Ethnomedicinal Knowledge of Plants Used in Nonconventional Medicine in the Management of Diabetes Mellitus in Kinshasa (Democratic Republic of the Congo)

Background People with diabetes, herbalists, and traditional medicine practitioners (TMPs) from Kinshasa use plants to treat diabetes, but no study has inventoried the plants used by these populations. The present study was conducted to identify the plants used in Kinshasa to treat diabetes mellitus. Methods The survey conducted in the form of a semistructured interview between March 2005 and August 2006 made it possible to collect ethnobotanical information from people with diabetes (n = 126), herbalists (n = 80), and TMPs (n = 120). Results The 326 subjects consulted (sex ratio M/F = 0.6, age 51 ± 7 years, and experience: 17 ± 5 years) provided information on 71 plants, most of which are trees (35%), belonging to 38 families dominated by Fabaceae (19.7%) and indicated in 51 other cases of consultation dominated by malaria (12%). From these 71 plants derived, 86 antidiabetic recipes were administered orally, where the leaf is the most used part (>50%) and the decoction (>46%) is the most common mode of preparation. This study reports for the first time the antidiabetic use of 11 species, among which Tephrosia vogeliiX (0.08), Chromolaena corymbosaX (0.06), and Baphia capparidifoliaX (0.06) present the highest consensus indexes (CI) and Marsdenia latifoliaW (UVp = 0.08) and Rauvolfia manniiX (UVp = 0.06) present the highest UVs. Conclusion The results show that Kinshasa people treat diabetes using several plants. Some are specific to the ecological environment; others are used in other regions. Pharmacological studies are underway to assess the therapeutic efficacy of these plants.


Introduction
Diabetes mellitus (DM) is a metabolic and chronic disease involving inappropriately elevated blood glucose levels (hyperglycemia).Hyperglycemia alone can impair pancreatic beta-cell function and contributes to impaired insulin secretion.Te body cannot produce and secrete sufcient insulin hormone or use it efectively.Tis insulin defciency leads to elevated blood glucose levels and decreases carbohydrate and protein metabolism [1,2].
Worldwide, 537 million adults (20-79 years old) live with diabetes.Tis number is expected to rise to 643 million by 2030 and 783 million by 2045.More than 3 out of 4 adults with diabetes live in low-income countries like DR Congo, and diabetes has been responsible for 6.7 million deaths in 2021, i.e., one end every 5 seconds [1].Cardiac, vascular, neurological, and renal damage and neuropathy may occur without appropriate treatment.Treatment includes diet, exercise, and medication [3].Given that most cases occur in low-income countries, where a signifcant fraction of the population resorts to traditional medicine, which essentially uses plant resources, medicinal plants constitute a credible alternative in the fght against diabetes mellitus.
Natural products have been shown to play an essential role in regulating pathophysiological signaling pathways, particularly in diabetes [4].Over 800 plant species showing hypoglycemic activities can be vital sources in discovering and developing new types of antidiabetic molecules [5].
Medicinal plants have a high potential to treat various ailments due to the presence of their signifcant bioactive phytoconstituents.Certain plants are rich sources of compounds reputed to be antidiabetic such as favonoids, alkaloids, phenolic compounds, and tannins, improving pancreatic tissues' efciency by increasing insulin secretion or decreasing intestinal glucose absorption [6].
Te World Health Organization insists that scientists conduct ethnomedicinal, ethnobotanical, and ethnopharmacological investigations to record and preserve traditional knowledge, create databases, and validate scientifcally traditional claims from the perspective of developing improved medication [7].
In the Democratic Republic of the Congo, a country with similarities to other developing countries, data on the prevalence of diabetes mellitus and the use rate of medicinal plants in their therapeutic load is not sufciently available.Although less systematic, some studies have reported presumed antidiabetic plants in Kinshasa [8,9].
Tis study completes the data reported in these studies while highlighting plants used by TMPs, diabetics, and herbalists in Kinshasa.

Experimental Framework.
Te city-province of Kinshasa is located between 4 °18′ and 4 °25′ south latitude and between 15 °18′ and 15 °22′ east longitude.It is bounded to the north and east by the province of Kwilu, to the south by the province of Congo Central, and to the west by the Republic of the Congo, with an average altitude of 300 m above the sea.Kinshasa city's climate is tropical.It is characterized by a long rainy season lasting for 8 months (October-July), discontinuous between January and February, followed by August and September in favor of the short dry season.Te vegetation of Kinshasa consists of degraded primitive forests, savannahs, and aquatic and semiaquatic formations in the valleys and Pool Malebo.It belongs to the Guinean-Congolese region, the Congolese basin domain, and the Congolese-Zambezian transition sector [10].

Ethnobotanical Data Collection. Tis cross-sectional descriptive ethnobotanical study was conducted between
March 2005 and August 2006 through semistructured interviews based on a questionnaire.Te discussion focused on knowledge about plants used to manage diabetes mellitus.Tree groups of subjects were consulted: people with diabetes, herbalists, and TMPs from Kinshasa.
People with diabetes were met in 4 health zones of the city of Kinshasa: Bumbu, Kalamu, Limete, and Makala, covering the biomedical centers for the care of people with diabetes in Kinshasa supervised by BDOM (diocesan ofce of biomedical works).Te reference health centers (RHCs) Libundi, Bondeko, Saint Clément, 2e Rue, the Bondeko clinic, and the Saint Joseph General Reference Hospital were concerned.
Te herbalists consulted during this study were met in 5 popular markets in Kinshasa, the central market, the Selembao market, the Matadi Kibala market, the Mariano market, and the UPN market.
Te TMPs were met in 4 communes of Kinshasa (Bumbu, Kalamu, Limete, and Makala).Tese municipalities are covered by the health zones selected during the survey of people with diabetes.TMPs were reached by snowballing from the TMPs provided by the population in each area concerned, and the investigations were carried out in Lingala.Te listed plant species were collected and placed in herbariums, then compared to the reference herbariums from Kisantu (National Agricultural Study and Research Institute), to identify the scientifc names.Tese were then formatted according to the Plants of the World online database: Plants of the World Online/Kew Science (https://powo.science.kew.org/) or African Plant Database (https://africanplantdatabase.ch/) or the World Flora Online (https://www.worldforaonline.org/).

Data Analysis.
Tree ethnobotanical indexes were calculated to assess the signifcant species: the usual value (UV), the fdelity index (FI), and the consensus index (CI).Te following formula determined the usual value (VU): VU = (Ui)/Ni, where Ui is the number of uses mentioned by an informant for a plant (organ) and Ni = the number of informants who cited the plant.Te following formula calculated the consensus index on the plant (organ) (CI): CI= Np/N, where Np is the number of people who cited the plant (organ) and N is the number of people who were consulted in the study.Te fdelity index of the recipe was calculated by the formula FI = nr/ Np, where nr = the number of people who cited the recipe and Np is the number of people who cited the plant.Apart from the 3 ethnobotanical indexes mentioned above, the relative citation frequency (RCF) was also determined.It was calculated by the formula F CR = nx100/N with n being the number of occurrences of the factor examined and N = total number of the population concerned.Tis factor was used to quantify various factors analyzed in this study, except those involved by the ethnobotanical indexes.
In this study, UV makes it possible to evaluate the medicinal importance of a plant in the environment; CI makes it possible to identify the level of consensus of the population on the use of a species in the management of diabetes mellitus; and FI makes it possible to establish the level of loyalty that emerges among informants on an antidiabetic recipe.

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Evidence-Based Complementary and Alternative Medicine  1).It should be noted, however, that the TMP class provided the largest most signifcant number of species, i.e., 31% (Figures 1(c) and 1(d)).
85% of identifed medicinal plants in the present study have been previously used in local medicines as antidiabetic plants (13%).However, 72% have demonstrated an antihyperglycemic efect.Nevertheless, this study highlights 11 plant species never reported before as antidiabetic plants, among which Tephrosia vogelii X (F CR � 7.98), Chromolaena corymbosa X (F CR � 6.44), and Baphia capparidifolia X (F CR � 5.52) are the most cited (Table 1).2).Te administration of the two types of recipes is essentially done orally, the leaf is the most used organ (50 and 58.3%), and decoction is the most predominant mode of preparation with 46.3 and 66.7% (Figure 4).

Ethnomedical Profle of Inventoried
Figure 4 indicates that Baphia capparidifolia, Chromolaena corymbosa, Marsdenia latifolia, Rauvolfa mannii, and Tephrosia vogelii are among the critical plant species, according to their consensus index and use value.
In these recipes (R81-R86), we can observe the associations of leaves-leaves, roots-roots, and leaves-roots, representing half of these associations.Only 12 of the 71 plants are involved in the recipes combining two plants.For these recipes of plants in association, the treatment duration varies between 30 and 45 days, and it is the combination of Albizia adianthifolia (leaves) and Annona senegalensis (roots) with an RCF of 4.6 which is the most cited: R85 (Table 3).
Te consensus indexes of the identifed antidiabetic recipes (ICR) varied between 0.01 and 0.31, with the highest value observed for the recipes R61, based on Persea americana X leaves, and R72, based on leaves of Senna alata X .
For the 11 plants reported for the frst time by this study as antidiabetics, the ICRs vary between 0.08 and 0.01, with Tephrosia vogelii X (0.08), Chromolaena corymbosa X (0.06), and Baphia capparidifolia X (0.06) showing the highest values.Usual plant UVp values vary between 0.02 and 0.12; the highest values were observed in Annona senegalensis W , Nauclea latifolia Y , and Erythrina abyssinica W with an UVp � 0.12 each.Note also that in the group of 11 taxa reported for prayer times by this study, UVp varies between 0.02 and 0.08; these are Marsdenia latifolia W (UVp � 0.08) and Rauvolfa mannii X (UVp � 0.06) which presented the highest values in this class (Table 2).

Sociodemographic Profle of Subjects Consulted.
Te surveyed and consulted during this study were either diabetics (38.7%) or herbalists (24.5%) or practitioners of traditional medicine (36.8%), primarily women (62.3%) whose majority age is between 48 and 58 years old.Still, the extremes are 18 and 70 years old.Tey mainly live either in the municipality of Kalamu (29.8%) or in Makala (29.4%), and their level of education is, on average, secondary (47.2%).Tey mainly exercise 4 types of profession, the most representative of which is either commerce (28.5%) or liberal work (24.2%).In most cases, they have experienced more than 11 years of use of medicinal plants in managing diabetes (Table 4).
We also sought to determine the correlation between a few variables that characterize the subjects consulted within the framework of this study.Te results show a positive linear correlation (R = 0.95, y = 0.4134x-6.5581)between the age of diabetic subjects and the number of years they have lived with diabetes.Similarly, a positive linear correlation is also observed between the age of herbalists and their years of experience (y = 0.5148x − 13.198, R 2 = 0.8372).In the same way, we noted a positive between the TMP age of the TMPs and the profession's expertise (y = 0.4076x − 8.3606, R 2 = 0.807) and their age with the number of patients they receive per quarter, y = 0.4525x − 10.394, R 2 = 0.9482 (Figure 6).

Discussion
Te Congolese, particularly the fora of Kinshasa, have plants that traditional medicine practitioners and the general population use to manage diabetes.Tis study was interested in inventorying these plants and presenting their Evidence-Based Complementary and Alternative Medicine Abelmoschus esculentus (L.) Moench X 0.61

Lv
In vitro α-glucosidase: 1 mg/mL, A: 70% [109] Sb In vitro α-glucosidase: 62.5 µg/mL, A: 20% [110] Ro [111] Rat: 150-300 mg/kg [ 2 and 3).Tese results are in agreement with the literature.Indeed, Fabaceae is reported to be the most prominent family of trees in Africa's tropical and dry forests [113].Tis importance of Fabaceae is observed both within the plant kingdom [114] and within African medicinal plants in particular [115].Te numerical predominance of Fabaceae in sub-Saharan Africa has been attributed to their ability to scavenge atmospheric nitrogen, allowing them to grow in nutrient-poor and rich soils [116].In our experimental framework, no accessible study has addressed the question of the preponderance of a botanical family over all the taxa used in traditional medicine in Kinshasa.Such a study would be desirable.However, the analysis of some ethnobotanical studies in Kinshasa shows that the Fabaceae constitutes one of the three most evoked families.Some previous studies in the Kinshasa reported the predominance of certain botanical families over others.As an illustration, a study on ethnopharmacological surveys of plants used in female intimate baths [116] mentioned the predominance of Rubiaceae (37%) and Fabaceae (11%).In contrast, another study on plants used to treat the symptoms of tuberculosis [117] reported the predominance of Fabaceae, Apocynaceae, and Lamiaceae, each with an FCR of 8.3%.In the same way, FCR = 47% and FCR = 12.7% were found respectively in the families of Rubiaceae and Fabaceae for a study on plants sold on the Kinshasa market [118], and an FCR of 7.7% in Fabaceae, Rubiaceae and Zingiberaceae for medicinal plants of the Lukunga district [119].Tere are also studies done on the management of diabetes in the region.Tis is the case of a survey carried out in the Kimbanseke and Selembao communes: n = 21, Rubiaceae F CR = 33.3%,Fabaceae F CR = 19.1% [9], or the study in Kwango and Kinshasa: n = 68, Fabaceae F CR = 19.1% [8].It would nevertheless be interesting to carry out an inventory of plants known to be medicinal in the DRC to highlight their specifc ethnobotanical characteristics.Tis concern has not been the subject of this study, which nevertheless contributes to highlighting the need for such data.
Te literature review carried out on 71 taxa shows that it is possible to group the plants into 3 classes: species for which no ethnobotanical or pharmacological information is available (class α), those with ethnopharmacological use without any scientifc evidence (class δ), and species for which scientifc evidence is available (class β) (Figure 1(d)).Te fact that 70% of species found are reported to be antihyperglycemic in vivo models (using rats) reinforces the credibility of the information obtained from our study.It suggests a high probability of fnding those with antihyperglycemic activity among the 30% of the remaining species.
Concerning ethnobotanical indexes, it should be noted that for an ethnobotanical study targeted towards a specifc pathology, the relative frequency of citations corresponds to the consensual citation index of the plant, which translates the consensus reached around a particular plant species on targeted use.Tere is a higher consensus for the 11 taxa not studied on using Tephrosia vogelii leaves (CIp = 0.08) as an antidiabetic than any other species of the same category (Table 2).Tis precedence which may result from this ethnobotanical index (CIp) is, however, to be put into perspective by the fact that a single category only told the plant of the subjects consulted, namely, people with diabetes, unlike, in particular, the leaves of the Crinum ornatum Z species which present the weakness of ethnobotanical index whose value is twice lower than that of Tephrosia vogelii (CIp = 0.04), but whose strength lies in the fact that it was informed simultaneously by the three sources: diabetics, TMPs, and herbalists, which reinforces the consensus around its use as an antidiabetic in the study environment.
Te study population uses three plant species most because of their highest UV of the series (0.12).Tese are Annona senegalensis, Erythrina abyssinica, and Nauclea latifolia (Table 2).Tis justifes their lower usual value of 0.02 (Table 2).All of its plants belong to the taxa category, whose ethnobotanical and pharmacological knowledge of diabetes has previously been reported.Terefore, the most common plants in the study would not be the most interesting in the context of this study, which aims to enhance the  Evidence-Based Complementary and Alternative Medicine    Malaria (FCR � 12%), cough (FCR � 9%), and diarrhea (FCR � 7%) constituted the 3 frst pathologies, apart from diabetes, for which the plants listed during this study are used.Tese pathologies are among the 10 most deadly pathologies in the DRC [121], suggesting that traditional medicine from Kinshasa will likely contribute to managing specifc pathologies of concern in DR Congo.It would be interesting to carry out studies to validate this ethnopharmacological knowledge to rightly understand the assistance of conventional medicine from Kinshasa in managing pathologies such as diabetes.
Te 71 inventoried plant taxa made it possible to list 86 antidiabetic recipes, 80 of which use a single plant (Table 2), and 6 recipes combine 2 simultaneous medicinal plants (Table 3).Nonetheless, considering all previous ethnopharmacological studies conducted in DR Congo [8,15,38,48], this one reports antidiabetic recipes of the plants used in association for the frst time.
Of all the antidiabetic recipes using a single plant and reported during this study, the leaf and the decoction constitute the most used organ and mode of preparation.Tese results (Figure 8) are in agreement with the studies carried out on the plants of Kisangani: leaf (57.6%), decoction (78.8%), and n � 33 [38], and plants of DR Congo gathered in a review article, leaves 39.2%, decoction: 60.5%, and n � 213 [52].Some disparities are nevertheless observed in a study in South Katanga, where the decoction (62.5%) was found to be the primary way of preparation and the root was found to be the most used organ: 41.3%, n � 95 [15].Te same is true in the study carried out simultaneously in Kwango and Kinshasa (n � 68), where the leaves at 65% proved to be the most used organ and maceration with 63% was found to be the most common mode of preparation solicited [8].Te herbal antidiabetic recipes    According to the subjects consulted, using a decoction would aim to extract and activate the active ingredient.Tis is a mixed idea, especially since this extraction procedure is more benefcial than harmful.Indeed, as much as it could facilitate the release of certain active principles often present in the plant in the form of glucosides, it could not only release specifc toxic secondary metabolites such as cyanogenic glycosides [122] but also deteriorate the active ingredient when the latter is thermolabile [123][124][125].Terefore, this practice remains to be assessed case-by-case, and only experimental work could determine its fair value.
About the various correlations established on specifc characteristics of the subjects consulted (Figure 8), this study shows that the older the diabetic issues, the longer they have lived with diabetes, which suggests that most of the subjects consulted would be diabetics from type 1.Similarly, the study reveals that the oldest TMPs, the most experienced and skilled, see more patients.Tis supposes that traditional medicine requires time to retain patients who would be more confdent towards the most experienced.Tis attitude is also observed in conventional medicine, where rationality would like the patient to be reassured by the doctor's experience before being consulted, especially for specifc pathologies.

Conclusion
Several plants are used in Kinshasa to manage diabetes mellitus by herbalists as well as by people with diabetes and traditional medicine practitioners.Tis study highlights not only antidiabetic recipes but also plants reported only in Kinshasa for the management of diabetes.It also evokes their usual values in this environment.It opens the way for a subsequent study to validate the antidiabetic use, particularly of particular species of the environment and those of specifc special interest there.
Plants.Te 71 plants inventoried during this study are used in 86 antidiabetic recipes, of which 80 recipes use one plant, and 6 combine two plants (Table W In vitro α-glucosidase: 25 μg/mL[107] Acacia karroo Hayne (Synonym)Voacanga africana Stapf W

8 2 :
Evidence-Based Complementary and Alternative Medicine Table Antidiabetic recipes in monophytotherapy and other indications.cell disease ER (number of citations per recipe); Eesp (number of citations per plant); CIR (consensus index of the recipe); CIp (consensus index of the plant); RRI (recipe reliability index); UVo (the usual value of the organ); UVp (the number of uses of the plant out of the number of uses of the set of species); NR (Nothing to report); Nu(number of uses); N (number of people consulted); Nu � 52; Complementary and Alternative Medicine paniculata, Baphia capparidifolia, Chromolaena corymbosa, Crotalaria medicaginea, Platymitra arborea, and Rauvolfa mannii.On the other hand, 11 medicinal plants, including Antidesma venosum, Costus phyllocephalus, Crinum ornatum, Diospyros heudelotii, Gladiolus gregarius, Lippia multifora, Millettia drastica, Mitragyna stipulosa, Palisota schweinfurthii, Tephrosia vogelii, and Terminalia mollis, have been quoted in traditional medicine as treating diabetes mellitus in various countries.However, they are not yet scientifcally validated (Table
: part used and proportion of the mixture; F: leaf; R: root; D.T.: duration of treatment; D: day; the F CR is expressed in % (n � 326); N °recipe-� antidiabetic recipe.

Figure 5 :
Figure 5: Other diseases are cured by the plants inventoried.

Figure 6 :
Figure 6: Correlations between Y-axis and X-axis variables of the characteristics of the subjects surveyed: Age lived since diagnosis of diabetes and age of diabetic subjects n=126 (a); Herbalism experience and age of herbalists n= 80 (b); Age of traditional medicine and practitioners (c); and Number of patients treated per quarter and age of traditional medicine practitioners (d).

Figure 7 :Figure 8 :
Figure 7: Map of Kinshasa city with diferent sites where data have been collected.

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Evidence-Based Complementary and Alternative Medicine used in Kinshasa align with the national trend, those used in Lubumbashi, the country's second-largest city.
Plants.Seventy-one plants were inventoried during this study.Tese plants were informed by 3 types of informants, herbalists (class Y), diabetics (class X), and TMPs (class W).

Table 1 :
Botanical characteristics and previous knowledge of the plants inventoried.

Table 3 :
Antidiabetic recipes that use two herbs in combination.

Table 4 :
General characteristics of the subjects consulted.Evidence-Based Complementary and Alternative Medicine ethnopharmacological knowledge of Kinshasa.If, in most cases, each plant inventoried during this study is also known and used by our resource persons for at least one other pathology, it should be emphasized that this is not the case with Tephrosia vogelii X and Platymitra arborea Y for which our informants only use it in the management of diabetes mellitus.
12P: practitioner of traditional medicine; experience in the diabetic category is the number of years since the patient was diagnosed with diabetes.12