Utilization and use categories of C. albidum
This study highlights the multipurpose character of
Chrysophyllum albidum in Benin. Four use categories were determined for the species. Three use categories (food, medicinal and firewood) emerged as having a high consensus degree among the informants in the region. Our findings are consistent with previous studies which reported rich and diverse array of uses of
C. albidum trees [
15,
33,
34]. For instance the species was mentioned to be highly valued in traditional medicine and its fruits widely consumed in Nigeria [
19,
35] as it was observed in our study area. While Adu-Boadu [
33] mentioned the medicinal value and nutritive value of various parts of
C. albidum, Boateng and Yeboah [
34] highlighted the trade value of this species’ fruits for food purpose in Ghana.
With respect to the different plant parts, results showed that the fruit (food property of the pulp) of the species was the most valuable non-timber forest product while the bark and leaves were used in folk medicine, which is in agreement with results from Edem
et al.[
36] and Odugbemi
et al.[
19]. The nutritional value of
C. albidum was already assessed by Edem
et al.[
36] who showed that the pulp of the fruit contains 8.8% of protein; 15.1% of lipid, 68.7% of carbohydrate, 3.4% of ash, and 4.0% of crude fiber. This high nutritional value might justify the relative importance of the fruit consumption by local populations and therefore, its presence in the traditional agroforestry systems in the studied area. However, food processing initiatives of the fruits are rare in Benin Republic while in other countries like Nigeria and Ghana, the transformation of these fruits for table jelly, drinks and others are growing initiatives [
15,
16,
37]. Previous studies also reported that the seeds of
C. albidum are rich in linoleic (38.4%) and oleic (29.6%) acids and could be used in free fatty acid production [
38,
39]. However this use form was not reported in our study area and the seeds are thrown away probably due to lack information on the potential of the seeds, and lack of facilities nearby to process it. Despite these potentials,
C. albidum is less exploited in the southern Benin than in Ghana and Nigeria and less incorporated to the commercial agricultural production system. The use of
C. albidum remains traditional and the species underutilized.
With regard to medicinal use, our findings revealed the specificity of the different plant parts in ailment curing. The bark of the species was locally used for healing coughing, icterus and yellow fever while the leaves were employed to treat malaria, high blood pressure and anemia. In southern Nigeria, it was reported that the bark was used to treat the yellow fever and malaria, while the leaves were used as an emollient and for the treatment of skin eruption, stomachache and diarrhea [
40,
41]. In this study, we reported the use of
C. albidum roots in traditional gynecology (treatment of sterility, sexual weakness) while Okunomo and Egho [
42] reported the fruits for the same purpose. This difference in
C. albidum plant part in traditional gynecology highlights the variability of ethno-knowledge between ethnic groups. These results emphasize the importance of undertaking biochemical analysis of the different plant parts in order to confirm or to infirm the traditional medicine use of the species. Yet, studies carried out in Nigeria showed that the leaf extract of
C. albidum contained antiplatelet and hypoglycemic compounds and could be employed in the treatment of myocardial infarction and diabetes mellitus respectively [
43]. The methanolic bark extract of
C. albidum contains anti-plasmodial substances and could be used in treating malaria [
44]. Moreover, it has also been reported that methanolic extracts from
C. albidum leaves presented strong antibacterial activity against common bacteria such as
Escherichia coli T. Escherich,
Salmonella typhimurium Loeffler,
Staphylococcus aureus Rosenbach [
45]. However, all these reported proprieties abovementioned remain laboratory findings (since they were only tested on rodents) and need to be further investigated. Nonetheless these are important findings for future biochemical and pharmacology studies of the species for medicinal properties.
Although the species was reported to be highly valued as timber in another regions (Uganda for instance) due to the appreciable physical and mechanical properties of its woods [
46], this was not the case in the southern Benin (Plateau of Allada). The species was generally only cut down in the case of other land use such as house building or road construction. In fact, the bole of
C. albidum often presents a network of fissures and this was reported locally as a major impediment for the species wood used as timber. Thus, contrary to many other trees species,
C. albidum did not appear to be threatened by logging. However, it should be noted that this species’ habitat has been considerably reduced due to the growing urbanization in the southern Benin.
Chrysophyllum albidumuse knowledge variation
Our findings showed significant differences on the species’ use value for medicine between age groups and genders. Previous studies on others plant species came to the same conclusion and stated the uneven distribution of indigenous knowledge for local plant use [
20,
23,
47]. However, in this study we did not find ethnic differences in use value of
C. albidum which is contrary to other studies on NTFPs [
4,
5,
21,
48‐
51]. This result may be related to the cultural link between the two investigated ethnic groups. Historically these two ethnic groups belong to the same cultural group “Alladanou”. Even though the Fon ethnic group migrated to the “Plateau of Abomey” in the centre part of Benin, the two groups still cohabit today on the “Plateau of Allada”. Nowadays, they are commonly mixed and share most folk knowledge, traditional value and rituals regarding many practices. Therefore, as far as ethnobotanical knowledge is concerned, we deduced that the cultural origin might be an important factor to take into account in medicinal plants value assessment. However further studies are needed to confirm that assertion not only in the specific case of
C. albidum but also for many other multipurpose plant species.
The significant increasing medicinal use value of
C. albidum with increasing informant age confirms the assertion of increasing ethno-medicine knowledge of plant species with age [
52‐
54]. Because of this age related knowledge, there could be a long-term loss of medicinal knowledge. The disappearance of the current "old generation" might involve the loss of folk medicine on
C. albidum since young informants mostly rely on modern medicine. Instead of being complementary, modern medicine appears sometimes as an impediment to the development of folk medicine [
55,
56]. So far, intensive and continued research on ethnomedicinal value of plants is needed not only for
C. albidum but for many other species in order to document and to preserve the traditional knowledge of local population other the time.
The current knowledge of C. albidum (mainly medicinal and alimentary use) provided by the informants in this study can be regarded as an opportunity for its conservation and cultivation for livelihood enhancement. Moreover, the large potentialities (pulp and seeds use in food industry, plant parts use in pharmaceutical laboratory) of the species and which are not fully exploited in the studied area may militate in favor of its conservation and promotion. The study also demonstrated that, the local current use of the species is not destructive (i.e. tree cutting for timber is scarce). The main concern of the species’ stands conservation is related to its habitat destruction. Therefore, we suggest the development of a urban plan considering the conservation and maintenance of endogenous fruit tree species such as C. albidum. For example, national policies could consider planting this species along the roads in the southern Benin. In order to fulfill this suggestion, research on the species' reproduction, growth and survival, and on the fruit phenotypic characterization should be carried out to provide baseline data for the selection and planting of superior individuals.