Medicinal plants of Guinea-Bissau: Therapeutic applications, ethnic diversity and knowledge transfer
Graphical abstract
Introduction
Given that public health services are often fragile in many sub-Saharan African countries (SSA) indigenous medical resources have figured prominently in studies and strategies for the improvement of primary health care (Moyo et al., 2015). Plants are still employed in the treatment of a vast gamut of health conditions by the great majority of the population. This is particularly the case in rural communities, which continue to largely or exclusively depend on medicinal flora to treat common and endemic disorders (Iwu, 2014). Thus efforts are being made to move towards the integration of indigenous medical knowledge and harmonise practices in health care systems in Africa as a whole (Kasilo et al., 2010) and in West Africa in particular (Busia and Kasilo, 2010).
Ranked 178 out of 188 countries that form part of the Human Development Index (HDI) (UNDP, 2015), Guinea Bissauan's have a life expectancy of 51 years for women and 49 for men. The main causes of infant mortality (103 per 1000 live births) and under five mortality (158 per 1000) are related to malaria, acute respiratory infections, diarrhoea and neo-natal disorders (INE, 2009, Ajibade et al., 2012). Maternal mortality also continues to constitute a serious threat to public health. Among the population as a whole, tuberculosis and HIV are also important factors in terms of their impact on mortality rates (WHO, 2013). Clinical statistics show that malaria accounts for more than half of all hospital consultations, followed by respiratory infections, diarrhoea, sexually transmitted diseases (STDs) and tuberculosis (Silva et al., 2007). The serious shortcomings of the country's health system in terms of funding, personnel, equipment and management, as well as the lack of adequate infrastructural and transport facilities, limit the access of the populations to biomedical assistance, especially in rural areas during the rainy season (MSP, 2008).
Since the first medical training facility was established in the country in 1987 with Cuban funding and personnel, teaching programs have adopted “a problem- solution approach with a strong community orientation” in primary health care (Fronteira et al., 2014). From the early 1990s the public health sector has pursued a policy of valuing indigenous medicine, however without integrating healers into clinical practice (Silva et al., 2007). Informal collaboration between public health services and local health practitioners has been reported, above all in rural areas (Indjai et al., 2010, Indjai et al., 2014). It is not uncommon for health professionals, who are themselves aware of indigenous medical practice, to advise patients to consult particular healers in order to treat orthopedic conditions (Crowley and Ribeiro, 1987) or for certain common ailments (Frazão-Moreira, 2009). Although the country recently proposed a national policy framework for indigenous medicine, so far no national programs, supervisory institutions or regulatory systems have been introduced for the use, production and sale of herbal medicine and local pharmacopeia (Kasilo et al., 2010, WHO, 2013).
Medicinal plants and preparations are widely available in local markets, and pharmacies, as well as through local practitioners. Manuals for herbal preparations based upon indigenous medicine have been compiled; one based upon the evaluation of an interdisciplinary group of local experts with advice on the management of herbal gardens (Caritas, 2004) and another based upon ethnobotanical field research with recipes for widely used species (Gomes et al., 2003). Calls for the regulation of indigenous healers’ activities have been made as well as for the collaboration of the National Health Institute (INASA) with regard to scientific research on the medicinal properties of local species.
The goal of this study is to prepare a comprehensive documentation of Guinea-Bissau's medicinal plants, thereby providing reliable information on a West African country for which published baseline data are severely lacking. For each of the medicinal plants presented here, it documents the (1) scientific and common names; (2) ecology and growth form; (3) geographical distribution; (4) therapeutic applications in accordance with disease groups; (5) other uses; and (6) their conservation status. In addition, by applying a multi-disciplinary approach, it places the analysis of the medicinal species, their properties and usage in a wider socio-cultural context demonstrating the relevance of local perceptions of species and their medicinal applications for the circulation and transmission of knowledge.
Section snippets
Study area
Guinea-Bissau (36,125 km2) is located in West Africa, between 10°59′–12°20′N and 13°40′–16°43′W, wedged between Senegal, Republic of Guinea and the Atlantic Ocean (see Fig. 1). With a total population of over 1,500,000 (INE, 2009), the country's population density is highest in the North Western areas (Cacheu and Oio), while the least populated areas are found in the South and Southeast regions (Tombalí and Boé) and the Bijagós Islands (INE, 2009). The capital Bissau, in the central coastal
Ethnobotanical data
From the extant 1507 vascular plant species (including 30 subspecies) with occurrence confirmed in Guinea-Bissau, a total of 218 medicinal species used in indigenous medicine were recorded (see Table 1), 102 of which are not referred in published sources on the country. About 14% of the total number of vascular plant species recorded in the country are employed in indigenous medicine, belonging to 63 families, being Fabaceae, Apocynaceae, Rubiaceae, Labiatae/Lamiaceae and Malvaceae, the most
Medicinal flora
Combining a thorough review of herbarium specimens and field surveys, our study recorded the presence of 218 medicinal plants in Guinea-Bissau, many of which are widely used elsewhere in sub-Saharan Africa. These species are important components of woodlands and savanna vegetation communities across the country. Their medicinal value, recorded for different ethnic groups and organised in disease groups based upon locally perceived health conditions, confirms their widespread use in terms of
Conclusion
Guinea-Bissau boasts a great cultural and biological diversity, and a high ethnobotanical value is attributed to its native flora. Its rich vascular native flora (1459 species) provides the principal source for products used in indigenous medicine (Catarino et al., 2008). The present study identifies 218 plant species-102 of which are not referred in published sources on the country-their distribution and therapeutic applications grouped in disease clusters based upon local notions of illness.
Authors' contributions
pH and MR conceptualised the study and drafted the manuscript. LC conducted the field surveys and assembled the ethnobotanical data. All the authors analysed the recorded ethnobotanical data, and revised and approved the final manuscript.
Acknowledgements
We wish to thank the Editor Prof. Michael Heinrich and the Reviewers for their thoughtful comments which greatly improved our paper. We are grateful to many collaborators in Guinea-Bissau for their assistance during fieldwork, and especially Bucar Indjai (INEP, Bissau). We also thank Agostino Palminha and Filipa Monteiro for the preparation of the Figures. Our gratitude also extends to IBAP (National Institute for Biodiversity and Protected Areas of Guinea-Bissau) and INEP (Instituto Nacional
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