Ethno-medicines for Mosquito Transmitted Diseases from South-western Nigeria

Ipomoea reniformis Chaos is claimed in Indian traditional medical practice to be useful in the treatment of epilepsy and neurological disorders. In the present study, pretreatment effect of methanolic extract of Ipomoea reniformis on epilepsy and psychosis was evaluated in rodents using standard procedures. Besides evaluating epileptic and behavioral parameters, neurotransmitters such as Gamma-Amino Butyric Acid (GABA) in epilepsy and in psychosis dopamine, noradrenaline and serotonin contents in the rodent brain were estimated. The extract pretreatment reduced maximal electro shock; Isoniazid (INH) and Pentylenetetrazole (PTZ) induced seizures and also significantly inhibited the attenuation of brain GABA levels by INH and PTZ in mice. These results suggested that the observed beneficial effect in epilepsy may be by enhancing the GABAergic system. The test drug also inhibited the apomorphine induced climbing and stereotyped behavior and showed significantly reduced levels of brain dopamine, noradrenaline and serotonin which may be due to blocking of central dopaminergic, noradrenergic and serotonergic pathways or by enhancing the GABAergic system. The results obtained in present study suggest that the title plant possesses antiepileptic and antipsychotic activities in rodents.


Introduction
Ipomoea reniformis (IR) also called as merremia emarginata (Burm. f.) is a procumbent herb belonging to the family convolvulaceae. In India, it is commonly known as Undirkana and Mushakparni. The plant is widely distributed in India, Sri Lanka, Philippines, Malaysia, Tropical Africa and mainly grows in rainy and winter season. In India, it is found in Southern part mainly counting Chennai, and some places of Andhra Pradesh [1]. Traditionally, IR has been used to treat diverse clinical conditions ranging from pain; fever to neurological disorders [2]. IR has been claimed to be useful for inflammation, headache, fever, cough, neuralgia, rheumatism and also in liver and kidney diseases [3]. The powder of leaves is used as a snuff during epileptic seizures. Juice acts as purgative and the root is having diuretic, laxative actions and applied in the disease of the eyes and gums [4].
The plant contains various neuroprotective chemical constituents such as caffeic, p-coumaric, ferulic and sinapic acid esters. Petroleum ether extract contains fats and fixed oil while aqueous extract contains amino acids, tannins (condensed and pseudo tannins) and starch [5]. IR has been reported to possess various pharmacological actions, mainly antidiabetic [6], antiinflammatory [7], nephroprotective [8], antibacterial [9], antioxidant and antimicrobial activity [10]. Further, the principle constituents of IR such as sinapic and ferulic acids have exhibited behavioural and pharmacological

Introduction
Mosquitoes are considered the deadliest insects in the world as they transmit diseases to more than 700 million people annually [1]. Mosquitoes are vectors of many diseases including chikungunya, dengue, encephalitis, malaria, yellow fever, among others [1]. Over one million people worldwide die from mosquito-borne diseases every year [2]. Vector control is one of the effective ways of controlling vector borne diseases. Mosquito vector control relies on the use of long lasting insecticidal nets (LLINs) [3] and/or indoor residual spraying (IRS) [4]. However, the extensive use of synthetic organic insecticides has resulted in environmental hazards and in the development of physiological resistance in vector species [5,6]. Development of insecticide resistance in mosquitoes has been a serious threat to current malaria control strategies [7]. This has necessitated the search for potential alternative sources, for effective mosquito control and with minimal environmental hazards. One of such alternatives is the use of plants for vector control. Several plants are used in traditional medicines

Study Area
The study area includes four Local Government Areas (LGA) situated within Oyo States, geographically located in the South-western Nigeria.

Data Collection
During 2012-2013, an ethno-botanical field survey was conducted into remote areas and local markets of the region under study in Oyo-state, Southwest Nigeria. Several visits were made to the areas to consult herb sellers, TMPs, herbalists locally known as babalawo and aged locals or elderly people to provide information on plant species frequently used in the treatment of insect transmitted diseases. Informed consent was obtained orally from all participants made up of the TMPs, herbalists, the elderly and herb sellers before the commencement of the interview. The use of semistructured questionnaire and oral interviews were adopted to obtain the relevant data. Ethno medicinal information obtained on the plants used in the treatment of insect transmitted diseases include; the plant part used, mode of preparation as well as administration of the various recipes. Samples of plants were thereafter collected and processed for the Department of Pharmacognosy Herbarium, University of Ibadan (DPHUI). Furthermore, the use-mentions index was calculated for all plants [17]. The use-mentions index (UMi) was taken as the number of use mentioned for a particular plant divided by the total number of respondents interviewed.

Enumeration of Recipes
Based on the information obtained from the respondents consulted in the study areas the preparation of various recipes was grouped into 12 as follows: 1.

Results and Discussion
Demographic data collected on the respondents showed that fourteen were males (58.3%), while ten (41.7%) were females. The close ratio of the male to female respondents here is of note in the practice of traditional medicine. This is against the opinion of African practitioners, who claim that traditional medicine practice should be exclusively reserved for the males [18][19][20]. The ages of the respondents ranged from 28-65 years. The survey revealed 37 plant species belonging to 25 families as traditional remedies for the treatment of insect transmitted diseases in the study area. Table 1 shows the list of identified plant species, families, local names and plant parts used. Euphorbiaceae is the most dominant family with 4 species accounting for 11%; followed by Meliaceae, Lamiaceae and Cucurbitaceae (with 3 species each), accounting for 8%; Fabaceae, Combretaceae, Bignoniaceae, Asteraceae and Apocynaceae (with 2 species each), accounted for 5%. The rest of the families had one species each (Fig. 1). Various plant parts like leaves, seed, bark, fruit or even whole plant are used in the form of body cream (pomade), as repellent, as concoction, juice, via bathing (with concocted black soap). The method of application and administration of the recipes varies from one case to the other, depending on the extent of infection by insect, as external application or internal administration. Among the plant parts used, leaf was the predominant (43.2%), followed by bark (32.4%) and whole plant (10.8%). Fruit/seed accounted for 5.4%, while root and whole plant/root contributed 2.7% each (Fig. 2). This observation indicating the leaf as the most commonly used plant part is in line with reports on the importance of leaf in herbal medicine in several studies [21][22][23]. Respondents that participated in the survey affirmed that both dry and freshly collected plants are efficient in herbal preparation except in some cases where freshly collected samples are preferred. The methods of preparations include decoction (boiling in water), concoction and roasting. Some plants were mentioned as being commonly cultivated around houses to drive away insects.      [67] have been studied. The most mentioned species among the plants encountered in the survey was Hyptis suaveolens with a use mentions index (UMi) of 0.250. This underscores the importance of H. suaveolens as a mosquitocidal and an insecticidal plant in the communities visited in Southwestern Nigeria. This is in consonant with reported repellent and insecticidal activities of H. suaveolens leaf essential oil against four stored-grain coleopteran pests [68]. Also, Chromolaena odorata, Nicotiana tabacum, Ocimum gratissimum and Xylopia aethiopica, each had the UMi of 0.167. These plants have been cited in many herbal remedies [69][70][71][72][73]. Vernonia was the only genus in which two species; V. amygdalina (UMi 0.125) and V. cinerea (UMi 0.042) was encountered in the survey. It shows that Vernonia plays significant role in herbal medicine. Vernonia amygadlinawhich is an indigenous leafy vegetable in Nigeria has been part of herbal recipes for the treatment of various ailments [74][75][76][77]. The other genera mentioned in the survey had only one species each.

Conclusion
The survey revealed indigenous knowledge of medicinal plants use in control of mosquito vector in the four local government areas. The frequent use of plants as traditional remedies by the people in the area suggests their established curative and therapeutic significance among the indigenes. The continued identification and documentation of medicinal plants as bio-insecticides is imperative for effective vector control management of the mosquito vector. Most of the plants mentioned have been investigated for various ailments. However, some of the plants encountered in the survey could be explored for future search for newer and safer mosquitocidal agents. Further studies to determine the active principles responsible for the effectiveness of the plants as well as pharmacological activity could be carried out to provide scientific basis in support of the ethnomedicinal uses of the plants.

Acknowledgement
The authors are grateful to the various categories of respondents, such as the herbalists, herb-sellers, elderly-people and other individuals (who inherited the knowledge on medicinal plant usage from their ancestors), for sharing their valuable information with open mindedness during the survey.