Background

The naturalists in South America

During the nineteenth century in Brazil, significant scientific expeditions were conducted by various naturalists with the purpose of cataloging the still undescribed biodiversity, mapping territories, promoting agriculture, exploring native natural products, and developing foreign trade [1, 2]. It is important to have clear that the South American biodiversity was unknown under a perspective of European colonizers but not to the indigenous peoples, which interacted with nature since millennia and knew properly the medicinal, edible, and other potentials of plant species, as well as the localities to collect the plants and how to cultivate some species. Unfortunately, indigenous peoples are still eclipsed in the historiography of the production and circulation of knowledge and technologies [3]. The naturalists, mostly Europeans, made valuable written records of the traditional use of plants in South America, with notable figures coming to Brazil such as Maximilian zu Wied-Neuwied (1815–1817) [4], Carl F. P. von Martius (1817–1820) [5], Auguste de Saint-Hilaire (1816–1822) [6], George Gardner (1836–1841) [7], Alfred Russel Wallace (1848–1852) [8], Henry Walter Bates (1848–1859) [9, 10], Richard Spruce (1849–1864) [11], among others [1, 12].

Many other naturalists were inventorying plant species in South America since the sixteenth century, such as Antonio Pigafetta (1520) in Patagonia [13]; Francisco Hernández (1570–1577) [14], Nicolas Monardes (1574) [15] and Martín Sessé (1788–1796) [16, 17] in Mexico; Paul Hermann in Surinam and the Guianas region [18]; Hans Sloane in Jamaica (1687–1689) [19]; Hipólito Ruiz and Antonio Pavón (1777–1786) and Joseph de Jussieu (1735–1771) in Peru [20, 21]; José Celestino Mutis (1782–1808) in Colombia [22]; Charles Plumier (1689–1697) in Martinique and Haiti [23]; Jean-Baptiste C. F. Aublet (1762) in the French Guiana [24], and Charles-Marie de la Condamine (1735–1744) from the Peruvian Andes to the Atlantic Ocean through the Amazon river [25].

Among all these names, the German Alexander von Humboldt was undoubtedly the most prominent naturalist of his time. Alongside the French Botanist Aimee Bonpland, Humboldt conducted an expedition to the Spanish American Colonies between 1799 and 1804, collecting more than 6000 plant specimens. Humboldt was a pioneer, inspiring an entire generation of naturalists who succeeded him to explore South American biodiversity. The information gathered by Humboldt greatly contributed to the growing knowledge of South American biodiversity, led to significant advances in understanding the American continent’s natural history and, most importantly, radically changed the view about the importance of nature for the life of the planet [26].

Although practically only male names are cited among naturalists, female naturalists had significant participation in constructing scientific knowledge regarding plant biodiversity for centuries. Women’s trajectories are often neglected by the history of science, and the scarcity of female names constructs the image that sciences were exclusively a male practice [27]. The most prominent female naturalist is certainly the German Maria Sibylla Merian, who published a book on insects and plants during an expedition in Surinam between 1699 and 1701 [28]. Nonetheless, Mariath and Baratto [27] found 28 female naturalists who participated in scientific expeditions from the seventeenth to the nineteenth century, recording or illustrating useful plants.

The Baron de Santa-Anna Nery: a propagandist of the Brazilian Amazon

Besides the naturalists, propagandists played an important role in promoting Brazilian natural resources. Often, governments would hire intellectuals to design and promote the region's characteristics abroad, aiming to promote the modernization of Brazil [29].

One of them was Frederico José de Santa-Anna Nery (1848–1901) (Fig. 1), who was born in the Brazilian Amazon, in Belém, the capital of the state of Pará, Brazil, but at the age of 14, he moved to Paris, France, and lived in Europe until his death [30]. He earned a Bachelor's degree in Letters and a Doctorate in Law from the University of Rome, and he worked for French newspapers and magazines (“L’Événement Écho de Paris”, “L’Opinion”, “Le Fígaro”, “L’América", “Republique Française”), as well as Italian (“La Tribuna”, “Libertá”, “Journal de Rome”, “Il Século”) and even Brazilian publications (“Jornal do Commercio”). He was the owner and editor of the “Revue du Monde Latin” and the director of the magazine “Le Brésil”, publications that always sought to portray a positive image of Brazil and Latin American countries [30, 31].

Fig. 1
figure 1

Portrait of Baron de Santa-Anna Nery (1848–1901) [32]

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Baron de Santa-Anna Nery referred to himself as a "volunteer propagandist" for Brazil in Europe, serving as an immigration agent to publicize the living conditions in the Amazonas province, advocating for the development and modernization of the Amazon [29, 33]. Due to his family's elite status in Manaus and Belém, he had the advantage of establishing political relationships with influential figures in the Brazilian government at the time, which sought to promote the colonization of the Amazon through European immigration [29]. An example of his political influence was when Santa-Anna Nery defended Brazil's image and interests in the territorial dispute over part of the Amazon (currently the state of Amapá, Brazil) with France (French Guiana). The French naturalist Henri Coudreau, who initially advocated for his country's interests, upon meeting and becoming friends with Santa-Anna Nery, became an ally of Brazil. In fact, Coudreau was even hired by the state of Pará to map the course of rivers that were still unknown, and this cartographic data was crucial for Brazil's defense of the contested Amazonian territory. Santa-Anna Nery played a significant role in this Brazilian victory in 1900, after the international arbitration by Switzerland, mainly due to his ability to discover ancient documents validating Brazil's rights over the territory, as well as his extensive sociability and influence within the political and social circles of Europe and Latin America [30, 34].

Santa-Anna Nery’s most famous book is "Le Pays des Amazones" (The Lands of the Amazons) [32], first published in 1885 (Fig. 2), which was sponsored by the government of Manaus with the aim of promoting the state of Amazonas to the outside world. Interestingly, this work was written in French and was only translated into Portuguese in 1979 by Ana Manzur Spira. In this book, the author portrays all the Amazonian regionalism and the work is divided into three focuses: The first is to highlight the natural abundance of the Amazon as a possibility to acquire wealth; the second is to dispel negative ideas about the region regarding climate and tropical diseases; and the third is to showcase the modernized urban spaces and economic opportunities that could be found in the region [33].

Fig. 2
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Cover page from the Baron de Santa-Anna Nery’s “Le Pays des Amazones,” first published in 1885 [32]

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In "Le Pays des Amazones", Santa-Anna Nery depicted the fauna, flora, minerals, habits, and lifestyles of the riverside dwellers, indigenous people, and immigrants. He extensively explores the rubber economy and the possibilities of economic progress based on agriculture and foreign labor, drawing from his own experiences and historical documents from prominent travelers who ventured through the Amazon, including figures such as Manuel Rodríguez (1684), Charles-Marie de la Condamine (1735–1744), Alexander von Humboldt (1799–1804), Spix and Martius (1817–1820), Louis Agassiz (1865–1866), among others [35]. In the book, the author dedicated a chapter to introduce and report on the plant kingdom and its relationship with humans, from the economic value of woods to plants used for treating diseases. The author systematizes the classification of plants according to their function, briefly discussing each category: construction woods used in common, naval, or civil construction; woods for carpentry and furniture manufacturing; edible plants; spices and aromatic plants; textile fibers; plant-based dyeing, tanning, and toning materials; oilseeds; medicinal substances; gums, gum-resins, resins, oil-resins, balms, and essences; vegetable ivory and concentrated juices [33, 35].

The aim of this work is to understand the historical context and ethnobotanical value of the plant species from the Brazilian Amazon at the end of the nineteenth century through an analysis of the book "Le Pays des Amazones" (1885) by Baron de Santa-Anna Nery. Furthermore, we aim to rescue the historical importance of the Baron de Santa-Anna Nery, a very influential Brazilian propagandist abroad at the end of the nineteenth century, but that was forgotten nowadays. This is the first analysis involving the comparison of historical ethnobotanical information with contemporary scientific evidence regarding the plants described in his book.

Methods

The original book “Le Pays des Amazones” published in 1885 [32] was consulted in the online catalog of the Biblioteca Brasiliana Guita e José Mindlin—PRCEU/USP (https://www.bbm.usp.br). The original 3rd edition [36] and its translated version into Portuguese [35] were consulted to compare information. After reading the book, all information about plants classified as medicinal or those that had therapeutic properties, or those with some other uses, was systematized in a table organized by botanical description, page number, vernacular name, plant part, origin, traditional uses and observations. The updated botanical names and the origin of each plant were verified in Plants of The World Online (https://powo.science.kew.org/), Tropicos (https://tropicos.org/home) or Flora e Funga do Brasil (http://floradobrasil.jbrj.gov.br/). Origin classification of the plants (Brazilian native, exotic, naturalized, or cultivated) followed the terminology adopted by Moro et al. [37]. Traditional uses were classified as following: (a) medicinal, (b) edible plants (food and beverages), (c) constructions (civil, naval and railway) and buildings, (d) spices and condiments, (e) ornaments and objects (ropes, brooms, rags, hammocks, nets, violin strings, ship wedges), (f) carpentry and furniture, (g) textile fibers (ropes, rags, linen, fabric, lace), (h) resins, oleoresins, gums, oils, balms, latex, rubber, essences for perfumery, (i) pigments, dyeing and tanning, (j) hunting and fishing, (k) lighting, (l) other uses (latex smoking, "tucupi" extraction, rituals, animal fodder, press, "plant milk"). Finally, using the scientific name of medicinal plants alone or in combination with their popular use as keywords, a search was carried out in Pubmed, ScienceDirect and Google Scholar in order to indicate current pharmacological studies that provide evidence about the described traditional uses, as well as general biological activities that have been studied.

Results and discussion

In the book "Le Pays des Amazones" [32, 35, 36], a total of 156 plant species were identified. Out of these, 132 species had their scientific names updated, while the remaining 24 lacked sufficient information. These species belong to 45 different families, with Fabaceae (23) and Arecaceae (17) the most represented, followed by Euphorbiaceae (10), Lauraceae (7) and Malvaceae (6); the remaining families each contained between 1 to 5 species.

Regarding the origin of the plants, 109 species were Brazilian native, 10 were exotic, 7 were cultivated and 6 were naturalized. It is important to clarify the terminology regarding the origin: (a) Native species are those naturally occurring in a specific location, with their presence in the area attributed to their own dispersal capacity and ecological competence, without human influence; (b) exotic or alien species are those that would not naturally occur in a given geographic region without human transport (intentionally or accidentally) to the new area; (c) cultivated plants are exotic species that may eventually reproduce in the environment where they were introduced. However, they are not capable of sustaining an autonomous population in the long term, requiring human management (cultivation); (d) naturalized plants are exotic species that can consistently reproduce in the location where they were introduced, establishing a self-perpetuating population without the need for direct human intervention. Nevertheless, they have not dispersed far from the introduction site and remain restricted to that location [37].

Considering only the medicinal plants, 36 species were identified (Table 1), among them 24 had their therapeutic indications defined by Baron de Santa-Anna Nery, while the other 12 were only assigned as “medicinal” not specified for what therapeutic purposes they were used, classified by us as “undefined.” The main medicinal indications reported were astringent (5), purgative/laxative (5), stimulant and tonic (5), vermifuge (4), febrifuge (3), sudorific (3), emetic, diuretic and antidysenteric (2). The traditional uses reported by Santa-Anna Nery are supported by pharmacological studies in approximately 75% (18) of the medicinal species in relation to those with defined purposes.

Table 1 Medicinal plants described in the book "Le Pays des Amazones" [The Lands of the Amazons] (1885) by Frederico José de Santa-Anna Nery (1848–1901)
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A total of 106 useful plants (non-medicinal) were included in Table 2, 9 with undefined uses and 97 with some traditional use, like edible species (27), constructions and buildings (15), spices and condiments (12), ornaments and objects (20), carpentry and furniture (10), textile fibers (11), resins, oleoresins, gums, oils, balms, latex, rubber and essences for perfumery (39), pigments, dyeing and tanning (9), hunting and fishing (5), lighting (3), among other uses.

Table 2 Useful plants (except medicinal plants) described in the book "Le Pays des Amazones" [The Lands of the Amazons] (1885) by Frederico José de Santa-Anna Nery (1848–1901)
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In a recent work by Pironon et al. [163], it is affirmed that there are currently 35,687 utilized plants in the world for human, vertebrate, and invertebrate food, materials (e.g., wood, fiber), fuels, social uses (e.g., narcotics, ritual, religious uses), poisons, medicines, environmental uses (e.g., intercrops, windbreaks, ornamentals), and gene sources (e.g., crop wild relatives). Some decades ago, Bennett [164] asked how ethnobotanists can help protect tropical forests and preserve the lives and traditional knowledge associated with Amazonia's indigenous peoples. The answer was that, first, they can identify native plant resources. That is the reason documenting and understanding the diversity and distribution of plant species used by humans is crucial to implementing conservation strategies and developing plant-based solutions to address global societal challenges such as hunger, diseases, and climate change [163].

In this context, historical ethnobotany emerges as a prominent science, which deals with the study of human-plant relationships in the past, primarily using the analysis of written historical documents such as publications, manuscripts, official records, and prescriptions, as well as iconographic sources and voucher specimens in herbaria [165,166,167]. Traditional knowledge about plant use and effectiveness contributes, for example, to the dissemination of therapeutic benefits, validating the information accumulated over centuries [168].

In this work we assessed such type of historical information and our results confirm that the book “Le Pays des Amazones” [32] is one of the sources containing valuable information about traditional uses of Amazonian biodiversity in the nineteenth century. Based on documents and reports from naturalists and his youthful memories and own traveling experiences, the Baron de Santa-Anna Nery shows to readers the huge potential of plant biodiversity. Santa-Anna Nery was in Paris when he wrote his main works about the Amazon, so many of his references were in his own past, in his memories, and in the indigenous objects he kept in his private collection. His experience among indigenous tribes during childhood, accompanying catechetical projects, was also important for his work. However, he undertook three journeys to the Amazon Basin regions from 1882 to 1887, interacting with the residents of the area, including indigenous peoples who became his informants [33, 169].

Starting from an exploratory perspective that promoted the idea that progress would be achieved through the manipulation and cultivation of nature, in line with the thoughts idealized by Count Buffon a century earlier [170], Baron de Santa-Anna Nery portrays the Amazon rainforest as "the land of rubber, the legendary El Dorado, the virgin lands awaiting the sowing of civilization. Its fauna is infinite; its flora, inexhaustible; its mineral wealth, mysterious". For Santa-Anna Nery [35], the Amazon Valley was destined to become a significant agricultural center if Europeans were willing to emigrate to the region: "Soon we will see the immense forests partially cleared, the banks of the great rivers cleansed, the interior plains transformed into cultivated fields. All this vastness, almost deserted today, will give way to productive work".

However, Santa-Anna Nery [35] warned of the need to study the Amazon before European exploration: "Civilization is sometimes synonymous with destruction. Man, in mastering Nature, mutilates it. He exterminates to reign. Instead of subjugating animals for his service, he kills them indiscriminately, without thinking of adapting them for domestic use. Instead of extracting from the forests what is necessary for his needs of food, shelter, furniture, navigation, medication, he fells randomly, with prodigal recklessness, and destroys, for the future, precious sources of well-being. It would be desirable for the naturalists and scientists to pass through the virgin lands before the settler, to establish the region's resources and ensure their conservation".

To better understand the propagandist intentions of Baron de Santa-Anna Nery in attracting European immigrants to the Amazon, it is important to demographically contextualize the Amazon region at the end of the nineteenth century. According to the census conducted at the end of 1890, the state of Amazonas, Brazil, had 147,115 inhabitants, representing a population density of about 0.08 inhabitants per square kilometer [35]. The Amazon, in this geographic scope comprising the states of Pará and Amazonas, was still considered wild, indigenous, and sparsely populated at this time—an erroneous and prejudiced view, according to Baron de Santa-Anna Nery himself [33]. The population of the state of Amazonas, according to Santa-Anna Nery, consisted of three main elements: Brazilians of all descents, catechized indigenous people, and foreigners from various origins, not counting the indigenous people who remained in a wild state [35].

From the cultural and social legacy of the Portuguese, who imposed their culture, ways of living, and modes of production on the indigenous people, along with the Northeastern Brazilians who came to work in the rubber tree (Hevea brasiliensis (Willd. ex A.Juss.) Müll.Arg.) plantations, transformations occurred marked by intense and diverse cultural exchanges [171]. The indigenous people were affected by diseases brought by the Europeans, such as smallpox, which proved fatal, and they succumbed to addictions like alcohol. Santa-Anna Nery also highlights that slave labor was incipient in the Amazon region, with at most a thousand enslaved Africans, and its abolition occurred in 1884, four years before the total abolition of slavery in Brazil. Rubber extraction, for example, was carried out mainly through the exploitation of the labor of indigenous people (who, according to a decree from 1757, could not be enslaved) and Northeastern migrants, especially from the state of Ceará, Brazil. It is in this context, from the second half of the nineteenth century, that Brazil sought to attract immigrants to occupy the regions far from major population centers. Despite the amount spent on the migration campaign, between 1855 and 1882, the country received about 500,000 immigrants, who mostly headed south, mainly Italians and Germans, while the north remained uninhabited [35].

Inserted into this demographic context of the Amazon highlighted by Santa-Anna Nery, he also presents in his book a survey regarding indigenous ethnicities from 1768 until the end of the nineteenth century (1899). He provides the names, place of origin identified by the river where they lived, and characteristics of 373 different ethnicities that existed in the state of Amazonas [35]. Of all the social elements in the Amazon, the indigenous population underwent the most significant cultural dismantling. Through interactions with Portuguese colonizers, the traditional knowledge of the indigenous people began to incorporate practices and knowledge considered civilized, mainly derived from European folk medicine. In addition to the Europeans, the indigenous people of the Amazon also engaged in the intense interactions with Northeastern Brazilians, introducing elements of African traditions inherited from enslaved Africans [171]. A valuable ethnobotanical contribution of the Baron, in this way, is the citation of vernacular names in the original language, with most of these names having indigenous origins, followed by Portuguese names.

Regarding botanical biodiversity, Baron de Santa Anna-Nery, drawing on his own knowledge and documents from naturalists of the eighteenth and nineteenth centuries, presented various possibilities for using Amazonian plants. The choice of plant species was driven by two main aspects: (a) To highlight the varieties of native natural resources that immigrants would find in the Amazon, demonstrating that there would be no shortage of raw materials for their daily needs, ranging from food to woods for building houses, substitutes for some plants used in Europe, such as guarana replacing coffee, appealing to the exoticism and vegetal abundance of the forest. There is an appreciation for regional plants and derived products, such as fruits, beverages, and stimulant plants, aiming to attract visitors eager to experience exotic products; (b) from an economic perspective, it mentioned native plants that could foster agricultural practices or generate profits through their exploitation [33].

In this sense, Santa-Anna Nery mentions in his book several plant species that were already well-known internationally at the end of the nineteenth century, precisely because they were involved in highly lucrative economic cycles, aiming to supply raw materials for export [172], such as the rubber tree (Hevea brasiliensis), copaiba (Copaifera spp.), ipecac (Carapichea ipecacuanha (Brot.) L. Andersson), “breu” oleoresin (Protium glabrum (Rose) Engl.), coca (Erythroxylon coca Lam.), “salsaparrilha” (Smilax spp.) and Brazil nut (Bertholletia excelsa Bonpl.), many of them formerly included in official medical compendia, such as the European Pharmacopoeias [3, 173,174,175]. Other plants were internationally recognized as foods and beverages, like guarana (Paullinia cupana Kunth), cashew (Anacardium occidentale L.), cacao (Theobroma spp.), manioc (Manihot esculenta Crantz.), pineapple (Ananas comosus (L.) Merr.), vanilla (Vanilla planifolia Andrews) and “pupunha” (Bactris gasipaes var. gasipaes Kunth), and others were extensively explored also for dyeing, such as Bixa orellana L. [173], and perfumery and carpentry, such as Dipteryx odorata (Aubl.) Forsyth f. and Cedrela odorata L., respectively [172].

Many plants cited in Santa-Anna Nery's book have been continuously compiled in various ethnobotanical studies in the Amazon since the end of the twentieth century: Acmella oleracea (L.) R.K. Jansen (medicine), Anacardium occidentale (food), Anadenanthera peregrina (L.) Speg. (not mentioned), Ananas comosus (food, medicine), Astrocaryum vulgare Mart. (construction, objects), Bertholletia excelsa (food, medicine, construction), Bixa orellana (dye, food, medicine), Bowdichia virgilioides Kunth (not mentioned), Brunfelsia uniflora (Pohl) D.Don (medicine), Calophyllum brasiliense Cambess. (not mentioned), Capsicum annuum L. (medicine), Carica papaya L. (food, medicine), Cedrela odorata (medicine), Copaifera spp. (medicine), Dioscorea sp. (food), Dipteryx odorata (medicine), Elaeis oleifera (Kunth) Cortés (food, medicine, construction), Euterpe oleracea Mart. (food), Genipa americana L. (dye, construction, food, medicine), Humiria balsamifera (Mart.) Cuatrec. (not mentioned), Hymenaea courbaril L. (not mentioned), Inga spp. (food, forage, fuel, medicine), Jacaranda copaia (Aubl.) D.Don (medicine), Leopoldinia piassaba Wallace (food, medicine, construction), Manicaria saccifera Gaertn. (food, medicine, construction), Manihot esculenta (food, ritual/mythical, medicine), Mauritia flexuosa L.f. (food), Musa x paradisiaca L. (medicine), Oenocarpus bacaba Mart. (food, medicine, construction), Oenocarpus bataua Mart. (food, medicine, construction), Paullinia cupana (medicine), Paullinia pinnata L. (toxic), Pradosia lactescens (Vell.) Radlk) (not mentioned), Psidium guajava L. (food, medicine), Theobroma cacao L. (food, medicine) and Vouacapoua americana Aubl. (not mentioned) [164, 176,177,178,179,180,181].

It is interesting to observe how many plants presented by Santa-Anna Nery continue to be traditionally used by Amazonian communities, even after almost 150 years since the book was published. These plants demonstrate resilience over time, persisting despite the availability of new and more effective medicines, improvements in health care, changes in epidemiology, and advancements in sanitary conditions. The resilience of local ecological systems is crucial for preserving local identity and culture [182].

Nevertheless, the majority of plants cited in Table 1 or 2 are restricted to a local Amazonian knowledge, not being included in medicinal or useful Brazilian plants guides. Only 23 non-native plants were cited in the inventory, such species introduced in Brazil since the sixteenth century by the Portuguese due to their economic, edible or medicinal potential [183]. Exotic species such as Tamarindus indica L., Zingiber officinale Roscoe, Styrax benzoin var. benzoin Dryand. and Cinnamomum sp. are native to African and Asian continents, while Smilax glauca Walter, Lecythis ollaria L., Protium glabrum, Psidium guajava, Carica papaya and Ipomoea batatas (L.) Lam. are native from America, mainly Central America. Some of these plants were important raw material and foods and were cultivated or naturalized for economic exploitation. That is the reason it is so important and strategic to access the potential of Amazonian native useful plants in Brazil. The Brazilian native plants are still very poorly known and their potential is still insufficiently exploited, which is further aggravated by the fact that these species are very often distributed in areas subjected to intense human action and therefore under severe threat of extinction [184]. The sustainable use of native biodiversity for bioeconomic purposes is one of the aspects of technological innovation in the twenty-first century. Sustainable management of resources from the Amazonian flora allows for income generation for small producers, providing raw materials for the production of genuinely local products such as cosmetics, phytotherapeutic medicines, traditional phytotherapeutic products, agricultural products, and more. Traditional knowledge related to plant species of industrial interest can be utilized for the development of products and processes that should benefit communities through fair and equitable benefit sharing [185].

Santa-Anna Nery predominantly highlighted in his work many native edible plants as well as those used in civil and naval construction. Large and imposing trees, such as "maçaranduba" (Manilkara bidentata (A.DC.) A. Chev. subsp. bidentata) and "guarabu" or "pau-roxo" (Peltogyne sp.), are described with heights exceeding 20 m and trunks measuring 1.20–2 m in diameter. The former is employed in the construction of railways and ship wedges, while the latter is esteemed for its high-quality wood. According to Santa-Anna Nery [32], “maçaranduba” was one of the most precious forest products in the Amazon at that time.

With descriptions like these, the Baron seeks to draw the attention of Europeans to what he deems "normal exploration" of the forest, that is, the use of natural resources for the everyday and economic needs of the community. In his words: "Wood is already beginning to be scarce in old Europe, deprived of its prehistoric forests; the time is not far off when we will be forced to seek new forest reserves in the new world. The Amazon holds in reserve, for centuries, a supply of wood capable of sustaining all local and foreign industries" [35].

In "Le Pays des Amazones," we find descriptions of various preparations based on native edible plants. For example, the cassava root (Manihot esculenta) is used in the production of both white and yellow flours, often as a substitute for bread, or in the preparation of “cauim,” an indigenous alcoholic beverage. This root is considered the staple of the population's diet and is commonly used in porridges and soups. “Tucupi'' is also mentioned, a liquid extracted from cassava, which is grated and compressed in the “tipiti,” an elastic tube made from the stalks of plants like “jacitara” (Desmoncus sp.) or “guarumá” (Ischnosiphon arouma (Aubl.) Körn.). “Tucupi,” when raw, was considered a violent plant poison containing cyanic acid as the active principle, although it is safe for consumption after boiling, as cyanic acid is volatile [32]. Indeed, cyanogenic glycosides are found in high percentages in cassava roots and leaves, such as linamarin and lotaustralin. These active constituents have neurotoxic and neurological effects because, after undergoing hydrolysis, they release cyanide derivatives. Cyanogenic compounds need to be removed by boiling, peeling, fermenting, and cooking the plant, resulting in a loss of up to 70% of these toxic substances [186].

The use of plants such as Serjania ferruginea (Lindl.) Mabb., Paullinia pinnata, and Magonia sp., known by the generic term "timbós" and utilized by indigenous people for fishing, is also described in the work: "The timbó was crushed, and the juice obtained was poured into a shallow and calm lake or river. After a few hours, the intoxicated fish would appear on the water's surface, and it was only a matter of collecting them in a boat; the small fish were disregarded" [32]. For instance, plants of the genus Serjania (e.g., S. lethalis A.St.-Hil.) contain saponins called serjanosides, with ichthyotoxic properties [187], and some species (e.g., S. tenuifolia Radlk., S. ferruginea) are still used today by traditional peoples of the Amazon [188,189,190].

Due to its importance in the late nineteenth century, the latex extracted from the rubber tree (Hevea spp.) has a chapter exclusively dedicated to its historical, social, and economic description. The first rubber boom lasted from 1880 until 1913, while the second boom resumed during World War II (1939–1945) [191].

According to Santa-Anna Nery [35], by the end of the 1890s, the annual international rubber consumption was around 50,000 tons. Rubber latex from the rubber tree was exported in its raw state, and abroad, the raw material was transformed and resold at higher prices to Brazil. Due to the significant interest at that time, especially driven by the automotive and bicycle industries that used latex for tire manufacturing, several European metropolises attempted to acclimate the rubber tree in their warm-climate colonies.

One well-known case is that of the British explorer Henry Alexander Wickham, who, at the service of the Kew Royal Botanical Garden, smuggled more than 70,000 Hevea seeds in 1876, with the purpose of the British crown cultivating them in Asian colonies. The 1910s were marked by rubber production in the East, notably English rubber produced in Malaysia, which timidly produced three tons in 1900, compared to over 26,000 tons produced in the Brazilian Amazon. In 1913, it began producing 47,000 tons compared to 38,000 tons of Brazilian rubber, marking the year of the break in the Brazilian monopoly on rubber export in favor of international production. By 1921, rubber plantations in the East were producing 1.5 million tons of rubber, compared to only 20,000 tons from the Amazon [192].

The nineteenth century was marked by the advancement of chemistry, with the isolation of the first molecule of natural origin, morphine, by the German pharmacist Friedrich Setürner in 1806 from opium (Papaver somniferum L.). This event revolutionized medicine, as the treatment of diseases using isolated substances (drugs) led to more effective and safer outcomes, with the standardization of dosages. Since then, throughout that century, the interest of pharmacists and chemists in isolating new molecules that could be used in therapy led to the isolation of numerous other drugs of plant origin, such as quinine, caffeine, atropine, and digoxin [193]. Baron de Santa-Anna Nery gives great prominence to native medicinal plants in "Le Pays des Amazones," once again focused on promoting Amazonian natural resources, but mainly emphasizing the idea of developing the industrialization process allied to the processing and rational exploitation of forest products, along with agricultural development to achieve an "economic revolution" [33].

Based on a documentary analysis of other naturalists who described the Amazon, Santa-Anna Nery accurately indicates the medicinal properties of various plants, while some species are simply classified as "medicinal" (undefined), probably based on his own memories regarding the therapeutic potential of plants he encountered when he was younger but did not find descriptions in the works of the naturalists he studied. In this study, it was possible to deepen the knowledge about the medicinal use of species through pharmacological studies, establishing a connection with the traditional usage information from the late nineteenth century to the pharmacological properties studied since then until the present day.

Pharmacological studies corroborate the traditional uses for many related medicinal plants: astringent plants such Bowdichia virgilioides [64], Krameria argentea Mart. ex Spreng. [84,85,86], and Psidium guajava [128]; laxative/purgative plants such as Tamarindus indica [79,80,81]; vermifuge plants such as Carica papaya [52], Ficus gomelleira Kunth & C.D.Bouché [30, 31] and Spigelia anthelmia L. [115, 116]; bitter tonic and febrifuge plants such as Carapa procera DC. [106] and Cedrela odorata [109]; expectorant, emetic, and amoebicidal properties of Carapichea ipecacuanha [131,132,133]; antivenom properties of Brunfelsia uniflora [154]; anesthetic, analgesic, anti-inflammatory and anti-scorbutic actions of Acmella oleracea [41,42,43]; stimulant activity of Paullinia cupana [141,142,143] and Erythroxylum coca [62, 63].

The indigenous procedure for preparing guaraná (P. cupana) for stimulant purposes is described in detail: “Its seeds are used to create a stimulating beverage by lightly roasting the beans, after drying them in the sun, and reducing them, with the addition of a small amount of water, to a paste to which whole or crushed seeds are added as desired. The guaraná paste is exported in the form of very hard sticks, with a reddish-brown color. The inhabitants of the region prepare the beverage by grating the guaraná with the dried tongue of the "pirarucu" fish (Arapaima gigas)” [32]. The procedure of the Sateré-Maué indigenous people, regarding the preparation of guaraná, is well-documented in scientific literature [194, 195].

No pharmacological studies were found to corroborate the emetic, laxative, and antisyphilitic activities of Jacaranda copaia, laxative action of Tabebuia insignis (Miq.) Sandwith. nor even Tecoma spp., astringent properties of Couepia sp. nor treatment of skin infections of Vateria sp.

Although many plant species cited in the book are only mentioned as “medicinal,” currently there are many studies confirming their pharmacological properties: hypoglycemic and antioxidant activities of Cassia grandis L.f. [69, 70]; anti-inflammatory, analgesic, wound healing, antimicrobial, anticariogenic and antiparasitic activities of Copaifera spp. [71,72,73,74,75,76,77]; anti-inflammatory and antiplatelet aggregation of Dipteryx odorata [78]; antifungal and anti-inflammatory potential of Aniba puchury-minor (Mart.) Mez [89]; antifungal and anticoagulant activities of Ocotea sassafras (Meisn.) Mez. [90, 91]; wound healing activity and Selenium poisoning potential of Lecythis ollaria [92,93,94]; antioxidant, anti-inflammatory and antialopecia activities, and neuroprotective, cardioprotective, hepatoprotective and nephroprotective potential of Theobroma cacao [100,101,102,103,104,105]; gastroprotective, antimicrobial, wound healing, antinociceptive and anti-inflammatory activities of Virola bicuhyba (Schott) Warb. [117,118,119,120]; antiplatelet, anti-inflammatory, neuroprotective, antioxidant, anti-glycant, antithrombotic, anticonvulsant and trypanocidal activities of Genipa americana [135,136,137,138,139,140]; anti-wrinkling and anti-melanogenic of Pradosia lactescens [148]; and nephroprotective, anti-inflammatory, cytotoxic, antioxidant, antihyperalgesia and antiasthmatic activities of Zingiber officinale [158,159,160,161,162].

Based on our results, we understand historical ethnobotany as a tool for biodiversity protection, aiming to understand the relationship and use in the past, as well as the development over time and the result of this use in the current context. Therefore, by learning from past experiences, it comprehends the present and facilitates the creation of sustainable and protective methods and solutions for the future. It demonstrates which uses and therapeutic indications are suitable for investigation, particularly regarding native plants, valuing and documenting the traditional knowledge of cultures affected by cultural erosion [196, 197]. In this sense, pharmacological investigations are important to ascertain the presence of active principles and compounds that have a specific therapeutic action, correlating traditional knowledge with scientific knowledge, thus directing research toward the possible development of a new drug, herbal medicine, or traditional herbal product [196]. The importance of this type of study is also due to the increase in deforestation in recent years, which contributes to genetic and cultural erosion of plants in Brazil, favoring the introduction of monoculture and exotic plants, consequently reducing biodiversity and the traditional use of native plants in the region [12].

More than a century later, Baron de Santa-Anna Nery [35] was right about a fact: "The Amazonian flora is still not entirely known; much is still lacking. A large number of species have not been taxonomically classified or described". Taxonomic data reveals that over 14,000 species are cataloged, with almost half of these being trees [198, 199]. However, it is estimated that the Amazon Basin region has over 50,000 plant species [200], with the majority remaining unknown.

Conclusion

The book "Le Pays des Amazones" was written and published during a period when very little was known about the Amazon region. When we analyze this work from a timeless perspective, with a particular focus on historical ethnobotany, we gain insights into the prevalent medical concerns of the time and the plant remedies employed to address these conditions. Furthermore, it becomes apparent that many of the medicinal plants documented in the book have since been the subject of pharmacological studies that confirm their therapeutic properties, while many other species still remain to be investigated. Besides medicinal plants, the analysis of this work inventoried various traditional uses of plant species, providing insights into understanding historical, social, and economic aspects of the late nineteenth century. Uncovering the historical ethnobotanical knowledge within "Le Pays des Amazones" is essential for preserving and sharing the history and contributions of Baron de Santa-Anna-Nery, whose legacy has somewhat faded in the broader context of Brazilian culture and literature.