Popular medicinal plants used by the Bantu people and Pygmies living in the administrative territories of Beni and Lubero ( DRC )

1 Département de Pytotechnie, Faculté des Sciences Agronomiques, Université Catholique du Graben, B.P 29 Butembo Nord Kivu, Democratic Republic of Congo. 2 Département d’Ecologie et gestion des Ressources végétales, Faculté des Sciences, Université de Kisangani, B.P 2012 Kisangani, Democratic Republic of Congo. 3 Herbarium de l'Université Libre de Bruxelles (BRLU), Université Libre de Bruxelles, 50 Avenue F. Roosevelt CP 265 B-1050 Bruxelles – Belgique.


INTRODUCTION
Medicinal plants occupy the most preponderant place in households in Democratic Republic of the Congo.This is due to the destruction of the economy of the nation, which makes three-quarters of the population totally dependent on natural resources to survive, and the inability of some modern medicines to cure some specific *Corresponding author.E-mail: eric.kasika@yahoo.fr.
Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License diseases (Léonart et al., 2006;Kabangu, 1990).Congo people cannot buy modern drugs because of poverty and lack of medical structures/facilities in the villages (Olivier et al., 2002).Congo is well reputed for its richness in flora, although this is not well known in Central Africa (CIFOR, 2007).
This study took place in the administrative territories of Beni and Lubero, which are situated in the Northern part of the Province of North Kivu.This ethno-botanical study is centred on the use of plants for popular traditional medicines by the Bantu people and Pygmies living in the same villages.The two administrative territories have undergone strong demographic pressure and have known several armed conflicts, namely 'war of liberation' and 'War of aggression or occupation'.These armed conflicts have aggravated the vulnerability of the population and its dependence on the use of natural resources.
The two administrative territories are majorly occupied by the Nande ethnic group (Bantu).There are also other ethnic groups, but of less numeric importance, among which are the Piri and Pygmies (Mbuti) groups (Jongen, 1970;PNUD, 1998;Vyakuno, 2006).This co-habitation certainly permitted the exchange of knowledge of the use of medicinal plants.Thus, the study observations centre on the following question: Do the Bantu people (Nande) and Pygmies (Mbuti) have the same level of knowledge of medicinal plants or herbal medicines, seeing that the former are generally farmers and sedentary settlers and the latter seminomads, hunters and fishers?
Since the Bantu people live in villages with ruderal plants and the Pygmies spend a good part of their lives in forest with so many medicinal plants, herbal medicine of the former would be different from the herbal medicine of the latter in the administrative territories of Beni and Lubero.
The aim of this study is therefore to study the common usage of herbal medicines between the Bantu people and Pygmies for treating similar ailments in their villages.It aims to discover whether there is some convergence in recourse to herbal medicine or whether each ethnic group has some kind of proper specialties.
It is worth noting that no specific research has been conducted on the issue of medicinal plants usage by the Bantu people and Pygmies living in Beni and Lubero administrative territories.
1 It is therefore paramount to investigate the convergences and divergences in the use of herbal medicine among the two tribes.Herbal medicine market is growing rapidly in Beni and Lubero administrative territories, and it generates substantial profits to the persons having knowledge of medicinal plants.
It is important to note that before colonization, most of the farmers of the two ethnic groups used to resort to some traditional medicinal products to cure human or animals' ailments.There was easy access to these products because of their linkage to relations between members of the whole community.The service was usually paid for in kind (Mafikiri, 1998).Nowadays, people with indigenous knowledge of herbal medicine usage have found some market in organising workshops on medicinal plant use.Trading on plants' parts (peels, roots, powder of leaves…) has become the generating activities of revenues in villages.The activity of trading in medicinal plants is seen as a relief to the population whose income is very low and does not have access to infrastructures and basic social services.Medicinal plants usage reduces medical costs, thereby making farmers to save their low incomes and only resort to modern medical centres or hospitals in case of emergency.

Area of the study
Beni and Lubero are situated in the Eastern part of the Democratic Republic of the Congo.Among the villages in the two areas, there are six villages in which the Bantu people and Pygmies live together.These six villages were chosen because this study is an ethno-botanical investigation (Figures 1 and 2).
Lubero borders Edward Lake and is located between 28°and 30° longitude East, and 0°34 and 0°30' latitude South.Beni is located between 29° and 30° longitude East, 0°30' latitude South and 1° latitude North.This area is limited in the Northern part by Ituri District and in the Southern part by the Republic of Uganda (Kasay, 1988).According to Vyakuno (2006), the population density is high in Lubero, but very low in Beni area.The population of the two administrative territories consists predominantly of the Bantu people (Nande).

Ethno-botanical surveys
The ethno-botanical survey was conducted in six villages where the two ethnic groups, Bantu and Pygmies live together.Ethnobotanical survey is recognized at Pharmacognostic level as the most efficient method for collecting data, and is not financially demanding (Balick, 1990;King and Tempesta, 1994;Cotton, 1996;Betti and Lejoly, 2009).Data were collected with a standardized questionnaire containing list of traditional medicines and pharmacopoeia (PHARMEL data) (Adjanohoun at al., 1994).
The method utilised to collect data is essentially based on preestablished questionnaire.A sample of 120 persons, most of them heads of households in the two ethnic groups, was interviewed.The informants (males and females) were chosen at random, taking 60 from each ethnic group.Although all the informants are aged between 20 and 70, they were divided into four subgroups.The subgroup of the informants aged between 31 and 40 was the most cooperative of all the four.The data obtained from the different households were supplemented by information gleaned during group discussions.During the collection of data, the focus was on diseases treated in the traditional way, herbal plants used to cure them, the methods used in preparing the traditional medicines used, their mode of administration and pharmaceutical presentation.
Most of the plants included in the present study and referred to by respondents were recommended by Professor Kamabu Vasombolwa of the University of Kisangani.Those medicinal plant species not recognised by the professor were sent to the Botanical Laboratory of the University of Kisangani for them to be recommended by an expert, Mr Kombozi.Those specimens that were not recognised were not included in the present study; they are left available for further analysis.The result obtained from the respondents of the two ethnic groups was compared to that obtained by other African researchers' studies on similar therapeutic usage of plants.

Treated diseases
From the study, the Bantu people and Pygmies, using medicinal plants traditionally treated 63 diseases.Both members of the two ethnic groups mentioned used medicinal plants to treat forty-five of these diseases.The most recurrent diseases pointed to by at least 20% of the respondents for the two ethnic groups are: Malaria (treated on average by 9 plant species by Bantu people and 6 by Pygmies), diarrhoea (5 plant species by Bantu people and 6 by Pygmies), gripes (5 plant species by Pygmies and 2 by the Bantu people), candida and yellow fever (6 plant species), migraine (3 plant species) and rheumatism (4 plant species).
The Jaccard similarity coefficient (or Jaccard Index), which is 72.58%, has shown that, popular traditional medicine of the Bantu people and Pygmies addresses diseases the same way and ethnic specificities are, in general, less remarkable.However, specific ways of treating specific diseases do exist.Thus, Pygmies are specialized in the treatment of hepatomegaly (liver enlargement), ovary cysts, toothaches and sterility.
Malaria is the disease mostly treated with medicinal plants, in Beni and Lubero area.Thus, a total number of 9 species of medicinal plants were used by the Bantu people and 7 by Pygmies to treat malaria.The two ethnic groups seem to use at least five (5) different herbal medicines to treat 18 different diseases, among which one should mention epilepsy (5 recipes are used).

General characteristics of medicinal recipes
The Bantu people and Pygmies of the six villages resort to respectively 341 and 239 medicinal recipes among which 53 remain similar.In general, the two groups mentioned 15 preparations.In both groups, aqueous preparations predominate.Decoction is the medicine preparation mostly used by them, followed by trituration and extraction.Figure 3 shows variation in medicinal preparations between both groups.The two adjoined boxes of dispersion respectively represent the frequencies of every medicinal preparation methods for both groups.
The Wallis test (χ2 = 99.9,dl = 14, p-value = 4.863e-15 < 0.05) demonstrates that there must exist some meaningful differences between the methods of preparing medicines by the Bantu people and Pygmies, though they live in the same village.On the other hand, statistical analysis of frequencies of medicine preparation does not show any difference between the six investigated villages.Indeed, P-v = 0.84 value is superior to 0.05.Twenty-six pharmaceutical different presentations of herbal medicine were identified in the 6 villages (Figure 4).The choice of one or other pharmaceutical presentation depends on the patient's state, the emergency of the case and the organ involved.There is no certitude on how the different pharmaceutical presentations found in Beni and Lubero are shared between the Pygmy and Bantu people living together in the area.The analysis of the figure shows a meaningful difference in pharmaceutical presentation between the two groups living in the same village.The P -value used for the frequency independence test (2.2e-16) is very low, 0.05.There are 17 ways of administering herbal medicine to patients.Oral ingestion is the most frequently used, with a rate of 53.45% among the Bantu people and 38.9% among the Pygmies.Figure 5 shows variations in ways of administering medicine to patients between the two groups living in the same villages.

Mode of preparation
The methods of administering medicine to patients vary considerably between the two communities.The analysis of χ2 reveals 124.5, with dl=16 and P-V = 2.2e-16.The value is very lower compared to the critical value of 0.05.

Floristic composition and convergences of plants' usage
Among 290 plant species whose medicinal virtues are recognized in traditional medicine of the two groups, 10 species are involved in the treatment of at least 10 different diseases in Beni and Lubero areas (Table 1).These most popular plants are: Allanblackia stanerana (18), Dichrocephala integrifolia ( 15), Ricinus communis (15) and Allium sativum (14).One specie, Allanblackia stanerana, is used by both groups alike in more than 5 villages, and two, Conyza sumatrensis and Harungana madagascariensis, in more than 3 villages.Ruderal plants were mostly used (40 %); forest plants, especially ligneous plants represent about 30% of species.The Pygmies who border forest area mostly use Forest species, whereas the Bantu people mostly use ruderal species.

Common therapeutic
The ethno-botanical investigations in the six villages where Bantus and Pygmies live together contributed to the identification of five disease groups treated using Pharmaceutical forms herbal medicine or popular medicinal plants.Diseases are treated differently by both groups in the six villages (Table 2).The Jaccard similarity coefficients obtained in comparing villages are below 50% in five villages out of six taken into account.However, 57.69% was recorded in Tandandale village, situated in Lubero.This convergence is due to the sedentary life of the Pygmies living in the village who have the tendency to use ruderal species similar to those used by the Bantu people.

Infectious and parasitic diseases
The fact that infectious diseases spread over all the six villages and showed no differences from one village to another, it is important to test whether there are any convergences between the two groups in their struggle to control infections.Figure 6 visualizes such affinities.The factorial correspondence analysis (Figure 6) shows that the Pygmies from two villages (Kalibo and Isigo) and the Bantu people from Isigo have similarities in the treatment of malaria and yellow fever.The Bantu people from the 4 villages (Maakangus, Kalibo, Tandandale and Kathundulas) have positive outcomes in the treatment of internal Candida.Six diseases, namely typhoid fever, shingles, amoebiasis, dysentery, tuberculosis and scabies are treated differently by members of the two ethnic groups.

Signs and states of non-defined morbidity, traumatic symptoms and poisoning
The first two axes show 61% of total inertia; in other words, 61% information contained in Figure 7 is summarized by the first two measurements.We will therefore only present in more details the interpretation of the results in relation to these two factorial axes.On one hand, the Pygmy people living in Kima and Maakengu villages, and the Bantu people of Kalibo village have    defined symptoms of ailments are treated differently in villages included in the present study.

Digestive system diseases
Figure 8 shows how digestive system diseases are treated throughout the villages of Beni and Lubero area.The analysis of the figure shows that ethnic groups living in the same village resort to different plants to treat digestive system diseases.

Diseases of the urogenital system
Figure 9 shows how the diseases of the urogenital system are treated throughout by the two ethnic groups (Bantu people and Pygmies) of Beni and Lubero villages.The analysis of the representation earlier mentioned reveals a strong similarity between the Pygmies of the Tandandale and Kima villages in the treatment of urogenital diseases such as sexual impotence and miscarriages.The Bantu people living in Kathundula and Maakengu villages address dysmenorrhoea and metrorrhagia in the same way they treat other kinds of bleeding.It is therefore clear that there is a divergence in the treatment of urogenital diseases.This may be explained by the fact that the ethnic groups seem to have expertise in some specific urogenital diseases.Thus, Pygmies treat more efficiently sexual impotence, whereas the Bantu people address well any vaginal bleeding.From the figure above, one may conclude that the two ethnic groups throughout the villages differently treat abscesses.However, Lumbago and Whitlow remain a speciality of Pygmies; the Bantu ethnic group more frequently treats gout and myositis.The disease causing swollen joints (Gout) and that of muscle inflammation and soreness are considered to be caused by excessive consumption of red meat coupled with sedentary life of Bantu people and lack of physical exercise.Indeed, Pygmies eat regularly red meat but as they actually move on feet and walk long distances a day, gout and myositis are rare among them.used by the Bantu people and Pygmies living in the same villages.It is evident from the analysis of this table that the calculated values are below 50%.The authors therefore conclude that the Bantu people and Pygmies living in the same village do not use the same plants in their traditional medicine.

Number of therapeutic preparations used in the same village
Numerous therapeutic preparations have been identified in popular traditional medicine per village in Beni and Lubero administrative territories.The Bantu people have resorted to 341 different therapeutic preparations, which are specific to this group alone, whereas 239 therapeutic preparations are specific to the Pygmy ethnic group.The two groups do use in common 53 therapeutic preparations.Since the Jaccard coefficients of similarity are very low (50%) (Table 4), the two groups do not have similar therapeutic preparations, despite the fact that they live in the same village.

Species of plants used against recurrent diseases
The analysis of the plant species against recurrent diseases in Figure 11 shows that Harungana The plant species, Allanblackia stanerana is signalled everywhere for its efficiency against gripes.Canarium schweinfourthiis, Allium sativum, Dichrocephala integrifolia and Harungana madagascariensis are mostly used against yellow fever, migraine and rheumatism.From the distribution of the plant species involved in 10 therapeutic preparations used for the ten different recurrent diseases, diarrhoea, yellow fever, rheumatism, and migraine are the most important.

Classification based on treatment of ailments or symptoms
The dendrogram (Figure12) regroups the data from a matrix of 33 lines of combinations of villages and plant species used in the treatment of recurrent diseases and of 6 columns of such recurrent diseases.The hierarchical classification of resemblance, based on the method of Ward (Euclidian distance), the popular traditional medicine of the two groups in the six villages investigated reveals six classes of similarity at the level of terminal knots (100% of similarity).There are five (5) Bantus-Pygmies classes and one (1) Pygmy class.The highest level (97% similarity) in four (4) groups is identified: one group of Bantus, one of Pygmies, and two groups of both Bantu and Pygmies.At 90% of similarity, the diagram reveals 3 classes of Bantu-Pygmies together.At the highest level of the tree (85% of similarity), two (2) classes of Bantu -Pygmy are perceptible.The independence test based on ethnic groups and the treatment of recurrent diseases factors (Wallis test) result in: χ 2 = 16, 7; dl= 9, P-value = 0.054 > 0.05.It can be deduced from Wallis test that the difference in the treatments of recurrent diseases is not significant.
The statistical analysis of the data relatively to plant species used by both groups revealed that there are some significant differences.Indeed, χ 2 = 10,9; dl= 4 and a p-value of 0.028 ˂ 0,05 make us to accept the nil hypothesis and to confirm that both groups living in the same administrative territories of Beni and Lubero use different plant species in their popular traditional medicines.

DISCUSSION
Seven recurrent diseases are treated by at least 20% of members of the Bantu and Pygmy ethnic groups.These 7 recurrent diseases include malaria, diarrhoea, colic, internal candida, yellow fever, migraine and rheumatism.Pygmies and Bantu people living in the same village make different therapeutic preparations from medicinal plants.Bantu people resort often to humid types of herbal medicines (decoction, steeping, distillation), whereas Pygmies prefer trituration and direct chewing of medicines.The pharmaceutical preparations and means of administration of medicine vary considerably between the two groups.Whereas the former resort to oral ingestion, the latter prefer scarification.
Similar usages of plants have been proven in both groups.''Mbuti '' and ''Nande '' use steeped Allanblackia stanerana peels to treat gripes and malaria.Triturated leaves of Conyza sumatrensis are used in the form of poultice on whitlows and its juice is used to treat colic and internal Candida.The decoction of Harungana madagascariensis peels (Lam.expoir) is used to treat yellow fever.This also has same use in Congo (Bitsindou and Lejoly, 1992), and Cameroon (Betti and Lejoly, 2009).
Decoction of Bidens pilosa leaves is mostly used to treat diarrhoea.Decoction of Harungana madagascariensis peels is used for malaria treatment.These species have also been mentioned for the same use in Congo-Brazzaville (Adjanohoun et al., 1988;Trabi et al., 2008).The decoction of the leaves of Bidens pilosa and the peels of Harungana madagascariensis is used for malaria treatment in the City of Bukavu (Kasali et al., 2014).Lantana camara is a plant species used for treating some diseases, among which are typhoid fever,  (Nguegang et al., 2005).Roots of Carica papaya are commonly used in Bantus' herbal medicine to treat gonorrhoea.This plant is also known for the same usage in South Kivu Province (RDC) (Balagizi et al., 2007;Kasali et al., 2013); even in Congo-Brazzaville for treating urogenital infections (Adjanohoun et al., 1994).Solanum aculeastrum roots are used by the Bantu people to treat infertility; the decoction of these roots is also known in South Africa for the same use (Schmelzer et al, 2008).
Pygmies in Beni and Lubero use the leaves of Piper capense, softened on fire, as suppositories against internal parasitic worms.They also have the same usage in Congo-Brazzaville herbal medicine (Schmeltzer et al, 2008).
The powder of dry fruits of Piper guineense is used in Beni and Lubero against sterility, the aqueous extract of dry fruits of the same plant has reproductive function in rats (Mbongue, 2005).The decoction of leaves of Mangifera indica was used for treating haemorrhoids in Beni and Lubero administrative territories.The same usage has been cited in traditional medicine of Twa Pygmies and Oto Bantus in Equator Province of RDC (Ilumbe et al, 2014;Kalanda and Ilumbe, 1993).
The Bantu and Pygmies use decoction of Morinda morindoides daily for malarial treatment.It also has the same usage in herbal medicine of Bantus and Twa (Pygmies) in Equator Province of RDC (Ilumbe, 2010).

Conclusion
The study lists some plant species commonly used in the traditional medicine of the Bantu people and Pygmies living in Beni and Lubero located in the Eastern part of the Democratic Republic of Congo.The result of this work shows that the choice of plant species depends on the ethnical group to which the traditional healer belongs.Similar usage of plant species presented with respect to other regions of Africa shows their medical virtue.Numerous species presented in Table 5, which have not been identified till now for the similar purpose in other regions, contribute to the originality of this work.The promising plants like Allanblackia stanerana and Solanum aculeastrum not yet marked worldwide should attract the attention of scientists and pharmaceutical corporations to determine their chemical structure and therapeutic activity.Numerous works of this kind should attract the attention of scientists to palliate the lack of knowledge of plants usage of such a great multi-staged vegetation of the East of the DRC

Figure 1 .
Figure 1.Map of the surveyed villages.

Figure 2 .
Figure 2. Map of distribution of the two ethnic groups in the surveyed villages.

Figure 6 .
Figure 6.Representation of correspondences of infectious and parasitic illnesses across villages.

Figure 10 Figure 7 .Figure 8 .
Figure 10 represents how different groups of the Bantu people from different villages address skin and joints

Figure 11 .
Figure 11.Representation of the AFC of species used against recurrent diseases in Bantu and Pygmy popular medicine.

Table 1 .
Plant species involved in the treatment of at least 10 different diseases.

Flora family Biotope Number of villages Bantu Pygmy
some strong convergences in the treatment of HIV/AIDS related symptoms or ailments affinities, as well as in the treatment of diseases provoked by abortion.The two ethnic groups are very divergent in their treatment of poisonings and wounds.On the other hand, the Bantu people living in Isigo and Kima villages do not treat snake bites, food allergies and fractures similarly.This finding shows that the Bantu people and Pygmies have similar ways of treating HIV / AIDS related ailments in Beni-Lubero villages where they live together.Any other non-

Table 2 .
Comparison of numbers of diseases treated in medicine of Bantus and pygmies in the 6 mixed villages.

Table 3 gives
, from the Jaccard Index, the indication of similarity of plants used in different herbal medicines Representation of the AFC of the uro-genital system treated throughout the villages investigated.
Eigenvalues Figure 9. Eigenvalues Figure 10.Representation of the AFC of skin and joints diseases treated throughout the villages.

Table 3 .
Comparison of plants used in traditional medicine by Bantus and Pygmies per village.

Table 4 .
Comparison of therapeutic preparations used by Bantus and by pygmies of 6 villages.Allanblackia stanerana and Ricinus Communis negatively correlate with the second axis and are used to treat diarrhoea.