During the search process, various specialized databases were exhaustively explored, including EBSCO, Scopus, and Web of Science. These databases were chosen for their broad coverage and for hosting a significant number of internationally relevant scientific publications. The search focused on identifying articles published in high-impact scientific journals, ensuring that the included studies were contemporary and relevant to the research topic. Despite the search’s scope, no prior systematic reviews specifically addressing ethnomedicinal knowledge in terms of the documentation, evaluation, and conservation of medicinal plants and their therapeutic applications were found. This finding underscores the originality and necessity of the present review to fill this gap in the scientific literature.

This study arises from a research question: What is the diversity and therapeutic value of medicinal plants documented in various cultures, and how have their ethnomedicinal applications been evaluated in the scientific literature?

The search was conducted in English, using the following keywords and their associated or related concepts: ethnomedicine (ancestral medicine, cultural medicine, folk medicine, indigenous medicine, natural medicine, traditional herbal medicine, traditional medicine) and medicinal plants (curative plants, healing herbs, healing plants, herbal medicine plants, herbal remedies, medicinal botanicals, medicinal flora, medicinal herbs). In this sense, the search equation used was: (ethno OR ancestral OR cultur OR folk OR indigen* OR natura* OR tradition*) AND (medicin* OR curativ* OR remed* OR healing) AND (plant* OR herb* OR flora OR botanic*).

For the systematic review, only articles published in peer-reviewed scientific journals indexed in the Scopus, EBSCO, and Web of Science (Core Collection) databases during the period from 2007 to July 2024 were included. These studies were written in English and directly addressed topics related to the documentation, evaluation, and conservation of medicinal plants in the context of ethnomedicine. Relevant studies investigated traditional knowledge, therapeutic applications, and the cultural value of medicinal plants in various cultures worldwide. Additionally, the selected articles included in their descriptors or abstracts terms associated with “ethnomedicine” (e.g., ancestral medicine, cultural medicine, folk medicine) and “medicinal plants” (e.g., curative plants, healing herbs, etc.), ensuring their thematic relevance to the review objectives.

On the other hand, studies that did not meet the previously mentioned criteria were excluded. This includes publications that were not peer-reviewed, such as literature reviews, editorials, letters to the editor, conference abstracts, and preliminary studies. Studies published outside the range of 2007 to 2024, as well as those written in languages other than English, were also excluded. Additionally, studies that did not focus on ethnomedicine or the therapeutic application of medicinal plants, especially those limited exclusively to pharmacological aspects without an ethnobotanical context, were excluded. Finally, duplicate or overlapping studies and those that did not provide sufficient detail on the evaluation, documentation, or conservation of ethnomedicinal knowledge were discarded, ensuring that only high-quality and relevant research was included in the review.

The researchers followed a multi-stage procedure to determine the final selection of articles. The initial database search yielded a list of 6,473 documents (N). Upon reviewing each title, 729 documents were unavailable, reducing the total to 5,744. Then, 359 duplicate titles across the databases were identified and removed. Subsequently, each document was reviewed to ensure it met the established criteria. The results were as follows: articles in languages other than English (142), non-empirical works (1,847), studies that did not focus on ethnomedicine or the therapeutic application of medicinal plants (1,932) and works that were not scientific articles (925).

Ultimately, 469 documents that did not provide sufficient detail on the evaluation, documentation, or conservation of ethnomedicinal knowledge were discarded, resulting in a final sample of 70 documents that met the inclusion and exclusion criteria for this systematic review.

Given that this review demands a deeper level of detail, it was deemed essential to compile a table that gathered key information. This table includes data on the year of publication, source of the research, theoretical framework adopted, type of study conducted, instruments used, perspective addressed, study population, stated objectives, obtained conclusions, as well as the language in which the work was published. Additionally, to enrich the analysis, a comparative analysis was conducted among the selected studies, allowing for the identification of significant similarities and differences in the approaches and findings presented in the reviewed literature. This comprehensive approach not only facilitates the organization and analysis of the data but also enables a better understanding of trends and patterns in ethnomedicinal research.

The analysis of the evolution of publications reveals significant development in the depth and focus of studies over the years. Figure 1. Number of studies published during the period from 2007 to July 2024 (refer to extended data) shows the number of studies published per year. ⁷²

The selected studies are categorized by periods as follows: (1)

Beginnings Focused on Documentation and Evaluation (2007-2010): In the early years, research primarily centered on the identification and documentation of medicinal plants, as well as the collection of information about their potential applications, such as dietary supplements. ^{1, 2} Starting in 2008, studies began analyzing the microbial activity of plants, marking a more quantitative and scientific approach. ³ Between 2009 and 2010, there was an increase in research aimed at understanding the chemical and pharmacological properties of plants, ^{4, 8} as well as evaluating their medicinal value in ethnoecological contexts. ⁹

Over the years, publications have evolved from an initial focus on the basic documentation and evaluation of medicinal plants to a more integrative and multidisciplinary approach, encompassing not only the conservation of traditional knowledge but also its scientific validation and preservation in global databases.

This distribution reflects a strong concentration of studies in countries with rich traditions in the use of medicinal plants and significant biological diversity, highlighting the global importance of ethnomedicine and ethnobotany. The current literature review identified:

India leads with 15 studies on ethnomedicinal knowledge, documentation, evaluation, and conservation of medicinal plants, reflecting its rich biodiversity and extensive tradition in the use of these plants. Pakistan follows with 12 studies focused on the documentation and analysis of traditional knowledge, while Bangladesh, with 10 studies, stands out for its focus on the conservation of ethnomedicinal practices. Indonesia, with 8 studies, shows strong interest in documenting and exploring the use of plants in traditional medicine, and Nigeria, with 5 studies, focuses on the evaluation of medicinal properties and documentation in rural communities.

Nepal and Tanzania, with 3 studies each, have contributed to the documentation and analysis of medicinal plant use in mountainous communities and the conservation of local species, respectively. Other countries, such as Mexico, Morocco, Bolivia, Venezuela, Binalud, Jordan, Papua New Guinea, China, Zimbabwe, the Philippines, Namibia, Serbia, Malaysia, and Ethiopia, have conducted one study each, demonstrating interest in the preservation and analysis of ethnomedicinal knowledge within their unique cultural and ecological contexts.

In the field of ethnomedicine and ethnobotany, the diversity of research conducted reflects a broad range of objectives, from the documentation and preservation of traditional knowledge to the evaluation of medicinal properties and the ecological impact of plant use. Categorizing these objectives into groups according to their general purpose provides a clearer understanding of how each study contributes to preserving and expanding knowledge about medicinal plants. Below are six main categories that group these objectives: (1)

Documentation and Preservation of Ethnomedicinal Knowledge: This group of objectives focuses on the collection, preservation, and promotion of traditional ethnomedicinal knowledge, which is essential for keeping ancestral practices related to the use of medicinal plants alive: •

Document medicinal plant species, practices, and traditional knowledge: Studies in this subgroup are dedicated to identifying and documenting the medicinal plants used in different communities, as well as gathering information on ethnomedicinal practices and knowledge. This includes research that identifies and documents plant species, and studies that gather information on medicinal plants used by folk practitioners. Other studies also contribute to creating detailed databases that preserve this knowledge, developing databases of medicinal plant species. ^{1, 8, 18}

In the reviewed studies on ethnomedicinal knowledge, the methodological approaches are primarily divided into three categories: quantitative, qualitative, and mixed methods.

The quantitative approach is predominant, utilized in 32 of the 70 reviewed studies. These studies focus on the collection and analysis of numerical data through surveys, structured questionnaires, and laboratory experiments. For example, a quantitative approach was employed to collect and analyze medicinal herbs using semi-structured questionnaires and laboratory tests, while other studies documented traditional knowledge through semi-structured questionnaires. ^{9, 61}

Qualitative studies make up a significant portion of the total, with 26 investigations. This approach is mainly used to explore and understand traditional knowledge, often through interviews, direct observations, and ethnographic techniques. For instance, some research employed semi-structured interviews and the collection of plant samples, while other studies used the rapport technique during ethnographic interviews. ^{63, 69}

The mixed-methods approach, which combines quantitative and qualitative methods, was used in 12 studies. These studies integrate the collection of quantitative data with the depth of qualitative research to provide a more comprehensive analysis. For example, interviews and semi-structured questionnaires were used, combining numerical data with detailed observations. ⁸

Moreover, the reviewed studies employ a wide variety of techniques and instruments for data collection, each adapted to the specific objectives of the research. The most common techniques are presented below: •

Semi-structured interviews and questionnaires: These are the most used instruments, present in 48 of the 70 studies. Semi-structured interviews allow researchers to collect detailed and flexible data, while questionnaires provide a structure to quantify responses. These methods were employed, for example, to explore ethnomedicinal knowledge. ^{23, 34}

In terms of approach, the reviewed studies show a significant preference for the quantitative approach, though a large portion also relies on qualitative and mixed methods to address the complexity of ethnomedicinal knowledge. The combination of semi-structured interviews with direct observation and field data collection techniques stands out as the most robust methodology for documenting and analyzing the use of medicinal plants. Studies that integrate experimental techniques offer added value by validating the therapeutic applications of the documented plants, allowing for a deeper understanding and conservation of this ancestral knowledge. The employed methodology reflects a balance between extensive data collection and in-depth exploration of specific cultural contexts, which together strengthen the credibility and applicability of the findings in the field of ethnomedicine.

The documentation of medicinal plants is a fundamental activity for the preservation of ethnobotanical and ethnomedicinal knowledge, which has been passed down through generations in many cultures. This process not only involves recording the species of plants used but also capturing details about their identification, distribution, collection methods, plant parts used, remedy preparation, and therapeutic uses. It is emphasized that the systematic documentation of medicinal plants is essential to ensure that this knowledge is not lost, especially in communities where the oral transmission of knowledge is declining due to modernization and the influence of Western medicine. ^{1, 17}

Work in Bangladesh highlights the importance of documenting not only plant species but also the knowledge and practices of traditional healers. ^{2, 8} This type of documentation is vital for maintaining the cultural and biological richness of local communities and provides a solid foundation for future research in pharmacology and conservation. On the other hand, it is illustrated how the detailed documentation of species in specific regions, such as the Wuliang Mountains in China or the Chinglai Valley in Pakistan, can help in understanding local biodiversity and the communities’ dependence on medicinal plants. ^{35, 37}

However, documentation faces several challenges. Acculturation, migration, and modernization have led to the loss of knowledge in many regions. It is warned that the loss of this knowledge is particularly acute among younger generations, who show a growing disinterest in traditional practices. ^{24, 44} This phenomenon not only threatens the extinction of valuable knowledge but also the disappearance of plant species that could have significant undiscovered medicinal uses.

To mitigate these risks, documentation must be a continuous and collaborative effort involving researchers, local communities, and conservation organizations. The integration of modern methods, such as electronic databases and digital identification tools, with traditional data collection practices can help preserve this knowledge more efficiently. Additionally, it is crucial that the documentation is accessible and available to future generations to ensure that this cultural and biological heritage is not lost.

Furthermore, the scientific evaluation of medicinal plants is a crucial step in transforming traditional knowledge into validated and safe therapeutic applications. Studies are presented that demonstrate the efficacy of certain plants in antimicrobial activity, a finding that has significant implications for the development of new antibiotics in a world where antimicrobial resistance is a growing concern. ^{3, 10} These studies underline the need to systematically evaluate the pharmacological properties of plants to identify bioactive compounds that can be used in modern medicine.

The evaluation is not limited to antimicrobial activity alone. It has been shown how certain plant extracts can enhance the efficacy of traditional antibiotics, suggesting that combinations of plants and medications could offer new therapeutic solutions. ^{8, 11} This synergistic approach between traditional and modern medicine opens a promising field for pharmacological research.

However, the evaluation faces significant challenges. It is highlighted that many plants have not yet been fully studied in terms of their chemical components and biological effects. ^{29, 30} The lack of detailed phytochemical studies and clinical trials is a barrier to incorporating these plants into conventional medicine. Additionally, the variability in the concentrations of active compounds, influenced by factors such as climate, soil, and collection techniques, makes the evaluation even more complex.

To overcome these challenges, a multidisciplinary approach that combines ethnobotany, chemistry, molecular biology, and pharmacology is essential. This approach can help identify, isolate, and synthesize bioactive compounds from medicinal plants and evaluate their safety and efficacy through controlled clinical trials. Additionally, collaboration with local communities, who possess deep knowledge of these plants, is fundamental to directing research toward the most promising species and practices.

Finally, the conservation of medicinal plants is a critical concern, as many of these species are threatened by overexploitation, habitat destruction, and climate change. It is emphasized how the commercial exploitation of medicinal plants has led to the reduction of wild populations, putting both biodiversity and the availability of essential medicinal resources for local communities at risk. ^{36, 38}

Conservation is not only an ecological issue but also a cultural and economic one. It is noted that medicinal plants are an integral part of the lives of many communities, not only for their therapeutic value but also as a source of income and as part of cultural identity. ^{39, 43} The loss of these plants would not only affect people’s health but also their cultural heritage and economic livelihood.

One of the biggest challenges for conservation is the lack of awareness and the absence of effective policies. Although local communities have vast knowledge about the use of medicinal plants, this knowledge is fading due to the lack of interest among younger generations and the pressure of modernization. ⁴³ The intensification of mining, agricultural expansion, and deforestation, as observed in the Aravalli Hills, exacerbates this situation by destroying the natural habitats of these plants. ³⁹

To address these issues, concerted efforts are needed on several fronts. The creation of protected areas and the implementation of sustainable cultivation practices can help preserve endangered species. Additionally, seed collection and the establishment of germplasm banks are important strategies to ensure that these plants can be restored in the future. Education and awareness among local communities, especially among the youth, are crucial for the long-term conservation of ethnobotanical knowledge and resources.

The therapeutic applications of medicinal plants are varied and cover a wide range of diseases and conditions. Since ancient times, communities have used plants to treat both common and complex ailments, from bacterial infections to chronic diseases like diabetes and cancer. It has been documented how medicinal plants have been effective in treating diseases that are difficult to manage with modern medicine, highlighting their continued relevance in healthcare. ^{12, 27}

Studies show that although some plants have well-documented therapeutic applications, many others remain underutilized and poorly understood, representing a vast field of opportunities for research and the development of new medicines. ^{37, 64} The scientific validation of these uses is essential for integrating traditional medicine into the modern healthcare system, providing treatments that are often more accessible and culturally acceptable for rural communities.

The challenge in the therapeutic application of medicinal plants lies in the variability of active compounds and the lack of standardization in preparation and administration methods. Moreover, it is crucial to evaluate the toxicity and potential side effects of these remedies before their widespread adoption. ^{39, 40} This requires not only rigorous clinical trials but also a careful approach to prevent the overexploitation of plants that may become scarce or endangered.

Finally, the integration of the therapeutic applications of medicinal plants into modern medicine should not be seen as a replacement but as a complement. Interdisciplinary research and collaboration between traditional healers, scientists, and healthcare professionals are key to developing more effective and accessible therapies. These collaborations can also promote the more sustainable use of natural resources, ensuring that medicinal plants remain a valuable source of health and well-being in the future.

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