4.1. Plants used to treat hemorrhoidal diseases.
Until now, traditional medicine has been the primary means of treating hemorrhoidal pathologies in Katanga, and various plants are used for this purpose. This study reports for the first time 24 taxa of the 100 plants reported in our surveys as plants used in the management of hemorrhoidal pathologies, in view of the available literature. These are Acmella caulirihza Delile (Asteraceae), Aidia micrantha (K.Schum.) Bullock ex F.White (Rubiaceae), Amaranthus hybridus L. (Amaranthaceae), Anonidium mannii (Oliv). Engl. & Diels (Annonaceae), Antirrhinum majus L. (Plantaginaceae), Baccharoides adoensis (Sch.Bip. ex Walp.) H.Robc (Asteraceae), Chromolaena odorata (L.) R.M. King & H. Rob. (Asteraceae), Crossopteryx febrifuga (Afzel. ex G.Don) Benthc (Rubiaceae), Diplorhyncus condylocarpon (Mull. Arg.) (Apocynaceae), Droogmansia munamensis De Wild (Fabaceae), Erigeron bonariensis L. (Asteraceae), Ficus laurifolia Lam.f (Moraceae), Ficus stuhlmannii Warb (Moraceae), Ficus sur Forssk (Moraceae), Garcinia punctata Oliv. (Clusiaceae), Indigofera capitata Kotschyb (Fabaceae), Mesosphaerum suaveolens (L.) Kuntze (Lamiaceae), Ocimum centraliafricanum R.E.Fr. (Lamiaceae), Passiflora foetida L. (Passifloraceae), Pericopsis angolensis (Baker) (Fabaceae), Symphytum officinale L. (Boraginaceae), Uapaca guineensis Müll.Arg.c (Phyllanthaceae), Zanha africana (Radlk.) Exellb (Sapindaceae) and Zanthoxylum chalybeum Engl. (Rutaceae) (Table 2). The most cited by more than 60% of interviewees are: Mesosphaerum suaveolens (CI: 0.704), Ficus laurifolia (CI: 0.635), Ficus stuhlmannii (CI: 0.635) and Erigeron bonariensis (CI: 0.623).
Of the 24 taxa, 14 have not previously been studied for their anti-hemorrhoidal activity. In order of importance of citation, the taxa are as follows: Crossopteryx febrifuga, Ficus stuhlmannii, Ficus laurifolia, Indigofera capitata, Diplorhynchus condylocarpon, Droogmansia munamensis, Baccharoides adoensis. Aidia micrantha, Erigeron bonariensis, Garcinia punctata, Acmella caulirhiza, Amaranthus hypochondriacus, Anonidium mannii, and Ocimum centralafricanum. According to Plants of the World Online (https://powo.science.kew.org ), all of these taxa are native to the DRC, with the exception of Erigeron bonariensis and Amaranthus hypochondriacus, which are introduced taxa.
Of the 14 taxa initially reported by this study as plants with anti-hemorrhoidal uses in Katanga, a literature search revealed that only eight taxa, namely Acmella caulirhiza [135], Aidia micrantha [78], Amaranthus hypochondriacus [136], Anonidium mannii [137], Crossopteryx febrifuga [40,41], Diplorhynchus condylocarpon [37,42,138], Droogmansia munamensis [40], Garcinia punctata [139,140] have previously been documented as medicinal plants in Congolese traditions.
Although not reported as medicinal plants in the Democratic Republic of the Congo (DRC), three of the fourteen taxa, Indigofera capitata, Baccharoides adoensis, and Erigeron bonariensis, are reported as medicinal plants in other African regions. In Nigeria [141] and, in Uganda [142], powder from Indigofera capitata is employed as a remedy for snakebites, while in the Republic of Congo, the dried infrutescences of this plant are utilized for their hallucinogenic properties [143]. In Zimbabwe, Baccharoides adoensis is traditionally employed for the treatment of fever, upper respiratory tract infections, and currently for tuberculosis [144]. In Kenya, the root decoction is utilized for the treatment of sexually transmitted diseases, heart and kidney problems, while the leaves are employed in the treatment of malaria and tuberculosis [145]. In South Africa, the decoction of Erigeron bonariensis [synonym: Conyza bonariensis (L.)] is a folk remedy that is widely used for the treatment of tuberculosis. The leaves of this plant are employed as folk medicine for the treatment of a number of ailments, including rheumatism, gout, cystitis, nephritis, dysmenorrhea, toothache, and headaches [146].
To the best of our knowledge, although Ficus stuhlmannii, Ficus laurifolia, and Ocimum centraliafricanum are considered native plants to the country, no medicinal use has yet been reported for any of them. This study, therefore, presents the first account of the related ethnomedicinal knowledge. The fact that Ocimum centraliafricanum was reported only by the household population indicates that ethnomedicinal knowledge in our study area is not the exclusive domain of traditional healers. This is further corroborated by the fact that ethnomedicinal knowledge in our area is a family legacy, as evidenced by the findings of previous studies [37,40,42,147]. Although these plants are not reported as having anti-hemorrhoidal uses, some taxa of the same genus are used in traditional medicine to treat hemorrhoidal ailments. This is exemplified by Ocimum gratissimum, whose leaves are utilized in Benin as a decoction against typhoid fever [148]. The same is true of the taxon Ocimum basilicum L described in the Persian pharmacopoeia, which has been demonstrated to possess anti-inflammatory and myorelaxant properties in vivo, thus confirming its indication in the management of hemorrhoids [149]. In the Ficus genus, several taxa have been reported to be used in traditional medicine to treat hemorrhoids, including Ficus vallischoudae delile [150], Ficus exasperata Vahl [151], Ficus carica L [149], Ficus umbellata (Vahl) [152], Ficus benghalensis [153], Ficus sycomorus L, Ficus palmata Forssk, and Ficus vasta Forssk [30]. The two taxa of the Ficus genus reported in our study contribute to the growing list of numerous species of this genus used in various cultures for the management of hemorrhoidal pathologies.
The majority of the medicinal plants mentioned by the respondents belong to the Fabaceae family, with 10 taxa identified (Fig. 3a). The prevalence of Fabaceae in this study can be attributed to the fact that it is the most dominant family of medicinal plants in the region. Ethnobotanical studies conducted in the Miombo region (Democratic Republic of the Congo, Tanzania, Angola, Zambia, Malawi, Zimbabwe, and Mozambique) have demonstrated that Fabaceae is the most prevalent family of medicinal plants. A case in point is the study conducted in the Sikonge district of Tanzania, which found that Fabaceae accounted for seven out of 28 taxa [35]. Another example is the study conducted in the province of Bié in Angola, which found that Fabaceae accounted for 12 out of 87 taxa [154]. A similar pattern was observed in the provinces of West, Copperbelt, Central, and Northern Zambia, where Fabaceae accounted for seven out of 35 taxa [155]. A similar pattern emerges from studies conducted in Zomba, Malawi, where Fabaceae accounted for 10 out of 54 taxa [156], and in Gokwe, Zimbabwe, where Fabaceae represented 13 out of 127 taxa [157]. A bibliographical review of medicinal plants in Mozambique also highlighted the preponderance of Fabaceae, with 95 out of 731 taxa [158]. In the Democratic Republic of the Congo (DRC), the Miombo forest covers the provinces of Lualaba, Tanganyika, and Haut-Katanga. In Haut-Katanga province, where the city of Lubumbashi is located, no study has inventoried and characterized all the medicinal plants in the region. However, several ethnomedicinal studies targeting a specific pathology have been carried out, and in most cases, Fabaceae have taken the lead. These include the study of plants used to treat gastrointestinal disorders in Kamina and Kanyama (n=10 taxa, Fabaceae =2 taxa [159], the study of anti-cariogenic plants in Lubumbashi (n=14 taxa, Fabaceae = 3 taxa [160], and the study of anti-malarial plants in the Lubumbashi area and its surroundings (n= 19, Fabaceae: 11 taxa [161], n= 96, Fabaceae = 22 taxa [41]). The study on anti-diabetic plants from Lubumbashi and its surroundings yielded 45 taxa, with Fabaceae accounting for 11 taxa [40]. The study on plants used against urogenital schistosomiasis yielded 61 taxa, with Fabaceae accounting for 17 taxa [37]. The study on plants used in the management of sexual dysfunctions in the Kampemba commune (Lubumbashi) yielded 21 taxa, with Fabaceae accounting for 7 taxa [162] is followed by the study on plants used in Lubumbashi and surrounding areas to treat gastritis (n=14, Fabaceae = 3 taxa [163]. Finally, the study on plants used in Lubumbashi to treat typhoid fever (n=54, Fabaceae = 20 taxa) [42] is presented.
Each of the plants reported in this study is named in one of the DRC's local languages, with Swahili, Luba, and Bemba being the most prevalent (Fig. 3b). This result is consistent with previous ethnobotanical studies conducted in the region [37,40,162,164], which have reported the predominance of Bemba and Luba in the practice of traditional medicine in Katanga. It is noteworthy that the names of ethnic groups not endemic to Katanga, such as Lingala and Kikongo, which are languages spoken in the west of the country, also appear in the list. This may be indicative of a certain degree of cultural cross-fertilization that traditional Katangese medicine has undergone [42].
A citation index: CI of 0.7 or greater was observed in three taxa, which were the most frequently cited in the overall study. The most frequently cited taxa were Phyllanthus amarus Schumach & Thonn f. (Phyllanthaceae), Terminalia mollis MA Lawson f. (Combretaceae) and Mesosphaerum suaveolens (L) Kuntze (Lamiaceae). These taxa were reported by both traditional healers and the general population. According to Plants of the World Online (https://powo.science.kew.org/ ), only Terminalia mollis is native to the DRC, while the two other taxa are introduced plants. To the best of our knowledge, only the first two taxa are reported as medicinal plants in the DRC.
In southern Katanga, the infusion of Phyllanthus amarus leaves is employed to treat asthma, diabetes, typhoid fever, hepatitis, bronchial infections, and peptic ulcer [42], while decoction of the whole plant is utilized to treat dysentery [39]. In Central-Kongo, infusion of the plant's leaves is employed to promote diuresis, while maceration of the roots is utilized to treat amoebiasis and snail fever [137]. Its potential use in the treatment of haemorrhoidal pathologies may be based not only on its anti-inflammatory properties, as demonstrated in vitro [115], but also on the numerous flavonoids reported in its leaves [165], which have been associated with strengthening blood vessel walls, increasing venous tone and lymphatic drainage, and normalizing capillary permeability at the anal level [166,167].
The root bark of Terminalia mollis is employed in Katanga as a decoction for a variety of ailments, including dysentery, intestinal worms, cancer, lice, diarrhea, abdominal pain [138,168], typhoid fever [42], sexual dysfunction [162], diabetes, and syphilis [40]. In powder form, they are employed as a treatment for jaundice. The anti-inflammatory activity observed in vitro and the presence of tannins in its root barks may be the basis for its use against hemorrhoids.
To the best of our knowledge, Mesosphaerum suaveolens has never been reported as a medicinal plant in the Democratic Republic of the Congo (DRC). However, the plant is a species that has been traditionally used for the treatment of a wide range of ailments, including stomach pain, cough, verminosis, ulcer, liver disease, fever, influenza, nasal congestion, and inflammation in various countries, such as Brazil, Benin, India, Nigeria, and Togo [169]. The use of the plant against hemorrhoids is linked to the presence of numerous phenolic compounds isolated from its leaves and to its anti-inflammatory activity in vitro [100].
The majority of the taxa identified in this study are either trees or shrubs (Fig. 5), which is consistent with previous ethnobotanical studies conducted in the region [39,42,161,170]. Previous ethnomedicinal studies targeting anti-hemorrhoidal plants have yielded varying results regarding the predominant morphology of the taxa used, depending on the study. In a study conducted in southwestern Nigeria, the majority of taxa inventoried were trees [70]. This is also the case for the study carried out in southeast Cameroon [34] or in Tabora, Tanzania [[35]. The results were similar to those reported in our study. In contrast, in studies conducted in Madurai district in India [171] or in north-central Nigeria [32], grass was in the majority. The morphological aspect of taxa is therefore not a specific characteristic of plants with a reputation for anti-hemorrhoidal action. However, the preferential use of tree or shrub morphological types offers the advantage of year-round availability of plant material, providing the possibility of uninterrupted pathology management throughout the year. However, this practice increases the risk of extinction of a taxon in great demand, especially in the current context of global warming [172–174]. It would be beneficial for traditional healers to receive training in plant taxon conservation techniques, particularly in situ and ex vivo methods and biotechnological approaches. Additionally, it is crucial for the country to regulate harvesting practices and the use of plant resources for the intensive management and conservation of medicinal plants, with the objective of perpetuating the practice of traditional medicine while eradicating the risk of extinction of interesting taxa.
4.2. Anti-hemorrhoidal Recipes
Of the 117 anti-hemorrhoidal recipes, over 60% are based on leaves, which have been prepared in 7 different ways, with decoction being the most common method (Figure 8). The preponderance of leaves and decoction as the part used and mode of extraction of the active ingredient are reported in various ethnobotanical studies carried out in Katanga [37,41,160,161]. However, it should be noted that these modes of extraction are not universally consistent. In other ethnobotanical studies conducted in the same region, the root was found to be the main organ used [40,175]. This diversity in the organ preferentially used is also observed in ethnobotanical studies focusing on plants with anti-hemorrhoidal uses. In some cases, the leaf is the most commonly used organ [30,32,176], while in others, the root [35,177–179], stem bark [34], or aerial parts [180] are the preferred choice. The lack of consensus on the most important organ for the use of plants in the management of hemorrhoidal pathologies can be justified by the diversity of compounds likely to contribute to the management of hemorrhoidal disorders. The utilization of leaves as a source of raw material offers a number of advantages. (i) Leaves are generally more accessible and abundant than other plant parts such as roots or bark, which may require damaging the plant to harvest [181]; (ii) they can contain a high concentration of bioactive compounds because they are the site of photosynthesis and other metabolic processes, which can lead to the accumulation of beneficial phytochemicals [182]. (iii) They are more readily dried and ground than other plant parts, which renders them more convenient for preparing extracts and medicines [182]. (iv) They are more sustainable as they can be harvested without killing the plant, allowing for continuous use and conservation of plant species [181].
In traditional medicine, the preparation of a medicinal recipe through the use of a decoction offers several advantages. Firstly, it is an optimal method for extracting active compounds that are stable at high temperatures. Secondly, the process does not necessitate the use of complex or expensive equipment, thereby facilitating its widespread applicability. Thirdly, the process is relatively straightforward and does not necessitate the involvement of a trained operator, which is advantageous in traditional settings. Fourthly, it is a cost-effective method that can be readily implemented in a domestic setting. Nevertheless, decoctions are unsuitable for the extraction of heat-sensitive constituents, as the boiling process may result in their degradation [183,184]. Nevertheless, it is necessary to await the results of biological experiments before a proper assessment of the choice of organ and method of preparation used for each recipe can be made.
In contrast to previous ethnobotanical studies conducted in the region, which predominantly reported oral administration [40–42], our study primarily focused on topical applications. This is consistent with previous studies on plants purported to have anti-hemorrhoidal properties [30,32,34]. This is particularly evident when considering the localized nature of hemorrhoidal pathologies.
The majority (n=101) of the recipes documented in this study utilize a single plant, a finding consistent with several ethnobotanical studies conducted in Katanga [37,38,40]. However, there are also recipes resulting from mixtures of two or three taxa (n=16), a pattern observed in other ethnobotanical studies conducted in the region [42,162]. While the combination of plants may be based on the search for a certain synergy, there is a risk of increasing the risk of drug interactions and collateral effects. Nevertheless, it is of the utmost importance to remain vigilant during biological experiments in order to ensure that each recipe is duly evaluated.
4.3. Knowledge of Hemorrhoidal Diseases
In this survey, respondents referred to hemorrhoidal pathologies in Swahili as "Kilonda ntumbu," which translates to "the wound of the belly." This term is linked to the perception among the local population that hemorrhoidal pathologies originate from a specific type of diet, which is reflected in the allusion to the stomach.
The fact that more than 65% of subjects mentioned symptoms typically associated with hemorrhoidal pathologies (Table 6) suggests that the people interviewed were familiar with the pathology for which they mentioned healing plants. This finding is consistent with previous studies that have demonstrated the prevalence of hemorrhoids in Lubumbashi [31].
4.4. Other pathologies treated by inventoried plants
In the Democratic Republic of the Congo (DRC), the 10 most deadly pathologies are in order of importance, as follows: malaria, tuberculosis, lower respiratory infections, neonatal disorders, diarrheal diseases, stroke, ischemic heart disease, road injuries, hypertensive heart disease, and cirrhosis and other chronic liver diseases [173]. Among the most deadly pathologies, the plants inventoried in this study were cited in the treatment of diarrhea (31 taxa), malaria (10 taxa), lower respiratory infections (7 taxa), and tuberculosis (2 taxa) (Table 4). It can be reasonably concluded that the resource persons consulted during this study have plant resources capable of coping with at least four of the ten most deadly pathologies in the Democratic Republic of the Congo. This provides indirect evidence of the capacity of traditional medicine in Lubumbashi to address the major health challenges facing the DRC.
In addition to hemorrhoidal pathologies, the resource persons have identified at least ten taxa for each of the following five pathologies: In descending order of importance, these are gastrointestinal disorders, diabetes, sexually transmitted infections, malaria, and wounds (Table 4). The availability of multiple taxa to treat a given pathology indicates the community's capacity to address the condition in question. Given that traditional medicine is culturally specific, this can provide insight into the particular management approaches of a given community in the context of specific pathologies.
4.5 The socio-demographic characteristics of the interviewees.
In contrast to previous ethnobotanical studies conducted in Lubumbashi, this study interviewed a greater proportion of women than men [40–42,162]. This discrepancy can be attributed to the fact that, unlike the present study, the aforementioned studies were conducted among practitioners of traditional medicine, predominantly men. In contrast, the present study's account was conducted with the general population, which, like the national population in the 40-60 age range, is predominantly female according to Index Mundi in 2023 (https://www.indexmundi.com ). Furthermore, the fact that the majority of informants were met in households may also explain the preponderance of women. Indeed, in households, the probability of encountering women during surveys is higher than that of encountering men, particularly given that in our society, household tasks are typically performed by women. Almost two-thirds of those surveyed had experience with the use of medicinal plants to treat their ailments, which suggests that traditional medicine plays a role in the study area. These data are consistent with a study conducted in the region on the practice of traditional medicine, which found that 79.4% of respondents had utilized traditional medicine to address their health or social concerns [31]. Moreover, several of the plants referenced in this study have been identified as anti-hemorrhoidal agents in other regions, and some have been demonstrated to possess indirect anti-hemorrhoidal properties (Table 2). These findings should enhance the credibility of the information presented in the present study.