Ethnobotanical study in a rural settlement in Amazon: contribution of local knowledge to public health policies

Medicinal plants continue to be appropriate and preferred alternatives for primary health care among rural Amazon populations, although their incorporation into conventional health services has been slow and challenging. Besides that, few Amazon plants have been considered in current public health policies. We sought here to better understand the role of medicinal plants in the therapeutic practices of residents of the Paulo Fonteles Land Settlement at Mosqueiro, a district within Belém (Pará State, Brazil) and identify species of potential value for government health services. Ethnobotanical data was obtained through semi-structured interviews with 61 residents. Results were analyzed using indices of use-report (Ur) and by consulting official documents of the Brazilian Ministry of Health (MS). The settlers use at least 61 exotic plants and 67 natives to Brazil; of the latter species, 21 were endemic to the Amazon region. The medicinal plants cited by the settlers were used for treating 76 symptoms and/or illnesses, especially related to digestive, respiratory, dermatological, and women's health problems; Anacardium occidentale, Alternanthera brasiliana, and Dalbergia monetaria had the highest URs. Forty plants are cited in MS documents. This research incentive more studies with Amazonian species and shows a list of 11 species for inclusion in health services offered to local populations.


Introduction
Medicinal plants continue widely used in developing countries to provide basic health assistance (Melro, et al., 2020;Heringer, et al., 2021). In Brazil, cultural, environmental, and economic factors contribute to use of these resources as the first choice of treatment. This country not only hosts the most diverse flora in the world with more than 55.000 species of plants but also has significant socio-cultural diversity (MMA, 2021). In addition, the plant-derived remedies can complement conventional pharmaceutical drugs, or cover gaps in more modern pharmaceutical treatments (World Health Organization (WHO), 2013).
The World Health Organization (WHO) has recommended the recognition about the use of these resources in the health field (WHO, 2013). In Brazil, these recommendations had an impact on the creation of the National Policies on Integrative and Complementary Practices (PNPIC) and Medicinal Plants and Herbal Medicines (PNPMF). Both aimed mainly to include the traditional therapeutic practices in the Unified Health System (SUS) and the guarantee of both safe and effective access to medicinal plants and herbal medicines (Brasil, 2016). Furthermore, these policies were essential to promote an extensive review and standardization of the administrative protocols and use of phytotherapeutics protocols and use of phytotherapeutics (Anvisa, 2008;2021;MS 2010) to allow and encourage their use as complementary pharmaceutical products in the SUS system (Almeida, et al., 2014). Independent of those national policies, many municipalities in Brazil have developed local initiatives for the use of medicinal plants and phytotherapeutics in public healthcare since the 1990s (Antonio, et al., 2013;Ogava, et al., 2003;Silva, et al., 2006) Almeida et al. (2014) examined the representivity of traditional phyto-pharmacopeias in official documents in order to propose the inclusion medicinal plants as alternatives within the SUS healthcare system, in conformity with national policies.
That study stressed the importance of considering regional and cultural traditional knowledge, as well as the regional Brazilian floras, to improve the role of PNPMF. In respect to the Brazilian Amazon, which contains the second most diverse flora in that country (Forzza, et al., 2020), it is important to note that in spite of its huge variety of native species with therapeutic potential (Bieski, et al., 2015;Coelho-Ferreira, 2009;Rodrigues, 2006) few of those plants have been studied to determine their safety and effectiveness. This fact may partially explain the inexpressive numbers of plants from that region recorded in official documents such as the National List of Plants of Interest to SUS -Renisus (Carvalho, et al., 2018). However, the the goals of the PNPMF and the Strategy for Traditional Medicine 2014 -2023 were designed to incentivize research into the native species of each Brazilian biome (WHO, 2013;Anvisa, 2016).
Among many social groups in the Amazon region are agricultural families in rural land settlement areas, which, together with traditional Amerindian communities, considered by the PNPMF to be indispensable actors in the structuring of productive chains of medicinal and psychotherapeutic plants (Brasil, 2016). One of the principal characteristics of rural settlements in the Amazon region has been their role in maintaining the Legal Reserve Forests required by Brazilian legislation (Cunha & Bortolotto, 2011). They also have potential for developing agro-extractivism projects that would lend value to Amazonian medicinal plants and foster the diversification of the economic activities of those rural groups (De Almeida, et al., 2013). Within that context, the present ethnobotanical study undertaken in the Paulo Fonteles Settlement Lands (APF), located in the Mosqueiro district (Belém, Pará State), sought to elucidate the roles of medicinal plants in local therapeutic practices and identify species of potential value to official health services.

Methodology
This research was based in a fieldwork ethnobotany using qualitative and quantitative approaches (Albuquerque, 2019). The date was obtained in the Paulo Fonteles settlement (PFS), located in the Brazilian Amazon in the Mosqueiro district, metropolitan region of Belém do Pará, in northern Brazil (01º04' -01º14'S, 48º19' -48º29'W). The PFS is situated in an estuary environment with marine influences, at approximately 15 m above sea level. The climate there is equatorial, with a mean annual temperature of 25.9 ºC, a mean relative humidity of 84%, and a mean annual rainfall of 2800 mm. The vegetation in the area is characterized by a few remnant trees of economic value, secondary forests ("capoeiras") in various stages of development, and pasture lands (INCRA, 2020). The settlement is located near an environmental protection area with great floristic diversity of upland and floodplain forest landscapes and mangrove swamps.
Established in 2006, the PFS occupies an area of 930 ha divided into 60 lots, with 50 families, all members of the Landless Workers' Movement -MST, totaling approximately 100 people whose principal economic activities are centered around subsistence agriculture. There is no basic sanitation infrastructure.
In order to generate representative data covering the entire community, at least one member of each resident family (18 years or older) was invited to participate. The overall sample was composed of 61 informants, of which 22 were men and 39 women, ranging in age from 18 to 80, and thus corresponding to approximately 50% of the total number of residents.
Fifteen of those collaborators had been living in the area even before the creation of the PFS, 23 have been living in the area for ten years since the settlement was officially established, and 21 arrived in the PFS up to eight years ago. As for the origins of the collaborators, 15 are native to the Mosqueiro district, 33 are from other municipalities in Pará State, and 13 arrived from other Brazilian states.
Fieldwork was undertaken between January and November/2015, using both a semi-structured interview and a free listing technique to obtain sociodemographic and ethnobotanical data (Albuquerque, et al., 2014). The informants were also asked to describe their therapeutic indications, methods of preparation and the plant part used.
At least one voucher for each plant cited in the interviews was collected, with the exception of 12 plants not encountered during guided tours or "walking in the woods" arranged with informants (Albuquerque, et al., 2014). The samples were identified by comparisons with collections at the MG herbarium at the Paraense Emílio Goeldi Museum and the help of technicians and taxonomists at that institution. The fertile specimens were deposited in that herbarium, with sterile material and fertile duplicate specimens being deposited in the Marlene Freitas da Silva herbarium (MFS) of the State University of Pará. The botanical classification system adopted was that of the Angiosperm Phylogeny Group -APG IV 2016 (Chase, et al., 2016).
We searched the species names and phytogeographical origins of the species using the Brazilian Flora Species 2020 List (JBRJ, 2017) and Mobot database, respectively.

Ethnomedicinal flora
A total of 126 plants were mentioned by the interviewees, of which 117 were identified to the species level, and nine to the genus level; the taxa were distributed among 110 genera and 54 families ( Table 1). The families Asteraceae, Fabaceae, and Lamiaceae stood out in terms of their large numbers of species. Those plants are mainly cultivated in backyards (71%), or collected in forest areas (24%), fields (4%), or gardens (4%). Most species were trees (53) and herbs (45), followed by shrubs (13) and lianas (12). The settler families use numerous native Brazilian (N = 64) and introduced (N = 61) species. Among the native species, 22 occur only in the Amazon biome, and are plants of significant relevance to the local pharmacopeia.
All vegetative parts were cited, with leaves (43%) being most widely used for preparing natural remedies. The 628 preparation recipes cited could be grouped into nine classes, especially extraction (teas) or maceration in water, followed by consumption in their fresh form as juice, syrup, alcoholic macerations, or application as a plaster or ointment.

ICPC categories and Informant Consensus Factor
The species mentioned were indicated for 76 health problems (symptoms and illnesses), distributed among 15 of the 17 ICPC categories ( Eight categories had RU ≥ 30, with the largest numbers of citations for digestive, respiratory and skin problems, and general symptoms. Of those eight categories, five native Amazon plant species stood out as indicated treatments. Anacardium occidentale (cashew) was the species most cited (RU = 22) in the "digestive" category, with its bark and leaves being used principally to treat infectious diarrhea. Alternanthera brasiliana (L.) Kuntze, locally known as "penicillin" or "ampicilin", was primarily used to treat skin problems due to its anti-inflammatory and wound-healing properties.
Dalbergia monetaria L. ("verônica") was found to be the most versatile species, being indicated in eight illness categories, especially for infirmities of the "female genital and breast systems" and inflammations of the uterus (or "woman's inflammations") involving excessive or irregular bleeding and vaginal secretions, according to the definitions of the informants. Phyllanthus niruri L. ("quebra-pedra") stood out among species indicated for urological problems, with kidney stones being the principal illness mentioned. Euphorbia tithymaloides L. ("coramina") received the greatest number of indications among illnesses and symptoms of the circulatory system, being commonly mentioned for treating high blood pressure, arrhythmia, and chest/heart pain.

Potential species for the formal health system
Of the cited species, 40 were recorded in at least one of the official documents consulted (Table 1). Cross referencing use-information about plants recorded in the present study with plants mentioned in official documents revealed that Sambucus nigra, Citrus aurantium, and Curcuma longa were the only species divergent in terms of their reported indications in the two contexts. In this plant list, there are 11 Brazilian species, that naturally occurring in the Amazon (Table 3). Two of these are endemic Amazonian species: Ptychopetalum olacoides Benth. was mentioned in the of the Brazilian pharmacopoeia 1 st and 2 nd Ed. Carapa guianensis Aubl. C. guianensis, listed in Renisus is the subject of one of the nine monographs published by the Brazilian Health Ministry with pre-clinical and clinical studies that confirm its anti-inflammatory activity. Quebra-pedra kidney problems 2,4,5, 6 Grenand, et al., 1987;Coelho-Ferreira, 2009;Bieski, et al., 2015 Portulaca pilosa L./221318 Amor crescido Inflammation, headache, control blood pressure, sore throat 4 Grenand, et al., 1987;Rodrigues, 2006;Bieski, et al., 2015 Lippia alba (Mill.) N.E.Br. ex P. Wilson/221298 Erva-cidreira Fever, headache, anxiolytic 5, 6 Pascual, et al. 2001;Coelho-Ferreira, 2009;Bieski, et al., 2015 Stachytarpheta cayennensis (Rich.)

Discussion
In this study, the informants constitute a heterogeneous group of people from different regions of the country, but who share agricultural activities throughout their lives, having medicinal plants as a priority resource in basic health care (Oliveira Melo, et al., 2021). The species collection registered here comprises plants of great importance in primary health care, whose uses have been widespread in the Amazon, where they are recurrent cultivation in backyards, bought in fairs and markets region, and planted in agro-forest systems (Santos, et al., 2018).
The expressive number of exotic plants cited is due in large part to their consumption in local diets and the necessity of the local inhabitants to be self-sustaining in terms of food resources, while at the same time taking advantage of many of those plants for their medicinal value. Exotic species are probably sought after to fill in gaps not satisfied by native species, which reflects their versatility (Alencar, et al., 2010) an important characteristic for rural populations that can quite often find themselves in situations of social vulnerability and dependent on plants within their reach (Cunha & Bortolotto, 2011). The Amazonian species cited in the present work demonstrates the importance of maintaining forest fragments in the metropolitan region of Belém (the state capital), which, among other functions, act as sources for a great number of native plants utilized for the primary health needs of small rural communities (Amaral, et al., 2012). Those species have been incorporated over many generations to treat common diseases among local populations (Berg, 2010). In addition, 82% of native species recorded in this study were found in backyards. The cultivation and management of these plants is important for the conservation of plant biodiversity, as they consist in a germplasm bank that can be useful to reduce the exploitation of primary vegetation and to facilitate the access to these areas when needed (Albuquerque, et al., 2008) The infirmities included within the outstanding categories in the present survey reflect physical factors that affect the community, such as precarious sanitary conditions, the hot and humid regional climate, smoke from burning vegetation, and the hard manual labor of farming. In 2016, diarrhea was the main cause of hospitalizations in the health system in the municipality of Belém (IBGE, 2016). Ethnobotanical studies undertaken in other rural Brazilian communities likewise reported high frequencies of those same infirmities (Cunha & Bortolotto, 2011;Almeida, et al., 2013).
The native plant species most cited in the present study are currently at different phases of scientific investigation.
Some of them have been the focus of research on the biological activities of their extracts and/or among those considered most promising or adequate for use in the SUS public health system, as cited in official MS documents. Other species are also widely known to traditional medicine practitioners, although they should be more closely investigated scientifically.
Anacardium occidentale is globally known for its nutritive and medicinal properties and is included in official medicinal plant registries (MS, 2010, Anvisa, 2010 and indicated to treat diarrhea. Its effectiveness against diarrhea was confirmed by Araújo et al., (2015). The review of Dantas et al. (2015) compiled information about its antimicrobial, antiinflammatory, analgesic, and wound-healing properties, besides other biological activities. Phyllanthus niruri L. "quebrapedra" stood out among species indicated for urological problems, with kidney stones being the principal illness mentioned.
Other species, on the other hand, although widely used locally, should be the target of further pharmacological and toxicological studies. As the amazon plant Dalbergia monetaria that stands out in this research for consensual e versatile use.
The studies about the properties of the D. monetaria are incipient. The ethyl acetate fraction from their bark and leaves demonstrated antibacterial activity against human pathogenic bacteria, especially Staphylococcus aureus and Pseudomonas (Moura, et al., 2020). Those authors suggested that the traditional medicinal use of D. monetaria might be related to the antibacterial activity of proanthocyanidins produced by the species.
Alternanthera brasiliana (L.) Kuntze, locally known as "ampicilin", was primarily used to treat skin problems due to its anti-inflammatory and wound-healing properties. This plant use has been have a long use historic in the Amazon region (Bieski, et al., 2015;Moraes, et al., 2020). The therapeutic potential of that plant has been demonstrated in numerous in vitro and in vivo studies confirming its significant wound-healing (Barua, et al. 2009), antimicrobial (Biavatti, et al., 2003), antinociceptive (Macedo, et al., 1999), anti-inflammatory, and analgesic properties (Fomagio, et al., 2012).
Euphorbia tithymaloides received the greatest number of indications among illnesses and symptoms of the circulatory system. Its effectiveness is related to the presence of cardiac glycosides (compounds active against cardiac insufficiency), and it is increasingly recommended for anti-tumor treatments (Fürst, et al., 2017). These plant demonstrates several biological activities that include anti-diabetic, analgesic, stomachic, hemostatic, anti-microbial, antifungal, anti-inflammatory, abortifacient, antivenom, anti-helminth and antibiotic (Srivastava, et al., 2019), although its mechanism(s) of action have not yet been fully investigated. The species is listed as toxic (Anvisa, 2014), possibly due to the presence of euphorbol and diterpene sterols, considered carcinogenic substances (Kumar, et al., 2015).
The list of 40 species recorded in this study and official documents exposes two aspects. The first of which refers to the agreement on the indication of use of these plants in both contexts. These plants have widespread uses worldwide, perhaps stimulated by globalization, which according to Leonti e Casu (2013)  considering their multiple functions within their natural environment.
The set of 11 amazon species have notable cultural value, a long history of traditional use, whose therapeutic value has confirmed in several chemical and biological studies. Justicia pectoralis Jacq., for example, was mentioned locally to treat colds and flu, indications reported for the use of this plant both in the RDC/2010 and in the Herbal Medicine Compendium 1 st and 2 nd Ed (Brasil, 2011;. This species also are listed in Renisus (MS, 2010), and has been the subject of studies that show its biological activity in the treatment of respiratory system diseases (Leal, et al., 2017) Lippia alba (Mill.) N.E.Br. ex P.
Wilson and P. niruri are either species that appear in several of the consulted documents. The other plants in Table 3 appear only in Renisus and ethnobotanical studies point to their historical traditional uses.
The plants-use represent popularized therapeutic alternatives of easy access to communities in vulnerable socioeconomic conditions, since can be easily cultivated in backyards, farm plots and secondary forests or founded in fairs and markets region (Santos, et al., 2018). These species should be better publicized to gain adhesion among SUS patients and health professionals, since that they are apt for use in basic care as offered by SUSespecially in municipalities in the Amazon region, according to the requisites of traditional use.
The inclusion of medicinal plants as alternative remedies in local SUS health stations could reduce public costs, facilitate access to them, and integrate popular culture with scientific knowledge to strengthen basic health treatments and reorient them towards the "front door" of the SUS system (Brasil, 2006). Previous experiences with the incorporation of those practices into the SUS network in Brazil revealed that, in spite of infrastructure difficulties and low investments in support of phytotherapies, medicinal plants represent low-cost and efficient alternatives widely appreciated by the populations being served (Antonio, et al., 2013;Ogava, et al., 2003;Silva, et al., 2006).

Conclusion
This study emphasizes the importance of medicinal plants in the primary health care of rural farmers in the Amazon.
They used species that occur naturally in the Amazon to heal the main health problems. These plants have been the subject of researches that confirms their therapeutic potential. Among the six species, highlighted, Alternanthera brasiliana and Dalbergia monetaria are not present in any document from the Ministry of Health. Hereby, we also draw attention to the requirement of more research with Amazonian plants, to ensure their inclusion in lists of species of interest to the SUS, since these documents do not present a representative number of species from this region. Finally, we highlight a list of 10 amazon species that must be available in the local health system, given their presence in official documents and traditional use in the country.
Therefore, this study encourages the development of more bioprospection research of Amazonian plants, whose traditional uses have been used for thousands of years by local populations. More knowledge of the therapeutic properties of these species is essential for its valorization within the scope of public health policies.