Ethnobotanical study on medicinal plants in Melit area (North Darfur), Western Sudan

Data collection and plant identification

Ethnobotanical data were collected from November 2021 to July 2022 based on semi-structured interviews. A total of 135 informants between the ages of 18 and 85 were interviewed independently to avoid others influence. The questionnaire was designed to collect data on (1) local names of the plants, (2) ailments treated by the plant, (3) plant parts used, (4) condition of the plant material (dried or fresh) and (5) modes of preparation and administration. Some social factors like the name, age and education level of the interviewed person were also recorded.

Collection and identification of the plants

Fresh plant specimens were collected using the normal plant collection procedure. Plants were identified by using keys of written floras such as Elamin [7] and Andrews [9–11]. Plants’ names were updated according to www.worldfloraonline.org. Voucher specimens were deposited at the Herbarium of Department of Botany, University of Khartoum.

Quantitative ethnobotanical data analysis

Data were subjected to ethnobotanical analysis tools including;

Informant consensus factor

To test homogeneity of knowledge, the informant consensus factor (ICF) was calculated [14]:

where N_ur refers to the number of use-reports for a particular use category and N_t refers to the number of taxa used for a particular use category by all informants. ICF values are low (near 0) if plants are chosen randomly or if there is no exchange of information about their use among informants and approach one (1) when there is a well-defined selection criterion in the community and/or if information is exchanged between informants [15].

The plants and their medicinal application

A total of 59 medicinal plants, belonging to 32 families and 55 genera, were recorded for their traditional uses in Melit area (Table 2). Fabaceae (Leguminosae) were represented by highest number of species (13) followed by Asteraceae and Malvaceae (4 each) and Poaceae (3). Apocynaceae, Boraginaceae, Capparaceae, Cucurbitaceae, Myrtaceae, Solanaceae and Zygophyllaceae were presented by 2 species each, while Acanthaceae, Alliaceae, Apiaceae, Arecaceae, Aristolochiaceae, Asphodelaceae, Brassicaceae, Burseraceae, Caricaceae, Combretaceae, Lamiaceae, Lythraceae, Meliaceae, Molluginaceae, Moraceae, Olacaceae, Orobanchaceae, Pedaliaceae, Ranunculaceae, Rhamnaceae and Rubiaceae by one species each.

Forty-five medicinal uses were recorded. The most frequently claimed medicinal uses were for the digestive system (16 plants, 7 uses), skin diseases (14 plants, 6 uses), while urinary (4 uses), respiratory systems (6 uses) and parasite infections (6 uses) were treated by 9 plants each. Poisonous animal bites (3 uses) were treated by 7 plants. Gynaecological diseases (6 uses) and muscolo-skeletical (1 use) diseases were treated by 6 plants each. Five plants each to treat blood system disorders (2 uses), pain (headache and teeth ache) and diabetes, while only one plant was reported for swellings.

Habitat of the plants

In terms of life form, analysis of data showed that herbs accounted for the highest proportion (30, 50.8%) followed by trees (21, 35.6%) and shrubs (8, 13.6%), respectively.

Parts of medicinal plants used

Analysis showed that informants use various parts of medicinal plants. Stem bark and fruits contributes about (12, 17.9% each), followed by whole plant and roots (11, 16.4% each), seeds (9, 13.4%), leaves (8, 11.9%), flowers (bud/calyx) and gum (2, 3% each), respectively.

Mode of preparation and path of administration

The informants prepared their remedies in various forms including decoction (31, 36.5%), poultice (16, 18.8%), maceration (13, 15.3%), infusion (11, 12.9%), or applied as smoke (5, 5.8%) powder (6, 8.2%) or taken as raw (3, 3.5%) from dried and subsequently collected plant parts (Fig. 2). 55.3% of preparations were orally administrated, while 44.7% were externally applied.

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Fig. 2

Mode of preparation of herbal drugs

Ethnobotanical diversity

Ethnobotanical survey in the local community of Melit in north Darfur State (Western Sudan) reported about 59 medicinal plants with 45 medicinal uses recorded from 135 informants. The plants belong to 32 families, and the family Fabaceae is represented by the highest number of species (13) in accordance with previous ethnobotanical studies in other regions of Sudan [17–23]. Herbaceous were the most used plants, and this could be due to their high abundance and easy collection. In fact, it was reported that herbaceous species accounted for 60% of native flora of Sudan, while woody species forming about 30% [5]. Herbs are mainly used in dried form as they are seasonally distributed. The majority of preparations were based from a single plant to cure many diseases suggesting the presences of several bioactive agents that can be effective against several disorder conditions. For example, Citrullus colocynthis is used to treat rheumatic pain, malaria, gonorrhoea and scorpion sting. Nigella sativa for corona virus, diabetes, head ache and prostate and Solanum forskalii for head diseases, malaria and snake bite. Also, in some cases a mixture of more than one plant is used to treat specific disease like malaria is treated with a combination of seeds of Solanum forskalii and Citrullus colocynthis. Healers in different African countries believe that the body requires treatment with several different plants to produces a healing effect either through complementary benefits or through synergistic effect [19]. In addition, magic and spirituality are well rooted in the Sudanese society and are often used in a mixed way in traditional medicine. The society here believes in evil eye, curse, satan strike and devil interference in people’s lives. Mental disorders and psychological problems are often attributed to act of genie or a curse. One of the methods they use for expelling evil spirit and genie is a blend of gum and dried plants burned in an incense burner made of clay from which smoke will rise and the patient is then exposed to that smoke. For bringing luck or attracting love, healers consider the skin route and therefore prescribe other special herbs worn around the arm. In this study, three plants, namely; Cassia arereh, Ocimum basilicum, and Ziziphus spina-christi, are used for the treatment of evil eye, while Solanum forskalii is used to bring chance. Stem bark and fruits followed by whole plant and roots were the most used parts for herbal preparations in agreement with ethnobotanical studies from Kordofan States (Western Sudan) [21, 23], Blue Nile State (South Eastern Sudan) [19] and contrary to results from other regions in Sudan where leaves were usually the favoured part [20, 22]. In most instances the same plant’s part being used for different purposes. Decoction is the most mode of preparation used and informants believed that heat better release bioactive components of the plants in water and also to avoid microbial attack. Healers are also aware of the correlation of the dose given to the age, physical and health conditions of patients. Also, some rituals that believed to have beneficial effect are also performed. Oral preparation is the main administration rout in most herbal remedies and additives like milk or honey or oil are frequently used to improve the acceptability of certain oral remedies in line with previous reports [17–23].

Comparative review of traditional usages of reported species with previous studies from Sudan

Comparison with all previous ethnobotany studies carried in Sudan as well as those reported in the Atlas for Medicinal Plants of the Sudan was done and summarized [17–23, 25–29] (Table 4). It was noted that many plant species identified in the present study were also reported with the same uses in other regions of the Sudan suggesting their reliable curative effects and also reflecting high cultural exchange between local communities in different regions of the Sudan [30]. Also, there are some species with different uses, like for example Leptadenia arborea is used to treat kidney stones in the present study, while in other regions of Sudan it is used against acid reflux, diarrhoea, swellings, dandrof and jaundice [18, 19, 21, 23, 27, 28]. Also, Aloe sinkatana is used to cure tonsillitis, while in other regions of Sudan it is used to treat wounds and headache [22, 25]. Eucalyptus globules, Hyphaene thebaica and Vangueria madagascariensis are used to treat hypertension in the present study, while in other regions of Sudan they are used to treat other diseases like diabetes, diarrhoea, kidney stones and wound [19, 21, 23, 25–29]. Ten plants, namely Carica papaya, Corchorus trilocularis, Eragrostis cilianensis, Heliotropium sudanicum, Mollugo cerviana, Psiadia punctulate, Rhynchosia minima, Solanum coagulans, Solanum forskalii and Tephrosia purpurea, were cited for the first time as medicinal plants used in Sudan traditional medicine. However, their ethnobotanical uses in other cultures around the world as well as their studied biological activities and phytoconstituents are summarized in Table 5. It was noted that no ethnobotanical uses and scientific studies were reported for Eragrostis cilianensis, Heliotropium sudanicum and Solanum forskalii, and thus, they are worth further studying over their phytochemical and biological properties. For other species, most of them have different traditional uses from those reported in the present study except for Carica papaya and Tephrosia purpurea. The former is also used in many countries like Nigeria, Philippines and India to treat rheumatism and skin disorders (Table 5). Tephrosia purpurea, which is also used in India to heal wounds, was found to possess wound healing potential by enhancing the fibroblast cells, collagen fibres and blood vessels formation [31]. Furthermore, a study on Psiadia punctulate, which is used to treat swellings in the current study, showed that the sesquiterpene 1β-hydroxy-8-oxo-cyperone (isolated from this plant) has significant antiproliferative activity towards Jurkat and HeLa (IC₅₀ = 12 and 18 µM, respectively) cells [32]. Mollugo cerviana, which is used to treat some skin disorders, was shown to possess potent anti-inflammatory property in the in vitro acute inflammation model of LPS-stimulated RAW 264.7 cells [33].

Frequent diseases and cited medicinal plants

Medicinal uses are distributed into 12 categories of ailments, and analysis revealed that the digestive system (16 plants, 7 uses), skin diseases (14 plants, 7 uses), urinary and respiratory systems (9 plants each, 5 uses), respectively, were the most frequently claimed medicinal uses, suggesting that these diseases were more likely the prevalent disease in the area. Moreover, the majority of ailment categories has ICF ≥ 0.71 indicating high degree of consensus between informants [34]. UV ranged between 0.10 and 2.37 (Table 1). Medicinal plants with high UV have usually more use-reports and high availability and importance [35]. On the other hand, attention should be considered for plants with low UV as their less use might increase the risk of disappearing of their curative knowledge. Blepharis linariifolia, Geigeria alata. Senna alexandrina, Psiadia punctulate, Mollugo cerviana, Balanites aegyptiaca and Vachellia nilotica were the most preferred species as they have high FL. In fact, these species except Mollugo cerviana and Psiadia punctulate are reported to have the same traditional uses in other regions of the Sudan [30]. Additionally, there are many scientific evidences supporting their traditional uses. For example, Geigeria alata that is used to treat diabetes has been proven to significantly reduced the serum glucose level in diabetic rats and to possess α-glucosidase inhibitory and pancreatic lipase inhibitory activities [36]. Balanites aegyptiaca that is used to treat rheumatic pain, jaundice, diarrhoea and dysentery is found to exert antioxidant, anti-inflammatory, anticancer, antinociceptive, hepatoprotective, hypocholesterolemic, diuretic, antibacterial, antiviral and anthelmintic activities [37]. Senna alexandrina is well known for its laxative effect since ancient time. Moreover, during the pandemic of COVID-19 which caused the death of hundreds of people in Sudan, informants used a number of plants. For example, they used Boswellia papyrifera resins, seeds of Nigella sativa and pods Vachellia nilotica (syn. Acacia nilotica) to make different preparations for the treatment of the virus. Another recipe is a mixture of clove (Syzygium aromticum) decoction and honey with lemon and lemon peel.

We would like to thank all the traditional healers and local people of the study area for sharing their knowledge, cooperation and hospitality.