Abstract: A series of semi-structured interviews with traditional practitioners from the South of Congo Brazzaville allowed us to gather the names of 200 plants entering traditional preparations against pain. Some were already well studied for their analgesic and/or psychotropic properties but others were very little documented. We selected 51 plants, belonging to 32 families, which seemed promising but had not yet been studied in laboratory. For each plant, we collected the following data: used plant parts, modes of preparation and administration, as well as indications relating to the treatment when they were available. Around 150 traditional recipes were thus recorded. In analgesic as well as in psychotropic preparations, leaves are the most used part (43 and 40% of citations, respectively), followed by roots or root bark (17-13%), aerial part (11-6%), stem and trunk bark (20-11%). Decoction is the major mode of preparation and in most cases the preparation is drunk or applied locally (friction, massage). As a rule, plants used, dosage and length of the treatment shall vary depending to age, sex and general health condition of the patient. Self-medication can thus be very dangerous, all the more because some of the plants we studied are easily bought in the market places of Brazzaville or Pointe Noire.
INTRODUCTION
Congo disposes of an important pharmacopoeia and like all Central African countries, of a rich flora, which gives us a great opportunity of studies and action for the promotion of pain-relieving compounds. As in most countries of the South, the Congolese population resorts essentially to medicinal plants for its health requirement. This may by choice for some persons, but it also reflects the lack of financial means for most people. It is the case for the treatment of pain, highlighted now because of the difficult socioeconomic conditions (armed conflicts, unemployment) and of the psychological and physical troubles that they generate (pain, psychoses, ulcer, mental diseases, etc.). In the traditional Congolese medicine, the well-being is perceived as holistic, meaning that pain relieving will both resort to analgesic and to psychoactive plants, in order to both heal the physical pain and allay the fears and anxieties of everyday life. This holistic conception of the health is common to all the countries of the Bantu area (Cocks and Moller, 2002; Akendengue et al., 2005). If these treatments are not supervised, they can turn out to be nocive to health or addictive. The growing practice in the towns of self-medication, without consultation of doctors or tradipractitioners (traditional practitioners) does not help. Koubouana et al. (2000) reported the death of young people in Congo Brazzaville by intoxication with Datura fastuosa and the survey of Maiga et al. (2005) showed that numerous toxic plants are sold in the markets in Mali and that without the indications of the tradipractitioners, people can easily get poisoned.
CERMA (Centre of Study and Research of Médecins d`Afrique) works to promote traditional medicine, in collaboration with an extended network of tradipractitioners in tropical Africa. We though urgent to start a vast program to study the potentialities of medicinal plants in pain relieving. Indeed, many Congolese plants commonly used by tradipractitioners for their pain-relieving activity have to this day never been studied, either in ethnobotany, pharmacology or chemistry. It was thus necessary to realize a systematic inventory of the information held by each tradipractitioner and to complete it by the data of the relevant literature, in order to dispose of accurate and coherent information. This collected information will be of use to tradipractitioners to enrich their practice thanks to the mutualisation of the knowledge. It will be also very useful for the actors of health who support tradipractitioners (as the Service of Traditional Medicine in Congo) and to the researchers, for the pharmacological validation of the traditional preparations and the isolation of the compounds responsible for the analgesic or psychotropic activity of these plants. We inventoried all the plants traditionally used by tradipractitioners (Nganga) of the south of Congo Brazzaville for pain-relieving. This systematic study was followed by a literature review to check whether the traditional activities had been validated in laboratory essays. In this article, we present 51 plants which stand out from the study as being at the same moment the most promising and the least studied.
MATERIALS AND METHODS
Study area: Besides the two main cities of Congo, Brazzaville
and Pointe-Noire, the zone covered for our study stretches in the south
of Congo, in the Pool region (Fig. 1). The two cities
count about 2,000 000 inhabitants and the villages of the Pool add 240,000
inhabitants to that count, the total population of the country being of
3,500 000 inhabitants (data of 2004). Vegetation is most often savannah,
with a few forest patches. The climate is of the «Guinean-forest»
kind, as it is the case for the major part of the country. The average
annual temperatures are tropical (between 23 and 27°C) and the annual
rainfall is around 1200 mm, with dry seasons between May and September.
| Fig. 1: | Study area in the South of Congo |
Method used for interviewing the tradipractitioners: A semi-structured interview form was designed to get information from the tradipractitioners` knowledge about the plants with analgesic and/or psychotropic indications. Interviewed tradipractitioners were either part of the network of Médecins d`Afrique or persons known to the members of this network and recommended by them. Makambila and Banzouzi conducted interviews during a period of 2 months, either in French or in Kikongo (a language in which most tradipractitioners of our study area expressed themselves more easily). Having ensured that the questioned tradipractitioners understood well the meaning of analgesic and psychotropic, the questionnaire was filled for every named plant. This questionnaire contained the contact details for interviewer and tradipractitioner, personal information about the tradipractitioner (age, sex, education level) and, for every plant, the following issues:
| • | Botanical information (family, genus and species, local names) |
| • | Used part(s) of the plant |
| • | Preparation, application and dosage of the remedies |
| • | Evaluation of success |
| • | Known side effects and contraindications |
In total, 26 tradipractitioners were interviewed.
Plant material: We could not collect plant material of all the plants mentioned by the tradipractitioners during our study. We shall discuss in this paper only the plants which names were most often given and for which we could get a herbarium specimen. Botanical determination for each of these plants was checked by the botanists of CERVE and a voucher specimen was deposited at the herbarium of the CERVE (collection numbers: MKC001-051). These plants will serve later for tests.
RESULTS AND DISCUSSION
Information on tradipractitioners: The 26 tradipractitioners were generally persons aged from 40 to 60, with a little more men (15/26) than women (11/26). Their level of education varied a lot, but 18 of them have at least completed their college years (secondary education) and 3 have studied at University. Each could provide a list of 5 to 10 plants potentially interesting for present study.
Plants intervening in analgesic and/or psychotropic preparations: Interviews allowed us to record the names of 200 Congolese plants intervening in analgesic and/or psychotropic preparations. A bibliographic research in online databases allowed us to put aside those who had already made the object of numerous studies and whose activities were well documented, such as Tabernanthe iboga, Datura stramonium, Cannabis sativa, Voacanga africana or Alchornea floribunda (De Smet, 1996) to name only them. We kept only plants having made the object in our knowledge of less than 5 chemical studies and for which we could easily collect specimens. This way, we reduced the number of plants presented in this study to 51, divided in 32 families. Twelve plants had analgesic indications (A) only, 9 plants had psychotropic indications (P) only and 30 plants were mentioned for both activities (Table 1). Among these 51 plants, 13 plants were reported only once, 34 plants were reported 2 to 5 times and 4 plants were named 6 times or more, either as analgesic, or as psychotropic.
These last species, obviously the most used, are Bryophyllum pinnatum
(Lam.) Oken (Crassulaceae), Erythrophleum guineense G.Don (Caesalpiniaceae),
Harungana madagascariensis Lam. ex Poir. (Hypericaceae) and Hymenocardia
acida Tul. (Euphorbiaceae). All 4 plants had both analgesic and psychotropic
indications. It was noted that if Elaeis guineensis Jacq. (Arecaceae)
was reported only 5 times as main plant in remedies, its oil often intervenes
as adjuvant. This plant is therefore also one of the most used. Only 5
plants, Bryophyllum pinnatum, Conyza sumatrensis, Culcasia scandens,
Eleais guineensis and Lippia adoensis have been studied
previously for their analgesic activity. For C. sumatrensis, the
analgesic activity is due to the presence of sesquiterpenoids and for
L. adoensis, the analgesic activity is due to its essential oil.
Psychotropic activity was studied for 7 plants, Cola acuminata,
Cola hispida, Mostuea hirsuta, Newbouldia laevis,
Piper umbellatum, Strychnos aculeata and Voacanga bracteata,
but without identifying a particular compound, apart from alkaloids for
V. bracteata. The references of the concerned studies are given
in Table 1. For the 39 others plants, traditional activity
remains to be confirmed scientifically. However, for some of these plants,
other species of the same genus have been studied, providing a source
of information and it has been pointed out in Table 1
when a genus had been studied for the activities which interest.
| Table 1: | Traditional indications of selected plants and laboratory confirmations of their activity |
Traditional analgesic and psychotropic preparations: We collected
155 preparations utilizing our plants. They are shown in Table
2, with indication of alleged activity (A for analgesic and P for
psychotropic). The majority of these preparations used a single plant
and most often only one plant part, 23 preparations only used combinations
of plants. In psychotropic preparations as well as in analgesic ones,
leaves are the most used part, representing 40 and 43% of citations, respectively.
Other used plant parts are roots or root bark (13-17%), aerial part (6-11%),
stem and trunk bark (11-20%). According to plants, between 1 and 4 different
parts can be used for the same type of indication. For 20 plants out of
51, tradipractitioners agree about the active part. So, there are the
leaves of Bryophyllum pinnatum, Clematis simensis, Crossopteryx
febrifuga, Dichrocephala integrifolia and Piper umbellatum
that are systematically reported. For other plants as Anonidium mannii,
this is the stem bark. In the case of Cnestis ferruginea or Ficus
mucuso, there are the fruits. For 23 other plants, tradipractitioners
use 2 parts, among which in general leaves. Finally, for the 8 remaining
plants, by cross-checking all the information, between 3 and 4 parts are
recommended. In some cases, there is a net separation between the plant
parts used in analgesic preparations and in psychotropic ones, as for
instance for Cola acuminata (bark analgesic, fruits and seeds psychotropic),
Cola hispida (leaves analgesic, seeds psychotropic), Crossopteryx
febrifuga (roots analgesic, leaves psychotropic) or Triumfetta
cordifolia (wood analgesic, leaves psychotropic). However, in most
cases, one or more parts of the same plant are used in both kinds of preparation.
| Table 2: | Analgesic and psychotropic preparations with the studied plants |
Modes of preparations are consistent with what is generally reported in Congolese traditional medicine (Hirt and Bindanda, 1993; Hagenbucher-Sacripanti, 1989; Adjanohoun et al., 1988; Bouquet, 1969): about 60% of plants are treated as aqueous decoction and 26% are simply squeezed to extract sap or pulp. Infusion arrives far behind (4%) and aqueous or hydro-alcoholic maceration (using palm wine) represents in total only 2% of reported modes of preparation. An original mode of preparation, calcination, was reported for 5% of recipes. In general, plants are used fresh and remedies are processed according to patients` requirements when they arrive and almost never beforehand.
Dosage of the remedies, application and duration of the treatments: The privileged mode of taking is the oral way (50%), followed by local application, friction and massages (20% in total), inhalation (8%) and by ocular or nasal instilment (6%). These modes of administration can be combined, as for instance oral way and local application for a decoction of Spilanthes uliginosa or then oral way, inhalation and enema for a decoction of Piper umbellatum leaves. We could not always understand the definite reasons of these combinations. The opinion of tradipractitioners is that they allow to hasten the expected effect of treatments. Dosage for the remedies and length of treatments were seldom given accurately (only for 10% of the preparations). When this information was available, we recorded it in Table 2. Some preparations are specifically designed for children, such as Celosia trigyna in enema. Tradipractitioners also pay a special attention to side effects and contraindications of preparation. For instance, they avoid the use of the abortive Gardenia jovis-tonantis when the patient is a pregnant woman. As a rule, plants used, dosage and length of the treatment shall vary depending to age, sex and general health condition of the patient.
Some plants included in our study are freely sold on the markets of Brazzaville and Pointe-Noire, the two main cities of Congo, which we visited. We can report Aframomum melegueta (fruits), Biophytum petersianum (whole plant), Brillantaisia patula (leaves), Cola acuminata (seeds and bark), Elaeis guineensis (fruits, seeds, stem, sap), Piper guineense (fruits). There were also other plants even more known and not included in our list, such as Cola nitida (seeds), Tabernanthe iboga (resins). And, in self-medication, these plants can be dangerous if preparations and dosage are not adapted to the patient. That is why, agreeing with tradipractitioners, we estimate urgent and necessary the systematic study of the analgesic and psychotropic plants which they know, with the intention of rationalize their utilization and have a toxicological assessment of all these plants.
CONCLUSION
Our field study with Congolese tradipractitioners enabled us to discover how much knowledge they have on the subject of analgesic and psychotropic plants, since they gave us about 200 plant names. There is therefore room for a better promotion of these plants. According to us, the first field study gave us a list of 51 plants interesting enough to be studied further. Each tradipractitioner has his favorite plants to treat the patients who come to consult him, but about 5 plants distinguish themselves because at least 7 of 26 questioned tradipractitioners use them. The big number of used plants can be explained to the fact that every tradipractitioner is interested in remedies used by the others and does not hesitate to learn from them to enlarge his knowledge. In most cases, a given remedy is specifically processed for a patient and will be changed for another one. Few remedies are prepared beforehand. The most frequent modes of preparations of remedies reported in this study are in accordance with those usually reported in Congolese traditional medicine: fresh leaves or roots, in decoction and most often drunk or locally applied. Present study raised the interest of tradipractitioners and they are very eager for this type of studies, from which they expect a mutualisation and therefore an enhancement of their knowledge. The following stage for us is a pharmacological screening (tests in vivo and in vitro) and studies of toxicity to estimate the cytotoxicity of preparations. In effect, to this day, only 14 plants on 51 have been studied in laboratory and a patent has been written for the triterpene saponins of Crossopteryx febrifuga. This work, important because request is strong from tradipractitioners and Community Health Centres such as those managed by Médecins d`Afrique, is under way. It is conducted by Mrs. Makambila, member of the CERVE and will make the object of a thesis at University Marien Ngouabi of Brazzaville.
ACKNOWLEDGMENTS
We are indebted to the tradipractitioners of the network of Médecins d`Afrique, who accomplished a consequent part of plants and data collection and the botanists of CERVE, who confirmed the botanical identification of collected plants, especially Gilbert Nzoungani. We also thank Misses Carole Vergne and Kirti Patel of the ICSN (CNRS, France) for their technical help in the redaction of this study and Pr Lallemand for his financial support.