Background

Limpopo Province is mostly dominated by the Pedi (57%), Tsonga (23%) and Venda (12%), ethnic groups while English and Afrikaans speaker only constitutes less than 4% combined [1]. However, there are other unofficial languages which includes Khelobedu, Setlokwa and Sehananwa falling under the Sotho or Pedi speaking people. Blouberg area, dominated by Pedi tribe, comprise of only two main health care facilities (Blouberg and Helena-Franz Hospital), a small remote town known as Senwabarwana and a few game reserves (Blouberg and Maleboho nature reserves). The population in this area, like in other rural African communities is reliant on traditional medicine (TM) as their basic source of health care [2, 3]. The other possible challenges in health care facilities within the study site may include long distances travelled to hospitals, long waiting on the queues, drug shortages, lack of proper laboratories with state of the art scientific equipment and attitudes of the health workers [4]. The area is one of the medicinal plants hotspots with only little plant species documented in the few surveys taken recently within the Province [5,6,7,8,9], but not strictly focussing on Blouberg area.

Several ethnobotanical studies have been taken world-wide, documenting different plant species and preserving the indigenous knowledge of various communities [10,11,12,13,14,15]. Most of these surveys may well serve as possible leads for the discovery of potent new drugs that may be used to combat most harmful infections that pose a serious threat to human and animal health. Traditional people believe in using TM or herbal therapy in treating various infections, mostly because plant species are abundant in nature in their surrounding environment, less priced and are believed to pose less or no side effects. Moreover, it is believed that herbal therapy is holistic, integrating the emotional, spiritual and mental well-being of the patients [16]. Furthermore, TM is culturally acceptable and there is a belief that it purges out any infection after treatment from hospitals [17]. Besides being the main source of drugs in the current threatened health care system with emerging multiple resistant organisms, the traditional medicine still receives little attention world-wide [18].

The enormous rise in HIV-AIDS infections in Africa pose a further threat to human life, resulting in variety of opportunistic infections which may include various skin infections inflammatory disorders, various forms of candidiasis, reactivation of the TB germ and other possible pulmonary infections, multiple forms of lymphoma and various Herpes infections [19,20,21]. The aim of the current work is to identify and document various plant species used by the lay people of Blouberg (Hananwa).

Methods

Study area

South Africa (Fig. 1) is divided into nine Provinces. Blouberg area, indigenously known as Hananwa, is situated in the Limpopo Province, 30 km north of Dendron and 95 km from Polokwane, and connects South Africa to both Botswana and Zimbabwe. Geographically, it is a deep rural area, mountainous and located between the Waterberg Wetlands and the Dongola Trans-frontier and extends right up to the Botswana border [22].

Fig. 1
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Map of South Africa, locating Blouberg area (red coloured area)

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The area is under kingship of the Leboho family and occupies an area of approximately 5054 km2 and a total population of about 166,243 people [23]. Big rivers such as Bohlokwe, Tswatšane, Mmatšope and other small rivers provide water to various livestock in the area. Mogalakwena River, with its rich biota which includes crocodiles, also cuts into the area. Various sites on the mountain Blouberg- a green mountain throughout the year, serves different purposes. Ploughing fields, burial site for the kings of the past and hunting grounds are amongst the most important sites in the mountain.

Selection of informants and interviews

A total of 40 informants which includes 20 traditional healers and 20 medicinal plants sellers from Blouberg area have been randomly sampled from a pool of informants attending meeting relating to African Dingaka Association of South Africa at Blouberg area from April 2008 to June 2016 using structured questionnaires, follow-up visits and field trips. Various visits were made to establish a rapport and more often assisting in plant collection for use in the African surgeries (consulting rooms). Informants were mostly from villages such as Lethaleng, Ga-Mochemi, Ditatšu, Ga-Rammutla A, Pickum B, Ga-Mashalane, Ga-Mmamolele, Ga-Broekmane, Dilaeneng, Ga-Machaba, Ga-Kibi, Ga-Mmaleboho, Ga-Radimang, Ga-Manaka, Sewale, Bosehla, Mohlabeng-wa-Malokela, Gwarung, Ga-Kobe, Sebotlane, Ga-Kibi, Devrede, Makgabeng, Marobjane, Inveraan and Bull-bull. The informants agreed to furnish information regarding the indigenous medicinal plant species used in the treatment of various infections treated by both healers and plant sellers using questionnaires, while noting the plant species named using Sehananwa as a local language. At a later date, informants were requested to identify the plant species at various collection sites.

Follow-up visits were later conducted with the intention of verifying the information given by informants, particularly the correspondence of indigenous names, and then later request further information on whether the plant species mentioned are used as a single plant material or in combination with other plant species. Only plant species mentioned by the informants at least three times were eligible for documentation [24]. Data on combinations of plants in the treatment of infections was documented, including mode of preparation and route of administration.

Collection and identification of medicinal plants

The plant species were collected, pressed and identified by botanists in the Department of Life and Consumer Sciences, Horticulture and College of Agriculture and Environmental Science (CAES) laboratories. The unknown plant materials to the authors and staff in the College of Agriculture and Environmental Sciences were send to National Botanical Institute (NBI) in Pretoria for identification (The personnel who assisted in identification includes Klopper, R.R., Mothogoane, M.S., Makgakga, M.C., Makwarela, L.E., Archer, R.H., Nkonki, T., Ready, J.A., Bester, S.P., Meyer, J.J., Ruiters, A.K. and Welamn, N). The voucher specimen of all the collected plant species were then lodged at University of South Africa herbarium in Florida. Other plant materials were also deposited into the NBI herbarium. These includes Cissus cornifolia, Neorautanenia mitis, Pollichia campestris, Ipomoea albivenia, Pterodiscus kellerianus, Ehretia rigida and Aptosimum lineare.

Data analysis

The analysis of data was carried out using both descriptive and inferential statistics using percentages and frequencies. The frequency index (FI), informant consensus factor (Fic) and Fidelity levels (FL) were calculated and compared. FI of the documented plant species were calculated using the formula:

$$ \mathrm{FI}=\mathrm{FC}/N\kern0.5em \times 100, $$

Where FI is the frequency of citation for one plant species by informants, FC is the number of informants who cited the use of the plant species and N is the total number of informants [25, 26]. Fic was calculated to determine the homogeneity of the information provided by the informants using the formula:

$$ \mathrm{FIC}={\mathrm{N}}_{\mathrm{ur}}\hbox{-} {\mathrm{N}}_{\mathrm{taxa}}/{\mathrm{N}}_{\mathrm{ur}}\hbox{-} 1 $$

Where Nur is the number of use reports, Ntaxa is the number of species in each use category [27], while FL was calculated using the formula:

$$ \mathrm{FL}={\mathrm{I}}_{\mathrm{p}}/{\mathrm{I}}_{\mathrm{u}}\mathrm{X}\ 100 $$

Where Ip is the number of informants who suggested the use of the species for the same major ailment and Iu represents the total number of informants who mentioned the species for any use [28].

Results

Socio-demographic information and diversity of plants species

The communities around Blouberg area use diverse flora in treatment of various ailments and local people possess a rich traditional knowledge on the use of medicinal plants as medicine. The age of our informants ranged from 30 to 88 years (Table 1). About 64% of our informants are aged between 40 and 65 years of age while 10% of our informants are below the age of 40 years. About 40% of our informants have never been to school and only one of the 40 participants possess a diploma in Education and is also a well-known traditional healer. A total of 82 plant species belonging to 42 different families were recorded in the current study (Table 2). Families such as Fabaceae (14.63%), Malvaceae (8.54%), Apocynaceae (7.32%), Solanaceae (6.10%), Convolvulaceae (4.88%), Euphorbiaceae (3.66%) and Vitaceae (3.66%) were well represented (Table 3) and are dominant, while families such as Rubiaceae, Olacaceae, Loganiaceae, Ebenaceae, Celastraceae, Asphodelaceae and Anacardiaceae reported 2.44% each. The other families recorded one plant species each.

Table 1 Demographic of informants
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Table 2 Ethnobotany of the Pedi tribe of Blouberg area, Limpopo Province, South Africa
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Table 3 Plant families with the largest (At least 3 species reported) number of species
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Growth forms, plant parts used and mode of administration of plant species

The reported plant species were dominated by herbs (46.34%), followed by trees (25.61%), shrubs (20.73) and climbers (7.32%) (Fig. 2). Out of the reported plant species, roots and bulbs (underground plant material) were the most used (58.6%), followed by stem bark (13.1%), whole plant (12.1%) and leaves (11.1%) (Fig. 3).

Fig. 2
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Growth forms of the reported plant species

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Fig. 3
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Plant parts used in the study

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Most of the plants materials are boiled and taken orally (73%) when treating various types of infections (Fig. 4). The other plant species may be topically applied (10.89%) to the skin, while the others may be burned (5.94%) or used to wash and rinse (5.94%) the infected body part. The inhalation, nasal administration, and plant materials which may be blown reported less than 5% each.

Fig. 4
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Mode of administration of reported medicinal plants

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Ailments treated and consensus agreement

The most reported plant species are used in the treatment of sexually transmitted infections (24) followed by those used in the management of HIV-AIDS related infections (15), stomach ache (14) and plant species used in the treatment of ethno-veterinary infections (9) while the informant consensus factors (Fic) of the mentioned ailment categories ranged from 0.78 to 1 as shown in Table 4. About 25 species revealed FL value of 100% against variety of diseases (Table 5).

Table 4 Consensus agreement about uses of medicinal plants for important ailment categories
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Table 5 Fidelity levels (FL) of plant species used for various uses by key informants
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Combination studies and plant species with Frerequency index ≥70

Eight medicinal plants species such as Elephantorrhiza elephantine, Waltheria indica, Securidaca longipedunculata, Blepharis diversispina, Peltophorum africanum, Cissus quadrangularis, Sclerocarrya birrea and Elephantorrhiza burkei reported FI value ≥70 hence have some pharmacological activities reported from literature (Table 6). About 12 combinations of medicinal plants species have been recorded in the current study (Table 7). Waltheria indica appeared in six of the 12 combinations, accounting to 50% and is used in the treatment of stomach ache, sexually transmitted infections, infertility, diarrhoea and strengthening of immunity in new born babies.

Table 6 Reported biological activity of the plant species with FI value ≥70
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Table 7 Reported combinations of various plant species in treating infections
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Discussions

Demographic information and diversity of use of plant species

Traditional knowledge is mainly transferred from one generation to the next through mouth and such information may evacuate and disappear for good with time or becomes limited as life evolves [29, 30]. The demographic information of selected informant’s data shows that males (55%) dominates in the traditional knowledge compared to 45% of females. Contrarily, other authors reported the females to dominate in the traditional knowledge [31, 32].

The families such as Fabaceae and Malvaceae are dominant in the current study, reporting 14.63 and 8.54% respectively. The dominance of the Fabaceae has also been reported several times in ethnobotanical surveys at different localities [33] world-wide. The use of the branches, sap and seeds were all reported to be much lesser. In the current study, the use of the underground plant part contributes (58.6%), while stem bark reported 13.1%. The use of underground, stem bark and whole plant (especially herbs which are uprooted) is of major concern as it is extremely detrimental to the health of the plant species and may lead to plant species extinction.

The informant consensus agreement

The technique is designed to highlight medicinal plant species that have a healing potential for a specific major illness. The plant species in major disease category, with FIC values of 1 or very close to 1 indicate a high rate of informant consensus on plant species used against the major specific illness [28]. In the current work, the plant species used in the treatment of joints, fractured bones, anti-poison, aphrodisiac, chest complaints, tonsillitis, asthma, vaal-sick and toothache reported FIC values of 1. A similar trend has been observed elsewhere in other countries [34, 35]. However, it should be noted that the number of species in the above mentioned ailment categories is also equivalent to1.

Fidelity levels (FL) of the preferred medicinal plant species

Fidelity level is designed to reveal the percentage of informants claiming the use of a certain plant for the same purpose [36]. FL values of documented plant species are reported in Table 5.

In the current study, about 25 species revealed FL value of 100% against variety of diseases, suggesting that the informant’s state of knowledge is common when it comes to the uses of such plant species. Although Mimusops zeyheri and Raphionacme hirsuta revealed FL value of 100%, there is no data in the literature supporting the pharmacological effect of such species against pathogenic strains belonging to the traditional sphere of sexually transmitted infections.

It should also be noted that three plant species, such as Bauhinia galpinii, Elephantorrhiza burkei and Cassia abbreviata, from family Fabaceae appeared as some of the preferred plant species used against sexually transmitted infections, eye infections and as anti-poison respectively. Furthermore, Peltophorum africanum, Eephantorrhiza elephantine, Elephantorrhiza burkei and revealed frequency index (FI) values of 78, 85 and 90 respectively (Table 2). These data suggests that the family Fabaceae is generally important and used in the treatment of various human and animal infections. Although E. burkei in the current study is preferred to treat eye infections, it was also reported in the treatment of diarrhoea within other Bapedi groups [37]. These difference may well suggest that the traditional knowledge on use of plant species in the treatment of infections may differ from one locality to the other. Although the current work revealed most preferred species used in the treatment of various pathogenic infections, the biological activity of such medicinal plants still needs to be explored and verified experimentally. Furthermore, the plant species with high FL values are of greater importance in treating the related human and animal infections from the study site.

Plant uses and ailments treated

The plant species reported in the current study are mostly used for treatment of human and animal infections while others are used for magical purposes. The most reported plant species are used in the treatment of sexually transmitted infections (24) followed by those used in the management of HIV-AIDS related infections (15), stomach ache (14) and plant species used in the treatment of ethno-veterinary infections (9). These results agrees with those of Peltzer et al., [38] who reported sexually transmitted infections to be mostly encountered and treated by African traditional healers. Amazingly, only a single plant each is reported to be used to treat pulmonary infections, mellitus diabetes and asthma.

Out of all the named medicinal plants in our survey, Gardenia volskensii is the only plant species reported to treat pulmonary related infections including tuberculosis. However, some of our informants revealed that for such purposes, bones from the chest of the Ostrich and nest of a dove “leeba” are chopped together and then administered to the patient. We found this difficult to validate scientifically as the doves may use different plant materials to build the nest and the age and gender of the ostrich was not identified in any of our informants. Solanum species are used to treat stomach related illnesses. One of our informants revealed that a mixture of a variety of Solanum species is the perfect solution to various stomach disorders and further used a name “Merolanarolana” referring to variety of such species when hiding the prescription form the patients. It should be noted that from the multi-purpose plant species reported, 28% species bears fruits and are identified as food plants as well. According to our informants, the use of the species as foodstuffs is not very important as there are no markets for such fruits within the study sites. However, the fruits are used as addition to foods within families and also eaten by boys when shepherding the cows on the mountains. The treatment of infections is more important than the food value. For the purpose of food, the indigenous people are reliant upon the agricultural crops such as maize, wheat, potatoes and leafy vegetables which are grown mainly during the summer season.

Magical and ethno-veterinary plants species

Out of 82 plant species reported in the study, about 12 plants are used for magical purposes, while 9 species are used in the treatment of various ethno-veterinary infections. Sarcostema acidium and Cassia abbreviata are the most reported magical plant species with frequency index of 58 and 45 respectively (Table 2), while Elephantorrhiza burkei and Elephathorrhiza elephantina are preferred for ethnoveterinary use with frequency index of 90 and 85 respectively. Plant species reported within this category are believed to be used to doctor homesteads there by protecting them from lightning, dispel the witches, returning some illnesses and calling upon some ancestral spirits. Cassia abbreviata is used for many other uses in various communities. However, the Pedi tribe use the multi-stemmed species mostly in the doctoring of homesteads. The multi-stems (Fig. 5) are believed to symbolise the number of huts in the family that might comprise of extended family members and a number of wives belonging to one husband [39].

Fig. 5
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Multi-stemmed Cassia abbreviata

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Food plants

Out of 82 plant species, 23 plants (28%) bear fruits are identified as food plants. Strychnos madagascariensis and Psidium guajava reported the highest FI value of 58, each while Azanza garckeana reported the lowest FI value of 5. Our current report corroborate that of Musina and Maroyi [40] who reported species such as Scleorcarrya birrea, Mangifera indica, Psidium guajava, Punica granatum and Vanguera infausta being used as food plants within Capricorn District, Limpopo Province. According to our knowledge, Cissus cornifolia was reported the first time within the country as a food source. However, it should be noted that the ethnobotanical survey of both the domesticated and wild edible fruits as sources of food within the Province is lagging behind and still needs to be enormously explored.

Significance of names of plant species

Some plant species in the study are named either according to their physical morphological features, growth form or their role in the traditional indigenous medicine. Urginea sanguinea is commonly known as “Sekanama” which means “like meat” referring to the blades from the bulb of the plant species and its reddish colour. Ximmenia caffra is called “Motshidikgomo”. Ximmenia species are generally called “Motshidi”, while the word “kgomo” means cow, which a symbol of a bigger material or object is referring to the size of the fruit of species which is bigger than other Ximmenia species. Hypoxis haemerocallidea is known as “Monna wa maledu” referring to the beed-like structures protruding from the bulb and it translates to “a man with beed”. “Makgonatsohle” is a plant species which is generally used to treat all illnesses relating to stomach and it translates to “cure all” referring to the ability of the plant species to cure all illnesses. Although there is a general trend that all reddish medicinal plants are used to cleanse the blood.

“Thotamadi” is the name given to plant species and is generally believed to cleanse the bloodstream much better than all other species. “Madi” means blood. Cissus quadrangularis is indigenously known as “Mohlabadipoo”. The word “hlaba” means stabbing or pinching, referring to the pinching-like feeling that a patient generally feels after fumigation of the plant species. Waltheria indica is known as Mokhutesela, refereeing to the ability of the plant species to cool the stomach. “Khuta” means heals or stops the roaring or ripens. Asparagus exuvialis is the plant species which the indigenous family that have a function at home normally burns to disperse the clouds that may cause rain when there are blackish or dark clouds which are associated with evil spirits. The idea is to let the rain come back at a later time interval. “Phatlalatsa” means disperse while “maru” refers to clouds.

Capobrotus eludis is indigenously called “tima” which means cooling off, referring to the ability of the plant species to cool off the pain, heat and fever associated with shingles, which is also known as “belt” (lepanta). Senna italica is commonly called “Morotelatshotshi”. In Sepedi, the word “tshotshi” refers to ants, while “moroto” means urine, which generally refers to the yellowish colour of the resulting liquid after immersing the roots in water overnight. The yellow colour may be coming out of the root kernels which are light yellow when matured. The plant species grows in abandoned ploughing land and always have ants in close proximity everywhere it grows. Indigenous taxonomy therefore makes more sense to the traditional community than the scientific society.

Mode of administration

In the current study, 73% of species are administered orally. The results in the current study corroborate that of other authors who reported the oral route as the most common mode of medicine administration [41, 42]. Besides Securidaca longipedunculata (root bark) which is taken along with mageu, all the medicinal plants species taken orally are cooked with tap water and drunk until the infections subsides or heal completely. S. longipedunculata is reported to be extremely bitter and have a lot of “after taste” and may at times result in vomiting. The use of mageu as a carrier assist in preventing such circumstances. Elsewhere, the root bark from S. longipedunculata is mixed with that of Zanthoxylum humile and taken with soft porridge to treat erectile dysfunction [43].

Frequency index of documented plant species

Except Blepharis diversispina, all the species are reported to possess a potent antimicrobial activity against a variety of pathogenic microbial strains. In a way, the results in our current study validates the affectivity of various plant species against patahogenic microbial strains. However, it is amazing that the biological activity of extracts and isolated compounds from B. diversispina are not explored.

Medicinal plants with the highest FI value have related ethnobotanical uses in other cultures. For example, Peltophorum africanum and Elephantorrhiza burkei have been reported in the treatment of sexually transmitted infections, skin infections and diarrhoea amongst the Tswana, VhaVenda and Tsonga cultural groups and a potency on such activities have been reported as well [44,45,46,47]. These species are of vital importance in the treatment of reported infections in combinations as shown below (Table 7). P. africanum has also been implicated in the treatment of various ethnoveterinary infections [48,49,50].

Combination studies of reported plant species

The combinations seems to be different from one traditional healer to the other. The purpose of compiling these combination studies was to assist the other researchers in selection of medicinal plant species relating to a specific illness. Earlier, [51], reported some different combination studies of related plant species, explaining that different traditional healers from different localities may use different plant species to treat different infections. The results in the current study shows that the traditional healers and plant sellers use variety of combinations in treating various ailments which includes sexually transmitted infections, eye infections, diarrhoea, and opportunistic infections associated with HIV-AIDS, new born babies illnesses and other gynaecological complaints as occurring in women. The other authors elsewhere reported the similar trend that indigenous systems use a combination of two or more plant species in treating infections [52]. However, from a scientific perspective, it may be difficult to determine which plant species contributes more active components than the others as there are a huge number of chemical compounds involved. However, these is generally believed to curb antimicrobial resistance.

Domesticated plant species

From our visits in the homes of the informants, we found species such as Withania somnifera, Ipomoea alba, Punica granatum, Carica papaya, Vangueria infausta, Sclerocarrya birrea, Kirkia acuminata, Cissus quadrangularis and Cassia abbreviata as some of the plant species grown in at least 10 homes. However, other authors reported most of the plant species found homes as part of a garden to be used only as food supplements and ornamental plants [53]. In our study, some plant species such as W. somnifera, C quadrangularis, K. acuminata and I. alba are only used as medicine used to treat variety of human and animal illnesses. When asked why only those species are being domesticated, most informants believe that the plant species are used more often than others and are gradually declining in their natural environment. However, some healers believe that some plant species are believed to be efficient in treating infections only when collected from the wild. Such healers further believes that plant species in the wild are natural and have a stronger power that comes from gods and the wind.

Conclusions

The traditional knowledge of the indigenous people of Blouberg varies from one traditional healer/ plat trader to the other. Traditional medicinal plants are mostly used in the treatment of human infections, especially sexually transmitted diseases, ethno-veterinary infections, as sources of food and for magical purposes. There is correlation in terms of ethnomedicinal use between cultures within Limpopo province. There is a need to explore the wild food plants as there is lack of data in that area of research. In the current, most plant species are used in the treatment of sexually transmitted infections, management of HIV-AIDS, stomach related infections and ethno-veterinary treatment. There is a need to further explore the possibility of documenting plant species used to treat such infections in future.