Ethnobotanical investigation on medicinal plants in Algoz area (South Kordofan), Sudan

Algoz area is situated in the northern part of South Kordofan state, and its borders are Northern Kordofan state from the north and northeast, West Kordofan state from the northwest, Dellang locality from the south and Habella locality from the southeast direction (Fig. 1). It is located between latitudes 12°–12° 30 N and longitudes 29° 48–300 E and 622 m above sea level, with a total area of 35,000 km². Short grass and short scattered trees prevail. The area is associated with exposed rocks crossing the central Sudan forming a surface water divide. The White Nile which is the main tributary of the River Nile bounds the hydrologic system to the east, while the highlands of Kordofan Plateau and the Nuba Mountains bound it to the west and the south respectively. Khor Abu Habil is a major seasonal wadi that crosses the study area and flows from the west to the east. The wadi disappears into the sand dunes a few kilometers before reaching the White Nile. The climate in the area is semi-arid with long hot summers (March–September) and short mild winters (December–February). Seasonal rainfall occurs only during summer (June–September) and varies between 200 mm/year in the north and 450 mm/year in the south [5].

Algoz area has a multi-population with tribes as Dar Shungool, Gaboosh, Dar Bati, Albargo, Albarno, Flata and some Arabic nomads. They are working mainly in agriculture, animal grazing and trade [6].

Ethnobotanical data were collected from March to November 2015. Information about the medicinal use of plants was collected by carrying out semi-structured interviews with 30 healers (24 male and 6 female) living in the investigated area. The questionnaire was designed to collect data on (i) local names of the plants, (ii) ailments treated by the plant, (iii) plant parts used, (iv) condition of the plant material (dried or fresh) and (v) modes of preparation and administration. Some social factors like the name, age, occupation and education level of the interviewed person were also recorded. Also, the geographic locality and date of the interview were recorded. Plant specimens were collected for taxonomic identification using keys of written floras such as Broun and Massey [7], Andrews [8‐11], Ross [12], Hutchinson and Dalziel [13], Maydell [14] and Elamin [15]. Voucher specimens were deposited at the Herbarium of Institute of Medicinal and Aromatic Plants, National Centre for Research, Sudan (MAPTMR-H). The botanical names and plant families are given according to the standards of the plant list (www.​ipni.​org/​).

Data analysis was carried out by using both the classical ethnobotanical systematic investigation and a numerical quantitative approach in order to evaluate the importance of the mentioned plant species in the investigated area. The quantitative study was carried out by calculating the following ethnobotanical indices:

A total of 94 medicinal plants, which belong to 45 families and 81 genera, were recorded in the study area. Results provide the following information for each species: scientific name, botanical family, local common name, plant habitat, plant part used, disease treated, route of administration and use value (Table 1). The most represented families are Leguminosae with 20 species followed by Combretaceae (6 species), Rubiaceae (5 species), Asteraceae (4 species), Lamiaceae, Poaceae, Tiliaceae and Zygophyllaceae (3 species each), Apocynaceae, Asclepiadaceae, Brassicaceae, Burseraceae, Cleomaceae, Capparaceae, Malvaceae and Meliaceae (2 species each), and other families were represented with one species each. This dominance of Leguminosae plants is a characteristic of the Sudan flora. The most commonly used species is Sarcocephalus latifolius with a UV of 2.07 followed by Guiera senegalensis with a UV of 1.87, Hydnora abyssinica with a UV of 1.83 and Geigeria alata with a UV of 1.67 respectively. Plants that treat three ailments and more (86%) represent the majority, followed by plants that treat single ailments (8%) and those that treat two ailments (6%) respectively.

Analysis of data based on their habitat showed that the reported species belong to herbs (43%), trees (28%), shrubs (22%), climbers (4%) and parasites (3%) (Fig. 2). The majority of medicinal plants are collected from the wild, and only 11% are cultivated or purchased (0.01%) from the market (Table 1).

Data on different plant parts used in traditional medicine are indicated in Fig. 3. Those that are used the most were the root and stem (21% each) followed by the fruit (15%), whole plant (14%), seed (12%), leaf (11%), gum/latex, bulb/corm and heartwood (0.02%) and flower (0.01%) respectively. There are cases where different parts of the same plant are being used for the treatment of different diseases.

A majority of remedies are administered orally (67%) where infusion (36%) and maceration (32%) are the most used methods. Some prescriptions can be prepared by both methods: infusion or maceration represented 13%, while decoction represented 11% of preparations. Dried powder or freshly collected plant parts are also used. Other prescriptions are used externally (33%) and applied as dry powder (29%), rub (23%), smoke (23%), poultices (20%) or as a wash (6%) (Table 2). Most of these preparations use water as a solvent extractor. Some herbalists used other adjuvants like honey, sugar, salt, milk, sour milk, yoghurt, ajeen (fermented dough), nisha (light porridge), atroon (sodium bicarbonate), bee wax, wax of goat and olive and sesame oil.

For the treatment of particular ailment, sometimes herbalists used more than one plant. For example, Allium sativum bulb is mixed with Zingiber officinale rhizome and applied to the anus for the treatment of haemorrhoids. A potion is prepared from the seed of Trigonella foenum-graecum, curcuma, Negilla sativa and bee honey for the treatment of uterus inflammation. Root of Tinospora bakis is mixed with Syzygium aromaticum (clove) for the treatment of malaria. Atroon is added to some preparations like those of Ziziphus spina-christi and Acacia oerfota for the treatment of dysentery and toothache respectively.

A comparative review with previous reports [3, 21‐23, 30‐33] from different parts of Sudan was performed to identify the new medicinal plants and new uses reported in this study (Table 4). The plants reported by Suleiman [21] for traditional plants used by communities of Northern Kordofan region included a total of 44 plant species with 22 species with same traditional uses which were reported also in this study, while 2 species, Blepharis linariifolia and Catunaregam nilotica (Xeromphis nilotica, Randia nilotica), were reported with different uses. EL-Kamali [3] reported 48 plant species for traditional plant uses in North Kordofan too with 15 species with same traditional uses which were reported also in this study and 5 species, Acacia nilotica subsp. adstringens, Aristolochia bracteolate, Cissus quadrangularis, Dichrostachys cinerea and Sarcocephalus latifolius (Nauclea latifolia), with different uses. Doka and Yagi [23] reported 49 plant species for traditional plant uses in West Kordofan with 16 species with same traditional uses which were reported also in this study, and 9 species were reported in this study with different uses; these included Acacia senegal, Acacia seyal, Arachis hypogaea, Balanites aegyptiaca, Cissus quadrangularis, Combretum aculeatum, Grewia flavescens, Tamarindus indica and Catunaregam nilotica. Musa et al. [22] reported 53 plant species for traditional plant uses in the Blue Nile State, southeastern Sudan, with 18 species with same traditional uses which were reported in this study and 13 species with different uses: Acacia senegal, Acacia seyal, Anogeissus leiocarpus, Carissa spinarum (C. edulis), Cissus quadrangularis, Grewia villosa, Lannea fruticose, Piliostigma reticulatum, Senna occidentalis, Strychnos spinose, Tephrosia uniflora, Terminalia laxiflora and Ximenia americana. Moreover, El Ghazali et al. [30‐33] in their books of Sudanese medicinal plants documented some of these plants for the same or very similar usages. In fact, there are 99 new traditional uses for some previously reported medicinal plants. For example, the whole plant of Striga hermonthica was previously reported to treat diabetes, but in this study, it is used also for menstrual cramps. The fruit of Senna occidentalis is reported to treat eczema beside its common use as a laxative. Plicosepalus acaciae is commonly used to enhance wound healing and as a lactagogue, but in this study, the smoke fumigant of the seeds is reported to repel insect from ear.

New species and new uses for species are reported for the first time in this study. For example, Anastatica hierochuntica, Ctenolepis cerasiformis, Echinops longifolius, Cleome gynandra, Maerua pseudopetalosa, Martynia annua, Oldenlandia uniflora, Opuntia ficus-indica, Solanum dubium, Sonchus cornutus, Tribulus terrestris and Drimia maritima were not being mentioned in any previous study for the traditional Sudanese medicine. Acanthorrhinum ramosissimum, Cleome viscosa and Setaria acromelaena which were used for evil eye were also reported for the first time.

The majorities of the healers declared that they had learned about medicinal plants from their parents or grandparents. The lack of systematic documentation for medicinal plant knowledge which appears to occur in many parts of the world may contribute to the loss of this knowledge, particularly for plants that are neglected or non-preferred [34‐36].