musa paradisiaca
|
Powder
|
1
|
0.01
|
0.42
|
41
|
Nauclea latifolia
|
Decoction
Infusion
Juice extract
|
1
|
0.01
|
0.42
|
42
|
Ocimum gratissimum
|
Juice extract
|
2
|
0.02
|
0.84
|
43
|
Olax subscorpiodea Oliv.
|
Decoction
|
3
|
0.03
|
1.26
|
44
|
Oxytenanthera abyssinica (A.Rich.) Munro
|
Juice extract
Infusion
|
1
|
0.01
|
0.42
|
45
|
Parkia biglobosa Jacq
|
Powder
|
1
|
0.01
|
0.42
|
46
|
Parquetina nigrescens (Afzel)
Bullock.
|
Juice extraction
Infusion
|
1
|
0.01
|
0.42
|
47
|
Picralima nitida
|
Powder
|
1
|
0.01
|
0.42
|
48
|
Psidium guajava
|
Infusion
|
1
|
0.01
|
0.42
|
49
|
Rauwolfia vomitoria Afzel.
|
Powder (pulverization)
|
2
|
0.02
|
0.84
|
50
|
Securidaca longepedunculata
|
Decoction
Infusion
|
1
|
0.01
|
0.42
|
51
|
Senna alata
|
Decoction
|
2
|
0.02
|
0.84
|
52
|
Senna podocarpa Guil. &Perr.
|
Decoction
Maceration
|
2
|
0.02
|
0.84
|
53
|
Sphenocentrum jollyanum Pierre
|
Powder
|
4
|
0.04
|
1.68
|
54
|
Strophanthus hispidus D.C
|
Decoction
Maceration
|
2
|
0.02
|
0.84
|
55
|
Tetrapleura tetraptera (Schun&Thonn) Taub.
|
Decoction
|
1
|
0.01
|
0.42
|
56
|
Uvaria afzelii Sc. Elliot
|
Decoction
|
4
|
0.04
|
1.68
|
57
|
Uvaria chamae P. Beauv
|
Decoction
|
1
|
0.01
|
0.42
|
58
|
Vernonia amygdalina
|
Juice extract
Maceration
Decoction
|
10
|
0.1
|
4.20
|
59
|
Xylopia aethiopica (Dunal) A.
Rich
|
Maceration
|
1
|
0.01
|
0.42
|
60
|
Zea mays
|
Juice extract
|
1
|
0.01
|
0.42
|
Literature analysis of all the 60 antidiabetic medicinal plants reported in this study revealed that large number of these plants have been reported in other climes to have significant antidiabetic activity during various laboratory experiments among which are plants like Parkia biglobosa , Vernonia amygdalina [58-61], Moringa oleifera [62], Allium cepa and Allium sativum [63-65, Picralima nitida, Ocimum gratissimum [66-68], Aloe vera, Anthocleista djalonensis [69] and Carica papaya [70-72].
The antidiabetic activity of Nauclea latifloria and Moringa oleifera have been validated scientifically [73-76]. There have been experimental evidences for the hypoglycemic activity of these medicinal plants, in experimental model of diabetes [58].
Quantitative analysis of survey data showed that the Fabaceae and Apocynaceae families have the highest Frequency of citation and Use mention indices which reflects the antidiabetic medicinal value of the 14-plant species mentioned under these two high scoring plant families. Their application in the traditional medicine of the study areas may be related to their availability, accessibility, their edibility and low carbohydrate content. For instance, legumes, a sub-family of Fabaceae are largely known to be very edible, high in protein, low in carbohydrate and interestingly have a low glycemic index [77]. In Nigeria, legumes are well domesticated and are cultivated both for food and as source of effective antidiabetic medicinal plants.