ETHNO-BOTANICAL STUDY OF PLANTS USED FOR TREATING MALARIA IN A FOREST: SAVANNA MARGIN AREA, EAST REGION, CAMEROON

Abstract

Ethno-botanical surveys were conducted in Andom, a village situated in a forest-savanna contact zone from December 2011 to April 2012 with the aim to gather plants that are used in traditional medicine. The method used is direct interviews conducted among adult people, mainly women. The 36 persons interviewed prescribed a total of 219 citations and 94 recipes of 59 plant species distributed in 49 genera and 27 families in the treatment of malaria or fever. About 51.6 % of the citations are made of combination of two, three; four, five, six, or seven plant species. Some plant species cited by Andom people are well recognized for their activity against Plasmodium, is a credibility index which can be attributed to the pharmacopoeia of those people. It also illustrates the efficiency of the method used to identify medicinal plants of the Andom village. Future studies should be directed towards implementing strategies and programmes to identify active chemical substances of other plant species which have not yet been investigated for their chemical and anti-malarial activities in the region.

Headnote

ABSTRACT

Ethno-botanical surveys were conducted in Andom, a village situated in a forest-savanna contact zone from December 2011 to April 2012 with the aim to gather plants that are used in traditional medicine. The method used is direct interviews conducted among adult people, mainly women. The 36 persons interviewed prescribed a total of 219 citations and 94 recipes of 59 plant species distributed in 49 genera and 27 families in the treatment of malaria or fever. About 51.6 % of the citations are made of combination of two, three; four, five, six, or seven plant species. Leaves are the plant parts that are largely used; decoctions are the pharmaceutical forms that are more cited; and recipes are essentially administered orally. A total of 29 plant species (57%) used by Andom people against malaria are also known in other regions of Cameroon and other African countries for the same use. Among these, eight plant species representing 27.6 % are well recognised in the literature for their real activity against malaria including: Alstonia boonei, Carica papaya, Citrus limon, Cymbopogon citratus, Enantia chlorantha, Morinda lucida, Picralima nitida, and Vernonia amygdalina. The fact that some plant species cited by Andom people are well recognized for their activity against Plasmodium, is a credibility index which can be attributed to the pharmacopoeia of those people on one hand and illustrates the efficiency of the method used to identify medicinal plants of the Andom village on the other hand. Future studies should be directed towards implementing strategies and programmes to identify active chemical substances of other plant species which have not yet been investigated for their chemical and anti-malarial activities in the region.

KEY WORDS: Forest-savanna contact zone, Medicinal plants; Malaria; Recipe; Andom village.

INTRODUCTION

Malaria is a global disease that is predominant in the tropics and caused by blood parasites, Plasmodium falciparum, Plasmodium ovale, Plasmodium malariae, and Plasmodium vivax. The parasite is transmitted to its human hosts via various mosquito species of the genus Anopheles. Malaria has a great morbidity than any other infectious diseases of the world as well as a contributing factor to poverty in tropical and subtropical regions such as sub-Saharan Africa (World Malarial Report, 2008). Plasmodium falciparum; the pathogenic most widespread human malaria is becoming increasingly resistant to anti-malarial drugs. The malaria parasite has gradually developed resistance to the most commonly used medicines. The resistance of Plasmodium spp. to drugs such as chloroquinone has become a serious problem in areas of endemic malaria such as Cameroon, and in malaria-free areas with occasional imported cases. This requires extra effort and continuous search for new drugs, especially with new mode of action (Muregi et al. cit. Saotoing et al., 2011; Oketch-Rabah and Mwangi, 1998). Ethnobotanical survey is an important step in the identification, selection and development of the therapeutic agents from medicinal plants (Balick, 1985, 1990, 1994; Cotton, 1996; King and Tempesta, 1994). This paper aims to analyze the traditional use of medicinal plants in the treatment of malaria in Andom, a village situated in the forest-savanah contact zone, East region, Cameroon.

MATERIAL AND METHODS

The study site

Andom village is in the Eastern region, in the Lom and Djerem division, Diang subdivision or commune. The village was established in 1925 and is located at about 45 km from Bertoua, the regional capital of East Cameroon. Houses line both sides of National Route 1, which is 3.5 km, East to West. The population of Andom village is about 2,500. The Bamvélé people are classified within the Tuki, Bantou group, and along with the Baka and Bororo peoples, live in Andom village. Among them, the Bamvélé people are the most prevalent ethnicity within Andom village. Andom is located at the forest-savanna transition zone, with the savanna being the main useful lands. Cassava, groundnuts, maize and cocoyams seem to be in this order, the most important crops cultivated in this savanna area. But some people are moving more and more in the forest zone in search of new and fertile soils for cultivation. The mixed cropping of cassava and groundnuts or maize under grass fallow is the most common cropping system used in Andom village. In this fallow, the wild plant species Chromolaena odorata, known locally as "Bokassa" abunds. Non-timber forest products including wild fruits (moabi, bush mango), caterpillar (egbagéndong), bushmeat (grass-cutter, rats, duikers) are used in the daily diet of the villagers as sources of complementary proteins. Andom village is rich in medicinal plants which are used for the daily healthcare.

Ethno-botanical survey

Data for this study were obtained from direct interviews with the local people conducted from December 2011 to April 2012 in Andom village. The survey aimed at identifying plants used in the popular pharmacopoeia among local people. The household was considered as the sample unit. In each household data were mostly recorded from adult women (mothers), because they usually knew the plants better than men and younger people. They provided useful and firsthand information on the popular use of medicinal plants. During the survey, we made enquiry "as to what ailments were treated by which plant species" rather than asking "which plants were used to treat which ailments". For each health problem cited, the name of the plants and the plant parts used were carefully recorded.

For each health problem cited, details of prescriptions (plant part used, mode of preparation, etc.) were carefully recorded. The vernacular names of the plants were recorded as much as possible, and the plants mentioned by the informants were collected. The final identification of plants was made at National Herbarium of Cameroon Yaounde (YA) with the help of Dr. Onana and Mr. Paul Mezili. Voucher herbal specimens, collected in three samples are kept at the YA.

The therapeutic statements were made of a specific disease, a symptom or a physiological effect. Information on the diagnosis of ailments was provided through a semi-structured interview of nurses or local health officials. In this paper, anti-malarial plants refer to the plants used for treating malaria or fever on a broader scale.

RESULTS

List of anti-malarial plants

A total of 36 persons (Table 1) provided information on the use of medicinal plants in treatment of malaria comprising 29 women and 7 men. The average age of the informant is 54 years old. A total of 51 plant species were cited for which a total of 219 citations were made on malaria (Table 2). The plant species cited are distributed in 49 genera and 27 families. The most cited plant species are: Alstonia boonei (24 citations), Enantia chlorantha (22), Rauvolfia vomitoria (13), Dichrocephala integrifolia (12), Carica papaya (10), Citrus limon (10), Schumanniophyton magnificum (9), and Capsicum frutescens (9). The most represented families are Asteraceae (7 plant species) and Apocynaceae (5). The most cited families are Apocynaceae (52 citations), Asteraceae (31), Annonaceae (25), Rubiaceae (15), Rutaceae (11), Solanaceae and Caricaceae (10 citations each).

The list of the 219 citations of anti-malarial plants recorded in Andom village is presented in table 3. Each citation or line in the table presents for a given plant species, the scientific name, the associated plant (s), the plant part cited, the mode of preparation, the voice (way) of administration, and the code of informant(s) who indicated the recipe in brackets. The first letter of the code refers to the gender (M: male, F: female), the number indicates the order number of the informant in each gender.

Characterization of recipes

Recipes are characterized by the plant part, the pharmaceutical form, the mode of administration, and the degree of association of plant species involved.

A total of nine plant parts were cited by Andom people for treating malaria, including: dead leaves, fresh leaves, roots, sap, seeds, stem barks, tubers, and fruits. Figure 1 illustrates the result. Fresh leaves (49% of citations) and stem barks (33%) are in this order the plant parts that are largely cited. Dead or dried leaves represent only 1.4% of citations. Sometimes, people of Andom village use the whole plant (1.4%).

A total of eleven different mode of preparation of plants (or pharmaceutical forms) were cited (figure 2): ash, decoction, drysqueeze, grind, infusion, maceration, oil, pounding, rapure, trituration, warm on firefriction-squeeze, and wine. Decoction (68% of citations) is the most important mode of preparation of anti-malarial plants.

The relative importance of the modes of administration of recipes used as anti-malarial by Andom people is illustrated in figure 3. A total of 14 modes of administration are shown including: application on stomach, auricular, bath, friction, massage, nasal instillation, application on nostril, oral, pressing on painful side, rectal, rubbing on body, scarification, and vapour bath. Oral voice is largely cited (56%), followed by vapour bath (15%) and nasal instillation (11%). About 51.6% of the citations are made of combination of two, three, four, five, six, or seventh plant species.

DISCUSSION

Characteristics of recipes

Recipes gathered in Andom village on antimalarial plants were compared to those obtained in the Dja Biosphere Reserve in the East Cameroon (Betti, 2001; 2003) and in the Ipassa-Makokou biosphere Reserve in Gabon (Betti et al., 2013), using almost the same method While leaves appear to be the most important plant parts used in Andom village and Ipassa-Makokou Biosphere Reserve (more than 50%), people living inside and in the periphery of the Dja Biosphere Reserve use mainly stem barks (60%) for treating malaria. Leaves arrive in the third position with only 11% of citations. Andom people have preferences in the use of freshly collected leaves (49%) than dried or dead leaves (1%). Studies had shown that there were quantitative and qualitative differences in the essential oil components of fresh and dry plant materials. Dry plant material might not be as potent as freshly collected materials (Idowu et al., 2010). As observed in the Dja and Ipassa-Makokou Biosphere Reserves, decoction is the main mode of preparation of recipes in Andom village. While people living in Andom village and the Dja Biosphere Reserve use mainly oral voices, those living in the Ipassa-Makokou Biosphere Reserve in Gabon, prefer vaporation baths as the way of administration of recipes in the treatment of malaria. About half of the recipes indicated for treating malaria by people living in Andom are made of combination of many plant species. In the Ipassa-Makokou Biosphere Reserve, 73% of recipes were made of combination of many plant species. According to Rasoanaivo et al. (2011), there is evidence that crude plant extracts often have greater anti-plasmodial activity than isolated constituents at an equivalent dose.

Use of medicinal plants out of Andom village

Citations of plants used in Andom village were compared to those mentioned in African countries. Table 4 presents each plant species cited in Andom, the countries where the same plants are indicated with the references in brackets. A total of 29 plants (57%) used by people living in Andom village as anti-malarial are also known in other region of Cameroon and other African countries for the same usage. The most cited plant species are: Alstonia boonei (8 countries), Rauvolfia vomitoria (7), Carica papaya (6), Cymbopogon citratus (5), Morinda lucida (5), and Mangifera indica (5), Enantia chlorantha (4), Picralima nitida (4).

Eight out of the twenty nine plant species (27.6%) also known for their anti-malarial usage out of Andom village are well recognized for their real activity against malaria including: Alstonia boonei, Carica papaya, Citrus limon, Cymbopogon citratus, Enantia chlorantha, Morinda lucida, Picralima nitida, and Vernonia amygdalina.

Alstonia boonei, Carica papaya, Citrus limon, Cymbopogon citratus, Enantia chlorantha, Picralima nitida and Vernonia amygdalina have been reported to be active against Plasmodium spp (Betti, 2001; 2003; Betti et al., 2013). Clinical investigation of Carica papaya, Cymbopogon citratus, Ocimum gratissimum, and Vernonia amygdalina, used as traditional medicines in Kinshasa, the Democratic Republic of Congo, to treat malaria patients showed significant removal of parasites in the blood, as well as elimination of clinical detection of disease (Taba et al., 2012). The anti-malarial activity of Morinda lucida (Rubiaceae) has been established on Plasmodium berghei (Makinde and Obih, 1985; Obih et al., 1985), P. yoelii nigeriensis (Agomo et al., 1992) and P. falciparum (Gbeassor et al., 1988; Koumaglo et al., 1992; Sittie et al., 1999; Tona et al., 1999). A prophylactic activity has also been established by Makinde and Salako (1991). According to Koumaglo et al. (1992), this activity is due to the presence of three compounds (anthraquinones) including digitolutein, rubiadin-1-methyl ether and damnacanthal isolated from the stem and root barks. Tona et al. (1999) having put in evidence Morinda's activity on leaves which do not contain the above compounds, concluded that the leaves' activity may come from other type of compounds. The age of development of the plant part does not have any effect on the activity of Morinda (Tona et al. 1999). Iwu (1994) revealed that the antimalarial activity of M. lucida is largely exploited in primary health centers in Nigeria. However studies have reported the toxicity of that plant species (Idowu et al., 2010).

CONCLUSION

The fact that some plant species cited by Andom people be recognized for their activity against Plasmodium, is a credibility index which can be attributed to the pharmacopoeia of those people. This also illustrates the efficiency of the method used to identify medicinal plants of the Andom village. The glaring development challenge at the background of what precedes is the pressing need to implement strategies and programmes to identify active chemical substances of other plant species of this list, which have not yet been investigated for their chemical and antimalarial activities.

ACKNOWLEDGEMENTS

We thank all the villagers who collaborated with us in this study.

This paper has been produced with the financial assistance of the Cameroon Government and the Japanese Cooperation (JICA) under the FOSAS Forest-Savanna Sustainability Project, Cameroon".

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Cite this article:

Betti. J. L., Caspa. R., Ambara. J., Kourogue. R. L., (2013), ETHNO-BOTANICAL STUDY OF PLANTS USED FOR TREATING MALARIA IN A FOREST: SAVANNA MARGIN AREA, EAST REGION, CAMEROON, Global J Res. Med. Plants & Indigen. Med., Volume 2(10): 692-708

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Source of Support: Government of Cameroon and the Japanese Cooperation (JICA) under the FOSAS Forest-Savanna Sustainability Project, Cameroon

Conflict of Interest: None Declared