Ethnobotanical Study of Medicinal Plants Used as Anti-Obesity Remedies in the Nomad and Hunter Communities of Burkina Faso

Background: Obesity is a global epidemic that affects both developed and developing countries. According to World Health Organization (WHO), in 2014, over 1.9 billion adults were overweight. Burkina Faso, like other countries, faces the problem of obesity, with a prevalence of 7.3%. The main cause is excessive intake of caloric foods combined with low physical activity, although genetic, endocrine and environmental influences (pollution) can sometimes be predisposing factors. This metabolic imbalance often leads to multiple pathologies (heart failure, Type II diabetes, cancers, etc.). Drugs have been developed for the treatment of these diseases; but in addition to having many side effects, locally these products are not economically accessible to the majority of the population. Burkina Faso, like the other countries bordering the Sahara, has often been confronted in the past with periods of famine during which populations have generally used anorectic plants to regulate their food needs. This traditional ethnobotanical knowledge has not been previously investigated. An ethnobotanical survey was conducted in Burkina Faso in the provinces of Seno (North) and Nayala (Northwest) to list the plants used by local people as an anorectic and/or fort weight loss. Methods: The survey, conducted in the two provinces concerned traditional healers, herbalists, hunters, nomads and resourceful people with knowledge of plants. It was conducted over a period of two months and data were collected following a structured interview with the respondents. The approach was based on dialogue in the language of choice of the respondent and the use of a questionnaire. The data have been structured and then statistically analyzed. Results: The fifty-five (55) respondents of the survey were aged between 40 and 80 years. Sixty-one (61) plant species, belonging to thirty-one (31) families were listed as appetite suppressants and/or for their anti-obesity properties. The main families of plants are Mimosaceae, Rubiaceae, Asclepiadaceae and Cesalpiniaceae. Fruits are the most used part of the plant organs. Consumption in the raw state or as a decoction are the two main forms of preparation. Conclusion: The great diversity of plants cited by informants demonstrates the existence of rich local knowledge to address obesity in Burkina Faso. Evaluation of the biochemical activity of the extracts of the most cited species could allow the development of a phytomedicine economically accessible to the majority of the population. This could allow for the preservation of biodiversity in this region which is weakened by climate change because some of the species cited are in fragile state or are threatened with extinction.


Introduction
Obesity is a condition that concerns people of all ages in both developed and developing countries. According to the World Health organization (WHO), in 2014, over 1.9 billion adults were overweight in the world. Burkina Faso has faced a fast growing obesity problem in the last decade, and today more than 7.3% of its population is affected [1]. In addition to being a social handicap, this metabolic imbalance is often associated with diseases such as hypertension, myocardial infarction, stroke, type II diabetes, dyslipidemia and certain cancers [2]. Excessive weight gain is usually caused by increased consumption of high caloric foods and decreased physical activity. Genetic (familial predisposition), biological (endocrine disorders), environmental (pollution) [3] factors may also contribute to this problem.
In Burkina Faso as in most developing countries, urbanization and socio-economic development are accompanied by a change in diet towards more with a high energy density foods (more meat, fat, salt and sugary foods) as well as a reduction in physical activity (mechanized transport) [4] resulting in increased storage of the excess calories as fat in adipose tissue. An aggravating cause of the situation in Africa is the antiquated traditional African conception of affluence, according to which obesity of women is a positive indicator of the material abundance of the family and of a good reproductive health. One can find, in the pharmaceutical market, some synthesis of chemical drugs that are used against obesity: Sibutral, Rimonabant, Isomeride, Xenical, Lorcaserin, Ponderal, Alli, and Qsymia. But the cost of these products generally puts them out of reach of most people; and worse, many of these products have many side effects [5].
That is the reason for the withdrawal from the market of some older drugs such as Sibutral, Rimonabant, Isomeride, Ponderal and Xenical [5,6]. The development of new antiobesity molecules from natural products has become a necessity. This seems realizable because in phytotherapy, several types of plants are used against this disease. The plant bioactive extracts would act through their inhibitory activities for digestive lipases, adipocyte differentiation, or by increasing thermogenesis and anorexia [7]. Burkina Faso, like other Sahelian countries, has often been confronted in the past with periods of famine. During these times of food shortage, people have generally used plants with anorectic effects to regulate their food and drink intake. Burkina Faso is also a savannah country with many nomadic and hunter societies. During their displacements or hunting parties, these people could be facing period of lack of food or water. These populations survived thanks to a strong ethnobotanical knowledge able to help in the management of satiety. However, in Burkina Faso there are few data on these plant species used as anorectics or against obesity. An ethnobotanical survey was conducted in the province of Seno (nomadic area in Burkina Faso northern area) and the Nayala (traditional hunting area in northwest of Burkina Faso) in order to collect information on plants used by local people as anorectics and/or to manage weight. This study aimed to establish an inventory of appetite suppressant or antiobesity plant species.

Study Area
Burkina Faso ( Figure 1) is a landlocked country located in the heart of West Africa and enclosed between six countries: Mali, Niger, Benin, Togo, Ghana and Cote d'Ivoire. It covers an area of approximately 274,000 km². It is located inside the loop of the Niger River between 10˝and 15n orth latitude and between 2˝east and 5˝30' west longitude. Its capital city is Ouagadougou. The climate is characterized by a long dry season (from October to May) and an irregular rainy season (from June to September). Monthly average temperatures range between 22˝C and 42˝C. Except for the extreme north which consists of desert or semi-desert, Burkina Faso is a savannah country. The homogenous and seasonal-dependent vegetal landscape is constituted by Parkia biglobosa (Néré in French), Vitellaria paradoxa (Karité in French), Cassia sp and Andasonia digitata ecosystems. This country is divided into 45 provinces grouped into 13 regions.  The surveys were conducted in the two north provinces where nomadic or hunting populations reside.
Seno Province, whose capital is Dori, is located in the north eastern area of Burkina Faso. It has 215 villages and an area of 6979 km 2 with a population of 264,815 people [8]. This locality has a Sahelian climate, characterized by a long dry season (May to October) and a short rainy season (average rainfall of 400 mm), with varying temperatures (10-43˝C), low humidity, wind and a large amounts of sunshine, typical of the Sahel. The vegetation is characterized by wooded and shrubby steppe that is heavily damaged. However, there are a few gallery forests which are generally located along the rivers (like the swamp of Dori or the Yakouta River). The dominant types of vegetation are thorn trees [9].
Famine is recurrent in this province. The predominant population is the Fulani group, who are nomadic herders. They have survived drought in this region through their knowledge of appetite suppressing plants.
Located in the northwest of Burkina Faso, Nayala province (whose capital is Toma) has an area of 3919 km 2 with a population of 156,861 and a northern Sudanian climate. The vegetation consists of shrub or herbaceous savannah with some groves near villages. Soils are clayey [10]. Many hunter groups live in this province. It often happens that these hunters lose themselves in the bush tracking a hunted animal. To survive these situations (temporary lack of water or food, which can take days), they have developed a rich ethnobotanical knowledge on plants possessing appetite suppressing or thirst quenching properties.

Data Collection
The ethnobotanical survey was conducted in the provinces of Seno and Nayala during the period from August to September 2013. Over 70 interviews were conducted in different localities of these provinces. Data were collected following a structured interview with traditional healers, herbalists and hunters. These groups are located in each of these areas, organized in associations. A preliminary meeting was held during which they were informed about the objectives of the study. After information was provided, the people who agreed to participate in the survey were individually interviewed. The approach was based on a dialogue using the language of choice of the respondent and the use of a questionnaire. A field trip was organized and plants mentioned in the interview were collected with the help of the respondent in order to make the herbal constitution. The intervention of interpreters was necessary in some cases. The cited and harvested plant specimens were identified by Professor Jeanne Millogo-Rasolodimby (Botanist, Department of Ecology/University of Ouagadougou).

Data Analysis
Survey data were first extracted manually then entered and processed by Excel software. The citation frequencies of all data obtained from this study was subjected to descriptive statistical analysis by calculating of frequency of plant citations, using the formula: The use value index (UVI) of a species for each use class is evaluated to show the importance that people attach to a given species in the localities [11]. It is obtained by calculating the following: Where U is the number of times that species is cited for a category of use and N the total number of informants.

Traditional Knowledge: Age and Gender
During the survey 55 people have been interviewed including 34 in Nayala and 21 in Seno. The mean age varies between 40 and 81 years and over 50% were between 50 and 70 years old ( Figure 2). The practice time (in years) varies between 7 and 35. Men represented 92.7% of the respondents versus 7.3% what were women. All were traditional healers, herbalists, hunters or elderly nomadic person with knowledge on plants. In total 62 plant species belonging to 32 families were listed as having anorectic and/or anti-obesity activity. Table 1 shows the list and ethno-botanic characteristics of these plant species.

Traditional Knowledge: Age and Gender
During the survey 55 people have been interviewed including 34 in Nayala and 21 in Seno. The mean age varies between 40 and 81 years and over 50% were between 50 and 70 years old ( Figure 2). The practice time (in years) varies between 7 and 35. Men represented 92.7% of the respondents versus 07.3% what were women. All were traditional healers, herbalists, hunters or elderly nomadic person with knowledge on plants. In total 62 plant species belonging to 32 families were listed as having anorectic and/or anti-obesity activity. Table 1 shows the list and ethno-botanic characteristics of these plant species.

Using part of differents plants organs (%)
Using part of differents plants organs (%)

Families of Plants Used
The study indicates that Mimosaceae, Rubiaceae, Asclepiadaceae, Cesalpiniaceae, Anacardiaceae, Apogynaceae, Meliaceae, Combretaceae and Tiliaceae have been the most cited as appetite suppressant/anti-obesity plants ( Figure 6

Discussion
The survey has allowed identifying 62 species of plants which have anorectic and/or anti-obesity activity. Most interviewees were men; female healers or hunters are rare in these provinces. In Africa these activities are mainly the responsibility of men and the knowledge is transmitted very often from father to son. The 62 species listed have already been studied for some properties (Table 5)

Discussion
The survey has allowed identifying 62 species of plants which have anorectic and/or anti-obesity activity. Most interviewees were men; female healers or hunters are rare in these provinces. In Africa these activities are mainly the responsibility of men and the knowledge is transmitted very often from father to son. The 62 species listed have already been studied for some properties (Table 5).
Eight species, namely Leptadenia hastata, Balanites aegyptiaca, Zizyphus mauritiana, Tamarindus indica, Khaya senegalensis, Brachystelma bingeri, Azadirachta indica, and Adansonia digitata have been cited both in Nayala and Seno. So, these plants grow well in a Sahelian or in a Sudanian climate. In this study Raphionacme daronii (F = 25.4%), Gardenia erubescens (F = 20.3%), Brachystelma bingeri (F = 15.3%), Commiphora africana (F = 11.9%) Leptadenia hastata (F = 10.2%) and Balanites aegyptiaca (F = 10.16%) are the six species which have presented the highest frequency of citation and greater use value indexes in the group of appetite suppressant plants species. This indicates the importance given to these plants by these populations in the treatment of obesity or as an anorectic.
Raw fresh material directly and decoctions are the two main forms of consumption. Anorectic or thirst quenching plants are usually eaten raw as they are most often used to immediately remedy a situation of hunger or thirst. The preparations generally involve a single plant material, but sometimes mixtures can also be used. In the latter, a synergistic effect may be supposed [12].

Zizyphus mauritiana
Lam. (Rhamnaceae) wild threatened species tannins, sterols and triterpenes, flavonoids, leucoanthocyanins [138] anti hyperglycemic activities, antihypertensive, and diuretic activity [139] According to the literature, Zizyphus mauritiana, Tamarindus indica and Moringa oleifera have previously been tested for anti-obesity activity [140][141][142]. This could be linked to a widespread use of these species in many regions for the same indication.
The most cited plants have already been studied for various activities: Balan ites aegyptiaca is mainly consumed in dearth times by the population [143], and it contains carbohydrates, steroidal saponines, fiber, gum [37] alkaloids and flavonoids [32]. It also contains galactose, mannose, arabinose, xylose, rhamnose and glucuronic acid [31]. Their fruits are used against diabetes [30,144] as well as the seeds [145]. The plant is also known having anti-tumor activity [33] and an anti-infertility property [146].
Commiphora africana contains cardiac glycosides and reducing sugars [147]. It has antimicrobial activity and is traditionally used against diarrhea [54].
Fruit and young leaves of Gardenia erubescens are consumed during dearth periods [148]. These fruits contain carbohydrates and fibers [149] and they are also rich in anthraquinones, tannins, sterols and triterpenes [77]. The leaves contain tannins, triterpene saponins, other triterpenoids, iridoids and sterols. The bark is rich in triterpene saponins, triterpenoids and sterols [37]. The leaves are used for the treatment of digestive parasites in small ruminants [78] and the bark of the trunk has analgesic and diuretic activity [79].
Gardenia erubescens is traditionally used against hepatitis [150]. Raphionacme daronii is a plant used during times of famine; it is eaten raw [148,151]. The tuber contains sugars and starch [114].
The tuber of Brachystelma bingeri is used against insufficient sperm and male sexual asthenia, and it is very nutritious, stimulating and can act as a tonic [37]. It is consumed during famine periods [143] and is rich in carbohydrates, saponins, triterpenes and sterols [37].
The most cited plants listed during the survey have not been investigated for an anti-obesity study. So, there is a need to test their bioactivity and eventually study the phytochemistry and pharmacological profile of these plants in order to scientifically support traditional ethnobotanical and to secure their use.

Conclusions
The ethnobotanical survey revealed the presence of an enormous biodiversity of plants used in these two north provinces of Burkina Faso to modulate appetite and thirst. This rich ethnobotanical background indicates the high potential of traditional knowledge to serve for the development of natural product-derivates as affordable medicines. This may contribute to the preservation of traditional knowledge on anti-obesity herbs of these two provinces of Burkina Faso. Twenty-two species cited are in fragile state or are threatened with extinction. This requires taking safeguard measures. It is therefore useful to study the ecology of these species, evaluate the resources and the natural regeneration potential. Reforestation with these species requires the mastery of the production of seeds and planting in areas of high use. This is an important endeavour that could help to fight against the massive destruction of these plants, in the context of climate change and the unprecedented human pressure on the environment. Investigation into these six most cited and not yet studied species could lead to the discovery of new products to address the obesity epidemic.