Ethnobotanical study of anti-malarials among communities in the municipal of Portel-PA, Brazil

Nearly all cultures use medicinal plants as a vital dietary resource, the ingredients collected from their surroundings being used for food and medicine. This study will provide the basis for further ethnopharmacological research by documenting the use of medicinal plants traditionally employed by the communities along the Aruanã River to treat malaria and related symptoms. While this is the first ethnobotanical study in this region, the socio-economic profile will also be evaluated as part of this study. We also aimed to review literature on traditional use of the cited species for comparison. Ethnobotanical data was collected using semi-structured interviews with 23 participants, which cited 29 species used to prevent and/or cure malaria and related symptoms. The interviewees ranged in age from 14 to 83, with 73.91% women, and 47.83% illiterate. Medicinal plants gathered from the wild and cultivated in gardens have been traditionally used to treat malaria and related symptoms among riverine communities. Documenting this local knowledge to compare with reviewed literature regarding efficacy and toxicity would be an essential part in the search for a new antimalarial agent.


Introduction
The Amazon Basin supports the largest remaining tract of tropical rainforest on the planet, being an ecosystem with the most diverse species, yet to be fully discovered [1][2][3] . Rich in both bio and cultural diversity, the Amazonian rainforest contributes towards global medicine, with medicinal plants possessing unique and varied biochemicals, which are one of the principal resources used to treat a variety of diseases [4][5][6] .
Due to their close contact and dependence on the local biodiversity as a therapeutic resource, communities in remote rainforest areas have considerable experience with medicinal plants [7] . This relationship between humans and plants is a source of information for ethnobotanical research, besides playing a key role in the Despite the vast range of antimalarials available in the Amazon region, high rates of malaria reoccurrences in isolated communities gives reason to suspect possible drug-resistant parasites, rendering the malaria treatment with chloroquinine, pyrimethamine, and sulfadoxine drugs ineffective, having been used worldwide for centuries [14,15,7,16] . In an environmentally sustainable manner, many isolated populations in the amazon use their biodiversity as an integral source for daily needs, with detailed and varied knowledge of the medicinal plants in their surrounding environment. Due to geographic isolation and limited access to medical care, malaria continues being a threat to riverine communities in the Amazon Basin. This explains how ethnopharmacological knowledge plays an important role in the employment of various species to prevent, treat and even cure malaria, and related diseases [17][18][19] .
Unfortunately, there has lacked consistent reports demonstrating the prevalence of malaria related diseases especially among children, due to single or repeated malaria episodes. According to the World Malaria Report (WMR), in sub-Saharan Africa, iron deficiency and malaria infection often coincide, anemia being a direct, as well as indirect, consequence of malaria. When promptly diagnosed and treated, mild cases of malaria can defer development whereas in severe cases the outcome is usually mortality [12] . With this scenario in view, the present study sought to recover knowledge and practices associated with plant resources as part of an important strategy linked to the conservation of biodiversity and the discovery of new medicines. It becomes necessary to evaluate socioeconomic aspects where medicinal plants are the most accessible for a population that depends on them to cure their infirmities, since the occurrence of frequent diseases have a correlation to human living conditions.

Description of the study area
This study was conducted along the Aruanã River, located in the municipality of Portel, a subregion of the Marajó archipelago in the state of Pará, Brazil (FIGURE 1). What today is the municipal of Portel was home to the Nheengaíba Indians in 1653, thus attributing to its present rich culture, and currently having an area of 25,384.96 km 2 , equivalent to 2.03% of the territory of the state of Pará [20] . According to [21] , the study area has a rainy tropical climate, characterized as hot and humid, with two well-defined seasons: rainy months (February through April) and dry months (August through October). The region has an annual rainfall of approximately 2,200 mm, and the annual average temperature is 21°C. In terms of religion, the populations in this study area are predominately Christian, the majority being Catholics followed by Protestants. There Portel-PA, Brazil Davis, Guimarães, Davis e Amarante are churches in this area as well. There is no organized sewage system; therefore, the residents dispose of their waste by open burning on their properties or in the river, over which most of the houses are built.
The communities in this study live approximately 110 kilometers from the city of Portel, or eighteen hours by boat. According to the Ministry of Health [22] , the municipality of Portel has high indices of malaria. Due to the yearly outbreak of the disease, a clinic on the Aruanã River, to which access is fluvial, is responsible for diagnosing and treating malaria. Fuel for small boats is scarce along the river, thus considered a highly valued resource. Ethnobotanical data were collected through semi-structured interviews randomly selected along the river. The medicinal plant information collected for this report was popular name, therapeutic indications, plant part used, preparation methods, and most frequent diseases that affects the family. The formularies applied included socioeconomic data such as gender, age, schooling level, profession, main income, and number of residents per home.

Socio-economic data collection
For data acquisition, two ethnobotanical field trips were performed during January and July 2018. The questions asked referred to the interviewees, such as name, age group, sex, schooling degree, and region of origin.
The communities comprise of native-born residents as well as those from various regions of the municipal, including neighboring municipalities. House-to-house interviews were conducted in which one interviewee gave the needed information on behalf of the remaining family members. The riverine communities along the Aruanã River make their livelihood from manioc and other cultural provisions, which they plant in small clearings near the riverbanks, as well as hunting and fishing. In riverine culture, the men hunt and clear the plots, while the women and children are responsible for planting, harvesting and processing manioc root into 'farinha', which is a staple food. The riverine people have a diversified economy based on fishing, hunting, small-scale agriculture, extraction and commercialization of forest products. The market for their products are trading boats, which trade in merchandise, such as coffee, beans, sugar, oil, and clothing. The riverine people use plants for a variety of purposes such as food, medicine, handcrafts, and construction.

Ethnobotanical data collection
A free list technique was used, which consisted of asking the informants to list any medicinal plants they knew and/or had used. For each specie mentioned, the participants described popular name, the plant part used, the preparation method, and the ailment for which the specie was indicated. While collecting ethnobotanical data, the interviewees showed their cultivated gardens where many medicinal plants are grown, as well as plant parts collected from the forest, for medicinal purposes. The riverine communities diverge in their notion of disease from Western ideas, due to the cultural and traditional context in which they are inserted. Therefore, we sought to categorize diseases mentioned by the participants that were related to malaria and liver disorders, such as fever, headache, anemia, hepatitis, and, as described by the interviewees, "for the liver".
For the principal plants mentioned, specimens were collected and deposited in the herbarium of the Museu Paraense Emílio Goeldi. The scientific names and the authorship were updated in accord with an online base of the Lista de Espécies da Flora do Brasil [23] and plant names have been checked and updated with the online website (www.theplantlist.org) of the Royal Botanic Gardens [24] .

Data analysis
The Index of Relative Importance (RI) of medicinal plants used by the communities was calculated according to the methodology proposed by [25] Excluding from this calculation, only the species mentioned by only one The CUP given is then corrected by the formula CUPc = CUP x FC which is equivalent to RI.

Literature review
The literature reviewed was from scientific journals in academic database (Google Scholar, SciElo, and

Socioeconomic characteristics of the informants
Twenty-three adults were interviewed in the communities along the Aruanã River, citing twenty-nine species to prevent and/or cure malaria and malaria-related liver diseases. Of those interviewed, seventeen were women (73.91%) and six (26.09%) were men. Only six interviewees were born in neighboring municipals, yet all of the informants live permanently on the Aruanã River. The interviewees were divided into three age groups, 10 (43.48%) in the range of 14 to 36 years old, 9 (39.13%) were 37 to 59 years old, and 4 (17.39%) were in the range of 60 to 83 years old. All interviewees were married or lived in a marital state, except for three participants that were either single, widowed or divorced. In terms of schooling level, 11 (47.83%) of the interviewees were illiterate and 12 (52.17%) had either completed or partially completed elementary schooling (TABLE 1). Due to precarious lifestyle in the communities, such as health services and schools, indigenous knowledge becomes a relevant therapeutic alternative, thus making it pertinent to being collected and documented. Gerais [26,27] , Santa Catarina [28] , Pará [25] , and Rio Grande do Sul [18] , yet differing from quilombola communities in Oriximiná, Pará, which cited mostly bark [7] . The plant part used varies according to the region, for instance, according to [9] , in the Atlantic forest, leaves are the most commercialized plant part. The preparation methods employed were teas, by decoction, and baths. Information obtained in this survey through interviews, mentioned common names and popular uses of the species indicated by the communities, as shown in TABLE 2. The Index of Relative Importance (RI) was calculated in relation to 29 species. This index was obtained by calculating the CUPc (corrected percentage of agreement on the main uses). According to [25] , the values of The results obtained in this study show that these communities employ a large variety of plants, possibly elevating the risk of intoxication due to a lack of scientific investigations. According to [29] , safe and efficient methods applied to the use of medicinal plants by communities can be questioned, since some use a variety of species that either have yet to be investigated or are considered toxic when administered orally, thus evidencing the necessity of an educational process in some populations. Most of the medicinal plants used, are cultivated in small gardens or balconies, followed by native plants collected in the nearby forest (FIGURE   3). It was noted in this study, that the inhabitants traditionally use many plants to treat common diseases, this information being transmitted from generation to generation orally.  [2] Arecaceae Euterpe precatoria Mart açai tree gathered native anemia root; seed 42.86 [7] Bactris gasipaes pupunha tree gathered native anemia roots 28.57 [30] Asteraceae Xanthium cavanillesii carrapichão herb gathered native liver roots 28.57 [7] Tanacetum vulgare L catinga de mulata herb headache leaves 14.29 [30] Spilanthes acmella jambu herb gathered native liver leaves 28.57 [18] (L) Murray Bidens pilosa L. picão herb gathered native liver; hepatitis leaves;root 42.86 [10] Bignoniaceae Fridericia chica (Bonpl.)L.G. pariri herb cultivated native anemia leaves 71.43 [31] Bixaceae Bixa orellana L. urucum shrubby cultivated native anemia roots 14.29 [32] Cecropiaceae Cecropia sp. embauba tree gathered native liver leaves 14.29 [26] Euphorbiaceae Jatropha curcas L. pião-branco shrubby cultivated exotic headache leaves; fruit 42.86 [10] Fabaceae Dipteryx odorata cumarú tree gathered native malaria; fever seeds 14.29 [33] Hymenaea courbaril jatobá tree gathered native anemia stem bark 14.29 [17] Schizolobium amazonicum paricá tree cultivated exotic liver leaves 14.29 [34] Vouacapoua americana Aubl acapú tree gathered native anemia stem bark 14.29 -
The safe use of medicinal plants is an important subject that requires further scrutiny, and yet too often overlooked. The study of medicinal plants not only contributes to a safer use of these resources by the populations, as well as brings to light the efficacy of new drugs for the treatment of diverse illnesses [35,36,25] .
Access to health services is one of the major difficulties encountered by the riverine communities, thus making medicinal plants a source of primary health care. The informants repeatedly mentioned the difficulties in accessing the clinic as well as lack of pharmaceutical drugs and materials necessary for treating basic health issues. Thus showing the important role medicinal plants play in the communities along the Aruanã River. Studies have evidenced similar results in [37] .
Despite the larger number of participants being in the youngest age group, indicating no evidence of knowledge loss, ethnobotanical knowledge needs to be documented for future research so that traditional phytotherapy may be validated with the intent to conserve traditional medicine. Studies [38,27] evidenced that the main way of knowledge transmission between generations requires intense contact between younger and older members of the society. There are differences between the knowledge of men and women; in general, women dominate the knowledge of plants that grow near residences, while men know more about plants that grow in the forest [27] .

Conclusion
This study in the communities along the Aruanã River showed that the indigenous knowledge, acquired through generations of experience with nature in understanding regional medicinal flora, could serve as a base for future studies to test what these riverine people practice for treating frequent diseases. Investigations in regards to scientific and botanical research are scarce in the location of this study, attributing relevance to this research and possibly being the first scientific paper on this subject in the local area.