Socio-cultural contribution to medicinal plants assessment and sustainable development: case of antidiabetic and antihypertensive plants in Cameroon.

Diabetes and hypertension rank among human diseases that are very difficult to control. The medicinal material of Cameroon can provide much information on ethnic folklore practices and traditional aspects of therapeutically important natural products. Cameroon has a very rich cultural diversity with different traditional systems of medicine that need more evidence-based studies on both crude extracts and purified phytomolecules. Therefore, an ethnobotanical study was conducted on 58 socio-cultural population groups living in different phytogeographic units of Cameroon in order to collect various medicinal plants or recipes. A two by two comparison of social-cultural groups of the same phytogeographic unit indicated a significant difference in 86.97% of medicinal plants or recipes comparisons' cases. A total of two hundred and eight recipes were identified, among which 75 were used for diabetes and hypertension treatment, 74 for hypertension alone, and 59 for diabetes alone. Also, two hundred and three plants were identified among which 33 were cultivated and marketed by 25 farming families engaged in integrated agriculture and selling of antidiabetic and antihypertensive plants to enhance their socio-economic status.


Introduction
Diabetes and hypertension rank among the chronic diseases that are very difficult to control. In Africa, particularly in Cameroon, traditional healers and a portion of the rural population possess a considerable patrimony of traditional knowledge on medicinal plants, heritage of their ancestral uses. So, great percentage patients in Cameroon live below the poverty line and have many difficulties in meeting fundamental living needs that include health services. As a result, some diabetic and/or hypertensive patients stop treatment and shift to herbal remedies of unconfirmed efficiency and safety [1][2][3]. Cameroon has a very rich cultural diversity with different traditional systems of medicine that need more evidence-based studies on plants, crude extracts and/or purified phytocompounds. Natural products have been the source of most active ingredients in western medicines. Utilization of natural products as pharmacological tools could lead to the development of a number of new major therapeutically active compounds [4]. Reports on potentially new chemical structures or pharmacological effects of medicinal plant extracts are mushrooming. Many hypoglycemic plants have been identified, and several of them induce the beta cells secretion of insulin. Diabetes and hypertension treatment requires plants with new mechanisms that may be able to reduce insulin resistance, act like injectable insulin at the tissue level, prevent the destruction of beta cells by antibodies or anti-illots beta action, regenerate beta cells, prevent the expression of specific disease-related genes, favor the intestinal absorption of glucose, and correct the abnormalities of the renin-angiotensin II-aldosterone system [1,5]. Therefore, sampling in different tribes may help in the identification of several plants with medicinal properties. The inter communities ethnobotanical information is essential to determine plants diversity, their interspecific variation, and the selection of good useful species. Increasing the awareness of traditional healers to perceive the eventual problems and solutions related to the plant materials used to treat diabetes and hypertension in different tribes, is essential for the identification of the best antidiabetic and antihypertensive plants. In this study, we identified or analyzed the medical potential of indigenous antidiabetic and antihypertensive plant species. We also endeavored to identify numerous medicinal plants by prospecting many traditional systems of medicine in Cameroon [6]. Hence, we answered some key research questions that included: are recipes used against diabetes and/or hypertension varied significantly between socio-cultural groups located in the same phytogeographic unit of the same phytogeoraphic region ( Figure 1). In other words, do the uses of medicinal plants easily transmitted from ethnic group to another? Do the populations of socio-cultural groups, living in the same phytogeographic unit use different plants to treat a given disease?.

Methodology
The process used to collect information on medicinal plants and treatment of diabetes and hypertension began by a field work based on harvest and identification of plants of interest in each ethnic group of interest. During this step ethnopharmacological details on preparation of recipes were collected from traditional healers. This description focused on the mode and the time of preparation, the mode of administration, the posology, the duration of treatment, the undesirable or secondary effects, the toxic effects, the diet and the disease treated. It was followed by the confirmation of botanical identification that was done at the National Herbarium of Cameroon. Voucher specimens were deposited in the Institute of Medical Research and Studies of Medicinal Plants in Yaounde, Cameroon. The research of usage similarity was conducted by comparing 2 by 2 recipes or plants collected in cultural communities living in the same phytogeographic unit. The list of plants and recipes per tribe was constituted. The regrouping of tribes by phytogeographic units was realized by superposing the Letouzey' vegetation map as described by Achoundong [7] and the location of the different socio-cultural groups of Cameroon [8]. The same methods were used for identifying the different socio-cultural groups. To answer research objective we interviewed a total of 1,131 persons belonging to 58 socio-cultural groups distributed in Cameroon territory ( Figure 1).

Importance economic evaluation of forest plants sold in Yaounde markets
Investigations were carried out on medicinal plants harvested and sold by 25 people in some highly populated market areas of Yaounde. Different plant packagings were previously identified, including bags or strings for all vendors and heaps for retailers (Table 1). This information permits to determine the annual average profits of each category of sellers. Determination of annual average profits of different sellers. There are three categories of sellers: the delivery men, permanent-retailers and collector-retailers. The delivery men, who for most of them were native of the plants' harvest zones, and relative of permanentretailers, sold the plant materials collected that include: barks, fruits, whole plants, rhizomes, and leafy stems.

Important roles of socio-cultural groups in ethnobotanical assessment
Comparisons of recipes between socio-cultural groups located in the same phytogeographic unit-Eighty six point ninety-seven percent (86.97%) of recipes or plants comparisons' cases between socio-cultural groups located in the same phytogeographic show that tribes use significantly different plants or recipes ( Table 2). Individuals of the same origin, the same culture and the same history live by groups more or less close. For this reason a survey conducted in several socio-cultural groups can permit to identify various recipes.  The individuals of the same origin, the same culture and the same history live by groups more or less close. We can conclude that a survey conducted in several socio-cultural groups can allow identifying several plants or recipes. Therefore, floral, climatic, edaphic and sociocultural differences between regions (2 X 2 compared) are found in the use of antidiabetic and/or antihypertensive plants or recipes. This conclusion is more valuable if the list of recorded plants is representative.
Research on the representativeness of plants recorded for antidiabetic and/or hypertension treatment in Cameroon.
The number of interviewees' socio-cultural group may be weak, at first sight. But it is in general widely superior to a minimum doorway of four individuals recommended by category for example socio-cultural group, within the context of ethnobotanical surveys [9,10]. The 1.131 interrogated Cameroonians appear negligible when compared with the total population of Cameroon estimated to 13 600 000 of habitants [11]. In this case the rate 0.0832% of participation is very weak. For practical reasons, the minimum doorway of sample difficultly attains 1% of entire population [10]. Many of reticence and distrust from the informants make this minimum doorway more reduced in the area of medicinal plants.

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The curbs in each case are illustrated in the Figure 2.
The best adjustment of the trend of each of these curves is a logarithmic function with the following equation: We must remark that this is true if the new specimen is distributed in the way that the sample repeated present the same characteristics like the first one, in ethnical point of view; in admitting that each socio-cultural group has a delimited territory, and the same affinity with others that is not taken in to consideration.
Therapeutic, ecological, food, socio-economic importance and statistical significance of recorded plants between the phytogeographic regions Therapeutic importance-By identifying or analyzing the medical potential of indigenous antidiabetic and antihypertensive species, this study has identified numerous medicinal plants by prospecting many traditional systems of medicine in Cameroon. Therefore, two hundred and eight recipes were recorded: Seventy-five (75) are both antidiabetic and antihypertensive, seventy-four (74) are used against hypertension, and fiftynine (59) are antidiabetic. These recipes were derived from 203 plants belonging to 68 families [9]. Among the 203 recorded plants, 33 have been shown to be very interesting because of their clinical outcomes in 182 patients who used them in self-medication [5].  [12]. Like in India, wild edible plants are widely consumed in the daily diet of local people in Cameroon [1]. They are critical for the sustenance of ethnic communities and also as source of income [13,14].

Ecological importance-Wide
Socio-economic importance-Commercialization of antidiabetic and/or antihypertensive plants and possibilities of sustainable development of many tribes. This Table 3 shows that a collector -retailer earns more than two times than a permanentretailer and 148,465,500 FCFA more than delivery man. Like the delivery man the collectorretailer doesn't buy the resources. We realize that the natural harvest and the retail sell are advantageous for the local commercialization of medicinal plants. Therefore, for the same resources sold in the market, personal collection following by retail may be highly recommended. Meanwhile, the formula tax, storage fee and municipal fee significantly decrease the income of permanent-retailers. Other profits are made from the sale of nonantidiabetic and/or anti-hypertensive medicinal plants. In general sellers of medicinal plants can fulfill their financial needs. However, plant harvesting pose a threat to the environment as it becomes more intense in areas far from urban and rural agglomerations.

Calculation of storage fees, hotel fees and tax by categories of sellers-Each
In  Ethnopharmacological preparation and ethnomedical administration of the standard recipes-Almost all the plants cited in this work were prepared and administrated as follow: 100 g of leafy stems of herbal species or 200 g of stem barks were boiled in 4 liters of water, for 25 minutes, each patient was then asked to drink a glass of extract (250 ml) in the morning; mi-day and evening, for 10 days. Specific preparation of each of these plants is detailed in [3,6]. No secondary and undesirable effects were recorded during the treatment. But the prolonged use of Rauvolfia vomitoria and Cissus quadrangularis can induce vomiting. Maceration of the same quantity of harvested material in the same volume of water, for a whole day, is also allowed for the following plants: Allium spp (bulb), Brassica oleracea and Aloe spp. In these cases, the same posology is respected [9].  Relationship between socio-cultural groups of interviewees and different phytogeographic units of Cameroon [6,9].  Summary of socio-economic data questionnaires for a plant.