Medicinal Plants Useful for Malaria Therapy in Okeigbo, Ondo State, Southwest Nigeria

There is increasing resistance of malaria parasites to chloroquine, the cheapest and commonly used drug for malaria in Nigeria. Artemisin, a product from medicinal plant indigenous to China, based on active principle of Artemisia annua, has been introduced into the Nigerian market. However not much has been done to project antimalaria properties of indigenous medicinal plants. This study thus, has the main objective of presenting medicinal plants used for malaria therapy in Okeigbo, Ondo State, South west Nigeria. Focus group discussions and interview were held about plants often found useful for malaria therapy in the community. Fifty species (local names) including for example: Morinda lucida (Oruwo), Enantia chlorantha (Awopa), Alstonia boonei (Ahun), Azadirachta indica (Dongoyaro) and Khaya grandifoliola (Oganwo) plants were found to be in use for malaria therapy at Okeigbo, Southwest, Nigeria. The parts of plants used could either be the barks, roots, leaves or whole plants. The recipes also, could be a combination of various species of plants or plant parts. This study highlights potential sources for the development of new antimalarial drugs from indigenous medicinal plants found in Okeigbo, Nigeria.


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.In Nigeria, malaria is mostly caused by P. falciparum and P. malariae.The female anopheles mosquito transmits these parasites to humans.Malaria has a great morbidity and mortality than any other infectious diseases of the world (World Malarial Report, 2005; Smith, 1978;WHO, 2000).Survey shows that 90% of the world's cases of malaria occur in sub-Saharan Africa.Nine out of ten cases of this disease occur in this region and record over one million deaths annually (World Malarial Report, 2005; Africa Union Memoir, 2005).High mortality rate is recorded in children and pregnant women (WHO, 2000), also the disease has negative impact on the economy of prevalent countries (African Summit on Roll Back Malaria, 2000;Abuja Malaria Summit, 2000).
In Nigeria, malaria is endemic throughout the country.World Health Organization (WHO) estimated malaria mortality rate for children under five in Nigeria at 729 per 100, 000.The Ministry of Health reported in April 2004 that malaria is responsible for one out of ten deaths in pregnant women and has caused the Federal Government of Nigeria over one billion Naira annually in treating malaria (Government in action, 2005).Medicinal plants have been used in the treatment and prevention of malaria in various parts of the world.Quinine extracted from the bark of the cinchona tree, was used as an antimalarial agent as early as 1632 (Baird et al., 1996) and by the 19 th century, it was still the only known antimalarial agent.Cinchona tree has been cultivated for this purpose all over the world.Primaquine and quinacrine were produced after the first World War.Chloroquine followed shortly thereafter in 1934 (Thomson and Werbel, 1972 ), in 1946 it was designated the drug of choice for treatment of malaria (Coatney, 1963).It is known as the cheapest, and drug of choice for malaria treatment in Nigeria.
Recent surveys had shown the emergence of chloroquine -resistant strains of malaria parasites.In Africa, chloroquine resistant Plasmodium falciparum was first found in 1978 in nonimmune travellers from Kenya and Tanzania (Campbell et al., 1979;Fogh et al., 1979).This was followed 2 to 3 years later by reports from Madagascar (Aronson et al., 1981) .Resistance spread from the African coastal areas inland and by 1983 had been observed in Sudan, Uganda Zambia and Malawi (Onori 1984;Ekue et al., 1983;Fogh et l., 1984;Slatter et al., 1983).The emergence of the ineffectiveness of chloroquine in combating malaria has led to additional studies, which had produced a new and effective antimalaria drug, Artemisin (World Malarial Report, 2005; Conference Report on the First International Meeting of the research initiative of Traditional Antimalaria Methods).The usefulness of this medicinal plant may hold the key to another new and effective antimalaria drug (UNESCO, 1998) in the future.
Indigenous medicinal plants in Nigeria used in combating malaria are yet to be projected in conferences as the foreign plants in spite of our rich flora diversity.Therefore, this present study has the main objective of presenting medicinal plants useful for malaria therapy in Okeigbo, Ondo State, Southwest of Nigeria.

Materials and Methods
This study was carried out in Okeigbo, Ondo State, Southwestern Nigeria.Okeigbo is a heterogeneous community, consisting of various groups of people from different parts of Southwest, Nigeria -Ife, Ifewara, Egbas, Owu, Offa, Ilorin, Ibadan, Ijebu, Ondo, Ilesha to mention a few and it is located at about 250km north of Lagos-State.This community has a single primary health care centre.The main occupations of the people are farming, teaching, hunting and petty trading.Some are also artisans, traditionalists and herbalists.
Focus group discussions and interviews were held with members of this community.Members involved in this study were mainly the traditional herbal chief (Asosanyin) who sees to the management and control of traditional practices of the use of herbs, traditional practitioners, herb sellers, primary and secondary school teachers, elderly members of the community 60 years and above; middle age members between the ages of 35-59 years old and health workers in the local Primary health centre.
Selections of these members were based on social status, occupation and those adjudged by the community to be knowledgeable in the ethno botanical uses of plants.Questions bothered on types and parts of plants often used for malaria therapy; methods for preparation and administration.Information on medicinal plants was compiled according to Generic name, family names, local names and parts of plants used.Collection of these plants cut across various locations in the community.Starting from the local garden at the back of houses, roadsides, farms, and mountain bases, secondary forest to primary forest.This was done with the aid of traditional practitioners.
Samples of plants collected were dried using absorbent paper, moistened with methylated spirit and mounted in accordance with conventional herbarium practice.Taxonomists in the Herbarium of Forestry Research Institute of Nigeria (FRIN), Ibadan, Oyo State led by Dr. G. Ugbogu and Mr. T.K. Odewo did scientific confirmation of some of the medicinal plants.

Results
Table 1 shows the list of medicinal plants often used for malaria therapy in Okeigbo, Ondo State, Nigeria.Table 2 shows medicinal plants that can be used alone in malaria therapy (monotherapy) while Table 3 shows plants used in combination of two, three, four, five or more different plants.Table 4 shows medicinal plants that are included as adjuncts in malaria herbal recipes, which are used as blood tonic or for clearing coated tongue (one of the symptoms of malaria).Chrysophyllum albidum (Bark) Parquetina nigrescens (Leaves) 3.

Discussion
From the array of medicinal plants used for malaria therapy in Oke-Igbo, Ondo-State, this study has shown that indigenous medicinal plants exist, that can be exploited in the development of new antimalarial drugs.(Table 1).These plants are similar to those used for malaria therapy in Ghana (UNESCO, 1997), Sierra Leone (Agbovie et al., 2002) and agree with the work of Oliver (Barnish and Samai, 1992) and Singha (Oliver, 1960) on medicinal plants of Nigeria.
In preparation of herb recipes for malaria therapy, single plants (monotherapy) can be used (Table 2) or in combination of more than one plant (table 3).The combination of these different plants is claimed to cure several ailments and dysfunctions associated with malaria in the body.For instance, plants claimed to cure coated tongue and those that replenish blood cells during malaria attack are included in herbal recipes for malaria as shown in Table 4.They are also regarded as plants useful for malaria therapy.The treatment is observed to be traditional with deep socio-cultural expression as recognized by WHO, 1978).
Significantly, majority of these plants when prepared are very bitter in taste.More so, it is believed that each active principle of component parts making up the recipe complement one another in the fight against malaria parasite.Further studies would be required to explain this activity among component parts of malaria recipes.Furthermore, selections of these component parts are often based on the severity of the disease.The active principle of these plants are often extracted through, infusion, decoction and tincture (Taylor, 2004).However, component of different herbal recipes in this study differ along lineage, class, cultural group, occupation, status and age group, suggesting the pluralistic and diverse nature of traditional medicine (Singha, 1965).In addition, during administration of these drugs, recipes that are considered to be very potent are required to be taken in little quantity to avoid side effects like stomach disorders.
Consequently, the ability of people, encountered in the course of this study, in giving at least an herbal prescription for malaria shows the prevalence of the disease and how it has been tackled over time.Therefore, these findings suggest that medicinal plants used for malaria therapy in Okeigbo, Ondo State, Nigeria are potential sources for the development of new antimalarial drugs from indigenous plants in Nigeria.

Conclusion
This study has attempted to highlight medicinal plant claimed to be used or associated with malaria therapy in the indigenous Yoruba community as prescribed or suggested by individuals or groups in Okeigbo, Southwest, Nigeria.These medicinal plants may probably contain yet undiscovered anti-malarial properties, which can serve as a template for the production of cheap anti-malaria drug from indigenous plants in Nigeria.There is a need for a multidisciplinary approach to develop potentially effective drugs while noting dangerous drugs and practices that should be discarded.

Table 1 :
Medicinal plants that are used for malaria therapy in Okeigbo, Ondo state, southwest Nigeria

Table 2 :
Medicinal plants that are used alone (not in combination) for malaria therapy in Okeigbo, Ondo state, Nigeria.

Table 3 :
Medicinal plants that are used in combination in Okeigbo.

Table 4 :
Medicinal plants that are adjuncts included in malaria therapy recipes